Sex ratios of births, mortality, and air pollution:can measuring the sex ratios of births help to identify health hazards from air pollution in industrial environments?

OBJECTIVES--To compare the sex ratios of births and mortality in 12 Scottish localities with residential exposure to pollution from a variety of industrial sources with those in 12 nearby and comparable localities without such exposure. METHODS--24 localities were defined by postcode sectors. SMRs for lung cancer and for all causes of death and sex ratios of births were calculated for each locality for the years 1979-83. Log linear regression was used to assess the relation between exposure, sex ratios, and mortality. RESULTS--Mortalities from all causes were consistently and significantly higher in the residential areas exposed to air pollution than in the non-exposed areas. A similar, but less consistently significant, excess of mortality from lung cancer in the exposed areas was also found. The associations between exposure to the general air pollution and abnormal sex ratios, and between abnormal sex ratios and mortality, were negligible. CONCLUSIONS--Sex ratios were not consistently affected when the concentrations or components of the air pollution were insufficiently toxic to cause substantially increased death rates. Monitoring of the sex ratio does not provide a reliable screening measure for detecting cryptic health hazards from industrial air pollution in the general residential environment

Twinning in human populations and in cattle exposed to air pollution from incinerators

Human populations and animals are often exposed to the airborne pollutants in plumes from incinerators. The incineration of chemical and other waste may release polychlorinated hydrocarbons, some of which have oestrogenic properties. Increased numbers of twins had been reported anecdotally in cattle at risk from plumes from two incinerators near the town of Bonnybridge in central Scotland and also in cattle near a chemical factory in Eire. It was decided to follow up these reports in central Scotland and also to test the hypothesis that the frequency of human twinning might be increased there. Data on human twin and single births in hospitals in central Scotland were obtained for the years 1975-83. The twinning rates in areas exposed to airborne pollution from incinerators were compared with the background rates present in neighbouring areas. Farmers provided information on calving among the herds of two farms close to the incinerators. The frequency of human twinning was increased, particularly after 1979, in the areas most at risk from air pollution from the incinerators. Among the dairy cattle, there was a dramatic increase in twinning at about the same time