Are Males More Susceptible to Ambient PM Than Females?

Abstract

Recent epidemiologic studies of modern air pollution show statistically significant relationships between fluctuations of daily nontrauma mortality and fluctuations of daily ambient particulate matter (PM) levels at low concentrations. A review of historic smoke-fog (smog) episodes (Meuse Valley, Belgium; Donora, PA; London, UK) was conducted to seek common characteristics of victims of higher concentrations of ambient PM to help identify a susceptible cohort for an effect at lower ambient PM concentrations. The Meuse Valley episode investigation (Firket, 1931) did not detail the age and sex of the victims, so we obtained complete death certificates from all the Belgian villages in the area over the period of the smog (December 1–7, 1930), and these data on gender and age are reported here for the first time. The results show ~50% excess male death rate (36&, 259) consistent with the previously reported excess male deaths in both the Donora Fog (15&, 59) and the London Fog (autopsied cases; 4l9tf, 2879). In all three episodes, mortality was predominantly amongst the aged, and most of those autopsied presented with preexisting cardiopulmonary lesions. Because the genders, ages, and smoking habits of the populations at risk were unrecorded, we are unable to adjust for an expectation of more aged females and higher male smoking rates. However, recent studies of PM and mortality have found no statistically significant different risks for smokers and nonsmokers (Pope et al., 1995). We present data on other causes of death that also have a 50% male excess death rate. We test an X-linkage genetic model that explains the ~50% excess male death rate using total U.S. infant mortality data and data on suicides by gas in Paris, and the model cannot be rejected as a reasonable fit. The findings of this study support the hypothesis that males are genetically more susceptible to the effects of ambient PM exposures.