Effects of prenatal exposure to polychlorinated biphenyls and dioxins on mental and motor development in Japanese children at 6 months of age.Several studies have shown that prenatal prenatal /pre·na·tal/ (-na´tal) preceding birth. pre·na·tal adj. Preceding birth. Also called antenatal. prenatal preceding birth. and/or postnatal postnatal /post·na·tal/ (-na´t'l) occurring after birth, with reference to the newborn. post·na·tal adj. Of or occurring after birth, especially in the period immediately after birth. background-level exposure to environmental chemicals, such as polychlorinated biphenyls polychlorinated biphenyls, (pol´ēklôr´  nā´tid bīfē´n (PCBs) and dioxins, induces adverse effects on
the neurodevelopment of children. However, other studies have not
detected any harmful influences on neurodevelopment. Furthermore, except
in western countries, no developmental tests have been carried out in
relation to detailed assessment of exposure to PCBs and dioxins. In this
study (the Hokkaido Study on Environment and Children's Health Children's Health DefinitionChildren's health encompasses the physical, mental, emotional, and social well-being of children from infancy through adolescence. ), the effect of prenatal exposure to background levels of PCBs and dioxins on infant neurodevelopment in Japan/Sapporo was elucidated. The associations between the total or individual isomer isomer (ī`səmər), in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of such compounds. level of PCBs and dioxins in 134 Japanese pregnant women's peripheral blood peripheral blood Cardiology Blood circulating in the system/body and the mental or motor development of their 6-month-old infants were evaluated using the second edition of the Bayley Scales of Infant Development Bay·ley Scales of Infant Development pl.n. Standardized tests used to assess the mental, motor, and behavioral progress of children during the first two and one-half years of life. . The mean level of total toxicity toxicity /tox·ic·i·ty/ (tok-sis´i-te) the quality of being poisonous, especially the degree of virulence of a toxic microbe or of a poison. equivalency equivalency the combining power of an electrolyte. See also equivalent. quantity (TEQ TEQ Toxicity Equivalent TEQ Time Domain Equalizer TEQ Teacher Education Quarterly TEQ Terra Est Quaestuosa (web-based game, Spanish: Lland is Profitable) TEQ The Evil Quakkers (gaming clan) ) was 18.8 (4.0-51.2) pg/g lipid lipid Any of a diverse class of organic compounds, found in all living things, that are greasy and insoluble in water. One of the three large classes of substances in foods and living cells, lipids contain more than twice as much energy (calories) per unit of weight as the in blood of 134 mothers. After adjustment for potential confounding variables A confounding variable (also confounding factor, lurking variable, a confound, or confounder) is an extraneous variable in a statistical or research model that should have been experimentally controlled, but was not. , the total TEQ value was shown not to be significantly associated with mental developmental index (MDI (1) (Multiple Document Interface) A Windows function that allows an application to display and lets the user work with more than one document at the same time. ) or psychomotor psychomotor /psy·cho·mo·tor/ (si?ko-mo´ter) pertaining to motor effects of cerebral or psychic activity. psy·cho·mo·tor adj. 1. developmental index (PDI PDI Protein Disulfide Isomerase PDI Personal Docente e Investigador (Spanish: Personal Educational and Investigating) PDI Pre Delivery Inspection PDI Professional Development Institute ). However, the levels of one polychlorinated dibenzo-p-dioxin (PCDD PCDD Polychlorinated Dibenzodioxins ) isomer, total PCDDs, and total PCDDs/polychlorinated dibenzofurans (PCDFs) were significantly negatively associated with MDI, and the levels of two PCDD isomers isomers (ī´sōmurz), n.pl 1. organic compounds having the same empirical formula–i.e. and three PCDF PCDF Polychlorinated Dibenzofurans PCDF Polychlorodibenzofuran PCDF People Centered Development Forum isomers were significantly negatively associated with the PDI. In conclusion, the background-level exposure of several isomers of dioxins during the prenatal period probably affects the motor development of 6-month-old infants more than it does their mental development. Key words: dioxins, infant development, maternal MATERNAL. That which belongs to, or comes from the mother: as, maternal authority, maternal relation, maternal estate, maternal line. Vide Line. blood, polychlorinated biphenyls (PCBs), prenatal exposure. doi: 10.1289/ehp.8614 available via http://dx.doi.org/[Online 15 December 2005] ********** Polychlorinated biphenyls (PCBs) and dioxins are persistent environmental pollutants environmental pollutants, n.pl the substances and conditions, including noise, that adversely affect the health and well-being of the people within a community. that occur in the environment. They have varying influences on the human body. Some harmful influences of prenatal and/or postnatal exposure to PCBs and dioxins on the neurodevelopment of infants have previously been shown. Longitudinal studies longitudinal studies, n.pl the epidemiologic studies that record data from a respresentative sample at repeated intervals over an extended span of time rather than at a single or limited number over a short period. have also been performed in both low-level (background-level) dioxin-contaminated areas and high-level 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. areas to demonstrate the effects of these pollutants pollutants see environmental pollution. on the neurodevelopment of children. Dozens of studies in background-level contaminated areas have been performed since the latter half of the 1980s, such as the North Carolina North Carolina, state in the SE United States. It is bordered by the Atlantic Ocean (E), South Carolina and Georgia (S), Tennessee (W), and Virginia (N). Facts and Figures Area, 52,586 sq mi (136,198 sq km). Pop. (USA) study (Gladen and Rogan 1991; Gladen et al. 1988, 2000; Rogan and Gladen 1991; Rogan et al. 1986), the Netherlands two-cities study (Huisman et al. 1995a, 1995b; Koopman-Esseboom et al. 1996; Lanting et al. 1998; Patandin et al. 1999; Vreugdenhil et al. 2002a, 2002b, 2004a, 2004b), the Dtisseldorf, Germany, study (Walkowiak et al. 2001; Winneke et al. 1998), and the U.S. 11-cities study (Daniels et al. 2003; Gray et al. 2005). The Bayley Scales of Infant Development (BSID BSID British Society for Investigative Dermatology BSID Bayley Scale of Infant Development BSID Brenodi Sixth Infantry Division (gaming) BSID Bachelor of Science in Industrial Design BSID Bay Station Identification ) or the BSID second edition (BSID-II) was used in all of these studies to evaluate infants' mental or motor development. As a result, the prenatal and/or postnatal exposure was shown to have a significant negative association with motor development during infancy infancy, stage of human development lasting from birth to approximately two years of age. The hallmarks of infancy are physical growth, motor development, vocal development, and cognitive and social development. , whereas significant associations were not found in young children (Gladen and Rogan 1991; Gladen et al. 1988; Koopman-Esseboom et al. 1996; Patandin et al. 1999; Rogan and Gladen 1991; Vreugdenhil et al. 2002a, 2004a). On the other hand, only one study showed a significant negative association between postnatal exposure and the cognitive development of young children (Walkowiak et al. 2001). In addition, another study showed a positive association between prenatal exposure and motor development during infancy in some of the diverse study sites across 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. (Daniels et al. 2003). Thus, consistent results relating to relating to relate prep → concernant relating to relate prep → bezüglich +gen, mit Bezug auf +acc the influence of background-level dioxin dioxin Aromatic compound, any of a group of contaminants produced in making herbicides (e.g., Agent Orange), disinfectants, and other agents. Their basic chemical structure consists of two benzene rings connected by a pair of oxygen atoms; when substituents on the rings are exposure on children's development have not been obtained. Longnecker et al. (2003) suggested that interpretation of human data regarding low-level, early-life PCB PCB: see polychlorinated biphenyl. PCB 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. exposure and subsequent neurodevelopment was problematic because levels of exposure were not similarly quantified across studies. In Japan, Tada and Nakamura (2000) examined the mental development of 1-year-old breast-fed breast·feed or breast-feed v. breast-fed , breast-feed·ing, breast-feeds v.tr. To feed (a baby) mother's milk from the breast; suckle. v.intr. To breastfeed a baby. infants and bottle-fed infants and reported that their mental development was within a normal range. However, this report was not based on detailed developmental tests such as BSID. Nagayama et al. (2004) examined the association between hexachlorocyclohexane, heptachlor heptachlor: see insecticides. epoxide epoxide /epox·ide/ (e-pok´sid) an organic compound containing a reactive group resulting from the union of an oxygen atom with two other atoms, usually carbon, that are themselves joined together. , chlordane chlordane (klōr`dān): see insecticide. , dieldrin dieldrin: see insecticides. , dichlorodiphenyltrichloroethane di·chlo·ro·di·phen·yl·tri·chlo·ro·eth·ane n. DDT. (DDT DDT or 2,2-bis(p-chlorophenyl)-1,1,1,-trichloroethane, chlorinated hydrocarbon compound used as an insecticide. First introduced during the 1940s, it killed insects that spread disease and feed on crops. ), PCBs, or dioxin in breast milk and the development of infants at 10 months. In that study, the authors evaluated the associations using the Enjohji Scales of Infant Development and reported that a significant negative association existed between PCBs and the development of comprehension comprehension Act of or capacity for grasping with the intellect. The term is most often used in connection with tests of reading skills and language abilities, though other abilities (e.g., mathematical reasoning) may also be examined. . The developmental tests that were used in these two studies were different from those of previous studies, and it was not possible to perform detailed evaluations. An additional problem was that detailed exposure measurements had not been performed in these studies. The aim of the present study was to examine the influence of environmental chemicals such as PCBs and dioxins on the mental and motor development of infants of the next generation in Sapporo, Japan. Consequently, we carried out detailed measurements of the levels of PCBs and dioxins in the mothers' peripheral blood and performed ncurodevelopmental assessments of their 6-month-old infants using BSID-II to examine the influence of prenatal exposure of these pollutants on the neurodevelopment of infants. Materials and Methods Study population. We recruited pregnant women between July 2002 and July 2004 from the Sapporo Toho Hospital in Hokkaido, Japan (this study became known as the Hokkaido Study on Environment and Children's Health). All the subjects were native Japanese and were resident in Sapporo and the surrounding sur·round tr.v. sur·round·ed, sur·round·ing, sur·rounds 1. To extend on all sides of simultaneously; encircle. 2. To enclose or confine on all sides so as to bar escape or outside communication. n. areas. The subjects completed the self-administered questionnaire survey after the second trimester Noun 1. second trimester - time period extending from the 13th to the 27th week of gestation trimester - a period of three months; especially one of the three three-month periods into which human pregnancy is divided during their last pregnancy. The questionnaire provided information relating to their dietary habits, exposure to chemical compounds in their daily life and at their work site, home environment, smoking, and medical histories of themselves and their partners. The prenatal information of the mothers and their children was collected from their medical records. This study was conducted with all the subjects' written informed consent and was approved by the institutional ethical board for epidemiologic studies epidemiologic study A study that compares 2 groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect; the investigators try to determine if any factor is associated with the health effect at Hokkaido University History Hokkaido University (Hokudai for short) was originally founded in 1876 as Sapporo Agricultural College (札幌農學校 Graduate School of Medicine. Exposure measures. A 40-mL blood sample was taken from the maternal peripheral vein Peripheral Veins are the veins not in the chest or abdomen (i.e. in the arms, hands, legs and feet). These veins lead deoxygenated blood from the capillaries in the extremities back to the heart. after the second trimester during their last pregnancy. When we were not able to take mother's blood due to the mother's anemia anemia (ənē`mēə), condition in which the concentration of hemoglobin in the circulating blood is below normal. Such a condition is caused by a deficient number of erythrocytes (red blood cells), an abnormally low level of hemoglobin during pregnancy, we took the blood during hospitalization hospitalization /hos·pi·tal·iza·tion/ (hos?pi-t'l-i-za´shun) 1. the placing of a patient in a hospital for treatment. 2. the term of confinement in a hospital. after delivery. All samples were stored at -80[degrees]C until analysis. The concentrations of PCBs and dioxins in the maternal blood were measured using high-resolution gas chromatography/high-resolution mass spectrometry mass spectrometry or mass spectroscopy Analytic technique by which chemical substances are identified by sorting gaseous ions by mass using electric and magnetic fields. (HRGC/HRMS) equipped with a solvent-cut large-volume injection system (SGE SGE Sun Grid Engine (cluster computing) SGE Starport: Galactic Empires (online game) SGE Siegerland Airport (Airport Code) SGE Small Group Evaluation SGE Support Group Europe Ltd., Victoria, Australia) at Fukuoka Institute of Health and Environmental Sciences. The gas chromatograph gas chromatograph n. An instrument used in gas chromatography to separate a sample of a volatile substance into its components. was an Agilent 6890 (Agilent Technologies This article needs sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article. Inc., Palo Alto Palo Alto, city, California Palo Alto (păl`ō ăl`tō), city (1990 pop. 55,900), Santa Clara co., W Calif.; inc. 1894. Although primarily residential, Palo Alto has aerospace, electronics, and advanced research industries. , CA, USA) equipped with an AutoSpecUltima NT (Micromass Ltd., Manchester, UK). The levels of PCBs and dioxins were measured in each isomer [seven polychlorinated dibenzo-p-dioxins (PCDDs): 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD TCDD tetrachlorodibenzodioxin. ), 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,6,7,8-HxCDD, 1,2,3,7,8,9-HxCDD, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD), octachlorodibenzo-p-dioxin (OCDD OCDD Office for Citizens with Developmental Disabilities (Louisiana State Department of Health and Hospitals) OCDD 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin OCDD Orthonormal Code Diversity Detection ); 10 polychlorinated dibenzofurans (PCDFs): 2,3,7,8-tetrachlorodibenzofuran (TCDF TCDF Tetrachlorodibenzofuran ), 2,3,7,8-pentachlorodibenzofuran (PeCDF), 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-hexachlorodibenzofuran (HxCDF), 1,2,3,6,7,8-HxCDF, 2,3,4,6,7,8-HxCDF, 1,2,3,7,8,9-HxCDF, 1,2,3,4,6,7,8-heptachlorodibenzofuran, 1,2,3,4,7,8,9-HpCDF, octachlorodibenzofuran (OCDF OCDF Optical Cable Distributor Fiber OCDF OBI Continuous Data Feed (financial market data realtime feed; Oslo, Norway) ); four non-ortho PCBs: 3,3',4',4'-tetracholorobiphenyl (TCB See trusted computing base. 1. (jargon) TCB - Trouble Came Back. 2. (security) TCB - (Orange Book) Trusted Computing Base. 3. (operating system) TCB - Task Control Block. ) (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 77), 3,4,4',5-TCB (congener 81), 3,3',4,4',5-pentachlorobiphenyl (PeCB) (congener 126), 3,3',4,4',5,5'-hexachlorobiphenyl (HxCB) (congener 169); eight mono-ortho PCBs: 2,3,3'4,4'-PeCB (congener 105), 2,3,4,4',5-PeCB (congener 114), 2,3',4,4',5-PeCB (congener 118), 2',3,4,4',5-PeCB (congener 123), 2,3,3',4,4',5-HxCB (congener 156), 2,3,3',4,4',5'-HxCB (congener 157), 2,3',4,4'5,5'-HxCB (congener 167), 2,3,3',4,4',5,5'-heptachlorobiphenyl (HpCB) (congener 189); and two di-ortho PCBs: 2,2'3,3',4,4',5-HpCB (congener 170), 2,2',3,4,4',5,5'-HpCB (congener 180)], and the total toxicity equivalency quantity (TEQ) levels were calculated (Iida and Todaka 2003; Todaka et al. 2003). Furthermore, for several subjects, 68 PCBs (including mono-ortho PCBs), which remained behind in the blood, were measured using HRGC/HRMS. Developmental measures. We used BSID-II (Bayley 1993) to assess the infants' mental and psychomotor development Noun 1. psychomotor development - progressive acquisition of skills involving both mental and motor activities growing, growth, ontogenesis, ontogeny, maturation, development - (biology) the process of an individual organism growing organically; a purely biological (mental, motor) at 6 months of age. BSID-II is a developmental test tool that is standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. for use in the United States and is most widely used as an infant assessment instrument in both clinical and research settings in the United States. The BSID-II mental scale assesses the age-appropriate children's level of cognitive, language, and personal/social development. The motor scale assesses fine and gross motor development. Mental and motor scores are based on the calibration calibration /cal·i·bra·tion/ (kal?i-bra´shun) determination of the accuracy of an instrument, usually by measurement of its variation from a standard, to ascertain necessary correction factors. scale from raw score and are represented as index scores. The mean values of the mental developmental index (MDI) and the psychomotor developmental index (PDI) were 100, and the standard deviation In statistics, the average amount a number varies from the average number in a series of numbers. (statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. was 15. Although BSID-II has a lot of strengths and weaknesses (Bayley 1993), it is a most useful test to measure the present attainment of developmental abilities of normal children (Bradley-Johnson 2001). Because BSID-II was not standardized in Japan, we translated a BSID-II manual in consultation with a manual for BSID, which was used in the development study reported by Kato et al. (1987, 1988). The children were brought to the community center in Sapporo, where they were tested in a quiet, private room in the presence of the parent(s) by one examiner. The development evaluation was performed by three occupational therapists occupational therapist A person trained to help people manage daily activities of living–dressing, cooking, etc, and other activities that promote recovery and regaining vocational skills Salary $51K + 4% bonus. See ADL. who have clinical experience in the field of developmental disabilities developmental disabilities (DD), n.pl the pathologic conditions that have their origin in the embryology and growth and development of an individual. DDs usually appear clinically before 18 years of age. . The examiners were unaware of the infants' PCB and dioxin exposure levels. First, for all examined children, the scoring was performed by the examiner who performed the examination, and then the scoring was double-checked by two other examiners based on a video that recorded the examination. We investigated the environmental conditions of the subjects using the questionnaire of home environment devised by Anme et al. (1997). Data analysis. We used the following eligibility criteria for analysis of subjects: no serious illnesses or complications during pregnancy and delivery, singleton sin·gle·ton n. An offspring born alone. singleton Medtalk One baby. Cf Triplet, Twin. babies born at term (37-42 weeks' gestation GESTATION, med. jur. The time during which a female, who has conceived, carries the embryo or foetus in her uterus. By the common consent of mankind, the term of gestation is considered to be ten lunar months, or forty weeks, equal to nine calendar months and a week. ), Apgar score Ap·gar score n. A system of evaluating a newborn's physical condition by assigning a value (0, 1, or 2) to each of five criteria: heart rate, respiratory effort, muscle tone, response to stimuli, and skin color. of > 7 at 1 min, infants without congenital anomalies congenital anomaly n. See birth defect. or diseases, and BSID-II completed. We performed multiple-regression analysis to examine the association between BSID-II scores (MDI, PDI) and the levels of PCBs and dioxins in maternal blood. The levels of PCBs and dioxins in maternal blood were logarithmically log·a·rithm n. Mathematics The power to which a base, such as 10, must be raised to produce a given number. If nx = a, the logarithm of a, with n as the base, is x; symbolically, logn a = x. transformed, and the analysis was adjusted for gestational age ges·ta·tion·al age n. See estimated gestational age. Gestational age The estimated age of a fetus expressed in weeks, calculated from the first day of the last normal menstrual period. (days), smoking during pregnancy, and caffeine caffeine (kăfēn`), odorless, slightly bitter alkaloid found in coffee, tea, kola nuts (see cola), ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (see cacao). intake during pregnancy (milligrams per day). When we examined the levels of PCBs and dioxins among blood sampling time (during pregnancy and after delivery) by the Mann-Whitney test, there were significant differences in the levels of OCDD (p < 0.001), 1,2,3,4,6,7,8-HpCDD (p < 0.001), total PCDDs (p < 0.01), and total PCDDs/PCDFs (p < 0.05) (data not shown). So the blood sampling time was adjusted in multiple regression Multiple regression The estimated relationship between a dependent variable and more than one explanatory variable. analysis. Results were considered significant if p < 0.05. Results One hundred thirty-five Adj. 1. one hundred thirty-five - being five more than one hundred thirty 135, cxxxv cardinal - being or denoting a numerical quantity but not order; "cardinal numbers" mother-infant pairs fulfilled ful·fill also ful·fil tr.v. ful·filled, ful·fill·ing, ful·fills also ful·fils 1. To bring into actuality; effect: fulfilled their promises. 2. the determined eligibility criteria of this study; they completed exposure measurements and BSID-II. One pair was excluded from the study because the PCB and dioxin levels in the maternal blood were extremely high. So, in total, 134 mother-infant pairs were included in the study. Characteristics of mothers and infants are presented in Table 1. The mean (+ SD) maternal age maternal age, n the age of the mother at the period of conception. was 31.1 [+ or -] 4.7 years; 13.4% of mothers continued smoking during pregnancy. Forty-four percent of mothers ate inshore in·shore adv. & adj. 1. Close to a shore. 2. Toward or coming toward a shore. inshore Adjective in or on the water, but close to the shore: fish during pregnancy at least once per week, and 58.2% of mothers ate deep-sea fish during pregnancy at least once per week. Fifty percent of infants were first-born, and 58.2% of infants had been breast-fed > 3 months. The mean scores of MDI and PDI were 91.9 [+ or -] 5.8 and 89.3 [+ or -] 10.5, respectively. Both values were lower than the standardized score. The relationships between MDI and PDI scores and the subjects' characteristics are presented in Table 2. For mothers' characteristics, caffeine intake during pregnancy was significantly negatively associated with PDI scores (r = -0.177, p = 0.04). For infants' characteristics, gestational age (days) was significantly positively associated with MDI scores (r = 0.178, p = 0.039) and PDI scores (r= 0.289,p = 0.001). The levels of PCBs and dioxins (picogram picogram /pi·co·gram/ (pg) (pi´ko-gram) one-trillionth (10-12) of a gram. pi·co·gram n. Abbr. pg One-trillionth (10-12) of a gram. per gram lipid) in maternal blood are presented in Table 3. For subjects with a level below the detection limit, we used a value equal to half the detection limit (Longnecker et al. 2000). The means (ranges) of levels of total PCDD/PCDF TEQ, total coplanar co·pla·nar adj. Lying or occurring in the same plane. Used of points, lines, or figures. co  pla·nar PCB TEQ, and total TEQ were 11.9
(2.1-31.2), 6.9 (1.1-22.2), and 18.8 (4.0-51.2) pg TEQ/g lipid,
respectively. The mean level of dioxins in this study was slightly lower
than that of the subjects in other studies of domestic areas with ages
similar to that in this study. In addition, the median level of PCB-153
in the maternal blood of 64 subjects in this study was 22.9 ng/g lipid,
which was lower than that in the previous study (Longnecker et al.
2003).Table 4 shows the results of the multiple regression analysis of the association between the levels of PCBs and dioxins in maternal blood and MDI and PDI scores. After adjustment for blood sampling time, gestational age (days), smoking during pregnancy, and caffeine intake during pregnancy (milligrams per day), PCDD isomer 1,2,3,4,6,7,8-HpCDD (p < 0.05), total PCDDs (p < 0.01), and total PCDDs/PCDFs (p < 0.05) were significantly negatively associated with MDI. On the other hand, PCDD isomers 1,2,3,7,8,9-HxCDD (p < 0.05) and 1,2,3,4,6,7,8-HpCDD (p < 0.01), 2,3,7,8-TCDF (p < 0.05), 1,2,3,7,8-PeCDF (p < 0.05), and PCDF isomer 1,2,3,6,7,8-HxCDF (p < 0.05) were significantly negatively associated with PDI. The total levels of PCBs and dioxins were not significantly associated with PDI, and the TEQ values were not significantly associated with MDI or PDI. Discussion To the best of our knowledge, this is the first report to investigate the association between the early neurodevelopment of infants and the total level and individual isomer level of Japanese pregnant women's blood at background levels. As a result, there was no association between the TEQ value of the maternal blood and the PCB/dioxin level, whereas the levels of several isomers of dioxins were significantly negatively associated with mental or motor development. The total levels of PCDDs or PCDDs/PCDFs were significantly associated with mental development, whereas the levels of several specific isomers of PCDDs or PCDFs were associated with motor development. In this study, the results of BSID-II were used as a neurodevelopment evaluation test for infants. The mean ([+ or -] SD) MDI and PDI scores were 91.9 [+ or -] 5.8 and PDI 89.3 [+ or -] 10.5, respectively. Both scores were lower than the standardized scores (100). Because there is a cultural difference and a verbal difference between Japan and the United States, the BSID-II must be used with care in Japan. In particular, we should use standardized "classification" to judge how to treat or intervene intervene v. to obtain the court's permission to enter into a lawsuit which has already started between other parties and to file a complaint stating the basis for a claim in the existing lawsuit. with a child. However, the first BSID edition was used in Japan for developmental evaluation of children. In addition, Oka et al. (2005) reported that there was a high correlation between BSID-II and the Kyoto Developmental Test that was standardized in Japan. A study in Taiwan stated that reproducibility reproducibility Lab medicine The degree of agreement among repeated measurements of a particular parameter, presented in terms of a standard deviation or coefficient of variation of the results in a set of measurements was high in BSID-II, even if there were cultural differences (Huang et al. 2000). Evaluation of neurodevelopment was limited to 6-month-old infants, and all the examiners scored all the infant subjects. Therefore, the BSID-II scores of the subjects in this study were directly comparable with each other. The mean (range) level of PCBs and dioxins in maternal blood was 18.8 (4.0-51.2) pg TEQ/g lipid in this study, lower than that of subjects in studies in other domestic areas (Watanabe 2000). Longnecker et al. (2003) reported that interpretation of human data regarding low-level, early-life PCB exposure and subsequent neurodevelopment was problematic because levels of exposure were not similarly quantified across studies. Therefore, the PCB levels across studies of neurodevelopment were expressed in a uniform manner using the median level of PCB-153 in maternal pregnancy serum. The median PCB-153 level in the U.S. 11-cities, the Dusseldorf, the Netherlands two-cities, and the North Carolina studies ranged from 80 to 140 ng/g lipid, which were within the range of background levels. The median level of PCB-153 in the maternal blood of 64 subjects in this study was 22.9 ng/g lipid, which was clearly a lower contamination level in comparison with the other studies. In this study, there was no significant association between the TEQ values of maternal blood PCB/dioxin level and mental and motor development, whereas there were significant negative associations with the levels of some isomers of dioxins and mental and motor development. The total levels of PCDDs or PCDDs/PCDFs were significantly associated with mental development, whereas the levels of several specific isomers of PCDDs or PCDFs were associated with motor development. There are many previous studies (Gladen et al. 1988; Koopman-Esseboom et al. 1996; Walkowiak et al. 2001) that show negative influences on the motor development of infants and young children rather than on their mental development. Although we used only the total PCB level or TEQ value as the exposure index in previous studies, we measured various levels of isomers of PCBs or dioxins in this study. In this study, there were no significant negative associations between the total levels of PCBs and dioxins and mental or motor development, whereas there were significant negative associations between motor development and levels of isomers of PCDDs and PCDFs. In this respect, it was impossible to explain the mechanism of our findings because there were few human or animal experimental studies investigating the association between individual isomer levels of PCBs and dioxins and neurodevelopment. So, at low-level exposure, total, and total TEQ values had only a minimal effect on mental and motor development. However, we found that several specific chemical compounds would have an adverse influence on motor development, whereas total PCDDs or total PCDDs/PCDFs would have an adverse influence on mental development. Gray et al. (2005) reported that the level of total PCBs in mothers in their study, which did not show a significantly negative association with the level of total PCBs and the outcome, was similar to those in other studies in which an adverse effect was found. On the other hand, the mixture of PCBs in their specimens was unusual compared with that in other studies. Levels of non-quantitated PCBs may also have varied in biologically significant ways. Thus, they speculated that they might have had a relatively benign benign /be·nign/ (be-nin´) not malignant; not recurrent; favorable for recovery. be·nign adj. Of no danger to health, especially relating to a tumorous growth; not malignant. mixture if the composition of PCBs affected neurotoxicity neurotoxicity /neu·ro·tox·ic·i·ty/ (noor?o-tok-sis´it-e) the quality of exerting a destructive or poisonous effect upon nerve tissue. . Therefore, the minimal effect of total and total TEQ values on mental and motor development in this study might be caused by the composition of PCBs and dioxins. In this study, we performed multiple-regression analysis to examine the association between BSID-II scores (MDI, PDI) and total and individual isomer level of PCBs and dioxins. Because we performed 45 statistical tests for MDI or PDI, this study had a multiple-testing problem. If we performed the Bonferroni adjustment for addressing the multiple-testing problem, all the significances would have disappeared. Furthermore, this study has a small sample size. These are the limitations of this study. However, because the measurement of PCBs and dioxins is highly complicated and is too expensive, it is difficult to measure these compounds in a large number of subjects. In recent studies of the associations between background-level exposure to PCBs and dioxins and infant neurodevelopment (Koopman-Esseboom et al. 1996; Walkowiak et al. 2001), the sample size was similar to our study. However, no studies have measured isomer levels of PCBs and dioxins to analyze the associations between individual isomer levels and infant neurodevelopment. Because exposure to PCBs and dioxins can be reduced to prevent their adverse effects on children's development, even if the [alpha] error rate rises to some extent, we consider it important to catch these adverse effects on children's development. Therefore, we believe that analysis of the associations between PCBs and dioxins and children's development in this study was valuable. In Japan, Nakai et al. (2004) also performed a prospective study to elucidate e·lu·ci·date v. e·lu·ci·dat·ed, e·lu·ci·dat·ing, e·lu·ci·dates v.tr. To make clear or plain, especially by explanation; clarify. v.intr. To give an explanation that serves to clarify. the influence of an endocrine-disrupting chemical on the neurodevelopment of children. Humans are the main source of various chemical compounds that are known pollutants, and food seems to be the main source of PCBs and dioxins in background-level exposure. Because the intake of marine products, such as fish or iodine iodine (ī`ədīn, –dĭn) [Gr.,=violet], nonmetallic chemical element; symbol I; at. no. 53; at. wt. 126.9045; m.p. 113.5°C;; b.p. 184.35°C;; sp. gr. 4.93 at 20°C;; valence −1, +1, +3, +5, or +7. , in an island country such as Japan would be greater than in western countries, a risk evaluation based on domestic dioxin/PCB data is important. Vreugdenhil et al. (2002b) pointed out that an improving tendency was shown in children of school age, even if there was a significant negative association between endocrine-disrupting chemical level and neurodevelopment of children during infancy. Breast-feeding breast-feeding /breast-feed·ing/ (brest´fed?ing) nursing; the feeding of an infant at the mother's breast. and a good home environment are regarded as important factors that improve the influence. Additional studies are needed to elucidate these results still further. Received 29 August 2005; accepted 15 December 2005. 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PCBs, DDE (Dynamic Data Exchange) A message protocol in Windows that allows application programs to request and exchange data between them automatically. DDE - Dynamic Data Exchange , and child development at 18 and 24 months. Ann Epidemiol 1:407-413. Rogan WJ, Gladen BC, McKinney JD, Carreras N, Hardy P, Thullen J, et al. 1986. Neonatal effects of transplacental transplacental /trans·pla·cen·tal/ (-plah-sen´tal) through the placenta. trans·pla·cen·tal adj. Relating to or involving passage through or across the placenta. exposure to PCBs and DDE. J Pediatr 109:335-341. Tada H, Nakamura Y. 2000. Dioxin in breast milk [in Japanese]. Food Sanit Res 50:16-18. Todeka T, Hirakawa H, Tobiihi K, lida T. 2003. New protocol of dioxins analysis in human blood. Fukuoke Igaku Zesshi 94:148-157. Van den Berg Van den Berg is the surname of:
Vreugdenhil H J, Lanting CI, Mulder PG, Boersme ER, Weisglas-Kuperus N. 2002a. Effects of prenatal PCB and dioxin background exposure on cognitive and motor abilities in Dutch children at school age. J Pediatr 140:48-56. Vreugdenhil HJ, Mulder PG, Emmen HH, Weisglas-Kuperus N. 2004a. Effects of perinatal exposure to PCBs on neuropsychological neu·ro·psy·chol·o·gy n. The branch of psychology that deals with the relationship between the nervous system, especially the brain, and cerebral or mental functions such as language, memory, and perception. functions in the Rotterdam cohort cohort /co·hort/ (ko´hort) 1. in epidemiology, a group of individuals sharing a common characteristic and observed over time in the group. 2. at 9 years of age. Neuropsychology neuropsychology Science concerned with the integration of psychological observations on behaviour with neurological observations on the central nervous system (CNS), including the brain. 18:185-193. Vreugdenhil HJ, Slijper FM, Lanting CI, Mulder PG, Weisglas-Kuperus N. 2002b. Effects of perinatal exposure to PCB and dioxin on play behavior in Dutch children at school age. Environ Health Perspect 110:A593-A598. Vreugdenhil HJ, Van Zanten GA, Brocaar MP, Mulder PG, Weisglas-Kuperus N. 2004b. Prenatal exposure to polychlorinated biphenyls end breastfeeding: opposing effects on auditory auditory /au·di·to·ry/ (aw´di-tor?e) 1. aural or otic; pertaining to the ear. 2. pertaining to hearing. au·di·to·ry adj. P300 latencies in 9-year-old Dutch children. Dev Med Child Neurol 46:398-405. Walkowiak J, Wiener JA, Fastabend A, Heinzow B, Kramer U, Schmidt E, et al. 2001. Enviromental exposure to polychlorinated biphenyls and quality of the home environment: effects on psychodevelopment in early childhood. Lancet lancet /lan·cet/ (lan´set) a small, pointed, two-edged surgical knife. lan·cet n. 358:1602-1607. Watanabe S. 2000. Dioxin exposure and health effects among Japanese [in Japanese]. Food Sanit Res 50:8-10. Winneke G, Bucholski A, Heinzow B, Kramer U, Schmidt E, Walkowiak J, et al. 1998. Developmental neurotoxicity of polychlorinated biphenyls (PCBS): cognitive and psychomotor functions in 7-month old children. Toxicol Lett 102-103:423-428. Sonomi Nakajima, (1,2) Yasuaki Saijo, (1) Shizue Kato, (1) Seiko Sasaki, (1) Akiko Uno, (1) Nobuo Kanagami, (3) Hironori Hirakawa, (4) Tsuguhide Hori, (4) Kazuhiro Tobiishi, (4) Takashi Todaka, (5) Yuji Nakamura, (6) Satoko Yanagiya, (6) Yasuhito Sengoku, (2) Takao Iida, (4) Fumihiro Sata, (1) and Reiko Kishi (1) (1) Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan; (2) Department of Occupational Therapy, School of Health Sciences, Sapporo Medical University, Sapporo, Japan; (3) Sapporo Toho Hospital, Sapporo, Japan; (4) Fukuoka Institute of Health and Environmental Sciences, Fukuoka, Japan; (5) Japan Food Hygiene hygiene, science of preserving and promoting the health of both the individual and the community. It has many aspects: personal hygiene (proper living habits, cleanliness of body and clothing, healthful diet, a balanced regimen of rest and exercise); domestic hygiene Association, Tokyo, Japan; (6) Division of Sensory sensory /sen·so·ry/ (sen´sor-e) pertaining to sensation. sen·so·ry adj. 1. Of or relating to the senses or sensation. 2. Integrative Dysfunction dysfunction /dys·func·tion/ (dis-funk´shun) disturbance, impairment, or abnormality of functioning of an organ.dysfunc´tional erectile dysfunction impotence (2). , Department of Occupational Therapy, Sapporo Medical University Graduate School of Health Sciences, Sapporo, Japan Address correspondence to S. Nakajima, Department of Public Health, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 5, Kita-ku, Sapporo Kita-ku (北区 060-8638, Japan. Telephone: 81-11-706-5068. Fax: 81-11-706-7805. E-mail address See Internet address. e-mail address - electronic mail address : sonomi@sapmed.ac.jp This study was supported by a Grant-in-Aid for Health Scientific Research from the Japan Ministry of Health, Labour and Welfare, and by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science. The authors declare they have no competing financial interests.
Table 1. Characteristics of mothers and infants (n = 134).
Characteristic No. (%)
Maternal characteristics
Age (years) 31.1 [+ or -] 4.71
Educational level (years)
[less than or equal to] 9 5 (3.7)
10-12 47 (35.1)
13-16 80 (59.7)
[greater than or equal to] 17 2 (1.5)
Economic status: annual income (yen)
< 3,000,000 21 (15.7)
3,000,000-5,000,000 60 (44.8)
5,000,000-7,000,000 37 (27.6)
7,000,000-10,000,000 13 (9.7)
> 10,000,000 3 (2.2)
Worked during pregnancy 22 (16.4)
Smoked during pregnancy 18 (13.4)
Fish intake during pregnancy
Inshore fish
Rarely/never 8 (6.0)
< 1 time/week 67 (50.0)
1-4 times/week 58 (43.3)
5 times/week 1 (0.7)
Deep-sea fish
Rarely/never 2 (1.5)
< 1 time/week 54 (40.3)
1-4 times/week 78 (58.2)
[greater than or equal to] 5 times/week 0
Caffeine intake during pregnancy 140.6 [+ or -] 91.5 (a)
(mg/day)
Alcohol intake before pregnancy 19.7 [+ or -] 71.9 (a)
(g/day)
Alcohol intake during pregnancy 0.9 [+ or -] 2.6 (a)
(g/day)
Blood sampling period
During pregnancy 86 (64.2)
After delivery 48 (35.8)
Child characteristics
Sex
Male 68 (50.7)
Female 66 (49.3)
Gestational age (days) 277.3 [+ or -] 8.1 (a)
Birth weight (g) 3124.8 [+ or -] 329.1 (a)
Length (cm) 48.2 [+ or -] 2.2 (a)
Head circumference (cm) 33.4 [+ or -] 1.2 (a)
First-born 67 (50.0)
Duration of breast-feeding, [greater
than or equal to] 3 months 78 (58.2)
Age at testing (days) 187.0 [+ or -] 4.4 (a)
BSID-II mental index score: MDI 91.9 [+ or -] 5.8 (a)
BSID-II motor index score: PDI 89.3 [+ or -] 10.5 (a)
Index of Child Care Environment (b) 22.7 [+ or -] 2.4 (a)
(a) Mean [+ or -] SD. (b) A perfect score is 30 points.
Table 2. BSID-II mental (MDI) and psychomotor (PDI) development scores
for infants in relation to mother and infant characteristics (n = 134).
MDI
Characteristic No. Mean [+ or -] SD p-value
Maternal characteristics
Age (years) r=0.042 0.626
Educational level
[less than or
equal to] 12 years 52 92.2 [+ or -] 5.0 0.647
[greater than or
equal to] 13 years 82 91.7 [+ or -] 6.2
Economic status: annual income
< 5,000,000 yen 81 91.6 [+ or -] 5.8 0.444
[greater than or equal
to] 5,000,000 yen 53 92.3 [+ or -] 5.8
Worked during pregnancy
No 112 91.5 [+ or -] 5.7 0.107
Yes 22 93.7 [+ or -] 6.0
Smoked during pregnancy
No 116 92.0 [+ or -] 5.8 0.469
Yes 18 90.9 [+ or -] 5.8
Inshore fish intake during
pregnancy
< 1 time/week; rarely/never 75 91.6 [+ or -] 6.0 0.612
[greater than or equal to] 1
time/week 59 92.2 [+ or -] 5.5
Deep-sea fish intake during
pregnancy
< 1 time/week; rarely/never 56 92.6 [+ or -] 5.3 0.198
[greater than or equal to] 1
time/week 78 91.3 [+ or -] 6.0
Caffeine intake during pregnancy
(mg/day) r=-0.063 0.470
Alcohol intake before pregnancy
(g/day) r=-0.050 0.564
Alcohol intake during pregnancy
(g/day) r=0.137 0.114
Blood sampling time
During pregnancy 86 92.0 [+ or -] 5.5 0.767
After delivery 48 91.7 [+ or -] 6.3
Child characteristics
Sex
Male 68 91.6 [+ or -] 5.8 0.595
Female 66 92.1 [+ or -] 5.8
Gestational age (days) r=0.178 0.039 *
Birth weight (g) r=0.103 0.237
Length (cm) r=0.058 0.506
Head circumference (cm) r=0.071 0.416
First-born
Yes 67 92.3 [+ or -] 6.1 0.356
No 67 91.4 [+ or -] 5.5
Duration of breast-feeding,
[greater than or equal
to] 3 months
Yes 78 92.1 [+ or -] 6.0 0.557
No 56 91.5 [+ or -] 5.5
Index of Child Care Environment r=-0.016 0.855
PDI
Characteristic Mean [+ or -] SD p-value
Maternal characteristics
Age (years) r=-0.059 0.496
Educational level
[less than or
equal to] 12 years 89.8 [+ or -] 10.8 0.676
[greater than or
equal to] 13 years 89.0 [+ or -] 10.4
Economic status: annual income
< 5,000,000 yen 89.4 [+ or -] 10.4 0.875
[greater than or equal
to] 5,000,000 yen 89.1 [+ or -] 10.7
Worked during pregnancy
No 89.1 [+ or -] 10.3 0.697
Yes 90.1 [+ or -] 11.8
Smoked during pregnancy
No 89.8 [+ or -] 10.6 0.183
Yes 86.2 [+ or -] 9.1
Inshore fish intake during
pregnancy
< 1 time/week; rarely/never 88.9 [+ or -] 11.3 0.670
[greater than or equal to] 1
time/week 89.7 [+ or -] 9.4
Deep-sea fish intake during
pregnancy
< 1 time/week; rarely/never 89.9 [+ or -] 10.6 0.542
[greater than or equal to] 1
time/week 88.8 [+ or -] 10.5
Caffeine intake during pregnancy
(mg/day) r=-0.177 0.040 *
Alcohol intake before pregnancy
(g/day) r=-0.099 0.256
Alcohol intake during pregnancy
(g/day) r=0.011 0.898
Blood sampling time
During pregnancy 88.8 [+ or -] 10.3 0.472
After delivery 90.2 [+ or -] 10.9
Child characteristics
Sex
Male 87.8 [+ or -] 9.9 0.084
Female 90.9 [+ or -] 10.9
Gestational age (days) r=0.289 0.001 *
Birth weight (g) r=0.086 0.323
Length (cm) r=-0.060 0.489
Head circumference (cm) r=-0.015 0.862
First-born
Yes 89.7 [+ or -] 10.5 0.617
No 88.8 [+ or -] 10.6
Duration of breast-feeding,
[greater than or equal
to] 3 months
Yes 89.9 [+ or -] 10.5 0.422
No 88.4 [+ or -] 10.5
Index of Child Care Environment r=-0.122 0.161
Student's t-test, Pearson's correlation
coefficient test: * p < 0.05; ** p < 0.01.
Table 3. Level of PCBs and dioxins
(pg/g lipid) in maternal blood (n = 134).
Detection Geometric
limit (a) Mean mean
PCDDs
2,3,7,8-TCDD 1.0 1.1 0.9
1,2,3,7,8-PeCDD 1.0 4.4 3.9
1,2,3,4,7,8-HxCDD 2.0 1.8 1.6
1,2,3,6,7,8-HxCDD 2.0 15.5 13.7
1,2,3,7,8,9-HxCDD 2.0 2.3 1.9
1,2,3,4,6,7,8-HxCDD 2.0 26.0 24.0
OCDD 4.0 504.7 468.0
PCDFs
2,3,7,8-TCDF 1.0 0.7 0.6
1,2,3,7,8-PeCDF 1.0 0.6 ND
2,3,4,7,8-PeCDF 1.0 6.5 5.8
1,2,3,4,7,8-HxCDF 2.0 2.6 2.3
1,2,3,6,7,8-HxCDF 2.0 3.0 2.6
2,3,4,6,7,8-HxCDF 2.0 1.1 1.1
1,2,3,7,8,9-HxCDF 2.0 ND ND
1,2,3,4,6,7,8-HpCDF 2.0 3.1 2.4
1,2,3,4,7,8,9-HpCDF 2.0 ND ND
OCDF 4.0 2.1 ND
Non-ortho PCBs
3,3',4',4'-TCB (77) 10.0 13.2 11.9
3,4,4',5-TCB (81) 10.0 ND ND
3,3',4,4',5-PeCB (126) 10.0 42.2 36.0
3,3',4,4',5,5'-HxCB (169) 10.0 31.9 28.3
Mano-ortho PCBs
2,3,3'4,4'-PeCB (105) 10.0 1637.6 1418.8
2,3,4,4',5-PeCB (114) 10.0 407.2 353.3
2,3',4,4',5-PeCB (118) 10.0 6582.0 5691.3
2',3,4,4',5-PeCB (123) 10.0 127.8 109.4
2,3,3",4,4',5-HxCB (156) 10.0 2213.2 1942.1
2,3,3',4,4',5'-HxCB (157) 10.0 557.2 485.4
2,3',4,4',5,5'-HxCB (167) 10.0 806.3 702.0
2,3,3',4,4',5,5'-HpCB (189) 10.0 244.7 209.2
Di-ortho PCBs
2,2',3,3',4,4',5-HpCB (170) 10.0 4518.4 3881.1
2,2',3,4,4',5,5'-HpCB (180) 10.0 13996.8 12063.7
Total
Total PCDDs 547.8 511.1
Total PCDFs 42.7 21.1
Total PCDDs/PCDFs 590.5 538.1
Total non-ortho PCBs 91.4 83.7
Total mono-ortho PCBs 12575.9 11042.2
Total coplanar PCBs 12667.3 11131.1
Total 13257.8 11770.9
WHO-98 (c)
Total PCDD TEQ 7.7 7.0
Total PCDF TEQ 4.2 3.8
Total PCDD/PCDF TEQ 11.9 10.9
Total non-ortho PCB TEQ 4.5 3.8
Total mono-ortho PCB TEQ 2.5 2.2
Total coplanar PCB TEQ 6.9 6.1
Total TEQ 18.8 17.2
Minimum 25th (b) 50th (b)
PCDDs
2,3,7,8-TCDD ND ND 1.1
1,2,3,7,8-PeCDD ND 3.1 4.2
1,2,3,4,7,8-HxCDD ND ND ND
1,2,3,6,7,8-HxCDD 2.4 10.4 14.5
1,2,3,7,8,9-HxCDD ND ND 2.2
1,2,3,4,6,7,8-HxCDD 9.6 18.2 23.3
OCDD 169.6 352.2 467.4
PCDFs
2,3,7,8-TCDF ND ND ND
1,2,3,7,8-PeCDF ND ND ND
2,3,4,7,8-PeCDF 1.4 4.5 6.0
1,2,3,4,7,8-HxCDF ND ND 2.6
1,2,3,6,7,8-HxCDF ND 2.2 2.8
2,3,4,6,7,8-HxCDF ND ND ND
1,2,3,7,8,9-HxCDF ND ND ND
1,2,3,4,6,7,8-HpCDF ND ND 2.5
1,2,3,4,7,8,9-HpCDF ND ND ND
OCDF ND ND ND
Non-ortho PCBs
3,3',4',4'-TCB (77) ND 10.5 12.8
3,4,4',5-TCB (81) ND ND ND
3,3',4,4',5-PeCB (126) ND 26.0 37.0
3,3',4,4',5,5'-HxCB (169) ND 21.5 29.2
Mano-ortho PCBs
2,3,3'4,4'-PeCB (105) 256.1 976.2 1423.9
2,3,4,4',5-PeCB (114) 79.3 248.6 363.9
2,3',4,4',5-PeCB (118) 1293.2 3912.5 5803.5
2',3,4,4',5-PeCB (123) 24.3 70.3 113.7
2,3,3",4,4',5-HxCB (156) 441.5 1307.2 1982.9
2,3,3',4,4',5'-HxCB (157) 85.1 333.3 507.0
2,3',4,4',5,5'-HxCB (167) 158.6 507.6 739.9
2,3,3',4,4',5,5'-HpCB (189) ND 138.1 222.7
Di-ortho PCBs
2,2',3,3',4,4',5-HpCB (170) 1104.9 2570.7 4155.7
2,2',3,4,4',5,5'-HpCB (180) 2704.4 8392.9 12813.5
Total
Total PCDDs 192.8 389.5 508.9
Total PCDFs 10.4 16.6 20.6
Total PCDDs/PCDFs 206.4 408.3 526.8
Total non-ortho PCBs 27.4 64.2 85.5
Total mono-ortho PCBs 2832.8 7812.5 11471.6
Total coplanar PCBs 2860.2 7868.6 11554.7
Total 3311.1 8431.7 12053.1
WHO-98 (c)
Total PCDD TEQ 1.6 5.3 7.2
Total PCDF TEQ 1.2 2.9 3.8
Total PCDD/PCDF TEQ 2.8 8.2 11.2
Total non-ortho PCB TEQ 0.6 2.7 3.9
Total mono-ortho PCB TEQ 0.6 1.6 2.2
Total coplanar PCB TEQ 1.1 4.4 6.2
Total TEQ 4.0 13.4 17.8
75th (b) Maximum
PCDDs
2,3,7,8-TCDD 1.4 3.1
1,2,3,7,8-PeCDD 5.4 11.9
1,2,3,4,7,8-HxCDD 2.3 13.6
1,2,3,6,7,8-HxCDD 18.3 43.6
1,2,3,7,8,9-HxCDD 3.2 7.4
1,2,3,4,6,7,8-HxCDD 31.5 69.7
OCDD 601.2 1491.5
PCDFs
2,3,7,8-TCDF ND 2.5
1,2,3,7,8-PeCDF ND 2.2
2,3,4,7,8-PeCDF 7.7 19.9
1,2,3,4,7,8-HxCDF 3.3 6.5
1,2,3,6,7,8-HxCDF 3.7 8.6
2,3,4,6,7,8-HxCDF ND 5.0
1,2,3,7,8,9-HxCDF ND ND
1,2,3,4,6,7,8-HpCDF 3.4 15.8
1,2,3,4,7,8,9-HpCDF ND ND
OCDF ND 11.0
Non-ortho PCBs
3,3',4',4'-TCB (77) 16.1 37.2
3,4,4',5-TCB (81) ND ND
3,3',4,4',5-PeCB (126) 54.9 141.7
3,3',4,4',5,5'-HxCB (169) 36.6 85.9
Mano-ortho PCBs
2,3,3'4,4'-PeCB (105) 2044.1 5420.8
2,3,4,4',5-PeCB (114) 488.5 1442.6
2,3',4,4',5-PeCB (118) 8192.7 20196.9
2',3,4,4',5-PeCB (123) 154.5 458.6
2,3,3",4,4',5-HxCB (156) 2737.5 6427.8
2,3,3',4,4',5'-HxCB (157) 675.4 1782.7
2,3',4,4',5,5'-HxCB (167) 1005.0 2275.3
2,3,3',4,4',5,5'-HpCB (189) 312.0 625.8
Di-ortho PCBs
2,2',3,3',4,4',5-HpCB (170) 5622.0 13620.5
2,2',3,4,4',5,5'-HpCB (180) 17957.1 41110.1
Total
Total PCDDs 646.9 1602.4
Total PCDFs 24.5 2877.3
Total PCDDs/PCDFs 675.1 3726.3
Total non-ortho PCBs 110.3 269.9
Total mono-ortho PCBs 15238.9 36382.2
Total coplanar PCBs 15352.0 36536.1
Total 15845.5 37267.2
WHO-98 (c)
Total PCDD TEQ 9.4 20.7
Total PCDF TEQ 5.0 12.4
Total PCDD/PCDF TEQ 14.0 31.2
Total non-ortho PCB TEQ 5.9 15.0
Total mono-ortho PCB TEQ 2.9 7.2
Total coplanar PCB TEQ 8.6 22.2
Total TEQ 23.4 51.2
Abbreviations: NO, nondetectable; WHO, World Health Organization.
(a) For subjects with a level below the detection limit, we used
a value equal to half the detection limit. (b) Percentiles. (c) The
calculation of TEG was estimated based on the toxic equivalent factor
values proposed by the WHO (Van den Berg 1998).
Table 4. BSID-II mental (MDI) and psychomotor (PDI) development
scores for infants in relation to the level of PCBs and dioxins
in maternal blood (n = 134).
MDI
[beta] (a) t p-Value
PCDDs
2,3,7,8-TCDD -0.154 -1.755 0.083
1,2,3,7,8-PeCDD 0.074 0.847 0.398
1,2,3,4,7,8-HxCDD -0.031 -0.352 0.725
1,2,3,6,7,8-HxCDD 0.033 0.365 0.716
1,2,3,7,8,9-HxCDD 0.006 0.067 0.946
1,2,3,4,6,7,8-HpCDD -0.222 -2.418 0.017 *
OCDD -0.177 -1.897 0.060
PCDFs
2,3,7,8-TCOF -0.053 -0.602 0.548
1,2,3,7,8-PeCDF 0.014 0.167 0.868
2,3,4,7,8-PeCDF 0.028 0.314 0.754
1,2,3,4,7,8-HxCDF -0.113 -1.255 0.212
1,2,3,6,7,8-HxCDF -0.101 -1.139 0.257
2,3,4,6,7,8-HxCDF 0.009 0.106 0.915
1,2,3,7,8,9-HxCDF ND ND ND
1,2,3,4,6,7,8-HpCDF -0.038 -0.438 0.662
1,2,3,4,7,8,9-HpCDF ND ND ND
OCDF -0.057 -0.657 0.512
Non-ortho PCBs
3,3',4',4'-TCB (77) 0.032 0.357 0.721
3,4,4',5-TCB (81) ND ND ND
3,3',4,4',5-PeCB (126) -0.003 -0.032 0.975
3,3',4,4',5,5'-HxCB (169) 0.013 0.147 0.884
Mono-ortho PCBs
2,3,3',4,4'-PeCB (105) -0.004 -0.047 0.963
2,3,4,4',5-PeCB (114) -0.024 -0.277 0.782
2,3',4,4',5-PeCB (118) -0.016 -0.182 0.856
2',3,4,4',5-PeCB (123) 0.033 0.379 0.705
2,3,3,4,4',5-HxCB (156) 0.001 0.008 0.994
2,3,3',4,4',5'-HxCB (157) -0.038 -0.431 0.667
2,3',4,4',5,5'-HxCB (167) -0.012 -0.140 0.889
2,3,3',4,4',5,5'-HpCB (189) -0.102 -1.182 0.239
Di-ortho PCBs
2,2",3,3',4,4',5-HpCB (170) -0.027 -0.310 0.757
2,2',3,4,4',5,5'-HpCB (180) -0.021 -0.246 0.806
Total
Total PCDDs -0.234 -2.649 0.009 **
Total PCDFs -0.048 -0.535 0.594
Total PCDDs/PCDFs -0.220 -2.485 0.014 *
Total non-ortho PCBs 0.032 0.365 0.716
Total mono-ortho PCBs -0.014 -0.165 0.869
Total coplanar PCBs -0.013 -0.155 0.877
Total -0.022 -0.247 0.805
WHO-98 (b)
Total PCDD TEQ 0.046 0.522 0.603
Total PCDF TEQ 0.016 0.182 0.856
Total PCDDs/PCDF TEQ 0.037 0.419 0.676
Total non-ortho PCB TEQ 0.020 0.233 0.816
Total mono-ortho PCB TEQ -0.011 -0.123 0.902
Total coplanar PCB TEQ 0.032 0.371 0.711
Total TEQ 0.049 0.550 0.583
PDI
[beta] (a) t p-Value
PCDDs
2,3,7,8-TCDD -0.125 -1.477 0.142
1,2,3,7,8-PeCDD -0.063 -0.758 0.450
1,2,3,4,7,8-HxCDD -0.135 -1.608 0.110
1,2,3,6,7,8-HxCDD -0.074 -0.873 0.384
1,2,3,7,8,9-HxCDD -0.209 -2.549 0.012 *
1,2,3,4,6,7,8-HpCDD -0.243 -2.806 0.006 **
OCDD -0.168 -1.895 0.060
PCDFs
2,3,7,8-TCOF -0.204 -2.516 0.013 *
1,2,3,7,8-PeCDF -0.203 -2.512 0.013 *
2,3,4,7,8-PeCDF -0.069 -0.822 0.413
1,2,3,4,7,8-HxCDF -0.153 -1.807 0.073
1,2,3,6,7,8-HxCDF -0.166 -1.989 0.049 *
2,3,4,6,7,8-HxCDF -0.074 -0.875 0.383
1,2,3,7,8,9-HxCDF ND ND ND
1,2,3,4,6,7,8-HpCDF -0.093 -1.123 0.264
1,2,3,4,7,8,9-HpCDF ND ND ND
OCDF -0.032 -0.385 0.701
Non-ortho PCBs
3,3',4',4'-TCB (77) -0.023 -0.274 0.785
3,4,4',5-TCB (81) ND ND ND
3,3',4,4',5-PeCB (126) -0.138 -1.674 0.097
3,3',4,4',5,5'-HxCB (169) -0.097 -1.181 0.240
Mono-ortho PCBs
2,3,3',4,4'-PeCB (105) -0.112 -1.366 0.174
2,3,4,4',5-PeCB (114) -0.132 -1.607 0.111
2,3',4,4',5-PeCB (118) -0.137 -1.671 0.097
2',3,4,4',5-PeCB (123) -0.108 -1.307 0.194
2,3,3,4,4',5-HxCB (156) -0.099 -1.201 0.232
2,3,3',4,4',5'-HxCB (157) -0.141 -1.723 0.087
2,3',4,4',5,5'-HxCB (167) -0.135 -1.652 0.101
2,3,3',4,4',5,5'-HpCB (189) -0.136 -1.662 0.099
Di-ortho PCBs
2,2",3,3',4,4',5-HpCB (170) -0.132 -1.612 0.109
2,2',3,4,4',5,5'-HpCB (180) -0.086 -1.042 0.299
Total
Total PCDDs -0.144 -1.686 0.094
Total PCDFs 0.071 0.833 0.407
Total PCDDs/PCDFs -0.090 -1.046 0.298
Total non-ortho PCBs -0.006 -0.076 0.939
Total mono-ortho PCBs -0.136 -1.663 0.099
Total coplanar PCBs -0.135 -1.650 0.101
Total -0.130 -1.584 0.116
WHO-98 (b)
Total PCDD TEQ 0.004 0.043 0.966
Total PCDF TEQ 0.057 0.671 0.503
Total PCDDs/PCDF TEQ 0.032 0.378 0.706
Total non-ortho PCB TEQ -0.017 -0.204 0.838
Total mono-ortho PCB TEQ -0.127 -1.544 0.125
Total coplanar PCB TEQ -0.053 -0.636 0.526
Total TEQ 0.007 0.080 0.936
Abbreviations: NO, nondetectable; WHO, World Health Organization.
(a) [beta] is the point increase in developmental score per PCB
and dioxin level (natural logarithm) adjusted for gestational age
(days), smoking during pregnancy, caffeine intake during pregnancy
(mg/day), and blood sampling time. (b) The calculation of TEQ was
estimated based on the toxic equivalent factor values proposed by
the WHO (Van den Berg 1998).
* p < 0.05; ** p < 0.01.
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