Sex matters: secular and geographical trends in sex differences in coronary heart disease mortality

Objective To examine secular trends and geographical variations in sex diff erences in mortality from coronary heart disease and investigate how these relate to distributions in risk factors. Design National and international data were used to examine secular trends and geographical variations in sex differences in mortality from coronary h eart disease and risk factors. Setting England and Wales, 1921-98; Australia, France,japan, Sweden, and th e United States, 1947-97; 50 countries, 1992-6. Data sources Office for National Statistics, World Health Organization, and Food and Agriculture Organization of the United Nations. Results The 20th century epidemic of coronary heart disease affected only m en in most industrialised countries and had a very rapid onset in England a nd Wales, which has been examined in detail. If this male only epidemic had not occurred there would have been 1.2 million fewer deaths from coronary heart disease in men in England and Wales over the past 50 years. Secular t rends in mean per capita fat consumption show a similar pattern to secular trends in coronary heart disease mortality in mn. Fat consumption is positi vely correlated with coronary heart disease mortality in men (r,=0.79; 95% confidence interval 0.70 to 0.86) and inversely associated with coronary he art disease mortality in women (-0.30; -0.49 to -0.08) over this time. Alth ough sex ratios for mortality from coronary heart disease show a clear peri od effect, those for lung cancer show a cohort effect. Sex ratios for strok e mortality were constant and close to unity for the entire period. Geograp hical variations in the sex ratio for coronary heart disease were associate d with mean per capita fat consumption (0.64; 0.44 to 0.78) but were not as sociated with the sex ratio for smoking. Conclusion Sex differences are largely the result of environmental factors and hence not inevitable. Understanding the factors that determine sex diff erences has important implications for public health, particularly for coun tries and parts of countries where the death rates for coronary heart disea se are currently increasing.