Body mass index and delayed conception: a European Multicenter Study on Infertility and Subfecundity.

Obesity has become a health problem in affluent societies, but few studies have investigated its effect on subfertility. Previous studies were based on select groups of women, focused mainly on ovulatory dysfunctions, and yielded controversial results. The authors evaluated the effect of body mass index on delayed conception by using a European population-based survey of pregnant women from five countries. Delayed conception was defined as a time to pregnancy that exceeded 9.5 months of unprotected intercourse. During 1992, 4,035 pregnant women from well-defined geographic areas were recruited consecutively at antenatal clinics or hospitals after at least 20 weeks of gestation. For women smokers, after adjustment for sociodemographic, biologic, and lifestyle-related factors, there was a strong association between obesity (body mass index of > or =30 kg/m2) and delayed conception (odds ratio = 11.54, 95% confidence interval: 3.68, 36.15) and also an increased risk for women whose body mass index was <20 kg/m2 (odds ratio = 1.70; 95% confidence interval: 1.01, 2.83). The same analysis conducted for women nonsmokers showed no association. The authors concluded that for women who achieve a clinically detectable pregnancy, those who are underweight or obese require a longer time to conceive only if they also smoke.

Mortality among residents near cokeworks in Great Britain.

OBJECTIVES: To investigate whether residents near cokeworks have a higher standardised mortality than those further away, particularly from cardiovascular and respiratory causes, which may be associated with pollution from cokeworks. METHOD: Cross sectional small area study with routinely collected postcoded mortality data and small area census statistics. Populations within 7.5 km of 22 cokeworks in Great Britain, 1981-92. Expected numbers of deaths within 2 and 7.5 km of cokeworks, and in eight distance bands up to 7.5 km of cokeworks, were calculated by indirect standardisation from national rates stratified for age and sex and a small area deprivation index, and adjusted for region. Age groups examined were all ages, 1-14, 15-64, 65-74, > or = 75. Only the 1-14 and 15-44 age groups were examined for asthma mortality. RESULTS: There was a 3% (95% confidence interval (95% CI) 1% to 4%) excess of all deaths within 2 km of cokeworks, and a significant decline in mortality with distance from cokeworks. The excess of deaths within 2 km was slightly higher for females and elderly people, but excesses within 2 km and declines in risk with distance were significant for all adult age groups and both sexes. The size of the excess within 2 km was 5% (95% CI 3% to 7%) for cardiovascular causes, 6% (95% CI 3% to 9%) for ischaemic heart disease, and 2% (95% CI -2% to 6%) for respiratory deaths, with significant declines in risk with distance for all these causes. There was a non-significant 15% (95% CI -1% to 101%) excess in asthma mortality in the 15-44 age group. There were no significant excesses in mortality among children but 95% CIs were wide. Within 2 km of cokeworks, the estimated additional excess all cause mortality for all ages combined related to region and mainly to the greater deprivation of the population over national levels was 12%. CONCLUSIONS: A small excess mortality near cokeworks as found in this study is plausible in the light of current evidence about the health impact of air pollution. However, in this study the effects of pollution from cokeworks, if any, are outweighed by the effects of deprivation on weighed by the effects of deprivation on mortality near cokeworks. It is not possible to confidently exclude socioeconomic confounding or biases resulting from inexact population estimation as explanations for the excess found.