Progress in the prevention of avoidable deaths has been distributed unequally among the population of the two sexes, and very unevenly among different age and social groups.
Average life expectancy in 1996 worldwide was 65 years. World statistics for 1982 indicate an average male/female life expectancy of 57.5 / 60.3 years in the world, 48.2 / 51.3 years in Africa, 53.5 / 53.8 years in South Asia, 61.8 / 66.5 years in Latin America, 65.9 / 70.1 years in East Asia, 65.5 / 69.9 years in Oceania, 66.5 / 75.4 years in the USSR, 70.4 / 78.1 years in North America, and 70.0 / 76.6 years in Europe. Thus in most parts of the world, men have a lower life expectancy than women - and the gap is increasing. The average world life expectancy in the period 1980-1985 was 60.3 years for women and 57.5 years for men. In the developed regions, the 5.7 years difference of 1950-1955 jumped to 7.3 years for 1970-1980, and in the period 1980-1985, women could expect to live 76.9 years compared with 69.4 years for men. In western Europe, current life expectancy is 69.8 years for men and 76.0 years for women, and in the USSR there is a difference of more than 9 years (65.0 for men and 73.3 for women). In these industrialized countries, mortality rates for males exceed those for females at all age groups. The least difference generally occurs in the youngest and oldest groups while the greatest difference occurs during adulthood. The sex difference in life expectancy is less pronounced in the developing world, women living an average of 1.8 years longer than men in the years 1975-1980; while for the period 1980-1985, life expectancies were 57.7 years for women and 55.5 years for men. For these areas, the regional variations are greater (more than 6 years in temperate South America, less than 3 years in North Africa and China), but the gap is also generally increasing. There are, however, some developing countries in which the male mortality rate is less than the female for some age groups. According to the World Health Organization, this is true in North Africa for the ages 1 to 4 years. There are at least four countries in Asia for which the mortality rate for women in certain age groups is sufficiently higher than for men to generate a life expectancy at birth lower for women than for men. There are also areas, for example in Latin America, where until recently, in the childbearing ages and sometimes in adolescence, the life expectancy of women was less than that of men. The reasons for differences in the death risks of men and women are many. Greater gains in life expectancy have accrued to women than to men. Various social, environmental and sanitary factors also cause a different incidence of deaths at different ages.
After the Second World War, social security systems were more or less completed in all industrialized countries, life expectancy had increased dramatically on average and it was widely believed that inequality with respect to death for all social groups was disappearing. The unprecedented and widely distributed progress in levels of living in the 1950s, 1960s and 1970s was a powerful reason for optimism. Yet the most recent studies in the developed countries suggest that the differences in mortality rates between social groups have not been narrowing in recent years. They rather suggest a great stability of social differences in life expectancy in a context of general and rapid improvement for all social groups.