Flame retardants in placenta and breast milk and cryptorchidism in newborn boys.
Polybrominated diphenyl ethers Polybrominated diphenyl ethers or PBDE, are a flame retardant sub-family of the brominated flame retardant group. They have been used in a wide array of household products, including fabrics, furniture, and electronics. (PBDEs) are widely used as flame retardants, and the general population is exposed through products such as upholstery, building materials Building materials used in the construction industry to create .
These categories of materials and products are used by and construction project managers to specify the materials and methods used for . , insulation, electronic equipment, and contaminated contaminated,
v 1. made radioactive by the addition of small quantities of radioactive material.
2. made contaminated by adding infective or radiographic materials.
3. an infective surface or object. food. PBDEs are added to polymers without being chemically bound and can leach into the environment, where they settle with air particles and sludge. They are persistent, and some--BDE-47, BDE-99, and BDE-153--can accumulate in lipid-rich tissues (Agency for Toxic Substances and Disease Registry The United States Agency for Toxic Substances and Disease Registry, (ATSDR) is an agency for the U.S. Department of Health and Human Services that is directed by a congressional mandate to perform specific functions concerning the effect on public health of hazardous 2004; Sjodin et al. 2003).
Concentrations of PBDE PBDE Polybrominated Diphenyl Ether
PBDE Pentabromodiphenyl Ether (flame retardant additive in plastics)
PBDE Parallel Block-Decodable Encoder in human European breast milk samples are generally low compared with those in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. , and considered to be well below the estimated lowest observed adverse effect level (LOAEL LOAEL Lowest Observed Adverse Effect Level ) of 1 mg/kg/day (Darnerud et al. 2001). Two technical mixtures, penta- and octa-mixtures of PBDEs, have been banned from use in Europe since 2003 (Darnerud et al. 2001), and Swedish studies indicated a decrease in breast milk levels since the middle of the 1990s (Meironyte et al.1999; Sjodin et al. 2003). However, annual production rates of some PBDEs are still considerable in some areas (Alaee et al. 2006; Betts 2002; Law et al. 2006). Animal studies show that some PBDEs exhibit endocrine-disrupting activity, which has been studied predominantly for thyroid hormone Thyroid hormone
Any of the chemical messengers produced by the thyroid gland, including thyrocalcitonin, a polypeptide, and thyroxine and triiodothyronine, which are iodinated thyronines. See Hormone, Thyrocalcitonin, Thyroid gland, Thyroxine transport and metabolism (Legler and Brouwer 2003), but data on adverse effects on reproductive outcome after gestational exposure are also emerging (Lilienthal et al. 2006).
The prevalence of cryptorchidism cryptorchidism /crypt·or·chid·ism/ (krip-tor´kid-izm) failure of one or both testes to descend into the scrotum.cryptor´chid
Cryptorchidism in newborn boys appears to have increased in some areas, such as Great Britain Great Britain, officially United Kingdom of Great Britain and Northern Ireland, constitutional monarchy (2005 est. pop. 60,441,000), 94,226 sq mi (244,044 sq km), on the British Isles, off W Europe. The country is often referred to simply as Britain. and Denmark, over the past decades, and its current prevalence is considerably higher in Denmark than in Finland (Anonymous 1986; Boisen et al. 2004). Although the reason for this is as yet unknown, the rapid increase in prevalence suggests that environmental factors are involved (Sharpe 2006; Skakkebaek et al. 2001). Adverse effects of fetal exposure to environmental chemicals on testicular testicular /tes·tic·u·lar/ (tes-tik´u-lar) pertaining to a testis.
Of or relating to a testicle or testis.
pertaining to the testis. descent and hormonal function may be detectable during the short physiologic activation of the pituitary-gonadal axis at approximately 3 months of age (Andersson et al. 1998; Main et al. 2000, 2006b; Suomi et al. 2006).
In this study we aimed to evaluate the association between exposure to 14 PBDEs (BDEs 28, 47, 66, 71, 75, 77, 85, 99, 100,119, 138, 153, 154, 183) in newborn boys and the position and function of the testes testes
Male reproductive organs (see reproductive system). Humans have two oval-shaped testes 1.5–2 in. (4–5 cm) long that produce sperm and androgens (mainly testosterone), contained in a sac (scrotum) behind the penis. .
Materials and Methods
The study was conducted according to according to
1. As stated or indicated by; on the authority of: according to historians.
2. In keeping with: according to instructions.
3. the Helsinki II Declaration (World Medical Association 2000) after informed oral and written consent of the parents. The ethical committees (Finland: 7/1996; Denmark: KF01-030/97) and the Danish Data Protection Agency Following the implementation of EU Directive 95/46/EC, regarding the protection of individuals with regards to the process of personal information and the movement of such, the Danish Data Protection Agency was created. (1997-1200-074) approved the study
Study population. We obtained breast milk samples and placentas from a joint prospective, longitudinal cohort study A cohort study is a form of longitudinal study used in medicine and social science. It is one type of study design.
In medicine, it is usually undertaken to obtain evidence to try to refute the existence of a suspected association between cause and disease; failure to refute performed 1997-2001 at Turku University Turku University may refer to:
Of, relating to, or involving two nations. study aimed at establishing contemporary prevalence rates for cryptorchidism and hypospadias hypospadias /hy·po·spa·di·as/ (-spa´de-is) a developmental anomaly in which the urethra opens inferior to its normal location; usually seen in males, with the opening on the underside of the penis or on the perineum. and evaluating risk factors by means of questionnaires and biological samples (blood, placentas, breast milk). Exposure measurements were prospectively planned to include persistent and nonpersistent non·per·sis·tent
Having a short life or existence under natural conditions. chemicals, some of which have been previously reported (Damgaard et al. 2006; Main et al. 2006a; Shen Shen, in the Bible, place, perhaps close to Bethel, near which Samuel set up the stone Ebenezer. et al. 2005, 2006, 2007). Recruitment strategy, inclusion criteria
Inclusion criteria are a set of conditions that must be met in order to participate in a clinical trial. , and clinical examination of the children (i.e., the identification of cryptorchidism) have been previously described (Boisen et al. 2004; Main et al. 2006b; Suomi et al. 2006) and were strictly standardized. Boys with normally descended testes, including retractile retractile /re·trac·tile/ (re-trak´til) able to be drawn back.
That can be drawn back or in, as the claws of a cat.
capable of being drawn back. testes, were used as controls in this study under the terms "controls" or "healthy boys." Boys with undescended testes Undescended Testes Definition
Also known as cryptorchidism, undescended testes is a congenital condition characterized by testicles that do not extend to the scrotum.
In the fetus, the testes are in the abdomen. (nonpalpable, inguinal inguinal /in·gui·nal/ (in´gwi-n'l) pertaining to the groin.
1. Of or located in the groin.
2. , suprascrotal, high scrotal scrotal /scro·tal/ (skro´t'l) pertaining to the scrotum.
pertaining to scrotum.
scrotal abscess ), either uni- or bilaterally at birth, were included in the group of cryptorchid cryptorchid
an animal with undescended testes. Called also rig, ridgling. boys.
All boys were examined at birth and at 3 months of age before the results of chemical analyses were known. Birth weight and length were obtained from hospital records. The supine length of the children was measured with infantometers (Denmark: Kidimeter, Raven Equipment Ltd., Essex, United Kingdom; Finland: Pedihealth Ky, Oulu, Finland). Weight was measured on a digital scale (Baby scale model; Solotop Oy, Helsinki, Finland). Weight for gestational age ges·ta·tion·al age
See estimated gestational age.
The estimated age of a fetus expressed in weeks, calculated from the first day of the last normal menstrual period. was calculated using national standards as percent deviation from the expected mean (Marsal et al. 1996; Pihkala et al. 1989), -22% being equivalent to -2 SDs.
Biological samples. In Denmark biological samples were collected from all participants (case-cohort design). In Finland, due to lack of storage space, biological samples were collected from boys with cryptorchidism at birth and matched controls [matching criteria: parity, maternal smoking (yes/no), diabetes (yes/no), gestational age ([+ or -] 7 days), and date of birth ([+ or -] 14 days)] as a nested case-control design.
From this bio-bank, we selected 280 placentas (168 Danish/112 Finnish) and 130 breast milk samples (65 Danish/65 Finnish) for PBDE measurements; this number was determined by funding. Birth examination data were used for classification of cryptorchid and healthy boys.
In Finland, placentas were selected from 56 case-control pairs, in which both placentas were available. In Denmark, all available placentas from cryptorchid boys were chosen (n = 39). Control placentas were selected randomly from the total Danish cohort (n = 129).
Hereafter, 65 breast milk samples were selected for each country, with the aims, if possible, of having equal numbers of samples from boys with and without cryptorchidism and of including the same mothers as for placenta placenta (pləsĕn`tə) or afterbirth, organ that develops in the uterus during pregnancy. It is a unique characteristic of the higher (or placental) mammals. In humans it is a thick mass, about 7 in. analyses. Only samples with a volume > 125 mL were included to ensure that all chemicals could be analysed. Milk from mothers of 29 cryptorchid boys and 36 randomly chosen control boys was included in Denmark. In Finland, milk samples were chosen from mothers of cryptorchid boys (n = 33), matched controls (n = 18), or random controls (n = 14).
For 86 boys, milk and placentas could be selected from the same mother-child pair (10 Danish boys with cryptorchidism, 33 Danish controls, 20 Finnish boys with cryptorchidism, 23 Finnish controls).
Collection of samples. Whole placentas were collected by the midwives and frozen immediately in two layers of polyethylene bags (-20 [degrees]C). Placentas were not bled before storage.
Each mother collected one breast milk sample. We wished to assess the average concentration of PBDEs during the period preceding the endogenous hormone surge in infants. Thus, each sample consisted of several small aliquots collected over successive feedings over several weeks and frozen in household freezers in 250-mL Pyrex glass bottles (1515/06D; Bibby Sterilin, Staffordshire, UK) with Teflon coated caps. The mothers were instructed orally and in writing to feed the baby, and then to sample aliquots (hind milk), beginning 1 month after birth. We chose this start point after discussion with the ethics committee ethics committee A multidisciplinary hospital body composed of a broad spectrum of personnel–eg, physicians, nurses, social workers, priests, and others, which addresses the moral and ethical issues within the hospital. See DNR, Institutional review board. for human subject studies to ensure that breast-feeding breast-feeding /breast-feed·ing/ (brest´fed?ing) nursing; the feeding of an infant at the mother's breast. had been well established. Mothers were instructed to collect samples into a clean household glass or porcelain container, avoiding, if possible, the use of breast pumps, and to freeze every portion immediately. Breast milk was delivered frozen to the hospital at the 3 months' examination and stored at -20 [degrees]C. In 57 of the 65 Danish mothers, but no Finnish mothers, information on breast pump use was obtained at sample delivery; 26 (46%) had used a pump on one or more occasions. No information was obtained on the type of breast pump (glass or plastic).
Blood samples. Venous nonfasting blood samples (4 mL) were drawn from the infants at the 3 months' examination (median age,3.0 months; range, 2.4-4.1); the overall success rate of obtaining a sample in the study was 74%. After clotting, the blood samples were centrifuged and the sera were separated and stored at -20 [degrees]C. All samples were analysed as duplicates and blinded for the technician at one laboratory (Rigshospitalet, Denmark) for reproductive hormones. Each run contained samples of both cryptorchid and healthy boys from both countries (up to 160 samples per analysis) to minimize any effect of interassay variation.
Hormone analyses. We analyzed serum follicle-stimulating hormone follicle-stimulating hormone (FSH): see gonadotropic hormone. (FSH FSH follicle-stimulating hormone.
Facioscapulohumeral muscular dystrophy (FSH) ), luteinizing hormone lu·te·in·iz·ing hormone
Abbr. LH A hormone produced by the anterior lobe of the pituitary gland that stimulates ovulation and the development of the corpus luteum in the female and the production of testosterone by the interstitial (LH), and sex hormone-binding globulin globulin, any of a large family of proteins of a spherical or globular shape that are widely distributed throughout the plant and animal kingdoms. Many of them have been prepared in pure crystalline form. (SHBG SHBG sex hormone.
sex hormone-binding globulin.
SHBG Sex hormone binding globulin, see there ) using time-resolved immunofluorometric assays (Delfia, Wallac Inc., Turku, Finland). Detection limits were0.06 and 0.05 IU/L for FSH and LH, respectively, and 0.23 nmol/L for SHBG. The intra- and interassay coefficients of variation(CV) were < 5% in both gonadotropin gonadotropin /go·nado·tro·pin/ (-tro´pin) any hormone that stimulates the gonads, especially follicle-stimulating hormone and luteinizing hormone. assaysand < 6% for SHBG. We measured serum testosterone by radioimmunoassay (Coat-a-Count; Diagnostic Products Corp., Los Angeles Los Angeles (lôs ăn`jələs, lŏs, ăn`jəlēz'), city (1990 pop. 3,485,398), seat of Los Angeles co., S Calif.; inc. 1850. , CA, USA), with a detection limit of 0.23 nmol/L and intra- and interassay CVs< 10%. Free testosterone index was calculated: (testosterone x100)/SHBG. We analyzed serum inhibin in·hib·in
A peptide hormone secreted by the follicular cells of the ovary and the Sertoli cells of the testis that inhibits secretion of follicle stimulating hormone from the anterior pituitary. B by a double antibody enzyme-immunometric assay (Main et al. 2006b). The detection limit was 20 pg/mL, and intra- and interassay CVs were < 15 % and < 18 %, respectively. Ratios between hormones were calculated: LH/testosterone, LH/free testosterone, FSH/inhibin B.
Analysis of PBDE. All PBDE analyses for both milk and placenta were performed at the laboratory at the Department of Environmental Health in Kuopio, Finland. Placentas were defrosted, and the umbilical cord umbilical cord (ŭmbĭl`ĭkəl), cordlike structure about 22 in. (56 cm) long in the pregnant human female, extending from the abdominal wall of the fetus to the placenta. and all readily removable membranes were discarded. Whole placentas were homogenized ho·mog·e·nize
v. ho·mog·e·nized, ho·mog·e·niz·ing, ho·mog·e·niz·es
1. To make homogeneous.
a. To reduce to particles and disperse throughout a fluid.
b. in a mixer (Buchi Mixer B-400; Buchi Laboratories AG, Flawil, Switzerland), and 75 g of the homogenate homogenate /ho·mog·e·nate/ (ho-moj´in-at) material obtained by homogenization.
material obtained by homogenization. was lyophilized ly·oph·i·lize
tr.v. ly·oph·i·lized, ly·oph·i·liz·ing, ly·oph·i·liz·es
To freeze-dry (blood plasma or other biological substances).
[lyophil(ic) + -ize. . Dried homogenate was pulverized pul·ver·ize
v. pul·ver·ized, pul·ver·iz·ing, pul·ver·iz·es
1. To pound, crush, or grind to a powder or dust.
2. To demolish.
v.intr. in a mortar and slurry was made by adding dichloromethane and cyclohexane cyclohexane (sī'kləhĕk`sān), C6H12, colorless liquid hydrocarbon. It is a cyclic alkane that melts at 6°C; and boils at 81°C;. It is nearly insoluble in water. (1:1 vol/vol) and concentrated sulphuric acid sulphuric acid: see sulfuric acid. . This slurry was spiked with six [.sup.13]C-labeled PBDE internal standards (BDEs 28, 47, 77, 99, 153, and 183) (Wellington Laboratories Inc., Guelph, Canada). Fat was not determined, and fat-based results were relying on the gravimetrically measured fat contents obtained from a German partner in this European Commission European Commission, branch of the governing body of the European Union (EU) invested with executive and some legislative powers. Located in Brussels, Belgium, it was founded in 1967 when the three treaty organizations comprising what was then the European Community project (Shen et al. 2005, 2006, 2007).
Breast milk samples (average volume, 70 mL) were thawed in sample bottles in a water bath (40 [degrees]C) for 1 hr and homogenized. Fat was extracted with a mixture of diethyl ether di·eth·yl ether
A pungent, volatile, highly flammable liquid derived from the distillation of ethyl alcohol with sulfuric acid and widely used as an inhalation anesthetic. Also called ethyl ether, ethyl oxide, sulfuric ether. and hexane hexane /hex·ane/ (hek´san) a saturated hydrogen obtained by distillation from petroleum.
n. (1:1.4 vol/vol) after addition of sodium oxalate oxalate /ox·a·late/ (ok´sah-lat) any salt of oxalic acid.
A salt or ester of oxalic acid. solution and ethanol(1:5 vol/vol). Fat content was determined gravimetrically after exchange of the solvent to hexane. An average 1.5 g of fat was spiked with the same set of internal standards used with placenta.
The procedure for decomposition of fat and sample cleanup has been described previously (Kiviranta et al. 2004). We quantified 14 PBDE analytes (BDEs 28, 75, 71, 47, 66, 77, 100, 119, 99, 85, 154, 153, 138, and 183) by selective-ion recording using a high resolution mass spectrometer (Autospec Ultima; Micromass Inc., Manchester, UK) at resolution 10,000. Gas chromatographic chro·mat·o·graph
An instrument that produces a chromatogram.
tr.v. chro·mat·o·graphed, chro·mat·o·graph·ing, chro·mat·o·graphs
To separate and analyze by chromatography. separation of the PBDEs was performed with a Hewlett Packard 6890 gas chromatograph with fused silica capillary column (DB5-MS, 60 m, 0.25 mm, 0.25 [micro]m; J&W Scientific, Folsom, CA, USA). As a recovery standard for internal PBDE standards polychlorinated biphenyl polychlorinated biphenyl or PCB, any of a group of organic compounds originally widely used in industrial processes but later found to be dangerous environmental pollutants. congener congener /con·ge·ner/ (kon´je-ner) something closely related to another thing, as a member of the same genus, a muscle having the same function as another, or a chemical compound closely related to another in composition and exerting 159 was used.
In the analysis of PBDEs at the Department of Environmental Health (National Public Health Institute, Kuopio, Finland), the technicians and chemists were blinded. Laboratory and cross-sample contamination was monitored by analyzing procedural blank samples. The concentrations of these blank samples were much lower than the concentrations in placenta and breast milk--on average, 3.6 and 2.6% of the average sum of PBDEs in placenta and milk, respectively.
Recoveries of individual internal PBDE standards were > 60%. Median limit of quantification (LOQ LOQ Limit of Quantitation
LOQ Limit Of Quantification
LOQ Loquitur (Latin: speaks)
LOQ Level of Quantification
LOQ List Of Questions
LOQ Laugh Out Quiet
LOQ Leadership Opinion Questionaire ) for placentas corresponding to a signal to noise ratio of 3:1, was 0.006 ng/g fat (range, 0.004-0.14 ng/g fat). Corresponding LOQs for breast milk were 0.004 ng/g fat (range, 0.0003-0.12 ng/g fat). In placenta, CVs for individual congeners were 10-20%, and > 20% at concentration levels 0.1-1 ng/g fat and < 0.1 ng/g fat, respectively. In breast milk samples corresponding values were < 10%, 10-20%, and > 20% at concentrations levels > 1 ng/g fat, 0.1-1 ng/g fat, and < 0.1 ng/g fat, respectively. Concentrations below the LOQ were considered to be equal to nil (lower bound results). The laboratory has successfully participated in interlaboratory comparison studies of PBDEs in different biological matrices including breast milk (Becher et al. 2001; Smastuen and Becher 2004; Smastuen and Becher 2005). The Finnish Accreditation Service (FINAS; Espoo, Finland) has verified the competence of the laboratory (testing laboratory T077) in performing PBDE analyses in biological samples according to the European Standard (EN ISO/IEC ISO/IEC International Organization for Standardization/International Electrotechnical Commission (ITU-T M 3000) 17025).
Population characteristics are given as medians and percentiles (2.5th, 97.5th). Differences between boys with and without cryptorchidism and between Danish and Finnish populations were analysed by Mann- Whitney U-test. Eighty-six boys participated with both breast milk and placenta samples.
We tested country differences for (log-transformed) PBDE concentrations in breast milk and placenta by multiple linear regression Linear regression
A statistical technique for fitting a straight line to a set of data points. including maternal age maternal age,
n the age of the mother at the period of conception. , parity (1, 2 and [greater than or equal to] 3) and prepregnancy body mass index (BMI BMI body mass index.
body mass index
Body mass index (BMI)
A measurement that has replaced weight as the preferred determinant of obesity. ; kilograms per square meter) in the model.
Correlations between individual PBDE congener concentrations, and between PBDE concentrations and date of childbirth within the Danish and Finnish cohort, respectively, were tested by Spearman spear·man
A man, especially a soldier, armed with a spear. correlation on non-transformed data. For each country the date of birth for the first child was set at zero; the date of birth for all consecutive children was then calculated as number of days elapsed e·lapse
intr.v. e·lapsed, e·laps·ing, e·laps·es
To slip by; pass: Weeks elapsed before we could start renovating.
n. since the first child of the same country-specific cohort. This variable was applied to control for any time trends in flame-retardant concentration in the study period 1997-2001.
We tested differences in PBDE concentrations between boys with and without cryptorchidism in a multiple regression Multiple regression
The estimated relationship between a dependent variable and more than one explanatory variable. model, including as covariates maternal age, parity, maternal prepregnancy BMI, and date of childbirth within the cohort (days) to control for factors that could affect PBDE concentrations in the sample. Prematurity and small size for gestational age (SGA SGA
small for gestational age
A term used to describe newborns who are below the 10th percentile in height or weight for their estimated gestational age. ) are well-known risk factors for cryptorchidism. Because the number of premature (5 Danish, 3 Finnish) and SGA children (3 Danish, 1 Finnish) was small in this study, analyses were carried out both with and without inclusion of these parameters. Analyses were carried out only for the most abundant seven congeners in breast milk (and their sum) and for the most abundant five congeners in placenta.
We used multiple linear regression analysis to assess the correlation between serum levels of reproductive hormones (log-transformed LH, FSH, SHBG, inhibin B), square root- transformed serum testosterone or free testosterone index, and log-transformed PBDE concentrations in breast milk. Covariates included in these analyses were country of origin, testicular position (cryptorchidism/control), and age at blood sampling (months).
There were no significant differences in maternal age, reported smoking, and parity between cryptorchid and control boys (Tables 1 and 2). Gestational age and birth weight were slightly lower in cryptorchid Danish (but not Finnish) boys than in controls. Diabetes was more prevalent in Finnish (but not Danish) mothers of cryptorchid boys than in their controls, because we could not always find controls matched by this criterion. The date of child-birth within the study period did not differ significantly between cryptorchid boys and controls (Denmark, p = 0.327; Finland, p = 0.949).
Table 1. Population characteristics [median (2.5th-97.5th percentiles)] for breast milk samples. Denmark Characteristic Control Cryptorchid p-Value* (n = 36) (n= 29) Maternal age 29.8 (23.0 29.8 (25.8 0.979 (years) to 42.6) to 39.2) BMI 22.9 (19.1 23.0 (17.9 0.997 (kg/[m.sup.2]) to 31.6) to 30.5) (a) Diabetes 1/35 1/28 0.877 (yes/no) Smoking 9/27 7/22 0.937 (yes/no) Parity (no.) 1 28 20 0.451 2 4 5 [greater than 4 4 or equal to] 3 Gestational age 284 (253 to 278 (219 to 0.039 (days) 297) 296) WGA (%) 1.89 (-23.5 0.62 (-29.7 0.687 to 35.6) to 30.5) Birth weight 3.73 (2.65 3.52 (1.31 0.139 (kg) to 5.15) to 4.85) Birth length 53 (48 to 52 (35 to 0.264 (cm) 57) 59) Cryptorchidism - 4 - at 3 months (no.) Prematurity 1 4 - (no.) (b) SGA (no.) 1 2 - Infant blood 21 24 samples (no.) Finland Characteristic Control Cryptorchid p-Value* (n = 32) (n= 33) Maternal age 27.7 (19.9 29.7 (21.5 0.306 (years) to 38.5) to 39.9) BMI 22.8 (18.4 22.0 (18.2 0.106 (kg/[m.sup.2]) to 35.6) to 27.9) (a) Diabetes 0/32 4/29 0.044 (yes/no) Smoking 4/28 6/27 0.529 (yes/no) Parity (no.) 1 19 17 0.405 2 9 9 [greater than 4 7 or equal to] 3 Gestational age 280 (160 to 281 (249 to 0.768 (days) 296) 296) WGA (%) -1.59 1.17 (-30.8 0.451 (-21.9 to to 27.3) 20.0) Birth weight 3.46 (2.86 3.83 (2.51 0.397 (kg) to 4.46) to 4.66) Birth length 51 (47 to 52 (46 to 0.826 (cm) 55) 55) Cryptorchidism - 25 - at 3 months (no.) Prematurity 2 1 (no.) (b) SGA (no.) 0 1 - Infant blood 25 26 samples (no.) WGA, weight for gestational age. (a) Maternal prepregnancy BMI. (b) < 259 days of gestation. *Difference between cryptorchid boys and controls. Table 2. Population characteristics [median (2.5th-97.5th percentiles)] for placentas. Denmark Characteristic Control (n= Cryptorchid p-Value* 129) (n= 39) Maternal age 31.0 (22.7 29.5 (25.7 0.723 (years) to 38.5) to 45.7) BMI 22.1 (18.2 21.5 (17.8 0.199 (kg/[m.sup.2]) to 35.5) to 36.1) (a) Diabetes 2/127 0/39 0.435 (yes/no) Smoking 32/91 11/28 0.788 (yes/no) Parity (no.) 1 81 26 0.628 2 36 10 [greater than 12 3 or equal to] 3 Gestational age 283 (254 to 276 (195 to 0.001 (days) 298) 294) WGA (%) 0.29 (-23.3 -0.83 (-39.5 0.921 to 34.9) to 44.4) Birth weight 3.63 (2.49 3.45 (0.75 0.038 (kg) to 5.06) to 4.75) Birth Length 53 (47 to 52 (32 to 0.230 (cm) 57) 60) Cryptorchidism - 8 - at 3 months (no.) Prematurity 6 6 - (no.) (b) SGA (no.) 5 2 - Infant blood 88 25 samples (no.) Finland Characteristic Control (n= Cryptorchid p-Value* 56) (n= 56) Maternal age 28.1 (20.6 29.1 (20.1 0.349 (years) to 38.1) to 42.2) BMI 22.3 (17.8 23.1 (17.8 0.062 (kg/[m.sup.2]) to 31.7) to 37.5) (a) Diabetes 0/55 10/46 0.001 (yes/no) Smoking 9/47 4/48 0.793 (yes/no) Parity (no.) 1 31 31 0.997 2 19 19 [greater than 6 6 or equal to] 3 Gestational age 280 (255 to 280 (258 to 0.940 (days) 293) 303) WGA (%) -0.32 -1.12 (-27.9 0.895 (-21.7 to to 25.0) 25.7) Birth weight 3.54 (2.85 3.63 (2.55 0.807 (kg) to 4.61) to 4.58) Birth Length 51 (47 to 51 (48 to 0.955 (cm) 55) 55) Cryptorchidism - 33 - at 3 months (no.) Prematurity 3 1 (no.) (b) SGA (no.) 0 3 - Infant blood 45 35 samples (no.) WGA, weight for gestational age. (a) Maternal prepregnancy BMI. (b) < 259 days of gestation. *Difference between cryptorchid boys and controls.
Danish mothers were slightly older than Finnish [30.6 years; 95% confidence interval confidence interval,
n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. (CI), 23.6-38.8 vs. 28.7 years; 95% CI, 21.4-39.7; p < 0.011], had a lower parity (p < 0.033) and smoked more frequently (p < 0.04). The prevalence of diabetes mellitus diabetes mellitus
Disorder of insufficient production of or reduced sensitivity to insulin. Insulin, synthesized in the islets of Langerhans (see Langerhans, islets of), is necessary to metabolize glucose. In diabetes, blood sugar levels increase (hyperglycemia). was higher among Finnish women (p < 0.004), but BMI before pregnancy (p = 0.678) did not differ significantly between the countries (p = 0.225).
Breast milk. Seven PBDEs were measurable in all breast milk samples (Table 3). Median concentrations were higher in Danish but not Finnish cryptorchid boys than in controls, reaching statistical significance for BDEs 47, 100, 28, 66, and 154. The sum of all seven congeners was significantly higher in cryptorchid boys than in controls if both countries were analyzed together (p < 0.007) (Figure 1), also if prematurity and SGA were included in the model (p < 0.035). Similar results were obtained for PBDE expressed as nanograms per liter (data shown only for the sum of all 14 congeners; Table 3). Table 4 shows the remaining seven congeners, which were below the detection limit in a substantial number of samples, and the sum of all 14 congeners.
Table 3. Seven PBDEs, detectable in all breast milk samples from Danish and Finnish boys with and without cryptorchidism [median (2.5th-97.5th percentiles)]. Denmark PBDE Control (n= 36) Cryptorchid (n= 29) p-Value* congener (ng/g fat) Sum of 7 3.21 (1.09-9.07) 4.12 (1.34-18.78) 0.017 congeners 47 1.05 (0.45-3.63) 1.53 (0.34-11.7) 0.018 153 1.0 (0.31-3.35) 1.18 (0.64-3.14) 0.226 99 0.44 (0.07-1.58) 0.64 (0.07-2.31) 0.132 100 0.26 (0.10-0.81) 0.37 (0.10-1.98) 0.019 28 0.10 (0.03-0.29) 0.13 (0.04-0.74) 0.030 66 0.04 (0.01-0.25) 0.08 (0.01-0.26) 0.0001 154 0.04 (0.01-0.13) 0.09 (a) (0.00-0.18) 0.0001 Sum of all 83.4 (29.2-396.9) 119.3 (34.6-757) 0.009 14 (ng/L) Finland PBDE Control (n= 32) Cryptorchid (n= 33) p-Value* congener (ng/g fat) Sum of 7 3.08 (1.04-29.17) 4.27 (1.43-56.30) 0.111 congeners 47 1.24 (0.4-15.20) 1.82 (0.65-38.90) 0.062 153 0.67 (0.22-2.97) 0.68 (0.27-3.63) 0.394 99 0.39 (0.13-5.94) 0.48 (0.09-13.10) 0.366 100 0.30 (0.12-1.42) 0.37 (0.11-5.18) 0.128 28 0.12 (0.03-2.44) 0.17 (0.05-0.68) 0.099 66 0.03 (0.01-1.38) 0.032 (0.01-0.19) 0.451 154 0.04 (0.02-0.18) 0.04 (0.02-0.54) 0.536 Sum of all 163.2 (17.7-1308.5) 119.2 (64.3-2657.4) 0.581 14 (ng/L) Both countries PBDE Control (n= 68) Cryptorchid (n= 62) p-Value* congener (ng/g fat) Sum of 7 3.16 (1.08-21.47) 4.16 (1.39-51.62) 0.007 congeners 47 1.12 (0.42-12.87) 1.56 (0.45-33.13) 0.003 153 0.81 (0.28-3.08) 0.94 (0.33-3.35) 0.156 99 0.42 (0.10-3.19) 0.53 (0.09-10.48) 0.091 100 0.27 (0.10-1.37) 0.37 (0.11-4.65) 0.008 28 0.10 (0.03-2.19) 0.15 (0.05-0.71) 0.005 66 0.03 (0.01-0.57) 0.05 (0.01-0.25) 0.002 154 0.04 (0.01-0.17) 0.05 (0.01-0.50) 0.001 Sum of all 104.2 (26.1-1188.4) 119.3 (36.4-1785.1) 0.046 14 (ng/L) (a) One unmeasurable sample.* Adjusted for maternal age, BMI, parity, and date of childbirth, for the combined data also for country of origin. Table 4. Seven less-prevalent PBDEs in breast milk samples from Danish and Finnish boys with and without cryptorchidism. Denmark PBDE congener (ng/g fat) Control (n= 36) % Cryptorchid (n= 29) % Sum of 14 congeners 3.27 (1.11-9.12) - 4.27 (1.34-19.10) - 183 0.05 (0.0-0.58) 78 0.05 (0.0-0.23) 62 85 0.005 (0.0-0.05) 67 0.07 (0.0-0.22) 97 75 0.001 (0.0-0.01) 61 0.0 (0.0-0.01) 28 77 0.001 (0.0-0.03) 53 0.01 (0.0-0.04) 65 119 0.0 (0.0-0.01) 25 0.0 (0.0-0.01) 48 138 0.0 (0.0-0.02) 28 0.0 (0.0-0.03) 28 Finland PBDE congener (ng/g fat) Control (n= 32) % Cryptorchid (n= 33) % Sum of 14 congeners 3.11 (1.04-29.5) - 4.27 (1.43-56.44) - 183 0.0 (0.0-0.17) 44 0.0 (0.0-0.49) 27 85 0.0 (0.0-0.12) 6 0.0 (0.0-0.08) 36 75 0.0 (0.0-0.06) 34 0.0 (0.0-0.03) 36 77 0.0 (0.0-0.12) 19 0.0 (0.0-0.02) 15 119 0.0 (0.0-0.02) 12 0.0 (0.0-0.01) 15 138 0.0 (0.0-0.01) 3 - 0 Concentrations are given as median (2.5th-97.5th percentiles). Percentages are of detectable samples. BDE-71 was not detected in any sample.
The concentrations of PBDE congeners in milk samples showed large variations between congeners and individuals (Figure 2). Individual congener concentrations were positively correlated with one another (r = 0.178-0.955, p < 0.0001).
There were no significant country differences in the sum of all congeners [Denmark,3.52 ng/g (95% CI, 1.26-14.2) vs. Finland, 3.44 ng/g (95% CI, 1.25-13.94), p = 0.754] or the sum of the most prevalent seven congeners, BDEs 47, 153, 99, 100, 28, 66, and 154 [Denmark, 3.24 ng/g (95% CI, 1.26-51.1) vs. Finland, 3.23 ng/g (95% CI, 1.26-51.0), p = 0.629]. Similar results were obtained if we analyzed only milk samples from mothers of healthy boys (data not shown). The estimated daily intake of PBDEs (sum of all) for an infant at 3 months of age (median infant body weight 6.58 kg, consuming 120 mL breast milk/kg) was a median of 16 ng/kg/day (range, 6-121 ng/kg/day). Breast milk lipid (percent wet weight) differed significantly between the countries (mean [+ or -] SD = 2.99 [+ or -] 1.38 in Denmark, 4.52 [+ or -] 1.56 in Finland; p < 0.0001). The lipid content was not significantly correlated with the sum of PBDE congeners (data not shown).
The pattern of congener distribution differed between the countries. BDE-28 was significantly higher in Finland than in Denmark (p < 0.021), with a similar tendency for BDE-47 (p < 0.077), which was the most prevalent congener. BDE-153 (p < 0.0001), BDE-66 (p < 0.026), and BDE-183 (p < 0.022) were significantly higher in Denmark than in Finland, with a similar tendency for BDE-99 (p < 0.073). For congeners at very low concentrations, the percentage of measurable samples was higher in Denmark than in Finland (Table 4). There was no significant effect of breast pump use during collection of samples on the concentration of any BDE See Borland Database Engine. congener in the Danish breast milk samples.
In the Danish but not the Finnish samples, the date of childbirth within the cohort was significantly correlated with the concentration of BDE-154 (r = -0.346, p < 0.005), BDE-85 (r = -0.434, p < 0.0001) and BDE-75 (r = 0.376, p < 0.002) with similar tendencies for BDE-66 (r = -0.211, p = 0.092) and BDE-77 (r = -0.214, p = 0.087).
Serum LH levels correlated positively with the sum of seven PBDEs in breast milk (r = 0.218, p < 0.033) as well as with individual congeners BDE-47 (r = 0.227, p < 0.027), BDE-100 (r = 0.293, p < 0.004), and BDE-154 (r = 0.203, p < 0.048). Country-specific analyses showed significant associations between serum LH and the above listed PBDEs and their sum for Finnish milk samples, but not Danish (data not shown). No other reproductive hormones or their ratios were significantly correlated with the concentration of PBDEs.
Placentas. The average levels of 14 PBDE congeners per gram fat in placentas were lower than in breast milk (Table 5), and more samples were nondetectable. Therefore, the sum of five congeners was used instead of the seven congeners used for milk. This had a minor influence on the total, because the sums of the five and the 14 congeners were very close.
Table 5. PBDEs in placentas from Danish and Finnish boys with and without cryptorchidism [median (2.5th-97.5th percentiles)]. Denmark PBDE Control (n= 129) % Cryptorchid (n = 39) % congener (ng/g fat) 47 0.39 (0.19-1.64) 100 0.40 (0.20-2.17) 100 153 0.44 (0.20-1.21) 100 0.41 (0.21-0.98) 100 99 0.23 (0.10-0.99) 100 0.18 (0.13-0.68) 100 100 0.11 (0.05-0.40) 100 0.10 (0.06-0.56) 100 28 0.03 (0.01-0.06) 100 0.03 (0.01-0.40) 100 Sum of 5 1.28 (0.59-3.26) 100 1.13 (0.79-4.45) 100 congeners 66 0.0 (0.0-0.03) 29 0.0 (0.0-0.04) 38 154 0.0 (0.0-0.03) 39 0.0 (0.0-0.02) 5 183 0.0 (0.0-0.14) 26 0.0 (0.0-0.09) 10 85 0.0 (0.0-0.01) 2 - 0 75 (0.003) 1 - 0 77 - 0 - 0 119 0.0 (0.0-0.002) 3 - 0 138 - 0 - 0 Sum of 14 1.31 (0.61-3.31) 1.13 (0.79-4.48) congeners Finland PBDE Control (n = 56) % Cryptorchid (n = 56) % congener (ng/g fat) 47 0.60 (0.12-6.19) 100 0.52 (0.12-4.07) 100 153 0.20 (0.08-0.92) 100 0.20 (0.10-0.53) 100 99 0.19 (0.04-1.57) 100 0.14 (0.04-1.20) 100 100 0.11 (0.03-0.79) 100 0.10 (0.04-0.68) 100 28 0.04 (0.01-0.52) 100 0.04 (0.01-0.12) 100 Sum of 5 1.16 (0.35-9.65) 100 1.05 (0.35-6.51) 100 congeners 66 0.01 (0.0-0.20) 64 0.01 (0.0-0.04) 62 154 0.01 (0.0-0.10) 79 0.0 (0.0-0.09) 34 183 - 0 0.0 (0.0-0.07) 5 85 0.0 (0.0-0.08) 25 0.0 (0.0-0.04) 34 75 - 0 - 0 77 0.0 (0.0-0.02) 4 - 0 119 - 0 (0.01) 2 138 0.0 (0.0-0.02) 2 - 0 Sum of 14 1.18 (0.35-9.89) 1.06 (0.36-6.67) congeners BDEs 153, 99, 100, and 28 were detected in all samples. BDE-71 was not detected in any sample. Percentages are of detectable samples.
The distribution of congeners resembled the distribution in breast milk, with BDE-47 and BDE-153 constituting the main fraction of PBDEs. There was no significant country difference for the sum of all 14 congeners (p = 0.198) or the sum of five (BDE-47, BDE-153, BDE-99, BDE-100, and BDE-28; p = 0.192). This was also true when only placentas from healthy boys were analyzed (data not shown). The concentrations of the five most prevalent congeners were positively correlated with each other (r = 0.171-0.827, p < 0.0001). Placenta lipid content (percent wet weight) differed significantly between the countries (mean [+ or -] SD =1.09 [+ or -]0.17 in Denmark, 1.21 [+ or -] 0.13 in Finland; p < 0.0001). Placenta lipid content was not significantly correlated with the sum of PBDE congeners (data not shown).
The date of childbirth within the cohort was significantly correlated in the Danish placentas with the concentration of BDE-66 (r = -0.246, p < 0.001), and in the Finnish placentas with BDE-85 (r = 0.239, p < 0.01) and BDE-153 (r = 0.275, p < 0.003).
There was no significant difference in the placenta concentration of the five most prevalent PBDEs between cryptorchid boys and healthy boys in Denmark (p = 0.10-0.976) or Finland (p = 0.09-0.835) or for their sum (p = 0.312 and p = 0.128, respectively). The results remained nonsignificant non·sig·nif·i·cant
1. Not significant.
2. Having, producing, or being a value obtained from a statistical test that lies within the limits for being of random occurrence. if prematurity and SGA were included in the model. There were no correlations between placental placental
pertaining to or emanating from placenta.
the placental separation of maternal and fetal blood which varies in its structure and permeability between the species. PBDEs and serum reproductive hormones in 3-month-old infants.
Paired samples. The median concentrations (nanograms per gram fat) of the 14 congeners in placenta were lower than the concentration found in the paired breast milk samples (n = 86) (Table 6), but there were significant correlations between the measurements, except for BDE-85 and BDE-138.
Table 6. Correlations between PBDE measurements in paired placenta and breast milk samples (ng/g fat) of 43 Danish and 43 Finnish boys [median (95% CI). PBDE congener Median placenta Median milk r p-Value 28 0.03 (0.02-0.39) 0.12 (0.03-1.85) 0.73 0.0001 47 0.42 (0.19-2.84) 1.27 (0.45-14.7) 0.64 0.0001 66 0.0 (0.0-0.06) 0.04 (0.01-0.27) 0.31 0.004 71 0.0 (0.0-0.0) 0.0 (0.0-0.0) - - 75 0.0 (0.0-0.0) 0.0 (0.0-0.02) 0.21 0.057 77 0.0 (0.0-0.004) 0.0 (0.0-0.03) 0.30 0.006 85 0.0 (0.0-0.06) 0.0 (0.0-0.12) -0.02 0.823 99 0.19 (0.06-1.30) 0.42 (0.09-5.27) 0.55 0.0001 100 0.11 (0.05-0.43) 0.29 (0.10-1.41) 0.74 0.0001 119 0.0 (0.0-0.0) 0.0 (0.0-0.01) - - 138 0.0 (0.0-0.0) 0.0 (0.0-0.02) -0.05 0.664 153 0.32 (0.11-0.93) 0.85 (0.27-3.11) 0.81 0.0001 154 0.0 (0.0-0.09) 0.04 (0.01-0.18) 0.26 0.015 183 0.0 (0.0-0.18) 0.02 (0.0-0.38) 0.26 0.015 Sum 1.19 (0.59-6.11) 3.23 (1.16-27.6) 0.66 0.0001 Due to nondetectable levels, correlations could not be computed for BDE-71 and BDE-119.
The sum of all congeners in milk was 3.39 (95% CI, 1.43-48.2) for boys with cryptorchidism and 3.15 (95% CI, 1.07-24.9) for controls (p = 0.228), and in placenta 1.22 (95% CI, 0.64-9.32) for boys with cryptorchidism and 1.17 (95% CI, 0.49-5.46) for controls (p = 0.871). Infant reproductive hormones at 3 months of age (27 Danish, 35 Finnish boys) were not correlated to PBDE concentrations in placenta or milk in this data subset.
To our knowledge, this is the first study describing an association between congenital cryptorchidism in humans and exposure to PBDEs. An association was found for the sum of seven PBDEs (BDEs 47, 153, 99, 100, 28, 66, 154) in breast milk as well as for the individual congeners BDEs 47, 100, 28, 66, and 154. Concentrations of BDEs 47, 100, and 154 were also positively correlated with increasing serum LH values. This suggested that a higher gonadotropin drive was necessary to ensure normal testosterone production by the Leydig cells Leydig cells
Cells that make up the endocrine tissue of the testis and produce testosterone. They are named for Franz von Leydig (1821–1908), the German professor of anatomy who first identified them. (Suomi et al. 2006), and thus a subtle primary testicular disfunction dis·func·tion
Variant of dysfunction. .
In this study we assessed infant exposure by measuring the concentration of PBDEs in breast milk, which reflects the accumulated body burden of the mother (Inoue et al. 2006; Jensen and Slorach 1991; Waliszewski et al. 2001). It also is a proxy for prenatal fetal exposure because PBDEs, especially the lower brominated compounds, can cross the placenta (Bi et al. 2006; Mazdai et al. 2003) and are transferred to breast milk during lactation lactation
Production of milk by female mammals after giving birth. The milk is discharged by the mammary glands in the breasts. Hormones triggered by delivery of the placenta and by nursing stimulate milk production. (Darnerud and Risberg 2006). However, when we assesssed exposure by measuring PBDE in placenta, the results did not support the above findings, despite the fact that 86 mother-child pairs were represented with both milk and placenta samples. At present, it is not clear why this is the case.
The concentration of all PBDE congeners per gram fat in placenta was considerably lower than in milk, and more congeners were nondetectable. These differences did not have any remarkable influence on analytical errors, because the amount of fat used for analysis was similar for placentas and milk samples. In theory, placenta should be a better proxy for fetal exposure than breast milk, because it represents the direct route of chemical transfer during pregnancy. The number of placentas analyzed in this study was larger than the number of milk samples, and should thus better represent the pool of cases and controls. We could not establish any obvious selection bias of milk donors. On the other hand, due to higher concentrations, milk analyses were somewhat more reliable toward the lower end of concentration. This should not be important, because the main group differences were seen at the higher end of PBDE concentrations. It is currently unknown whether PBDEs accumulate in placenta, but our paired samples indicated that this may not be the case. We found positive correlations between measurements in placenta and breast milk, but three to four times lower absolute concentrations in placenta. Placenta concentrations may resemble measurements in single blood samples, and thus reflect the situation at delivery but not the long-term exposure.
There is some controversy as to whether the placental transport of PBDEs may differ between lower and higher brominated PBDEs. An American study reported a strong correlation of lipid-adjusted BDE concentrations in maternal serum at term and cord blood cord blood
Blood present in the umbilical vessels at the time of delivery. (Mazdai et al. 2003), whereas studies from countries with a generally lower exposure level found weaker correlations and higher values in maternal than in fetal samples (Bi et al. 2006). Segregation from serum into breast milk samples did not always follow a 1:1 pattern. The congener distribution appeared to be similar for lower brominated BDEs (Bi et al. 2006; Mazdai et al. 2003), whereas higher brominated BDEs such as BDE-209 were 10 times higher in serum than in breast milk (Inoue et al. 2006). Thus, the relative distribution of congeners between placenta and breast milk may also depend on the fat composition of these two matrices causing different solubility. We found significantly higher fat concentrations in the Finnish than in the Danish samples, which may reflect dietary habits in the two countries, because both long-term and short-term diet as well as the nutritional status nutritional status,
n the assessment of the state of nourishment of a patient or subject. may influence content and composition of breast milk lipids (Ortiz-Olaya et al.1996).
Current knowledge about human reproductive health consequences after exposure to PBDEs is very limited (Agency for Toxic Substances and Disease Registry 2004). A study from Taiwan showed an association between the sum of 12 PBDE congeners in breast milk, 10 of which were the same as in our study, and lower birth weight and length (Chao et al. 2007). Recently, a Swedish case-control study case-control study,
n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. found higher values of PBDEs (sum of BDEs 47, 153, and 99) in blood samples from mothers of young men with testicular cancer testicular cancer
Malignant tumour of the testis, or testicle. Although relatively rare, testicular cancer is the most common malignancy for men between the ages of 20 and 34. It typically affects men between 15 and 39 years old. than in age-matched controls (Hardell et al. 2006). However, maternal PBDE exposure was assessed 15-25 years after the critical time period--that is, at the time of the cancer diagnosis--which considerably weakens the possibility to establish a causal link between exposure and outcome. Also in this study (Hardell et al. 2006), exposures to other persistent chemicals occurred simultaneously, and it cannot be determined how these substances interact in their effect on reproductive development. Testicular cancer is the most severe clinical symptom of the testicular dysgenesis dysgenesis /dys·gen·e·sis/ (-jen´e-sis) defective development; malformation.
gonadal dysgenesis syndrome (TDS TDS
total dissolved solids. ), which also encompasses impaired semen quality semen quality Urology The measurable parameters of semen–eg, sperm concentration, total sperm count per ejaculate, % of motile sperm, number of abnormal and immature sperm , congenital cryptorchidism, and hypospadias (Skakkebaek et al. 2001). TDS may be caused by genetic, hormonal, or environmental factors (Sharpe 2006; Skakkebaek et al. 2001). Prenatal exposure to PBDEs may have an adverse effect on testicular growth and differentiation in utero in utero (in u´ter-o) [L.] within the uterus.
In the uterus.
in utero adv. .
In animal studies, penta-brominated PBDEs showed antiandrogenic activity (Stoker et al. 2005). A peripubertal single-dose exposure to a commercial mixture of penta-BDEs delayed the onset of puberty in male and female rats (Stoker et al. 2004) and suppressed the growth of the seminal vesicles and ventral ventral /ven·tral/ (ven´tral)
1. pertaining to the abdomen or to any venter.
2. directed toward or situated on the belly surface; opposite of dorsal.
adj. prostate. In adult rats, a single-dose exposure significantly increased LH concentration in serum (Stoker et al. 2005). Our observation of an association between PBDE levels in breast milk and serum LH in infants at 3 months of age is in line with these animal data. Gestational exposure of rats to BDE-99 caused a shortening of the anogenital a·no·gen·i·tal
Relating to the anus and the genitals.
relating to the region of the anus and the genitalia, especially the external genitalia. distance in male and female rats, reduction in primordial and secondary ovarian follicles Ovarian follicles
Structures found within the ovary that produce eggs.
Mentioned in: Polycystic Ovary Syndrome , a lower sperm count sperm count Urology A measure of the concentration of sperm in semen Normal ±100 million/mL. See Post-vasectomy sperm count, Semen analysis. , and lower estradiol and testosterone levels in adulthood (Kuriyama et al. 2005; Lilienthal et al. 2006). In vitro in vitro /in vi·tro/ (in ve´tro) [L.] within a glass; observable in a test tube; in an artificial environment.
In an artificial environment outside a living organism. assays showed a competitive androgen receptor binding for BDEs 47, 99, and 100. BDEs 47, 71, and 100 inhibited dihydrotestosterone-induced transcriptional activity (Stoker et al. 2005). Because testicular descent is highly androgen-dependent (Toppari 2003), the adverse effect of PBDE on testicular descent could be caused by their antiandrogenic properties.
In addition, BDEs 47, 100, 75, and 51, particularly their hydroxylated metabolites Metabolites
Substances produced by metabolism or by a metabolic process.
Mentioned in: Interactions , are weakly estrogenic, and BDEs 153, 166, and 190 are antiestrogenic in vitro (Legler and Brouwer 2003; Meerts et al. 2001). Exposure of female rats to BDE-99 led to the formation of abundant vesicles and vacuolization of the ovary ovary, ductless gland of the female in which the ova (female reproductive cells) are produced. In vertebrate animals the ovary also secretes the sex hormones estrogen and progesterone, which control the development of the sexual organs and the secondary sexual (Talsness et al. 2005), which showed signs of compromised steroidogenesis steroidogenesis /ste·roi·do·gen·e·sis/ (ste-roi?do-jen´e-sis) production of steroids, as by the adrenal glands.steroidogen´ic
The biological synthesis of steroids. . Prenatal female exposure to BDE-99 in rats affected estrogen target genes in the uterus (Ceccatelli et al. 2006). Thus, the delicate balance between androgens Androgens
Male sex hormones produced by the adrenal glands and testes, the male sex glands.
Mentioned in: Acne, Congenital Adrenal Hyperplasia, Finasteride, Homocysteine, Polycystic Ovary Syndrome, Salpingo-Oophorectomy
and estrogens Estrogens
Hormones produced by the ovaries, the female sex glands.
Mentioned in: Acne, Polycystic Ovary Syndrome
n. in the fetus may become altered by PBDE exposure. In mice, the metabolism of BDE-47 was highly dependent on the developmental stage of the animal, being slowest in pups (Staskal et al. 2006). Whether this also plays a role for human fetal development is currently unknown. Most exposure doses used in animal studies are several orders of magnitude higher than the levels of PBDEs found in breast milk in our study. However, there is emerging evidence that also low-dose exposure to, for example, BDE-99 close to levels found in human adipose tissue adipose tissue (ăd`əpōs'): see connective tissue.
or fatty tissue
Connective tissue consisting mainly of fat cells, specialized to synthesize and contain large globules of fat, within a may have an adverse effect on the reproductive health of the offspring (Anonymous 2005; Kuriyama et al. 2005).
The distribution pattern of BDE congeners in breast milk corresponded to the distribution of BDE congeners in commercially available mixtures of PBDEs (Alaee et al. 2006; Darnerud et al. 2001; Law et al. 2006; Lilienthal et al. 2006). The absolute concentrations found in our study are within the same order of magnitude A change in quantity or volume as measured by the decimal point. For example, from tens to hundreds is one order of magnitude. Tens to thousands is two orders of magnitude; tens to millions is three orders of magnitude, etc. as reported from other Nordic and European countries (Jaraczewska et al. 2006; Kalantzi et al. 2004; Lind et al. 2003; Strandman et al. 2000) as well as China (Bi et al. 2006) and Japan (Eslami et al. 2006; Inoue et al. 2006). There are, however, significant geographic differences between and within these countries, which point toward differences in general contamination levels. In our study, the total amount of PBDEs did not differ between Finnish and Danish milk or placenta samples, but the pattern of congener distribution varied, which indicated different sources and timing of exposure. PBDE levels reported from American studies of breast milk appear to be considerably higher (Betts 2002). In contrast, the previous exponential increase in penta-PBDEs in Swedish breast milk samples since the 1970s has reversed since the late 1990s (Law et al. 2006; Meironyte et al. 1999; Sjodin et al. 2003), when penta-BDEs were gradually phased out. The collection of breast milk samples in our study covered a 5-year period, and we found a negative correlation between the level of PBDEs in breast milk and the infant date of birth. This is in line with the expected decline in the use of penta-PBDEs in the two regions. The high variability in PBDE concentrations among individual mothers has been described also for other human matrices (McDonald 2002), and may reflect variability in both exposure and metabolism. Deca-BDE can be converted through sunlight exposure into lower brominated BDEs, which are more readily absorbed from the intestine and bioaccumulate due to their longer half-life than deca-BDE (Watanabe and Tatsukawa 1987). However, it is as yet unknown how much this process contributes to human environmental exposure to lower brominated PBDEs.
Exposure to PBDEs cannot explain the observed geographic difference in the prevalence of cryptorchidism between Denmark and Finland. Breast milk contains significant levels of other persistent and nonpersistent chemical compounds (Damgaard et al. 2006; Main et al. 2006a), which can affect perinatal testicular development. Mothers with high levels of PBDE exposure also may be exposed to high levels of other persistent chemicals. Thus, the combined exposure to multiple environmental factors may cause the association between congenital cryptorchidism and PBDE concentration in breast milk (Koppe et al. 2006). In addition, other lifestyle factors and genetic susceptibility may play a role (Damgaard et al. 2007; Sharpe 2006; Virtanen et al. 2006). In our total study population, the geographic difference in the prevalence of cryptorchidism was observed mainly for mild forms of undescended testes, which had a high degree of spontaneous postnatal postnatal /post·na·tal/ (-na´t'l) occurring after birth, with reference to the newborn.
Of or occurring after birth, especially in the period immediately after birth. descent (Boisen et al. 2004). This pattern was also seen in this subpopulation sub·pop·u·la·tion
A part or subdivision of a population, especially one originating from some other population: microbial subpopulations.
Noun 1. , in which PBDEs was analyzed. However, also mild and transient forms of cryptorchidism are associated with a subtle impairment of primary testicular function (Suomi et al. 2006).
In conclusion, we used two different biological matrices in this study to assess infant perinatal exposure. Breast milk, but not placenta, showed an association with congenital cryptorchidism. There are valid arguments for either matrix, and risk assessment will require more scrutiny. The association between PBDE contamination levels in breast milk and congenital cryptorchidism is still of concern because exposure to PBDEs is considerable in some areas.
Agency for Toxic Substances and Disease Registry. 2004. Toxicological Profile for Polybrominated Biphenyls polybrominated biphenyls
see biphenyl. and Polybrominated Diphenyl Ethers (PBBs and PBDEs). Available: www.atsdr.cdc.gov/toxprofiles/tp68.html [accessed 30 March 2007]
Alaee M, Arias P, Sjodin A, Bergman A. 2006. An overview of commercially used brominated flame-retardants, their application, their use in different countries/regions and possible modes of release. Environ Int 29:683-689
Andersson A-M A-M Alternating Maximization (algorithm) , Toppari J, Haavisto A-M, Petersen JH, Simell T, Simell O, et al. 1998. Longitudinal reproductive hormone profiles in infants: peak of inhibin B levels in infant boys exceeds levels in adult men. J Clin Endocrinol Metab 83:675-681.
[Anonymous]. 1986. Cryptorchidism: an apparent substantial increase since 1960. John Radcliffe Hospital The John Radcliffe Hospital is a large tertiary teaching hospital in Oxford, UK.
It is the main teaching hospital for Oxford University and Oxford Brookes University. As such, it is a well developed centre of medical research. Cryptorchidism Study Group. BMJ BMJ n abbr (= British Medical Journal) → vom BMA herausgegebene Zeitschrift 293:1401-1404.
[Anonymous]. 2005. Polybrominated diphenyl diphenyl /di·phen·yl/ (di-fen´il) a toxic compound comprising two linked benzene rings, used as a fungistat in containers for shipping citrus fruits.
See biphenyl. ether levels among United States residents: daily intake and risk of harm to the developing brain and reproductive organs Reproductive organs
The group of organs (including the testes, ovaries, and uterus) whose purpose is to produce a new individual and continue the species.
Mentioned in: Choriocarcinoma . Integr Environ Assess Manag 1:343-354.
Becher G, Nicolaysen T, Thomsen C. 2001. Interlaboratory Comparison on Dioxins in Food 2001. Final Report 4. Oslo, Norway:Folkehelsa.
Betts K. 2002. Rapidly rising PBDE levels in North America. Environ Sci Technol 36:50A-52A.
Bi X, Qy W, Sheng sheng
(Chinese; “sage” or “saint”)
In Chinese belief, a mortal who attains extraordinary or supernatural powers by self-cultivation and serves as a model for others. Confucius used the term to refer to exemplary rulers of the past. G, Zhang W, Mau B, Chen D, et al. 2006. Polybrominated diphenyl ethers in South China, maternal and fetal blood and breast milk. Environ Pollut 144:1024-1030.
Boisen KA, Kaleva M, Main KM, Virtanen HE, Haavisto A-M, Schmidt IM, et al. 2004. Difference in prevalence of congenital cryptorchidism in infants between two Nordic countries. Lancet 363:1264-1269.
Ceccatelli R, Faass O, Schlumpf M, Lichtensteiger W. 2006. Gene expression and estrogen sensitivity in rat uterus after developmental exposure to the polybrominated diphenyl ether PBDE-99 and PCB PCB: see polychlorinated biphenyl.
in full polychlorinated biphenyl
Any of a class of highly stable organic compounds prepared by the reaction of chlorine with biphenyl, a two-ring compound. . Toxicology 220:104-116.
Chao HR, Wang SL, Lee WJ, Wang YF, Papke O. 2007. Levels of polybrominated diphenyl ethers (PBDEs) in breast milk from central Taiwan and their relation to infant birth outcome and maternal menstruation menstruation, periodic flow of blood and cells from the lining of the uterus in humans and most other primates, occurring about every 28 days in women. Menstruation commences at puberty (usually between age 10 and 17). effects. Environ Int 33:239-245.
Damgaard IN, Jensen TK, Petersen JH, Skakkebaek NE, Toppari T, Main KM. 2007. Cryptorchidism and maternal alcohol consumption during pregnancy. Environ Health Perspect 115:272-277.
Damgaard IN, Skakkebaek NE, Toppari J, Virtanen HE, Shen H, Schramm KW, et al. 2006. Persistent pesticides in human breast milk and cryptorchidism. Environ Health Perspect 114:1133-1138.
Darnerud PO, Eriksen GS, Johannesson T, Larsen PB, Viluksela M. 2001. Polybrominated diphenyl ethers: occurrence, dietary exposure and toxicology. Environ Health Perspect 109(suppl 1):49-68.
Darnerud PO, Risberg S. 2006. Tissue localization Customizing software and documentation for a particular country. It includes the translation of menus and messages into the native spoken language as well as changes in the user interface to accommodate different alphabets and culture. See internationalization and l10n. of tetraand pentabromodiphenyl ether congeners (BDE-47, 85 and-99) in perinatal and adult C57BL mice. Chemosphere chemosphere: see atmosphere. 62:485-493.
Eslami B, Koizumi A, Ohta S, Inoue K, Aozasa O, Harad K, et al. 2006. Large-scale evaluation of the current level of polybrominated diphenyl ethers (PBDEs) in breast milk from 13 regions of Japan. Chemosphere 63:554-561.
Hardell L, van Bavel B, Lindstrom G, Eriksson M, Carlberg M. 2006. In uteroexposure to persistent organic pollutants in relation to testicular cancer risk. Int J Androl 29:228-234.
Inoue K, Harada K, Takenaka K, Uehara S, Kono M, Shimizu T, et al. 2006. Levels and concentration of polychlorinated biphenyls polychlorinated biphenyls, (pol´ēklôr´nā´tid bīfē´n and polybrominated diphenyl ethers in serum and breast milk in Japanese mothers. Environ Health Perspect 114:1179-1185.
Jaraczewska K, Lulek J, Cobaci A, Voorspoels S, Kaluba-Skotarczak A, Drews K, et al. 2006. Distribution of polychlorinated biphenyls, organochlorine or·gan·o·chlo·rine
Any of various hydrocarbon pesticides, such as DDT, that contain chlorine. pesticides and polybrominated diphenyl ethers in human umbilical cord serum, maternal serum and milk from Wielkopolska region, Poland. Sci Total Environ 372:20-31.
Jensen AA, Slorach SA. 1991. Chemical Contaminants in Human Milk. Boston, MA:CRC (Cyclical Redundancy Checking) An error checking technique used to ensure the accuracy of transmitting digital data. The transmitted messages are divided into predetermined lengths which, used as dividends, are divided by a fixed divisor. Press.
Kalantzi OL, Martin FL, Thomas GO, Alcock RE, Tang HR, Drury SC, et al. 2004. Different levels of polybrominated diphenyl ethers (PBDEs) and chlorinated chlorinated /chlo·ri·nat·ed/ (klor´i-nat?ed) treated or charged with chlorine.
charged with chlorine.
some, e.g. compounds in breast milk from two U.K. regions. Environ Health Perspect 112:1085-1091.
Kiviranta H, Ovaskainen ML, Vartiainen T. 2004. Market basket study on dietary intake of OCDD/Fs, PCBs and PBDEs in Finland. Environ Int 30:923-932.
Koppe JG, Bartonova A, Bolte G, Bistrup ML, Busby C, Butter M, et al. 2006. Exposure to multiple environmental agents and their effect. Acta Paediatr (Suppl) 95:106-113.
Kuriyama SN, Talsness CE, Grote K, Chahoud I. 2005. Developmental exposure to low dose PBDE-99: effects on male fertility and neurobehaviour in rat offspring. Environ Health Perspect 113:149-154.
Law RJ, Allchin CR, de Boer J, Covaci A, Herzke D, Lepom P, et al. 2006. Levels and trends of brominated flame-retardants in the European environment. Chemosphere 64:187-208.
Legler J, Brouwer A. 2003. Are brominated flame-retardants endocrine disrupters? Environ Int 29:879-885.
Lilienthal H, Hack A, Roth-Harer A, Wichert Grande S, Talsness CE. 2006. Effects of developmental exposure to 2,2'4,4',5-pentabromodiphenyl ether (PBDE-99) on sex steroids, sexual development, and sexually dimorphic dimorphic
see dimorphic fungus. behavior in rats. Environ Health Perspect 114:194-201.
Lind Y, Darnerud PO, Atuma S, Aune M, Becker W, Bjerselius R, et al. 2003. Polybrominated diphenyl esters in breast milk from Uppsala County, Sweden. Environ Res 93:186-194.
Main KM, Mortensen GK, Kaleva M, Boisen K, Damgaard I, Chellakooty M, et al. 2006a. Human breast milk contamination with phthalates Phthalates, or phthalate esters, are a group of chemical compounds that are mainly used as plasticizers (substances added to plastics to increase their flexibility). They are chiefly used to turn polyvinyl chloride from a hard plastic into a flexible plastic. and alterations of endogenous reproductive hormones in 3-month-old infants. Environ Health Perspect 114:270-276.
Main KM, Schmith IM, Skakkebaek NE. 2000. A possible role for reproductive hormones in newborn boys: progressive hypogonadism Hypogonadism Definition
Hypogonadism is the condition more prevalent in males in which the production of sex hormones and germ cells are inadequate. without the postnatal testosterone peak. J Clin Endocrinol Metab 85:4905-4907.
Main KM, Toppari J, Suomi AM, Kaleva M, Chellakooty M, Schmidt IM, et al. 2006b. Larger testes and higher inhibin B levels in Finnish than in Danish newborn boys. J Clin Endocrinol Metab 91:2732-2737.
Marsal K, Persson PH, Larsen T, Lilja H, Selbing A, Sultan B. 1996. Intrauterine intrauterine /in·tra·uter·ine/ (-u´ter-in) within the uterus.
Within the uterus.
Situated or occuring in the uterus. growth curves based on ultrasonically estimated fetal weights. Acta Paediatr 85:843-848.
Mazdai A, Dodder dodder: see morning glory.
Any of the leafless, twining, parasitic vines (see parasitism) that make up the genus Cuscuta (family Cuscutaceae), containing more than 150 species found throughout temperate and tropical regions. NG, Anernathy MP, Hites RA, Bigsby RM. 2003. Polybrominated diphenyl ethers in maternal and fetal blood samples. Environ Health Perspect 111:1249-1252.
McDonald TA. 2002. A perspective on the potential health risks of PBDEs. Chemosphere 46:745-755.
Meerts IA, Letcher RJ, Hoving S, Marsh G, Bergman A, Lemmen JG, et al. 2001. In vitroestrogenicity of polybrominated diphenyl ethers, hydroxylated PBDEs, and polybrominated bisphenol A compounds. Environ Health Perspect 109:399-407.
Meironyte D, Noren K, Bergman A. 1999. Analysis of polybrominated diphenyl ethers in Swedish human milk. A time-related trend study, 1972-1997. J Toxicol Environ Health A 58:329-341.
Ortiz-Olaya N, Flores Flores, town, Guatemala
Flores (flōrəs), town (1990 est. pop. 2,200), capital of Petén department, N Guatemala. Flores was built on an island in the southern part of Lake Petén Itzá and on the site of the ME, De Santiago S. 1996 Significance of lipid consumption during lactation. Rev Invest Clin 48:473-478.
Pihkala J, Hakala T, Voutilainen P, Raivio K. 1989. Characteristic of recent fetal growth curves in Finland. Duodecim 105:1540-1546.
Sharpe RM. 2006. Pathways of endocrine disruption during male sexual differentiation sexual differentiation See Hermaphroditism, hirsutism, Müllerian ducts, Precocious puberty, Pseudoprecocious puberty, Tanner staging, Testis-determining factor, Virilization, Wolffian ducts, XXX, XXY, XXXY, XYY syndromes, Y Chromosome. and masculinization masculinization /mas·cu·lin·iza·tion/ (-lin-i-za´shun)
1. normal development of male primary or secondary sex characters in a male.
2. development of male secondary sex characters in a female or prepubescent male. . Best Pract Res Clin Endocrinol Metab 20:91-110.
Shen H, Main KM, Kaleva M, Virtanen H, Haavisto AM, Skakkebaek NE, et al. 2005. Prenatal organochlorine pesticides in placentas from Finland: exposure of male infants born during 1997-2001. Placenta 26: 512-514.
Shen H, Main KM, Virtanen HE, Damgaard IN, Haavisto AM, Kaleva M, et al. 2007. From mother to child: investigation of prenatal and postnatal exposure to persistent bioaccumulating toxicants using breast milk and placenta biomonitoring. Chemosphere 67:S256-S262.
Shen H, Virtanen HE, Main KM, Kaleva M, Andersson AM, Skakkebaek NE, et al. 2006. Enantiomeric rations as an indicator of exposure processes for persistent pollutants in human placentas. Chemosphere 62:390-395.
Sjodin A, Patterson DGJr, Bergman A. 2003. A review on human exposure to brominated flame-retardants--partic-ularly polybrominated diphenyl ethers. Environ Int 29:829-839.
Skakkebaek NE, Rajpert-De Meyts E, Main KM. 2001.Testicular dysgenesis syndrome: an increasingly common developmental disorder developmental disorder Psychiatry An impairment in normal development of language, motor, cognitive and/or motor skills, generally recognized before age 18 which is expected to continue indefinitely and constitutes a substantial impairment Etiology Mental with environmental aspects. Hum Reprod 16:972-978.
Smastuen Haug L, Becher G. 2004. Interlaboratory Comparison on Dioxins in Food 2004. Fifth Round of An International Study. Oslo, Norway:Norwegian Institute of Public Health The Norwegian Institute of Public Health (Nasjonalt folkehelseinstitutt, Folkehelseinstituttet) is a national center established in 2002 for expert knowledge of epidemiology, infectious disease control, environmental medicine, forensic toxicology and research on .
Smastuen Haug L, Becher G. 2005. Interlaboratory Comparison on Dioxins in Food 2005. Sixth Round of An International Study. Oslo, Norway:Norwegian Institute of Public Health.
Staskal DF, Diliberto JJ, Birnbaum LS. 2006. Disposition of BDE 47 in developing mice. Toxicol Sci 90:309-316.
Stoker TE, Cooper RL, Lambright VS, Wilson F, Gray LE. 2005. Invivoand in vitroanti-androgenic effects of DE- de- word element [L.], down; from; sometimes negative or privative, and often intensive.
1. Do or make the opposite of; reverse: decomposition.
2. 71, a commercial polybrominated diphenyl ether (PBDE) mixture. Toxicol Appl Pharmacol 207:78-88.
Stoker TE, Laws SC, Crofton KM, Hedge JM, Ferrell JM, Cooper RL. 2004. Assessment of DE-71, a commercial polybrominated diphenyl ether (PBDE) mixture in the EDSP EDSP Exchange Delivery Settlement Price (finance/investing)
EDSP Endocrine Disruptors Screening Program
EDSP Electronic Digital Signal Processing
EDSP Engineering Design Support to Production male and female pubertal protocols. Toxicol Sci 78:144-155.
Strandman T, Koistinen J, Variainen T. 2000. Levels of some polybrominated diphenyl ethers (PBDEs) in placenta and human milk. Organohalogen Compounds 47:61-64.
Suomi A-M, Main KM, Kaleva M, Schmidt IM, Chellakooty M, Virtanen HE, et al. 2006. Hormonal changes in 3-month-old cryptorchid boys. J Clin Endocrinol Metab 91:953-958.
Talsness CE, Shakibaei N, Kuriyama SN, Grande SW, Sterner-Kock A, Schnitker P, et al. 2005. Ultra structural changes observed in rat ovaries Ovaries
The female sex organs that make eggs and female hormones.
Mentioned in: Choriocarcinoma
ovaries (ō´v following in uteroand lactational exposure to low doses of a polybrominated flame retardant. Toxicol Lett 157:189-202.
Toppari J. 2003. Physiology and disorders of testicular descent. Endocr Dev 5:104-109.
Virtanen HE, Tapanainen AE, Kaleva MM, Suomi AM, Main KM, Skakkebaek NE, et al. 2006. Mild gestational diabetes Gestational Diabetes Definition
Gestational diabetes is a condition that occurs during pregnancy. Like other forms of diabetes, gestational diabetes involves a defect in the way the body processes and uses sugars (glucose) in the diet. as a risk factor for congenital cryptorchidism. J Clin Endocrinol Metab 91:4862-4865.
Waliszewski SM, Aquirre AA, Infanzon RM, Silva CS, Siliceo J. 2001. Organochlorine pesticide levels in maternal adipose tissue, maternal blood serum Blood serum
A component of blood.
Mentioned in: Bites and Stings
the residual fluid of blood after clotting has occurred. It is plasma after the fibrinogen has been removed. , umbilical blood serum, and milk from inhabitants
The game is based loosely on the concepts from SameGame. of Veracruz, Mexico. Arch Environ Contam Toxicol 40:432-438.
Watanabe I, Tatsukawa R. 1987. Formation of brominated dibenzofurans from the photolysis photolysis
Breakdown of molecules into smaller units via absorption of light. Flash photolysis, an experimental technique developed by Manfred Eigen, Ronald George Weyford Norrish, and George Porter, studies short-lived chemical intermediates formed in many photochemical of flame-retardant deca-bromodiphenyl ether in hexane solution by UV and sunlight. Bull Environ Contam Toxicol 39:953-959.
World Medical Association. 2000. Declaration of Helsinki For the political accords, see .
. There is also another Declaration of Helsinki, dealing with the Information Society. Introduction
The Declaration of Helsinki, was developed by the World Medical Association : Ethical principles for medical research involving human subjects. Bull Med Eth 162:8-11.
Katharina Maria Main, (1) Hannu Kiviranta, (2) Helena Eeva Virtanen, (3) Erno Sundqvist, (3) Jouni Tapio Tuomisto, (2) Jouko Tuomisto, (2) Terttu Vartiainen, (2),(4) Niels Erik Skakkebaek, (1) and Jorma Toppari (1),(3)
(1) University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark; (2) National Public Health Institute, Department of Environmental Health, Kuopio, Finland; (3) Departments of Physiology and Paediatrics, University of Turku For The university founded in 1640, see .
The Royal Academy of Turku
Address correspondence to K.M. Main, University Department of Growth and Reproduction, Section 5064, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. Telephone: (+45) 3545-5085. Fax: (+45) 3545-6054. E-mail: katharina.main@ rh.regionh.dk
Children were examined by members of The Nordic Cryptorchidism Study Group: in Denmark,K.A. Boisen, M. Chellakooty,I.N. Damgaard, andI.M. Schmidt; in Finland, M.M. Kaleva and A.-M.Suomi.
This study was supported by the European Commission (QLK4-CT-1999-01422, QLK4-CT-2001-00269, QLK4-2002-0063); The Danish Medical Research Council (9700833, 9700909); the Svend Andersen's, Velux, and Novo Nordisk Foundations; The Turku University Central Hospital; Sigrid Juselius Foundation; and the Academy of Finland The Academy of Finland (Finnish: Suomen Akatemia) is a governmental funding body for scientific research in Finland. It is based in the Finnish capital, Helsinki. Yearly, the Academy administers over 200 million euros to Finnish research activities. Over 3. .
The sponsors had no part in study design, data collection, analysis, interpretation, or writing of the manuscript. The article does not represent the opinion of the European Commission, which is not responsible for any use that might be made of data appearing therein.
The authors declare they have no competing financial interests.
Received 24 November 2006; accepted 30 May 2007.