A catastrophe in the 21st century: the public health situation in South Africa following HIV/AIDS.

During the early 1900s, African populations in South Africa were subject to very widespread infections which especially affected the young. This resulted in high mortality rates and a low life expectancy of 20-25 years. By the mid-century, mortality rates from infections had decreased considerably. Moreover, the occurrences of non-communicable diseases, even in urban areas, remained very low. In the 1970s, the proportion of Africans aged 50 or over that reached 70 years was 38.5%, higher than that in the juxtaposed white population, which was 35.5%. And by 1985, the life expectancy of Africans reached 61 years for males and 63 years for females, probably the highest in sub-Saharan African populations. Since then, however, the African continent has been devastated by the AIDS epidemic. In 2001, HIV was responsible for the death of a third of the African population in South Africa, but even higher proportions prevailed in Botswana and in Tanzania. The calamitous advent of the HIV infection has caused major falls in life expectancy, in the case of Africans in South Africa reducing this to just 43 years. With little hope of meaningful changes occurring in sexual habits or of an early vaccine becoming available, the infection's high morbidity/mortality burden is likely to continue.

Nutrition, diet, physical activity, smoking, and longevity: from primitive hunter-gatherer to present passive consumer--how far can we go?

In millennia past, and until recently, among hunter-gatherers and like populations, in all populations, in measure, down through the ages, the securing of sufficient food was life's primary purpose. Virtually all people were physically very active during early life and later in their everyday occupations. In contrast, nowadays, in Western populations, with relative abundance of food, the way of life is mainly one of enjoyment of meals, of work, and of leisure time, in a context of as few as one child per family, and with long survival times of about 75 to 80 y, due in large part to much reduced child mortality and the effective treatments of disorders and diseases. As to changes in food consumption, compared with the erratic and often monotonous fares of the past, both far and not so distant, everyday diets have changed tremendously in variety, nutritional value, and palatability such that, inter alia, overeating is almost inevitable. Compounding the latter, sedentariness is the rule, in contrast to the previously very high level of everyday physical activity in the masses of populations. In consequence, one speculation is that, by 2230, "all Americans will be obese." Although the living of much longer lives is highly gratifying, understandably, all wish to have longer "healthy life expectancy," i.e. to suffer as little as possible before death. However, with regard to the present-day "passive consumer," although the practical recommendations for leading still healthier lives, dietarily and non-dietarily, are well known, very few are interested, and still fewer practice them. Nevertheless, for the few who, with determination, are eager to improve their lifestyles, there could be highly profitable lengthening of years of "healthy life expectancy" by eating less, eating more plant foods, being much more physically active, and restricting non-dietary risk factors (smoking, alcohol consumption).

With recent changes in environmental factors among Africans in South Africa, how have cancer occurrences been affected?

In South Africa, with changes in environmental factors, varyingly, there have been measures of westernization of diet, with slight rises in intakes of energy and fat, with more of animal, but less of plant foods, being eaten, and with a fall in dietary fibre intake. Smoking practice has increased, particularly in males, likewise alcohol consumption. Physical activity has fallen, especially in urban dwellers. Changes in cancer incidence rates, as reported in the South African Cancer Registry for the periods 1986 and 1993-1995 have been investigated. Additionally, changes in percentages of cancers in hospitals in Johannesburg during 1953-1955 and in Durban during 1994-1996, have been looked into. The high occurrences of oesophageal and cervix cancers have fallen slightly, although more so in respect of liver cancer. But there have been rises, widely varying, in the cases of cancers of the lung, prostate and breast. While some of these changes would be expected from the changes in environmental factors, many cancer occurrence situations remain problematical, e.g. the continuing low occurrence of colorectal cancer. Recently, the rapidly rising epidemic of HIV/AIDS has slightly increased the occurrence of certain cancers, particularly Kaposi's sarcoma and non-Hodgkin's lymphoma. Regarding prevention, chances of cancer control in Africans, through lessening personal risk factors, are very remote, which unfortunately also prevails in large measure in western populations, regarding their reluctance to make the recommended beneficial changes.

Variations in occurrences of nutrition-related diseases in Sub-Saharan Africans in stages of transition: what of the future?

In many Sub-Saharan African populations, in particular urban dwellers, there have been marked rises in the prevalences of obesity in women, hypertension, diabetes, and cerebral vascular disease. Yet there have been only slight rises in coronary heart disease. To learn more of the roles of the various influencing factors in the puzzling situations described, some aspects of the past and present occurrences of these diseases are described and discussed, with comparisons being made with corresponding situations in African Americans, as well as in certain white populations. Despite increases in the knowledge of influencing factors, such fail to explain fully the epidemiologic situations described. As to the future, judging from the experiences of other populations, despite continuing indigence, within the next generation significant rises in coronary heart disease in certain African populations seem to be inevitable. However, in many of those populations, in particular those in the South, the extent of changes, apart from those linked with level of socioeconomic state, will be strongly affected by the rising epidemic of human immunodeficiency virus and acquired immunodeficiency syndrome.