The geographical distribution of Kaposi's sarcoma and of lymphomas in Africa before the AIDS epidemic.

Estimated incidence rates are presented for three human immunodeficiency virus (HIV)-associated cancers [Kaposi's sarcoma (KS), Burkitt's lymphoma (BL) and other non-Hodgkin's lymphomas (NHLs)] from across the African continent, based on data collected before the HIV epidemic. Mapping of the rates and comparisons with a range of geographical variables indicate completely different distributions for KS and BL but a degree of similarity in the occurrence of Burkitt's lymphoma and other NHLs. Comparisons with rates elsewhere in the world suggest, most notably, that KS was as common in some regions of sub-Saharan Africa as was cancer of the colon in much of Western Europe. Comparison with data from the era of AIDS indicates 20-fold increases in the occurrence of Kaposi's sarcoma in Uganda and Zimbabwe. The highest rates for BL were three to four times the rates for leukaemia at young ages in Western populations, but the general incidence of other NHL was no higher than in the West and very low rates were indicated for much of southern Africa.

Towards a new system of health: the challenge of Western disease.

Over the last three decades, the concept of Western disease has become well established. Medicine has approached this group of diseases by searching for new cures but has achieved relatively little success. We argue that medicine should now accept the failure of this strategy and place a major emphasis on prevention. The key objective is to change the climate of opinion so that prevention is taken seriously by the general population. The chief activity should be a wide ranging public education campaign so as to persuade people to live a healthier lifestyle. Medicine will require restructuring in order to carry out this work. Medical education needs to be reformed so that medical students receive the necessary training. This must be done as part of an integrated approach in which government, industry and medical research all play a major role. Governments should use taxation and subsidies in areas such as food and tobacco so as to shift consumption patterns towards healthier products. Governments must also tighten laws on tobacco sales and advertising, support health education, and improve food labelling. Industry must be made far more responsive to the health needs of the population. This should be done both by public education, so as to alter demand, and by government action. Medical research should change its emphasis from studying the detailed mechanisms of disease ("complex research") to studying the role of lifestyle factors ("simple research").

Putting the wrong fuel in the tank.

Three recent observations when considered together indicate means whereby the health of Western countries could be improved and certain diseases still rare in developing countries avoided. The first is the recognition that many of the commonest chronic disorders in more economically developed countries are characteristic of modern Western lifestyles; the second is that these disorders can be considered to be manifestations of maladaptation to a new environment; and the third is the knowledge now available of the types of environment to which man has, through evolution, adapted.

Prevalence of diverticular disease, hiatus hernia, and pelvic phleboliths in black and white Americans.

Phleboliths, and especially diverticular disease and hiatus hernia, are rarer in developing countries than in economically more developed communities, but all three conditions were as common in Black as in White Americans. This finding suggests that they are due to environmental rather than to genetic causes. A deficient intake of dietary fibre may be the common factor predisposing to these three conditions.

The prevalence of appendiceal fecaliths in patients with and without appendicitis. A comparative study from Canada and South Africa.

Appendicitis is more common in developed than in developing societies and appendiceal fecaliths are thought to have an etiologic role in the disease. The geographic distribution of appendiceal fecaliths was investigated by systematic, intraoperative palpation of the appendix in patients in Toronto, Canada and Johannesburg, South Africa. The incidences of fecaliths found on pathologic sectioning of the appendix in appendicitis patients in both societies were compared. In the Canadian population, the prevalence of fecaliths in patients whose appendices were palpated incidentally was 32% versus 52% for those with appendicitis (p less than 0.01). In the African population, the prevalence of fecaliths in patients whose appendices were palpated incidentally was four per cent versus 23% for those with appendicitis (p = 0.04). The difference in prevalence of incidental appendiceal fecaliths in the two populations was statistically significant (p less than 0.005). The prevalence of fecaliths is higher in developed countries, such as Canada, than in developing countries, such as Africa, and is also higher in patients with than in those without appendicitis. These data support the theory that the low-fiber diets consumed in developed countries lead to fecalith formation, which then predisposes to appendicitis.

The discovery of Burkitt's lymphoma.

An account is given of the steps that led to the recognition of the tumor that became known as Burkitt's lymphoma. This is followed by a description of the methods employed in the subsequent epidemiologic studies, the manner in which successive hypotheses of etiology were erected and demolished, and the discovery by Epstein and his colleagues of the Epstein-Barr virus. The impact that this tumor has had on aspects of cancer research is considered.

Eradicating sources or removing results.

With few exceptions, the prevalence of disease has never been reduced by improved treatment. Success has followed identifying and eliminating, or reducing, causative factors. This has been true of infective disease in the West and of the great tropical epidemics. Yet vastly greater endeavour and expenditure are devoted to the treatment of non-infective diseases than to efforts to identify and tackle their causes. This in spite of the fact that they are increasingly recognized as characteristic of modern western culture.

Western diseases and their emergence related to diet.

Many of the commonest diseases in the economically more developed communities are characteristic of modern Western culture. Evidence is presented suggesting that they represent a failure of adaptation to the dramatic changes in diet that have been associated with the emergence of modern Western culture. Dietary changes aimed at the alleviation and prevention of these diseases are discussed and recommended.