BACKGROUND:Evidence in animal models and humans suggests that exposure to polycyclic aromatic hydrocarbons (PAHs) may lead to birth defects. To our knowledge, this relationship has not been evaluated for craniosynostosis, a birth defect characterized by the premature closure of sutures in the skull. We conducted a case-control study to examine associations between maternal occupational exposure to PAHs and craniosynostosis.METHODS:We used data from craniosynostosis cases and control infants in the National Birth Defects Prevention Study (NBDPS) with estimated delivery dates from 1997 to 2002. Industrial hygienists reviewed occupational data from the computer-assisted telephone interview and assigned a yes/no rating of probable occupational PAH exposure for each job from 1 month before conception through delivery. We used logistic regression to assess the association between occupational exposure to PAHs and craniosynostosis.RESULTS:The prevalence of exposure was 5.3% in case mothers (16/300) and 3.7% in control mothers (107/2,886). We observed a positive association between exposure to PAHs during the 1 month before conception through the third month of pregnancy and craniosynostosis (odds ratio [OR] = 1.75; 95% confidence interval [CI], 1.01-3.05) after adjusting for maternal age and maternal education. The number of cases for each craniosynostosis subtype limited subtype analyses to sagittal craniosynostosis; the odds ratio remained similar (OR = 1.76, 95% CI, 0.82-3.75), but was not significant.CONCLUSION:Our findings support a moderate association between maternal occupational exposure to PAHs and craniosynostosis. Additional work is needed to better characterize susceptibility and the role PAHs may play on specific craniosynostosis subtypes.
BACKGROUND:Associations have been reported between maternal radiation exposure and birth defects. No such studies were found on radon. Our objective was to determine if there is an association between living in areas with higher radon levels and birth defects.METHODS:The Texas Birth Defects Registry provided data on all birth defects from 1999 to 2009 from the entire state. Mean radon levels by geologic region came from the Texas Indoor Radon Survey. The association between radon and birth defects was estimated using multilevel mixed effect Poisson regression.RESULTS:Birth defects overall were not associated with residential radon levels. Of the 100 other birth defect groups with at least 500 cases, 14 were significantly elevated in areas with high mean radon level in crude analyses, and 9 after adjustment for confounders. Cleft lip with/without cleft palate had an adjusted prevalence ratio of 1.16 per 1 picoCurie/liter (pCi/L) increase in exposure to region mean radon, 95% confidence interval, 1.08-1.26. Cystic hygroma / lymphangioma had an adjusted prevalence ratio of 1.22 per 1 pCi/L increase, 95% confidence interval, 1.02-1.46. Other associations were suggested but not as consistent: three skeletal defects, Down syndrome, other specified anomalies of the brain, and other specified anomalies of the bladder and urethra.CONCLUSION:In the first study of residential radon and birth defects, we found associations with cleft lip w/wo cleft palate and cystic hygroma / lymphangioma. Other associations were suggested. The ecological nature of this study and multiple comparisons suggest that our results be interpreted with caution.
BACKGROUND:Craniofacial microsomia (CFM) is a congenital condition with wide phenotypic variability, including hypoplasia of the mandible and external ear. We assembled a cohort of children with facial features within the CFM spectrum and children without known craniofacial anomalies. We sought to develop a standardized approach to assess and describe the facial characteristics of the study cohort, using multiple sources of information gathered over the course of this longitudinal study and to create case subgroups with shared phenotypic features. METHODS:Participants were enrolled between 1996 and 2002. We classified the facial phenotype from photographs, ratings using a modified version of the Orbital, Ear, Mandible, Nerve, Soft tissue (OMENS) pictorial system, data from medical record abstraction, and health history questionnaires. RESULTS:The participant sample included 142 cases and 290 controls. The average age was 13.5 years (standard deviation, 1.3 years; range, 11.1-17.1 years). Sixty-one percent of cases were male, 74% were white non-Hispanic. Among cases, the most common features were microtia (66%) and mandibular hypoplasia (50%). Case subgroups with meaningful group definitions included: (1) microtia without other CFM-related features (n = 24), (2) microtia with mandibular hypoplasia (n = 46), (3) other combinations of CFM- related facial features (n = 51), and (4) atypical features (n = 21). CONCLUSION:We developed a standardized approach for integrating multiple data sources to phenotype individuals with CFM, and created subgroups based on clinically-meaningful, shared characteristics. We hope that this system can be used to explore associations between phenotype and clinical outcomes of children with CFM and to identify the etiology of CFM. Birth Defects Research (Part A) 106:915-926, 2016.© 2016 Wiley Periodicals, Inc.
BACKGROUNDWe examined associations of birth defects with residential proximity to commercial agricultural pesticide applications in California. Subjects included 367 cases representing five types of birth defects and 785 nonmalformed controls born 1997 to 2006.METHODSAssociations with any versus no exposure to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for covariates. Overall, 46% of cases and 38% of controls were classified as exposed to pesticides within a 500 m radius of mother's address during a 3-month periconceptional window.RESULTSWe estimated odds ratios (ORs) for 85 groups and 95 chemicals with five or more exposed cases and control mothers. Ninety-five percent confidence intervals (CI) excluded 1.0 for 11 ORs for groups and 22 ORs for chemicals, ranging from 1.9 to 3.1 for groups and 1.8 to 4.9 for chemicals except for two that were <1 (noted below).CONCLUSIONFor groups, these ORs were for anotia/microtia (n = 95 cases) and dichlorophenoxy acids/esters and neonicotinoids; anorectal atresia/stenosis (n = 77) and alcohol/ethers and organophosphates (these ORs were < 1.0); transverse limb deficiencies (n = 59) and dichlorophenoxy acids/esters, petroleum derivatives, and triazines; and craniosynostosis (n = 79) and alcohol/ethers, avermectins, neonicotinoids, and organophosphates. For chemicals, ORs were: anotia/microtia and five pesticides from the groups dichlorophenoxy acids/esters, copper-containing compounds, neonicotinoids, organophosphates, and triazines; transverse limb deficiency and six pesticides - oxyfluorfen and pesticides from the groups copper-containing compounds, 2,6-dinitroanilines, neonicotinoids, petroleum derivatives and polyalkyloxy compounds; craniosynostosis and 10 pesticides - oxyfluorfen and pesticides from the groups alcohol/ethers, avermectins, n-methyl-carbamates, neonicotinoids, ogranophosphates (two chemicals), polyalkyloxy compounds (two chemicals), and pyrethroids; and congenital diaphragmatic hernia (n = 62) and a copper-containing compound.
BACKGROUND An increasing number of radiologic exams are performed in the United States, but very few studies have examined the effects of maternal exposure to radiologic exams during the periconceptional period and birth defects. OBJECTIVES To assess the association between maternal exposure to radiologic exams during the periconceptional period and 19 categories of birth defects using a large population-based study of birth defects. METHODS We studied 27,809 case mothers and 10,200 control mothers who participated in the National Birth Defects Prevention Study and delivered between 1997 and 2009. Maternal exposure to radiologic exams that delivered ionizing radiation to the urinary tract, lumbar spine, abdomen, or pelvis were identified based on the mother's report of type of radiologic exams, organ or body part scanned and the month during which the exam occurred RESULTS Overall, 0.9% of mothers reported exposure to one of these types of radiographic exams during the periconceptional period. We observed significant associations between maternal exposure during the first trimester and isolated Dandy-Walker malformation (odds ratio = 7.7; 95% confidence interval, 1.8-33) and isolated d-transposition of the great arteries (odds ratio = 3.8; 95% confidence interval, 1.4-10.3). However, the result for isolated Dandy-Walker malformation was based on only two exposed cases. CONCLUSION These results should be interpreted cautiously because multiple statistical tests were conducted and measurements of exposure were based on maternal report. However, our results may be useful for generating hypotheses for future studies. Birth Defects Research (Part A) 106:563-572, 2016. © 2016 Wiley Periodicals, Inc.
