Day-to-day and seasonal fluctuations of urban mortality in Houston, Texas

Mortality, exclusive of that caused by accidents, for Houston, Texas, from 1971 to 1973 was studied for temporal patterns and for associations with daily maximum and minimum temperature, relative humidity, barometric pressure, and precipitation. The sensitive and unbiased method of spectral analysis permitted the consideration of time lags between events. The findings revealed significant seasonal difference in mortality with the highest being in winter and more interestingly, strong lagged associations were found between short-term upswings in mortality and specific weather conditions, such as those characterized by low air temperature and high barometric pressure. In combination these weather features are typical of winter anticyclones. The peaks in mortality were evident after cold spells within periods of two weeks. Furthermore, episodes of elevated mortality also were observed subsequent to heat waves such as those during the summer of 1971.