Chlorination disinfection by-products and risk of congenital anomalies in England and Wales.

BACKGROUND: Increased risk of various congenital anomalies has been reported to be associated with trihalomethane (THM) exposure in the water supply. OBJECTIVES: We conducted a registry-based study to determine the relationship between THM concentrations and the risk of congenital anomalies in England and Wales. METHODS: We obtained congenital anomaly data from the National Congenital Anomalies System, regional registries, and the national terminations registry; THM data were obtained from water companies. Total THM (< 30, 30 to < 60, > or =60 microg/L), total brominated exposure (< 10, 10 to < 20, > or =20 microg/L), and bromoform exposure (< 2, 2 to < 4, > or =4 microg/L) were modeled at the place of residence for the first trimester of pregnancy. We included 2,605,226 live births, stillbirths, and terminations with 22,828 cases of congenital anomalies. Analyses using fixed- and random-effects models were performed for broadly defined groups of anomalies (cleft palate/lip, abdominal wall, major cardiac, neural tube, urinary and respiratory defects), a more restricted set of anomalies with better ascertainment, and for isolated and multiple anomalies. Data were adjusted for sex, maternal age, and socioeconomic status. RESULTS: We found no statistically significant trends across exposure categories for either the broadly defined or more restricted sets of anomalies. For the restricted set of anomalies with isolated defects, there were significant (p < 0.05) excess risks in the high-exposure categories of total THMs for ventricular septal defects [odds ratio (OR) = 1.43; 95% confidence interval (CI), 1.00-2.04] and of bromoform for major cardiovascular defects and gastroschisis (OR = 1.18; 95% CI, 1.00-1.39; and OR = 1.38; 95% CI, 1.00-1.92, respectively). CONCLUSION: In this large national study we found little evidence for a relationship between THM concentrations in drinking water and risk of congenital anomalies.

Down syndrome in births near landfill sites.

OBJECTIVES: The aim of the study was to examine the risk of giving birth to a child with Down syndrome associated with residence near landfill sites in England and Wales. METHODS: A 2-km zone around 6289 landfill sites processing special (hazardous), non-special and unknown waste type was used to indicate exposure. Postcodes within the 2-km zone were classified as 'exposed' and people living beyond 2 km comprised the reference population. Health outcome data were Down syndrome registrations from a national registry including 21 cytogenetic laboratories in England and Wales, for the years 1989 to 1998. With a Bayesian regression model, we calculated relative risks for the population living within 2 km of landfill sites relative to the reference population, assuming a common relative risk for all landfill sites. Adjustments were made for major confounders. RESULTS: There were 4640 cases of Down syndrome within 2 km of a landfill site. We found no excess risks of Down syndrome related to landfill sites. Adjustment for socio-economic status (SES) did not influence our estimates. There were no differences in risk between hazardous waste sites and other landfill sites. CONCLUSION: We found no excess risk of Down syndrome in populations living near landfill sites.

Long-term associations of outdoor air pollution with mortality in Great Britain.

BACKGROUND: Recent studies have indicated long-term effects on mortality of particulate and sulphur dioxide (SO(2)) pollution, but uncertainties remain over the size of any effects, potential latency and generalisability. METHODS: A small area study was performed across electoral wards in Great Britain of mean annual black smoke (BS) and SO(2) concentrations (from 1966) and subsequent all-cause and cause-specific mortality using random effect models within a Bayesian framework adjusted for social deprivation and urban/rural classification. Different latencies and changes in associations over time were assessed. RESULTS: Significant associations were found between BS and SO(2) concentrations and mortality. The effects were stronger for respiratory illness than other causes of mortality for the most recent exposure periods (shorter latency times) and most recent mortality period (lower pollutant concentrations). In pooled analysis across four sequential 4 year mortality periods (1982-98), adjusted excess relative risk for respiratory mortality was 3.6% (95% CI 2.6% to 4.5%) per 10 microg/m(3) BS and 13.2% (95% CI 11.5% to 14.9%) per 10 ppb SO(2), and in the most recent period (1994-8) it was 19.3% (95% CI 5.1% to 35.7%) and 21.7% (95% CI 2.9% to 38.5%), respectively. CONCLUSIONS: These findings add to the evidence that air pollution has long-term effects on mortality and point to continuing public health risks even at the relatively lower levels of BS and SO(2) that now occur. They therefore have importance for policies on public health protection through regulation and control of air pollution.

Relation of trihalomethane concentrations in public water supplies to stillbirth and birth weight in three water regions in England.

We investigated the association between total trihalomethanes (TTHMs) and risk of stillbirth and low and very low birth weight in three water regions in England, 1992-1998; associations with individual trihalomethanes (THMs) were also examined. Modeled estimates of quarterly TTHM concentrations in water zones, categorized as low (< 30 microg/L), medium (30-59 microg/L), or high (> or = 60 microg/L), were linked to approximately 1 million routine birth and stillbirth records using maternal residence at time of birth. In one region, where there was a positive socioeconomic deprivation gradient across exposure categories, there was also a positive, significant association of TTHM with risk of stillbirth and low and very low birth weight. Overall summary estimates across the three regions using a random-effects model to allow for between-region heterogeneity in exposure effects showed small excess risks in areas with high TTHM concentrations for stillbirths [odds ratio (OR) = 1.11; 95% confidence interval (CI), 1.00-1.23), low birth weight (OR = 1.09; 95% CI, 0.93-1.27), and very low birth weight (OR = 1.05; 95% CI, 0.82-1.34). Among the individual THMs, chloroform showed a similar pattern of risk as TTHM, but no association was found with concentrations of bromodichloromethane or total brominated THMs. Our findings overall suggest a significant association of stillbirths with maternal residence in areas with high TTHM exposure. Further work is needed looking at cause-specific stillbirths and effects of other disinfection by-products and to help differentiate between alternative (noncausal) explanations and those that may derive from the water supply.