Mite and pet allergen levels in homes of children born to allergic and nonallergic parents: the PIAMA study. (Children's Health: Articles).The Prevention and Incidence of Asthma asthma (ăz`mə, ăs`–), chronic inflammatory respiratory disease characterized by periodic attacks of wheezing, shortness of breath, and a tight feeling in the chest. A cough producing sticky mucus is symptomatic. and Mite Allergy allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-causing substances, can be airborne substances (e.g. (PIAMA) study is a birth 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 that investigates the influence of allergen allergen /al·ler·gen/ (al´er-jen) an antigenic substance capable of producing immediate hypersensitivity (allergy).allergen´ic pollen allergen exposure on the development of allergy and asthma in the first several years of life. The objectives of this study were to investigate the relationship between a family history bf allergy and/or asthma and exposure of newborn newborn /new·born/ (noo´born?) 1. recently born. 2. newborn infant. new·born adj. Very recently born. n. A neonate. children to mite and pet allergen and to study the influence of different home and occupant occupant n. 1) someone living in a residence or using premises, as a tenant or owner. 2) a person who takes possession of real property or a thing which has no known owner, intending to gain ownership. (See: occupancy) characteristics on mite allergen exposure. Dust was sampled from the child's mattress and the parental mattress at 3 months after birth of the index child and analyzed an·a·lyze tr.v. an·a·lyzed, an·a·lyz·ing, an·a·lyz·es 1. To examine methodically by separating into parts and studying their interrelations. 2. Chemistry To make a chemical analysis of. 3. for mite and pet allergens. Subjects were divided in groups according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. history of asthma and allergy in their parents, and allergen exposure was studied in the different groups. Cat allergen exposure was significantly lower on parental mattresses in families with allergic al·ler·gic adj. 1. Of, caused, or characterized by an allergy. 2. Having an allergy or exhibiting an allergic reaction to a substance. allergic pertaining to or caused by allergy. mothers, but-dog allergen exposure was not different. Mite allergen exposure was lower on parental mattresses in families with allergic mothers. Use of mite allergen-impermeable mattress covers reduced mite allergen exposure. Some other characteristics such as age of home and mattress were also found to influence mite allergen exposure. Parental mattresses in homes of allergic mothers had lower cat and mite (but not dog) allergen loadings than mattresses in homes of nonallergic parents. Paternal PATERNAL. That which belongs to the father or comes from him: as, paternal power, paternal relation, paternal estate, paternal line. Vide Line. (as opposed to maternal MATERNAL. That which belongs to, or comes from the mother: as, maternal authority, maternal relation, maternal estate, maternal line. Vide Line. ) allergy seemed to have little influence. Key words: allergens, infants, mites, pets. Environ en·vi·ron tr.v. en·vi·roned, en·vi·ron·ing, en·vi·rons To encircle; surround. See Synonyms at surround. [Middle English envirounen, from Old French environner Health Perspect 110:A693-A698 (2002). [Online 10 October 2002] http ://ehpnet1.niehs.nih.gov/docs/2002/110pA693-A698vanstrien/abstract.html ********** A family history of asthma or allergy is associated with an increased risk of developing allergy and asthma (Horst and Halken 2000; Sears 1998; Strachan 1999). Allergic families are likely to take rfieasures to decrease exposure to allergens (Brunekreef et al. 1992; van Strien et al. 1995). Previously, we showed that allergic parents of infants included in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study more often reported taking allergen-avoidance measures and had a cat at home less often than did nonallergic parents (Wijga et al. 2001). Such selective allergen avoidance could complicate com·pli·cate tr. & intr.v. com·pli·cat·ed, com·pli·cat·ing, com·pli·cates 1. To make or become complex or perplexing. 2. To twist or become twisted together. adj. 1. studies of the relationship between allergen exposure and development of allergic disease in children. Early allergen exposure is associated with sensitization sensitization /sen·si·ti·za·tion/ (sen?si-ti-za´shun) 1. administration of an antigen to induce a primary immune response. 2. exposure to allergen that results in the development of hypersensitivity. in children (Verhoeffet al. 1994; Wahn et al. 1997), but it is still unclear whether the development of asthma is also affected (Custovic et al. 2001; Lau et al. 2000). Allergen avoidance measures and several different housing and occupant characteristics might influence mite allergen concentrations, as has been shown in a number of studies (Chew et al. 1998, 1999; Simpson Simp·son , Sir James Young 1811-1870. British obstetrician and a founder of gynecology. He is also known for introducing the use of chloroform as an anesthetic. et al. 2001; van Strien et al. 1994; Wickens et al. 2001). Characteristics associated commonly with higher mite allergen concentrations were increasing numbers of occupants, older homes, older mattresses, and dampness damp adj. damp·er, damp·est 1. Slightly wet. See Synonyms at wet. 2. Archaic Dejected. n. 1. Moisture in the air; humidity. 2. of the home. A large part of the variation in mite allergen concentrations is usually not explained by housing and occupant characteristics; therefore these characteristics remain relatively poor predictors of mite allergen exposure levels (Chew et al. 1999). Furthermore, Dermatophagoides pteronyssinus Der·ma·toph·a·goi·des pter·o·nys·si·nus n. A cosmopolitan species of mites that are found in house dust and are a common cause of atopic asthma. (Der p 1) and D. farinae (Der f1) concentrations in house dust are weakly weak·ly adj. weak·li·er, weak·li·est Delicate in constitution; frail or sickly. adv. 1. With little physical strength or force. 2. With little strength of character. correlated cor·re·late v. cor·re·lat·ed, cor·re·lat·ing, cor·re·lates v.tr. 1. To put or bring into causal, complementary, parallel, or reciprocal relation. 2. with each other, suggesting that different housing characteristics influence concentrations of these two mite allergens (Gross et al. 2000). In this study we investigated whether parental allergy and asthma are associated with allergen concentrations in mattress dust and which housing characteristics influence Derp 1 and Der fl concentrations in mattress dust. Materials and Methods The PIAMA study is a prospective birth cohort study, consisting of two parts: a natural history part, in which no intervention A procedure used in a lawsuit by which the court allows a third person who was not originally a party to the suit to become a party, by joining with either the plaintiff or the defendant. takes place, and a double-blind placebo-controlled intervention part in which the effect of mite-impermeable mattress encasings is studied. Pregnant women were recruited into the study during the first trimester Noun 1. first trimester - time period extending from the first day of the last menstrual period through 12 weeks of gestation trimester - a period of three months; especially one of the three three-month periods into which human pregnancy is divided of pregnancy and were selected on the basis of self-reported allergies Allergies Definition Allergies are abnormal reactions of the immune system that occur in response to otherwise harmless substances. Description Allergies are among the most common of medical disorders. and/or asthma, using a validated val·i·date tr.v. val·i·dat·ed, val·i·dat·ing, val·i·dates 1. To declare or make legally valid. 2. To mark with an indication of official sanction. 3. questionnaire (Lakwijk et al. 1998) that was distributed by 52 midwife MIDWIFE, med. jur. A woman who practices midwifery; a woman who pursues the business of an account. 2. A midwife is required to perform the business she undertakes with proper skill, and if she be guilty of any mala praxis, (q.v. practices and obstetric ob·stet·ric or ob·stet·ri·cal adj. Of or relating to the profession of obstetrics or the care of women during and after pregnancy. obstetrical, obstetric pertaining to or emanating from obstetrics. clinics in the Netherlands. In total, 3,291 pregnant women were included in the natural history study (NHS NHS abbr. National Health Service NHS (in Britain) National Health Service ), of which 472 reported an inhalant inhalant /in·hal·ant/ (in-hal´ant) 1. something meant to be inhaled; see inhalation (def. 3). 2. a class of psychoactive substances whose volatile vapors are subject to abuse. allergy and/or asthma (NHS-a, response rate 62%) and 2,819 did not report an allergy, or asthma (NHS-na, response rate 55%). Wijga et al. (2001) described recruitment and inclusion of the natural history subjects in more detail. In the intervention study, 855 pregnant women reporting allergies and/or asthma were included (response rate 42%) and randomly assigned as·sign tr.v. as·signed, as·sign·ing, as·signs 1. To set apart for a particular purpose; designate: assigned a day for the inspection. 2. to a placebo placebo (pləsē`bō), inert substance given instead of a potent drug. Placebo medications are sometimes prescribed when a drug is not really needed or when one would not be appropriate because they make patients feel well taken care of. and an active group. Selection criteria for the group of allergic mothers in the natural history study and in the intervention study were the same. In 810 subjects, the intervention measures were applied--416 in the active group (IS-act) and 394 in the placebo group (IS-pi). The intervention consisted of mite-impermeable mattress covers for the parents' and the child's bed in the active group and cotton mattress covers in the placebo group, applied in the third trimester Noun 1. third trimester - time period extending from the 28th week of gestation until delivery trimester - a period of three months; especially one of the three three-month periods into which human pregnancy is divided of pregnancy. All subjects in the intervention study were eligible for a home visit at 3 months after the birth, and all subjects with an allergic mother and a random sample (n = 655) of the subjects with a nonallergic mother were eligible in the natural history study. At 3 months after the birth in 716 (367 in the active group and 349 in the placebo group) homes in the intervention study, dust samples were collected. In the natural history study, dust samples were collected in 427 homes (91%) of mothers reporting an allergy and/or asthma, and 610 homes (93%) of mothers not reporting an allergy or asthma. Allergy and asthma in the father were assessed using the same questions that were used for the mother; these questions were asked in the third trimester of pregnancy and were not used to select subjects for the different subgroups of the study. We obtained written informed consent from all parents. Dust sampling and analysis. Trained fieldworkers took dust samples from the parents' mattress and the child's mattress after the blanket (but not the bottom sheet) was removed, so dust was sampled from the entire upper surface of the sheets, on which the subjects actually slept. Dust was sampled using a Rowenta Dymbo vacuum cleaner vacuum cleaner, mechanical device using a draft of air to remove dust, loose dirt, or other particulate matter from dry surfaces. It is especially useful on highly textured surfaces, such as carpets and upholstery, that are difficult to clean by wiping or brushing. (Rowenta, Offenbach, Germany) at 1,200 W, with an ALK-filter holder (ALK ALK Alkohol (German: alcohol) ALK Alkaline ALK Anaplastic Lymphoma Kinase ALK Automatisierte Liegenschaftskarte ALK Activin Receptor-Like Kinase ALK Alkylation ALK Srilankan Airlines (ICAO code) , Horsholm, Denmark). Paper filters (no. 589; Schleicher & Schuell, Dassel, Germany) were put in 500-mL disposable disposable Nursing adjective Referring to that which is discarded or disposed of noun An item used in health care-related Pt contact which is discarded after use–eg masks, gloves, gowns, needles, paper products, syringes, wipes. See Biohazardous waste. polyethylene polyethylene (pŏl'ēĕth`əlēn), widely used plastic. It is a polymer of ethylene, CH2=CH2, having the formula (-CH2-CH2-)n butter dishes and weighed before sampling after at least 24 hr equilibration equilibration /equi·li·bra·tion/ (e-kwil?i-bra´shun) the achievement of a balance between opposing elements or forces. occlusal equilibration at 20[degrees]C and 50% relative humidity relative humidity n. The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage. . At the sampling site the filter was placed in the filter holder using forceps. Sampling was done from the total mattress surface of each bed for 2 min. After sampling, the dust and the filter were put back into the butter dish and frozen at the end of the day (-20[degreesC). After thawing and acclimatization acclimatization Any of numerous gradual, long-term responses of an individual organism to changes in its environment. The responses are more or less habitual and reversible should conditions revert to an earlier state. for 24 hr, the butter dish was weighed again and the total amount of dust was recorded. Weighing was done on a Mettler 261 AT (Mettler-Toledo, Tiel TIEL. An old manner of spelling tel. Such as nul tiel record, no such record. , the Netherlands) analytical balance analytical balance n. A balance for chemical analysis. Noun 1. analytical balance - a beam balance of great precision used in quantitative chemical analysis chemical balance . The limit of detection for this procedure was 11 mg dust, based on repeated weighing of-blank samples. The dust and the filter were extracted for 2 hr by shaking with phosphate-buffered saline saline /sa·line/ (sa´len) (sa´lin) salty; of the nature of a salt; containing a salt or salts. normal saline , physiological saline physiologic saline solution. (8 g NaCl NaCl sodium chloride. , 0.2g KCl, 1.44 g [Na.sub.2]HP[O.sub.4], 0.24 g K[H.sub.2]P[O.sub.4], 0.5 g Na[N.sub.3] in 1 L doubly distilled water Noun 1. distilled water - water that has been purified by distillation H2O, water - binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; , adjusted to pH 7.2). For 0-300 mg dust, 3 mL was used;, 5 mL for 300-500 mg, 10 mL for 500-1,000 mg, and 20 mL for more than 1,000 mg. Aliquots of the extracts were stored at -20[degrees]C, until analysis. Dust extracts were analyzed for Der p 1, Der f1, Fel d 1, and Can f 1, using reagents for a sandwich enzyme enzyme, biological catalyst. The term enzyme comes from zymosis, the Greek word for fermentation, a process accomplished by yeast cells and long known to the brewing industry, which occupied the attention of many 19th-century chemists. immunoassay Immunoassay An assay that quantifies antigen or antibody by immunochemical means. The antigen can be a relatively simple substance such as a drug, or a complex one such as a protein or a virus. , purchased from Indoor Biotechnologies (Cardiff, UK). As catching antibody for the Der p 1 and Der fl assays mouse IgG anti-mite monoclonal antibodies This is a list of monoclonal antibodies, antibodies which are clones of a single parent cell. When used as medications, the generic names end in -mab (see "Nomenclature of monoclonal antibodies"). 5H8 and 6A8, respectively, were used. Both assays use biotinylated Mouse IgG1 anti-mite monoclonal monoclonal /mono·clo·nal/ (-klon´al) 1. derived from a single cell. 2. pertaining to a single clone. mon·o·clo·nal n. 4C1 as a detecting antibody. For Fel d 1 and Can f 1 the monoclonal antibodies 6F9 and 6E9 were used, respectively, as catching antibody; and as detecting antibodies monoclonal anti-Fel d 1 94/01 and polyclonal polyclonal /poly·clo·nal/ (-klon´'l) 1. derived from different cells. 2. pertaining to several clones. polyclonal derived from different cells; pertaining to several clones. anti-Can f 1 were used. Avidine peroxidase peroxidase /per·ox·i·dase/ (per-ok´si-das) any of a group of iron-porphyrin enzymes that catalyze the oxidation of some organic substrates in the presence of hydrogen peroxide. per·ox·i·dase n. (DAKO, Glostrup, Denmark) was used as conjugate conjugate /con·ju·gate/ (kon´jdbobr-gat) 1. paired, or equally coupled; working in unison. 2. a conjugate diameter of the pelvic inlet; used alone usually to denote the true conjugate diameter; see for Der p 1, Der fl, and Fel d 1 assays, whereas polyclonal horse anti-rabbit IgG-peroxidase (CLB CLB Club CLB Columbus Blue Jackets (NHL hockey) CLB Combat Logistics Battalion (US Marine Corps) CLB Configurable Logic Block (microchip technology) , Amsterdam, The Netherlands) was used for the Can f 1 assay. Ortho phenylene phen·yl·ene n. A bivalent organic radical, C6H4, derived from benzene by removal of two hydrogen atoms. phenylene The radical C6H4 diamene in a citric acid citric acid or 2-hydroxy-1,2,3-propanetricarboxylic acid, HO2CCH2C(OH)(CO2H)CH2CO2 sodium phosphate sodium phosphate n. Any of various sodium salts of phosphoric acid, especially NaH2PO4, Na2HPO4, and Na3PO4, widely used in pharmaceutical manufacturing, medicine, and chemistry. buffer buffer, solution that can keep its relative acidity or alkalinity constant, i.e., keep its pH constant, despite the addition of strong acids or strong bases. (pH 5.5) with 8202 was used as substrate The base layer of a structure such as a chip, multichip module (MCM), printed circuit board or disk platter. Silicon is the most widely used substrate for chips. Fiberglass (FR4) is mostly used for printed circuit boards, and ceramic is used for MCMs. , and the reaction was stopped with 2 M HCI (Human Computer Interaction) Refers to the design and implementation of computer systems that people interact with. It includes desktop systems as well as embedded systems in all kinds of devices. . Absorbance absorbance /ab·sor·bance/ (-sor´bans) 1. in analytical chemistry, a measure of the light that a solution does not transmit compared to a pure solution. Symbol . 2. was read at 492 nm. All extracts were diluted di·lute tr.v. di·lut·ed, di·lut·ing, di·lutes 1. To make thinner or less concentrated by adding a liquid such as water. 2. To lessen the force, strength, purity, or brilliance of, especially by admixture. 5-, 10-, and 20-fold, and more if required. The median coefficient of variation Coefficient of Variation A measure of investment risk that defines risk as the standard deviation per unit of expected return. (CV) of analysis on the same day was 7.9%, 8.1%, 10.4%, and 16.0% for Der p 1, Der fl, Fel d 1, and Can f 1, respectively. The lower limit of detection was 8 ng/mL for Der p 1, 6 ng/mL for Der fl, 0.4 mU/mL for Fel d 1, and 20 ng/mL for Can f 1 for 5-fold diluted samples. Samples with undetectable amounts of allergen were given a value of two-thirds of the detection limit because the distributions were log-normal. The undetectable values were not distributed equally over the range below the limit of detection, but there will be more dose to the detection limit than close to zero. To reflect this, we arbitrarily chose a value between 0.5 and 1 at two-thirds. This was done for the results of 36%, 27%, 1%, and 60% of the samples taken from the parental mattress, and 65%, 52%, 13%, and 68% of the samples taken from the child's mattress, respectively, for Der p 1, Der fl, Fel d 1, and Can f 1. Of dust samples with an undetectable amount of dust (< 11 mg), the amount of allergen per gram dust was not calculated and is therefore missing from all analyses. This was true for two samples taken from the parental mattress and 93 (5%) samples taken from the child's mattress. About 20% of the samples were analyzed in duplicate DUPLICATE. The double of anything. 2. It is usually applied to agreements, letters, receipts, and the like, when two originals are made of either of them. Each copy has the same effect. from a second aliquot aliquot (al-ee-kwoh) adj. a definite fractional share, usually applied when dividing and distributing a dead person's estate or trust assets. (See: share) on a different day. Only for samples detectable on one or both occasions was the CV calculated. For Der p 1, Der fl, Fel d 1, and Can f 1 the median CV was 15.2%, 19.0%, 32.9%, and 37.3% respectively. Statistical analysis. Differences in median dust and allergen levels between groups of parents with and without allergies and/or asthma in the natural history study were tested using Wilcoxon's two-sample test. We also assessed the influence of season of sampling on both mite allergens separately, using In-transformed allergen concentrations and 3-month moving averages, to diminish random variation (Chatfield 1996). Because sampling in the PIAMA study was done throughout the year, we had to account for season. We did so using multiple linear regression Linear regression A statistical technique for fitting a straight line to a set of data points. analysis, with dummy variables This article is not about "dummy variables" as that term is usually understood in mathematics. See free variables and bound variables. In regression analysis, a dummy variable for the different seasons January-March, April-June, July-September, and October-December). The months October, November, and December (autumn) were used as the reference season in all analyses. All housing and occupant characteristics were categorized cat·e·go·rize tr.v. cat·e·go·rized, cat·e·go·riz·ing, cat·e·go·riz·es To put into a category or categories; classify. cat and entered in multiple linear regression models, using In-transformed dust and mite allergen concentrations as dependent variables. We used the regression coefficient Regression coefficient Term yielded by regression analysis that indicates the sensitivity of the dependent variable to a particular independent variable. See: Parameter. regression coefficient for each variable to calculate the relative difference the value of this variable made for the dependent variable (i.e., the dust or allergen concentration). The reference concentration is the concentration a subject would have had when all variables were in the reference category. Dust samples with undetectable allergen levels were included in all analyses. Because the results for allergen loads expressed in unit per square meter Noun 1. square meter - a centare is 1/100th of an are centare, square metre area unit, square measure - a system of units used to measure areas were similar to those expressed per gram dust, the results are presented for allergen loads expressed in units per square meter only--a more direct measure of exposure to the total amount of allergen per surface unit. To illustrate the similarity Similarity is some degree of symmetry in either analogy and resemblance between two or more concepts or objects. The notion of similarity rests either on exact or approximate repetitions of patterns in the compared items. , a graphic presentation of mite allergen levels by season is presented for both expressions, p-Values < 0.05 were regarded as statistically significant. Results Table 1 shows percentages of subjects with different housing and other characteristics, possibly associated with mite allergen concentrations. Tables 2 and 3 show dust and allergen quantities per square meter for the child's bed and the parents bed, respectively. Both tables show data from the NHS only. On the mattresses of the children, there were no differences in mite and pet allergen loadings in relation to parental allergy. The mattresses of the parents showed a slightly different picture: Cat allergen loadings were lower when the mother or both parents were allergic. Mite allergen levels may vary by season. Samples in this study were taken throughout the year. The geometric mean (mathematics) geometric mean - The Nth root of the product of N numbers. If each number in a list of numbers was replaced with their geometric mean, then multiplying them all together would still give the same result. amounts and concentrations of Der p 1 and Der fl for both beds per month of sampling are shown in Figure 1, which shows 3-month moving averages. The graphs show that both mite allergens follow a clear seasonal pattern. Levels of both allergens were higher in autumn and reached their lowest level at the end of winter. Seasonal influence was stronger for Der f 1 (factor 2 change) than for Der p 1 (factor 1.5 change). [FIGURE 1 OMITTED] In Tables 4 and 5 various home and occupant characteristics are shown with regard to their influence on the amount of dust and Der p 1 + Der f 1 (Der 1, ng/[m.sub.2]). Table 4 shows that the amount of dust, as well as the amount of mite allergens per square meter from the child's bed, was significantly lower for children in the active group of the intervention study, compared to the natural history group with allergic mothers. Child's mattresses in the intervention study placebo group had comparable amounts of dust and mite allergen concentrations as mattresses in the natural history group with allergic mothers. Other characteristics associated with higher concentrations of Der 1 in dust from the child's bed were age of the mattress, absence of double-glazed windows in the child's bedroom, season, and the child having older siblings siblings npl (formal) → frères et sœurs mpl (de mêmes parents) . Table 5 shows that the amount of dust as well as both mite allergen concentrations in the parents' bed, were significantly lower in the intervention study active group, compared to the natural history group with allergic mothers. Placebo mattress covers lowered Der 1 loadings as well, and dust and Der 1 loadings were higher on mattresses of nonallergic than allergic mothers. In addition, Der 1 levels varied with season and region, were higher in older mattresses and houses, and lower when the child was firstborn first·born adj. First in order of birth; born first. n. The child in a family who is born first. Noun 1. firstborn - the offspring who came first in the order of birth eldest . Despite the fact that many determinants were investigated, only a small fraction of the variance The discrepancy between what a party to a lawsuit alleges will be proved in pleadings and what the party actually proves at trial. In Zoning law, an official permit to use property in a manner that departs from the way in which other property in the same locality in Der 1 loadings-could be explained by our models. Table 6 shows that the overwhelming determinant determinant, a polynomial expression that is inherent in the entries of a square matrix. The size n of the square matrix, as determined from the number of entries in any row or column, is called the order of the determinant. of cat and dog allergen in the child's mattress was presence of a cat or dog in the home. In addition, there was a modest influence of the presence of mattress covers and mechanical ventilation mechanical ventilation n. A mode of assisted or controlled ventilation using mechanical devices that cycle automatically to generate airway pressure. (with dog allergen), and age of mattress (with cat allergen). Table 7 shows the results for the parents' mattresses. Again, the influence of the presence of a cat or dog in the home is Overwhelming. Presence of mattress covers were more important on parents' than on babies' mattresses; few other factors reached significance. Discussion This study showed that in the PIAMA birth 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. , children of mothers with inhalant allergy and/or asthma were born into an environment with lower cat allergen concentrations in mattress dust of parents, which was completely explained by a lower prevalence of cat ownership. Der 1 loadings were also lower on parents' mattresses in families with allergic mothers. Several home characteristics such as age of home and mattress were shown to increase mite allergen concentrations. Families with allergic fathers but not allergic mothers did not have lower mattress loadings of any allergen compared to families in which no parent was allergic. Wijga et al. (2001) showed that parents with an allergy reported taking allergen-avoidance measures while furnishing their homes. This study shows that mite allergen levels on parents' mattresses are indeed lower when the mother is allergic. Once maternal allergy was taken into account, however, reported allergen-avoidance measures had no further influence. In previous studies, the Der p 1 concentration in mattress dust from homes of allergic subjects was also found to be lower than in homes of nonallergic subjects (van Strien et al. 1995; Verhoeffet al. 1994). Parents' but not children's mattresses in families with allergic mothers had less cat allergen, as was expected, since Wijga et al. (2001) showed that families in which both parents are allergic were less likely to own a cat than families without parental allergies. The difference between allergic and nonallergic mothers disappeared after taking the difference in cat ownership into account. For dog allergen there was no difference in the allergen concentration of mattress dust between families with or without maternal allergies and/or asthma. This corresponds to the fact that owning a dog was not influenced by allergies and/or asthma reported by the parents (Wijga et al. 2001). Mite allergen concentrations were low in this study compared to earlier studies we conducted in the Netherlands (van Strien et al. 1994, 1995). Concentrations of mite allergen in children's mattresses were comparable, however, to concentrations found by Custovic et al. (2000) on babies' mattresses, and also comparable to the levels found by Wahn et al. (1997). A direct comparison between samples taken in previous studies and samples taken in the PIAMA study is fairly difficult because the subjects as well as dust sampling and analysis were different. More study of the changes in mite allergen concentrations and the possible reasons for these changes (Simpson et al. 2001) is justified. Different home and subject characteristics were studied with regard to their influence on mite allergen concentrations. This revealed that even at low concentrations some characteristics were still associated with mite allergen levels. Firstborn children had, on average, lower mite allergen concentrations in dust from their own beds, and the parents also had lower mite allergen concentrations in dust from their beds. This effect was not caused by the use of new mattresses because the age of the mattress was included in all models, but it could have been caused by the use of new bedding for the child's bed and the parents' bed. Chew et al. (1999) showed that dust from mattresses in apartments had significantly lower mite allergen concentrations. In this study, parents' mattress Der p 1 concentrations were lower, but Der f 1 concentrations were significantly higher (data not shown), with a net result that Der 1 levels were not significantly higher in apartments. Der p 1 concentrations seemed to be influenced more by housing characteristics associated with dampness and the age of the house, whereas Der f 1 was more influenced by seasonal changes and age of the mattress (data not shown). Overall, the characteristics studied here explained only about 10% of the variation in mite allergen concentrations, whereas in a previous study 25% of the variation in the Der p 1 concentration of dust from the beds of schoolchildren schoolchildren school npl → écoliers mpl; (at secondary school) → collégiens mpl; lycéens mpl schoolchildren school was explained by the same type of characteristics (van Strien et al. 1994). This is likely related to the much lower allergen levels in this study. Comparison of children using mite-impermeable mattress covers with similarly selected children without mattress covers showed that mite allergen loadings were lower in dust from the parents' mattress as well as children's mattresses. For children's mattresses, this seemed primarily an effect of smaller dust loadings, but for parents' mattresses, the effect on mite allergen loadings was much larger than for dust loadings. In conclusion, cat allergen exposure was lower in parents' mattresses in families of children born to allergic parents, and dog allergen was not affected. Mite allergen exposure was lower on the parents' mattress in families with allergic mothers compared to nonallergic mothers. Only a low percentage of the variation in mite allergen concentrations could be explained by housing and occupant characteristics. The major determinant of pet allergen loadings was having a pet in the home.
Table 1. Number and percentage of characteristics of the 1,753 homes
and their occupants in which dust samples were taken at three months
after birth.
Variable, categories No. Percent Missing
(%)
Study group
NHS-a 427 24.4
NHS-na 610 34.7
IS-placebo 349 20.0
IS-active 367 21.0
Age of mother at birth > 30 years 943 53.8 4.1
Age of father at birth > 30 years 1,241 70.8 5.9
Education level
Low 733 41.8 11.2
Region in the Netherlands
North 543 31.0
Middle 663 37.8
West 547 31.2
Allergen avoidance measures 614 35.0 0.7
Carpeted infant bedroom floor 780 44.5 16.1
Carpeted parental bedroom floor 1,110 63.3 4.1
Living in apartment 267 15.2 3.1
Double-glazed windows in infant bedroom 857 48.9 16.8
Double-glazed windows in parental bedroom 950 54.2 4.3
Age of infant bed
New 437 24.9 18.9
1-2 years 465 26.5
> 2 years 519 29.6
Age of parental bed
< 3 years 423 24.1 9.2
3-6 years 652 37.2
> 6 years 517 29.5
Mechanical ventilation 915 52.2 3.9
Construction period of house
After 1975 816 46.6 7.0
1920-1975 682 38.9
Before 1920 133 7.8
Damp stains (anywhere) 585 33.4 11.4
Firstborn child 874 49.9 2.9
Season of sampling
Autumn 406 23.2 2.7
Winter 486 27.7
Spring 512 29.2
Summer 302 17.2
Table 2. Median dust and allergen concentrations in children's
mattresses, natural history study (interquartile range in parentheses).
Both parents Only mother
not allergic allergic
Allergen (n = 418) (n = 287)
Dust (mg/[m.sup.2]) 174 (94-299) 176 (100-289)
Der p 1 (ng/[m.sup.2]) 74 (37-178) 74 (37-151)
Der f 1 (ng/[m.sup.2]) 57 (28-134) 63 (28-215)
Fel d 1 (mU/[m.sup.2]) 65 (11-544) 49 (12-325)
Can f 1 (ng/[m.sup.2]) 185 (93-481) 185 (93-586)
Only father Both parents
allergic allergic
Allergen (n= 162) (n= 121)
Dust (mg/[m.sup.2]) 187 (106-278) 198 (109-353)
Der p 1 (ng/[m.sup.2]) 83 (38-224) 74 (40-181)
Der f 1 (ng/[m.sup.2]) 60 (29-278) 74 (43-241) *
Fel d 1 (mU/[m.sup.2]) 49 (12-313) 47 (9-236)
Can f 1 (ng/[m.sup.2]) 185 (93-318) 185 (93-417)
* p < 0.1 (Wilcoxon two-sample test, compared to both parents not
allergic).
Table 3. Median dust and allergen concentrations in parents'
mattresses, natural history study (interquartile range in parentheses).
Both parents Only mother
not allergic allergic
Allergen (n = 427) (n = 291)
Dust (mg/[m.sup.2]) 268 (169-426) 256 (154-370) *
Der p 1 (ng/[m.sup.2]) 132 (33-850) 94 (30-502) (#)
Der f 1 (ng/[m.sup.2]) 88 (28-667) 88 (26-611)
Fel d 1 (mU/[m.sup.2]) 64 (16-367) 40 (12-311) (#)
Can f 1 (ng/[m.sup.2]) 111 (67-295) 95 (63-363)
Only father Both parents
allergic allergic
Allergen (n = 165) (n = 121)
Dust (mg/[m.sup.2]) 284 (186-393) 252 (169-370)
Der p 1 (ng/[m.sup.2]) 161 (40-1,078) 76 (30-568)
Der f 1 (ng/[m.sup.2]) 144 (29-574) 91 (25-425)
Fel d 1 (mU/[m.sup.2]) 50 (17-326) 24 (11-101) **
Can f 1 (ng/[m.sup.2]) 95 (71-249) 88 (64-233)
* p < 0.1; ** p < 0.01; (#) p < 0.05 (Wilcoxon two-sample test,
compared to both parents not allergic).
Table 4. Relative difference in dust and total mite allergen (Der p 1 +
Der f 1) on the child's mattress, in relation to various housing and
occupant characteristics. (a)
Variable Contrast
Study group NHS-na vs. NHS-a
IS-pl vs. NHS-a
IS-act vs. NHS-a
Age of mother at birth > 30 years Yes vs. no
Age of father at birth > 30 years Yes vs. no
Education level High vs. low
Region in the Netherlands Middle vs. north
West vs. north
Allergen avoidance measures taken No vs. yes
Carpeted bedroom floor Yes vs. no
Living in apartment Yes vs. no
Double-glazed windows Yes vs. no
Age of mattress 1-2 years vs. new
> 2 years vs. new
Mechanical ventilation No vs. yes
Construction period of house 1920-1975 vs. after 1975
Before 1920 vs. after 1975
Damp stains (anywhere) Yes vs. no
Firstborn child Yes vs. no
Season of sampling Winter vs. autumn
Spring vs. autumn
Summer vs. autumn
No.
Adjusted [R.sup.2]
Dust Der p 1 + Der f 1
168 mg/[m.sup.2] 248 mg/[m.sup.2]
Variable (b) (b)
Study group 0.9 (0.8-1.1) 1.0 (0.8-1.2)
1.0 (0.9-1.2) 1.0 (0.8-1.2)
0.8 (0.7-0.9) ** 0.8 (0.6-0.9) (#)
Age of mother at birth > 30
years 1.1 (1.0-1.3) (#) 1.2 (1.0-1.5) (#)
Age of father at birth > 30
years 0.9 (0.8-1.1) 1.0 (0.8-1.2)
Education level 1.0 (0.9-1.1) 1.1 (1.0-1.3)
Region in the Netherlands 0.8 (0.7-0.9) ** 0.9 (0.8-1.1)
0.8 (0.7-0.9) ** 0.8 (0.7-1.0) *
Allergen avoidance measures
taken 1.1 (1.0-1.2) 1.0 (0.9-1.2)
Carpeted bedroom floor 1.0 (0.9-1.1) 1.1 (0.9-1.2)
Living in apartment 1.0 (0.9-1.2) 1.2 (0.9-1.6)
Double-glazed windows 0.9 (0.8-1.1) 0.8 (0.7-1.0) (#)
Age of mattress 1.1 (1.0-1.3) * 1.1 (0.9-1.3)
1.2 (1.0-1.4) (#) 1.8 (1.4-2.2) **
Mechanical ventilation 0.9 (0.8-1.0) * 0.9 (0.7-1.1)
Construction period of house 1.1 (1.0-1.3) 1.1 (0.9-1.4)
1.0 (0.8-1.3) 1.2 (0.9-1.7)
Damp stains (anywhere) 1.1 (1.0-1.2) 1.1 (1.0-1.3) *
Firstborn child 0.9 (0.8-1.0) (#) 0.6 (0.5-0.8) **
Season of sampling 0.9 (0.8-1.0) 0.7 (0.6-0.9) **
1.1 (1.0-1.3) 0.7 (0.6-0.9) **
1.1 (1.0-1.3) 1.0 (0.8-1.3)
No. 1,083 1,024
Adjusted [R.sup.2] 0.05 0.14
(a) Concentration ratio between presence and absence of characteristic
described in table. (b) Concentration is the reference concentration a
subject would have had when all variables in the model assume the
reference value (0). * p < 0.1; ** p < 0.01; (#) p< 0.05.
Table 5. Relative difference in dust and total mite allergen (Der p 1
+ Der f 1) on the parents' mattress, in relation to various housing
and occupant characteristics. (a)
Variable Contrast
Study group NHS-a vs. NHS-a
IS-pl vs. NHS-a
IS-act vs. NHS-a
Age of mother at birth > 30 years Yes vs. no
Age of father at birth > 30 years Yes vs. no
Education level High vs. low
Region in the Netherlands Middle vs. north
West vs. north
Allergen avoidance measures taken No vs. yes
Carpeted bedroom floor Yes vs. no
Living in apartment Yes vs. no
Double-glazed windows Yes vs. no
Age of mattress 3-6 years vs. < 3 years
> 6 years vs. < 3 years
Mechanical ventilation No vs. yes
Construction period of house 1920-1975 vs. after 1975
Before 1920 vs. after 1975
Damp stains (anywhere) Yes vs. no
Firstborn child Yes vs. no
Season of sampling Winter vs. autumn
Spring vs. autumn
Summer vs. autumn
No.
Adjusted [R.sup.2]
Dust Der p 1 + Der f 1
385 mg/[m.sup.2] 381 ng/[m.sup.2]
Variable (b) (b)
Study group 1.1 (1.0-1.2) (#) 1.4 (1.1-1.8) (#)
0.9 (0.8-1.0) 0.7 (0.6-1.0) *
0.7 (0.6-0.8) ** 0.4 (0.3-0.5) **
Age of mother at birth
> 30 years 1.0 (0.9-1.1) 1.1 (0.9-1.4)
Age of father at birth
> 30 years 0.9 (0.8-1.0) 0.9 (0.7-1.2)
Education level 1.0 (0.9-1.0) 1.0 (0.9-1.3)
Region in the Netherlands 1.0 (0.9-1.1) 0.7 (0.5-0.8) **
0.6 (0.6-0.7) ** 0.5 (0.4-0.6) **
Allergen avoidance measures
taken 0.9 (0.8-1.0) 1.1 (0.9-1.3)
Carpeted bedroom floor 0.9 (0.8-1.0) ** 0.9 (0.8-1.1)
Living in apartment 1.1 (1.0-1.3) * 1.1 (0.8-1.5)
Double-glazed windows 0.9 (0.8-1.0) * 0.9 (0.7-1.0)
Age of mattress 1.0 (0.9-1.1) 1.9 (1.5-2.4) **
1.0 (0.9-1.1) 1.7 (1.3-2.2) **
Mechanical ventilation 1.0 (0.9-1.1) 1.0 (0.8-1.3)
Construction period of house 1.1 (0.9-1.2) 1.5 (1.2-1.9) **
0.9 (0.8-1.1) 1.3 (0.9-2.0)
Damp stains (anywhere) 1.0 (0.9-1.1) 1.2 (0.9-1.4)
Firstborn child 1.0 (0.9-1.1) 0.8 (0.6-0.9) (#)
Season of sampling 0.9 (0.8-1.0) 0.7 (0.5-0.8) **
0.9 (0.8-1.0) 0.6 (0.5-0.8) **
1.0 (0.9-1.1) 1.1 (0.8-1.4)
No. 1,135 1,081
Adjusted [R.sup.2] 0.14 0.17
(a) Concentration ratio between presence and absence of characteristic
described in table. (b) Concentration is the reference concentration a
subject would have had when all variables in the model assume the
reference value (0). * p < 0.1; ** p < 0.01; * p < 0.05.
Table 6. Relative difference in cat and dog allergen (Fel d 1 and Can
f 1) on the child's mattress, in relation to various housing and
occupant characteristics. (a)
Variable Contrast
Cat or dog in home Yes vs. no
Study group NHS-na vs. NHS-a
IS-pl vs. NHS-a
IS-act vs. NHS-a
Age of mother at birth > 30 years Yes vs. no
Age of father at birth > 30 years Yes vs. no
Education level High vs. low
Region in the Netherlands Middle vs. north
West vs. north
Allergen avoidance measures taken No vs. yes
Carpeted bedroom floor Yes vs. no
Living in apartment Yes vs. no
Double-glazed windows Yes vs. no
Age of mattress 1-2 years vs. new
> 2 years vs. new
Mechanical ventilation No vs. yes
Construction period of house 1920-1975 vs. after 1975
Before 1920 vs. after 1975
Damp stains (anywhere) Yes vs. no
Firstborn child Yes vs. no
Season of sampling Winter vs. autumn
Spring vs. autumn
Summer vs. autumn
No.
Adjusted [R.sup.2]
Fel d 1 Can f 1
31 mU/[m.sup.2] 249 mU/[m.sup.2]
Variable (b) (b)
Cat or dog in home 14.4(11.4-18.2) ** 9.1 (7.7-10.8) **
Study group 0.9 (0.7-1.2) 1.0 (0.8-1.1)
1.2 (0.9-1.7) 1.0 (0.8-1.2)
0.8 (0.6-1.1) 0.8 (0.7-0.9) (#)
Age of mother at birth
> 30 years 1.2 (0.9-1.5) 1.0 (0.9-1.2)
Age of father at birth
> 30 years 0.9 (0.7-1.2) 0.9 (0.8-1.1)
Education level 0.9 (0.7-1.1) 1.0 (0.9-1.2)
Region in the Netherlands 0.8 (0.6-1.0) * 1.0 (0.9-1.2)
0.8 (0.6-1.1) 0.9 (0.8-1.1)
Allergen avoidance measures
taken 1.0 (0.8-1.3) 1.0 (0.9-1.1)
Carpeted bedroom floor 0.9 (0.7-1.1) 1.0 (0.8-1.1)
Living in apartment 1.1 (0.8-1.6) 1.0 (0.8-1.2)
Double-glazed windows 0.9 (0.7-1.1) 0.9 (0.8-1.0) *
Age of mattress 1.3 (1.0-1.7) * 1.1 (0.9-1.2)
1.4 (1.0-1.9) (#) 1.0 (0.9-1.2)
Mechanical ventilation 0.9 (0.7-1.1) 0.8 (0.7-1.0) (#)
Construction period of house 1.1 (0.8-1.5) 1.1 (0.9-1.3)
0.9 (0.5-1.4) 0.9 (0.7-1.2)
Damp stains (anywhere) 1.1 (0.9-1.4) 1.0 (0.9-1.2)
Firstborn child 1.2 (0.9-1.5) 1.0 (0.9-1.2)
Season of sampling 0.8 (0.6-1.0) * 0.9 (0.8-1.1)
0.9 (0.7-1.2) 1.0 (0.8-1.2)
0.7 (0.5-1.0) * 0.9 (0.8-1.1)
No. 1,031 1,021
Adjusted [R.sup.2] 0.35 0.40
(a) Concentration ratio between presence and absence of characteristic
described in table. (b) Concentration is the reference concentration a
subject would have had when all variables in the model assume the
reference value (0). * p < 0.1; ** p < 0.01; * p < 0.05.
Table 7. Relative difference in cat and dog allergen (Fel d 1 and Can
f 1) on the parents' mattress, in relation to various housing and
occupant characteristics. (a)
Variable Contrast
Cat or dog in home Yes vs. no
Study group NHS-na vs. NHS-a
IS-pl vs. NHS-a
IS-act vs. NHS-a
Age of mother at birth > 30 years Yes vs. no
Age of father at birth > 30 years Yes vs. no
Education level High vs. low
Region in the Netherlands Middle vs. north
West vs. north
Allergen avoidance measures taken No vs. yes
Carpeted bedroom floor Yes vs. no
Living in apartment Yes vs. no
Double-glazed windows Yes vs. no
Age of mattress 1-2 years vs. new
> 2 years vs. new
Mechanical ventilation No vs. yes
Construction period of house 1920-1975 vs. after 1975
Before 1920 vs. after 1975
Damp stains (anywhere) Yes vs. no
Firstborn child Yes vs. no
Season of sampling Winter vs. autumn
Spring vs. autumn
Summer vs. autumn
No.
Adjusted [R.sup.2]
Fel d 1 Can f 1
48 mU/[m.sup.2] 183 ng/[m.sup.2]
Variable (b) (b)
Cat or dog in home 15.8 (13.4-18.6) ** 20.3 (17.3-23.8) **
Study group 1.1 (0.9-1.4) 1.1 (1.0-1.3)
1.0 (0.8-1.2) 0.8 (0.6-0.9) **
0.6 (0.5-0.8) ** 0.6 (0.5-0.7) **
Age of mother at birth
> 30 years 1.0 (0.8-1.2) 1.0 (0.8-1.1)
Age of father at birth
> 30 years 0.8 (0.6-0.9) ** 0.9 (0.8-1.0)
Education level 1.1 (0.9-1.3) 0.9 (0.8-1.0) (#)
Region in the Netherlands 0.9 (0.7-1.1) 1.0 (0.9-1.1)
0.7 (0.5-0.8) ** 0.8 (0.7-1.0) (#)
Allergen avoidance measures 0.9 (0.7-1.1) 0.9 (0.8-1.1)
taken
Carpeted bedroom floor 0.8 (0.7-0.9) ** 0.8 (0.7-0.9) **
Living in apartment 1.3 (1.0-1.7) (#) 1.1 (0.9-1.3)
Double-glazed windows 0.9 (0.8-1.1) 0.9 (0.8-1.0) *
Age of mattress 0.9 (0.8-1.1) 1.0 (0.9-1.1)
0.9 (0.7-1.1) 0.9 (0.8-1.1)
Mechanical ventilation 1.0 (0.8-1.2) 1.0 (0.9-1.1)
Construction period of
house 1.2 (1.0-1.5) 1.1 (0.9-1.3)
1.1 (0.8-1.6) 1.0 (0.7-1.2)
Damp stains (anywhere) 1.0 (0.9-1.2) 0.9 (0.8-1.0)
Firstborn child 0.9 (0.8-1.1) 1.1 (0.9-1.2)
Season of sampling 1.0 (0.8-1.2) 0.9 (0.8-1.1)
1.0 (0.8-1.2) 0.9 (0.8-1.1)
1.0 (0.8-1.3) 1.1 (0.9-1.3)
No. 1,028 1,064
Adjusted [R.sup.2] 0.54 0.61
(a) Concentration ratio between presence and absence of characteristic
described in table. (b) Concentration is the reference concentration a
subject would have had when all variables in the model assume the
reference value (0). * p < 0.1; ** p < 0.01; * p < 0.05.
REFERENCES Brunekreef B, Groot B, Hoek G. 1992. Pets, allergy, and respiratory symptoms in children. Int J Epidemiol 21(2):338-342. Chatfield C. 1996. The Analysis of Time Series. 5th ed. London:Chapman & Hall. Chew GL, Burge HA, Dockery OW, Muilenberg ML, Weiss ST, Gold DR. 1998. Limitations of a home characteristics questionnaire as a predictor of indoor allergen levels. Am J Respir Crit Care Med 157:1536-1541. Chew GL, Higgins KM, Gold DR, Muilenberg ML, Burge HA. 1999. Monthly measurements of indoor allergens and the influence of housing type in a northeastern US city. Allergy 54:1058-1066. Custovic A, Simpson BM, Simpson A, Hallam C, Craven CRAVEN. A word of obloquy, which in trials by battle, was pronounced by the vanquished; upon which judgment was rendered against him. M, Brutsche M, et al. 2000. Manchester Asthma and Allergy Study: low-allergen environment can be achieved and maintained during pregnancy and in early life. J Allergy Clin Immunol 105:252-258. Custovic A, Simpson BM, Simpson A, Kissen P, Woodcock woodcock: see snipe. woodcock Any of five species (family Scolopacidae) of plump, sharp-billed migratory birds of damp, dense woodlands in North America, Europe, and Asia. A. 2001. Effect of environmental manipulation in pregnancy and early life on respiratory symptoms and atopy atopy /at·o·py/ (at´ah-pe) a genetic predisposition toward the development of immediate hypersensitivity reactions against common environmental antigens (atopic allergy), most commonly manifested as allergic rhinitis but also as during first year of life: a randomized ran·dom·ize tr.v. ran·dom·ized, ran·dom·iz·ing, ran·dom·iz·es To make random in arrangement, especially in order to control the variables in an experiment. trial. Lancet lancet /lan·cet/ (lan´set) a small, pointed, two-edged surgical knife. lan·cet n. 358:188-193. Gross I, Heinrich J, Fahtbusch B, Jager L, Bischof W, Wichmann HE. 2000. Indoor determinants of Der p 1 and Der f 1 concentrations in house dust are different. Clin Exp Allergy 30:376-382. Horst A, Halken S. 2000. The role of allergy in childhood asthma. Allergy 55:600-608. Lakwijk N, van Strien RT, Doekes G, Brunekreef B, Gerritsen J. 1998. Validation See validate. validation - The stage in the software life-cycle at the end of the development process where software is evaluated to ensure that it complies with the requirements. of a screening questionnaire for atopy with serum IgE tests in a population of pregnant Dutch women. Clin Exp Allergy 28(4):454-458. Lau S, Illi S, Sommerfeld C, Niggemann B, Bergmann R, von Mutius E, et al. 2000. Early exposure to house-dust mite and cat allergens and development of childhood asthma: a cohort study: Multicentre Allergy Study Group. Lancet 356:1392-1397. Sears MR. 1998. Evolution of asthma through childhood. Clin Exp Allergy 28(suppl 5):82-89. Simpson A, Woodcock A, Custovic A. 2001. Housing characteristics and mite allergen levels: to humidity humidity, moisture content of the atmosphere, a primary element of climate. Humidity measurements include absolute humidity, the mass of water vapor per unit volume of natural air; relative humidity (usually meant when the term humidity and beyond [Editorial]. Clin Exp Allergy 31:803-805. Strachan DP. 1999. The epidemiology epidemiology, field of medicine concerned with the study of epidemics, outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause of childhood asthma. Allergy 54:7-11. van Strien RT, Verhoeff AP, Brunekreef B, van Wijnen JH. 1994. Mite antigen antigen: see immunity. antigen Foreign substance in the body that induces an immune response. The antigen stimulates lymphocytes to produce antibodies or to attack the antigen directly (see antibody;immunity). in house dust: relationship with different housing characteristics in the Netherlands. Clin Exp Allergy 24:84,3-853. van Strien RT, Verhoeff AP, van Wijnen JH, Doekes G, de Meer G, Brunekreef B. 1995. Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms. Clin Exp Allergy 25:1184-1189. Verhoeff AP, van Strien RT, van Wijnen JH, Brunekreef B. 1994. House dust mite house dust mite Dermatophagoides farinae, D pteronyssoides A mite that feeds on household detritus, which is often highly allergenic; exposure to HDMs can be measured by RAST allergen (Der p 1) and respiratory symptoms in children: a 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. . Clin Exp Allergy 24:1061-1069. Wahn U, Lau S, Bergmann Fi, Kulig M, Forster J, Bergmann K, et al. 1997. Indoor allergen exposure is a risk factor for sensitization during the first three years of life. J Allergy Clin Immunol 99:763-769. Wickens K, Mason K, Fitzharris P, Siebers R, Hearfield M, Cunningham M, et al. 2001. The importance of housing characteristics in determining Der p 1 levels in carpets in New Zealand New Zealand (zē`lənd), island country (2005 est. pop. 4,035,000), 104,454 sq mi (270,534 sq km), in the S Pacific Ocean, over 1,000 mi (1,600 km) SE of Australia. The capital is Wellington; the largest city and leading port is Auckland. homes. Clin Exp Allergy 31:827-835. Wijga A, Smit HA, Brunekreef B, Gerritsen J, Kerkhof M, Koopman LP, et al. 2001. Are children at high familial familial /fa·mil·i·al/ (fah-mil´e-il) occurring in more members of a family than would be expected by chance. fa·mil·ial adj. risk of developing allergy born into a low risk environment? The PIAMA Birth Cohort Study. Clin Exp Allergy 31:576-581. Rob T. van Strien, (1) Laurens P. Koopman, (2) Marjan Kerkhof, (3) Jack Spithoven, (1) Johan C. de Jongste, (2) Jorrit Gerritsen, (4) Herman J. Neijens, (2) Rob C. Aalberse, (5) Henriette A. Smit, (6) and Bert Brunekreef (1) (1) Department of Environmental and Occupational Health, Institute for Risk Assessment Sciences, Utrecht University The university's motto is "Sol Iustitiae Illustra Nos", which means "Sun of Justice, shine upon us". Utrecht University is led by the University Board, consisting of Yvonne van Rooy (president), prof.dr. Willem Hendrik Gispen (rector magnificus) and Hans Amman. , Utrecht, The Netherlands; (2) Department of Pediatrics pediatrics (pēdēă`trĭks), branch of medicine dedicated to the attainment of the best physical, emotional, and social health for infants, children, and young people generally. , Sophia Children's Hospital A children's hospital is a hospital which offers its services exclusively to children. The number of children's hospitals proliferated in the 20th century, as pediatric medical and surgical specialties separated from internal medicine and adult surgical specialties. , Rotterdam, The Netherlands; (3) Department of Epidemiology and Statistics, University Groningen, Groningen, The Netherlands; (4) Department of Pediatric pediatric /pe·di·at·ric/ (pe?de-at´rik) pertaining to the health of children. pe·di·at·ric adj. Of or relating to pediatrics. Respiratory Medicine, University Hospital Groningen, Groningen, The Netherlands; (5) Central Laboratory for the Blood Transfusion blood transfusion, transfer of blood from one person to another, or from one animal to another of the same species. Transfusions are performed to replace a substantial loss of blood and as supportive treatment in certain diseases and blood disorders. Service, Department of Allergy, Amsterdam, The Netherlands; (6) National Institute of Public Health and the Environment, Bilthoven, The Netherlands Address correspondence to B. Brunekreef, Utrecht University, IRAS-EOH, PO Box 80176, 3508 TD Utrecht, The Netherlands. Telephone: +31 302535400. Fax: +31 302539499. E-mail: b.brunekreef@iras.uu.nl Received 30 January 2002; accepted 17 June 2002. |
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