Effects of temperature and snowfall on mortality in Pennsylvania

The relation between exposure to severe cold weather and mortality is exami ned in a retrospective study of deaths occurring during the month of Januar y from 1991 to 1996 in Pennsylvania. Using division-days as units of observ ation (n = 1,560) aggregated from death certificates and geographic divisio ns, the authors estimated mortality rates for total deaths and deaths due t o ischemic heart disease, cerebrovascular diseases, and respiratory disease s by analyses based on generalized estimating equations. Total mortality in creased on days of "extreme" climatic conditions, that is, when snowfall wa s greater than 3 cm and when temperatures were below -7 degrees C (rate rat io (RR) = 1.27, 95 percent confidence interval (CI) 1.12-1.44). On days of extreme conditions, mortality due to ischemic heart diseases tripled among males aged 35-49 years (RR = 3.54, 95 percent CI 2.35-5.35), increased for men aged 50-64 years (RR = 1.77, 95 percent CI 1.32-2.38), and rose for mal es aged 65 years and older (RR = 1.58, 95 percent CI 1.37-1.82), when compa red with milder conditions. Among females, mortality for those aged 65 year s and older increased for respiratory causes (RR = 1.68, 95 percent CI 1.28 -2.21) and cerebrovascular causes (RR = 1.47, 95 percent CI 1.13-1.91). Col d and snow exposure may be hazardous among men as young as 35 years.