Tobacco smoking and sex ratios in the United States.

Abstract

Results of an investigation into the effect of smoking on U.S. age-specific sex ratios indicate that the contribution of smoking to imablances in these ratios in substantial. 1st, the mathematics of the stationary population model is used to analyze the overall trend in age-specific stationary population sex ratios for 1910 and 1962, without reference to smoking. As age-specific and sex-specific mortality rates at the younger ages declined to nearly zero during this period, most male-female differences between those rates also declined. As a result, sex ratios at the younger ages decreased more slowly with age in 1962 than in 1910. Average U.S. annual cigarette consumption per person for ages 15 and over increased from 49 in 1910 to 3958 in 1962. Splitting overall age-specific and sex-specific mortality rates into smoking and nonsmoking components, the analysis is extended to examine the effects of smoking, utilizing age-specific mortality rates derived by linearly interpolating and extrapolating American Cancer Society mortality data. Percent reductions in age-specific sex ratios due to smoking probably represent fairly accurately the true values in the U.S. population in 1962. Reductions in sex ratios at each age from what they would have been if the total population had been nonsmoking varies from 0% at age 35 to 20% at age 85. It is apparent that smoking has a cumulative effect on the sex ratio with increased age.