Maternal periconceptional exposure to drinking water disinfection by-products and neural tube defects in offspring.

BACKGROUND: Associations between maternal periconceptional exposure to disinfection by-products (DBPs) in drinking water and neural tube defects (NTDs) in offspring are inconclusive, limited in part by exposure misclassification. METHODS: Maternal interview reports of drinking water sources and consumption from the National Birth Defects Prevention Study were linked with DBP concentrations in public water system monitoring data for case children with an NTD and control children delivered during 2000-2005. DBPs analyzed were total trihalomethanes, the five most common haloacetic acids combined, and individual species. Associations were estimated for all NTDs combined and selected subtypes (spina bifida, anencephaly) with maternal periconceptional exposure to DBPs in public water systems and with average daily periconceptional ingestion of DBPs accounting for individual-level consumption and filtration information. Mixed effects logistic regression models with maternal race/ethnicity and educational attainment at delivery as fixed effects and study site as a random intercept were applied. RESULTS: Overall, 111 case and 649 control children were eligible for analyses. Adjusted odds ratios for maternal exposure to DBPs in public water systems ranged from 0.8-1.5 for all NTDs combined, 0.6-2.0 for spina bifida, and 0.7-1.9 for anencephaly; respective ranges for average daily maternal ingestion of DBPs were 0.7-1.1, 0.5-1.5, and 0.6-1.8. Several positive estimates (≥1.2) were observed, but all confidence intervals included the null. CONCLUSIONS: Using community- and individual-level data from a large, US, population-based, case-control study, we observed statistically nonsignificant associations between maternal periconceptional exposure to total and individual DBP species in drinking water and NTDs and subtypes.

Prenatal diagnosis and cesarean section in a large, population-based birth defects registry.

OBJECTIVE: To describe the patterns of cesarean section (CS) and vaginal delivery by type of birth defect and determine whether prenatal diagnosis predicts a higher or lower likelihood of CS for selected defect categories. METHODS: Data from a large population-based registry were analyzed to determine percentages of vaginal versus CS delivery for each of 49 categories of birth defects. Odds ratios and statistical significance were computed to determine if a record of prenatal diagnosis (PND) predicted delivery mode. Cases were liveborn children with any of these defects born in Texas between 1997 and 2005. RESULTS: Forty-three percent of infants in the study were delivered by CS, with a range of 25.3% (aniridia) to 62.4% (spina bifida). A record of prenatal diagnosis of the primary assigned birth defect was found in 43.0% of all records but varied substantially by defect category. PND significantly predicted higher CS percentages for spina bifida without anencephaly, encephalocele, hydrocephaly, transposition of the great vessels, ventricular septal defect, pulmonary valve atresia/stenosis, craniosynostosis, diaphragmatic hernia, gastroschisis, and trisomy 21. Vaginal delivery was predicted by PND of anencephaly, agenesis, aplasia, or hypoplasia of the lung, renal agenesis or dysgenesis, and trisomy 18. CONCLUSION: Texas children with birth defects are more likely to have been delivered by CS than the population in general. For several types of defects, prenatal diagnosis is predictive of higher odds of CS; for others, especially fatal defects, PND predicts lower CS likelihood.

Urban-rural residence and the occurrence of neural tube defects in Texas, 1999-2003.

Neural tube birth defects (NTDs) affect more than 4000 pregnancies in the US annually. The etiology of NTDs is believed to be multifactorial, but much remains unknown. We examined the pattern and magnitude of urban-rural variation in anencephaly, spina bifida without anencephaly, and encephalocele in Texas in relation with urban-rural residence for the period 1999-2003. There was no evidence that urban-rural residence was associated with changes in the rate of anencephaly or spina bifida without anencephaly in unadjusted or adjusted analyses. In contrast, rates of encephalocele were statistically significantly higher in areas classified as suburban or more rural compared to urban areas using four different urban-rural residence indicators.

The population-based prevalence of achondroplasia and thanatophoric dysplasia in selected regions of the US.

There have been no large population-based studies of the prevalence of achondroplasia and thanatophroic dysplasia in the United States. This study compared data from seven population-based birth defects monitoring programs in the United States. We also present data on the association between older paternal age and these birth defects, which has been described in earlier studies. The prevalence of achondroplasia ranged from 0.36 to 0.60 per 10,000 livebirths (1/27,780-1/16,670 livebirths). The prevalence of thanatophoric dysplasia ranged from 0.21 to 0.30 per 10,000 livebirths (1/33,330-1/47,620 livebirths). In Texas, fathers that were 25-29, 30-34, 35-39, and > or =40 years of age had significantly increased rates of de novo achondroplasia among their offspring compared with younger fathers. The adjusted prevalence odds ratios were 2.8 (95% CI; 1.2, 6.7), 2.8 (95% CI; 1.0, 7.6), 4.9 (95% CI; 1.7, 14.3), and 5.0 (95% CI; 1.5, 16.1), respectively. Using the same age categories, the crude prevalence odds ratios for de novo cases of thanatophoric dysplasia in Texas were 5.8 (95% CI; 1.7, 9.8), 3.9 (95% CI; 1.1, 6.7), 6.1 (95% CI; 1.6, 10.6), and 10.2 (95% CI; 2.6, 17.8), respectively. These data suggest that thanatophoric dysplasia is one-third to one-half as frequent as achondroplasia. The differences in the prevalence of these conditions across monitoring programs were consistent with random fluctuation. Birth defects monitoring programs may be a good source of ascertainment for population-based studies of achondroplasia and thanatophoric dysplasia, provided that diagnoses are confirmed by review of medical records.

Relation between ambient air quality and selected birth defects, seven county study, Texas, 1997-2000.

A population-based case-control study investigated the association between maternal exposure to air pollutants, carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter <10 microm in aerodynamic diameter during weeks 3-8 of pregnancy and the risk of selected cardiac birth defects and oral clefts in livebirths and fetal deaths between 1997 and 2000 in seven Texas counties. Controls were frequency matched to cases on year of birth, vital status, and maternal county of residence at delivery. Stationary monitoring data were used to estimate air pollution exposure. Logistic regression models adjusted for covariates available in the vital record. When the highest quartile of exposure was compared with the lowest, the authors observed positive associations between carbon monoxide and tetralogy of Fallot (odds ratio = 2.04, 95% confidence interval: 1.26, 3.29), particulate matter <10 microm in aerodynamic diameter and isolated atrial septal defects (odds ratio = 2.27, 95% confidence interval: 1.43, 3.60), and sulfur dioxide and isolated ventricular septal defects (odds ratio = 2.16, 95% confidence interval: 1.51, 3.09). There were inverse associations between carbon monoxide and isolated atrial septal defects and between ozone and isolated ventricular septal defects. Evidence that air pollution exposure influences the risk of oral clefts was limited. Suggestive results support a previously reported finding of an association between ozone exposure and pulmonary artery and valve defects.

The National Birth Defects Prevention Study.

The National Birth Defects Prevention Study was designed to identify infants with major birth defects and evaluate genetic and environmental factors associated with the occurrence of birth defects. The ongoing case-control study covers an annual birth population of 482,000 and includes cases identified from birth defect surveillance registries in eight states. Infants used as controls are randomly selected from birth certificates or birth hospital records. Mothers of case and control infants are interviewed and parents are asked to collect buccal cells from themselves and their infants for DNA testing. Information gathered from the interviews and the DNA specimens will be used to study independent genetic and environmental factors and gene-environment interactions for a broad range of birth defects. As of December 2000, 7,470 cases and 3,821 controls had been ascertained in the eight states. Interviews had been completed with 70% of the eligible case and control mothers, buccal cell collection had begun in all of the study sites, and researchers were developing analysis plans for the compiled data. This study is the largest and broadest collaborative effort ever conducted among the nation's leading birth defect researchers. The unprecedented statistical power that will result from this study will enable scientists to study the epidemiology of some rare birth defects for the first time. The compiled interview data and banked DNA of approximately 35 categories of birth defects will facilitate future research as new hypotheses and improved technologies emerge.

Diurnal variation in responses to influenza vaccine.

Data from two field trials of influenza vaccine were examined for an association between vaccination time and subject response. Both were conducted on adults and involved the same antigens and dose via intramuscular injection. In one study (Princeton) a diurnal pattern in antibody response to the antigen A/Philippines, but not to A/Chile or B/USSR, was detected after the first vaccination administered during summer 1984, but not after the second revaccination given during summer 1985. In a second study (Houston) conducted during autumn 1985, no diurnal pattern in antibody response was detected for any of the antigens assessed. No diurnal pattern in systemic reactions was observed. Previously vaccinated subjects of both studies more commonly experienced local reactions of arm redness, hardness, and soreness after afternoon versus morning (p < 0.05) injection upon revaccination, both before and after adjustment for possible confounders of age and gender.

A comparison of the health status of Riverdale residents with residents of the rest of Toronto based on the Toronto Community Health Survey.

OBJECTIVES: To compare the health status of Riverdale residents with residents of the rest of Toronto. DESIGN: Cross-sectional telephone survey. SETTING: Toronto. TIME FRAME: October 1988-June 1989. PARTICIPANTS: Four hundred and fourteen residents of Riverdale, a residential-industrial area of Toronto, and 866 residents of the rest of Toronto, age 15 years and older in households with telephones. MAIN RESULTS: Respondents in Riverdale compared to respondents in the rest of Toronto were more likely to speak languages other than English, have less formal education, and be of Oriental ethnic origin. Perceived health status varied between the two areas, but no significant difference existed in diagnosed morbidity. Riverdale respondents were much more aware of food and soil contamination than respondents from the rest of Toronto.

Toronto tap water: perception of its quality and use of alternatives.

A cross-sectional telephone survey determined attitudes of City of Toronto residents toward the quality of their tap water, and their usage of alternative drinking water sources. Overall, 49% of households rated the water as good or very good, although 73% felt that it contained some or a lot of chemical pollutants. An alternative to tap water was used by 40.5% of households; 35% were 'regular' users, obtaining at least 50% of their consumed water this way. In terms of specific alternatives, 22.5% of households consumed bottled water, 11% treated tap water additionally with a home device, and 12% boiled their water. For 'regular users', the proportions were 19.5%, 10% and 10% respectively. This surprisingly high and probably increasing usage of alternatives may have implications for regulation.

Temporal patterns of reported single-vehicle car and truck accidents in Texas, U.S.A. during 1980-1983.

Reported single car and truck accidents due specifically to driver 'fatigue' for the 4-year span of 1980-1983 were analyzed for 24-hr, 7-d and 1-yr patterns. Three types of data were examined: (1) accidents in rural Texas, (2) accidents only in San Antonio, the fourth largest city in Texas and (3) accident ratio (number of accidents per time interval divided by traffic volume for the interval) in this city. A statistically significant seasonal variation of relatively low amplitude with peaks in May and July was detected only for accidents in rural areas. High-amplitude periodicities of 7 d were evident in all the data sets, with a peak on the weekend. A very prominent 24-hr pattern was detected as well, with the acrophase determined by single cosinor around 0300. A slight secondary peak in accidents, around 1500, was evident in the data from the rural areas. This secondary peak represented a 12-hr rhythm in addition to the 24-hr. Overall, features of the temporal patterns in accidents over 24 hr and over the year in urban and rural areas differed only slightly. Accident ratios yielded results similar to accident frequencies. However, with regard to the rural data, the shape of the 24-hr temporal pattern varied with driver age; older drivers exhibited a flatter curve with a more pronounced afternoon rather than early morning (around 0300) peak.