Risk of congenital anomalies after the opening of landfill sites.

Concern that living near a particular landfill site in Wales caused increased risk of births with congenital malformations led us to examine whether residents living close to 24 landfill sites in Wales experienced increased rates of congenital anomalies after the landfills opened compared with before they opened. We carried out a small-area study in which expected rates of congenital anomalies in births to mothers living within 2 km of the sites, before and after opening of the sites, were estimated from a logistic regression model fitted to all births in residents living at least 4 km away from these sites and hence not likely to be subject to contamination from a landfill, adjusting for hospital catchment area, year of birth, sex, maternal age, and socioeconomic deprivation score. We investigated all births from 1983 through 1997 with at least one recorded congenital anomaly [International Classification of Diseases, Ninth Revision (ICD-9), codes 7400-7599; International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), codes Q000-Q999]. The ratio of the observed to expected rates of congenital anomalies before landfills opened was 0.87 [95% confidence interval (CI), 0.75-1.00], and this increased to 1.21 (95% CI, 1.04-1.40) after opening, giving a standardized risk ratio of 1.39 (95% CI, 1.12-1.72). Enhanced congenital malformation surveillance data collected from 1998 through 2000 showed a standardized risk ratio of 1.04 (95% CI, 0.88-1.21). Causal inferences are difficult because of possible biases from incomplete case ascertainment, lack of data on individual-level exposures, and other socioeconomic and lifestyle factors that may confound a relationship with area of residence. However, the increase in risk after the sites opened requires continued enhanced surveillance of congenital anomalies, and site-specific chemical exposure studies. Key words: congenital malformations, epidemiology, landfill, small-area health statistics.

Morbidity, deprivation and drug prescribing: factors affecting variations in prescribing between doctors' practices.

Analyses are reported of the prescribing quality and behaviour of 131 doctors' practices in a South Wales health authority during the first quarter of 1997. Prescribing of specific groups of drugs are examined, namely antidepressants; bronchodilators and inhaled corticosteroids for treating asthma; and oral antidiabetics and insulin for diabetes. It is hypothesised that the volumes and costs of prescriptions are determined by the characteristics of both doctors/practices (number and age of doctors; training and fundholding status of practices; single-handed practices and doctors per patient) and their patients (age; gender; ethnicity; deprivation). The health authority's population is characterised by substantial inequalities in wealth and health. Statistical analyses reveal the consistent influence of deprivation on prescribing costs and volumes, with the exception of items of insulin. Supply factors exert more selective influences. Thus, the number of doctors per practice and per patient has a positive influence on antidepressant prescribing; fundholding status is associated with lower costs for bronchodilator prescribing; and older doctors tend to prescribe more bronchodilators and oral antidiabetics. Residuals from the statistical analyses suggest further systematic influences, notably advice from hospital consultants, as well as more localised and less consistent effects.