Background: The mortality level from all causes is different between populations and it has decreased for both men and women in most countries in the last decades. However, there is a difference in the male/female sex ratio of mortality between populations and its time trends and the reasons for these differences remain unclear.
Methods: The sex ratio of all-cause mortality and the main causes of death, i.e. total cardiovascular disease and cancer, for 30 populations in 1988 (mean of 1987-1989), and the time trends of the sex ratio for 27 populations are analysed.
Results: Large differences in the sex ratio of mortality exist among the studied populations. The sex ratio of all-cause, total cardiovascular and cancer mortality markedly increased in most countries during recent decades.
Conclusions: The sex ratio of all-cause mortality and its time trends correlated significantly and positively with the sex ratio of mortality and its time trends from total cardiovascular disease and cancer. The differences of the sex ratio of mortality and their time trends between populations cannot be explained by genetic factors. They could be attributed to differences in life style. A different exposure and different reaction to the risk factors of cardiovascular diseases and cancer, e.g. saturated fat intake, alcohol intake and smoking habits, between men and women are considered to be the main causes for these differences in the sex ratio of mortality.