TRENDS IN MORTALITY AND HEALTH-STATUS IN SOUTH-AFRICA OVER THE LAST 1000 YEARS AND THEIR IMPLICATIONS FOR THE OPPORTUNITY FOR NATURAL-SELECTION

Comparison of palaeodemographic and palaeopathological data on the 900 years old Iron Age population of the Mapungubwe complex on Limpopo (N orthern Transvaal) with modern health statistics allows general assess ment of changes in mortality and morbidity in S African Black populati on. Newborn life expectancy rose from 18.9 nine hundred years ago to 5 3.8 years in 1980 and rose further to 59.4 years in 1990. These last t wo figures are still below respective 65.6 and 67.5 years for the whit e population of S. Africa. This considerable drop in mortality towards 20th century resulted in very substantial decrease of the opportunity for natural selection through differential mortality. In the Iron Age only about a quarter of newborn individuals could fully participate i n the reproduction of new generations while now about 90% have this op portunity. This change is similar to that occurring in other parts of the world at transition from traditional economies to the fully develo ped industrial ones. Since bony signs of chronic diseases are nor comm on on the skeletons of Iron Age peoples it seems that major causes of their high premature mortality were acute infectious diseases. These a re now controlled by simple means. This produced substantial decrease in mortality of infants, children and young adults irrespective of sti ll high incidence of chronic diseases such as tuberculosis and leprosy , Since mortality of blacks living in the same country as whites is st ill higher it is obvious that there is room for improvement that will come by means of socioeconomic advancement.