Survival rate at middle age in developing and western populations.

Whereas expectation of life at birth invariably is greater in more privileged populations, the respective survival patterns at middle age can be entirely different. Comparisons have been made between South African and other populations, using, as a survival index, the number who are 70 years or more at present, as a percentage of the number who were 50 years or more 19 years earlier (data for the desired 20-year period were not available for all populations). Briefly (1) South African Negroes had the highest index; Indians both in India and South Africa the lowest; Caucasian populations in South Africa, United States, and England and Wales, were intermediate. (2) Indices for females were higher than for males; the disparity was least in Indians, but greatest for the population of England and Wales. Evidently, with progressive sophistication of diet and manner of life, the concomitant change from infections to degenerative diseases, as main causes of death at middle age and beyond, reduces rather than increases chances of survival.