Appendicitis, fibre intake and bowel behaviour in ethnic groups in South Africa.

Information on appendicectomy-prevalence was secured on 15,317 16-20-year-old South African pupils and students—Negroes, Coloureds (Eurafricans), Indians and Caucasians. Data were also obtained on crude fibre-intake, frequency of defaecation, and transit-time of digesta. Among students, 18-20 years, appendicectomy was very uncommon in rural Negroes (0·5%) and periurban Negroes (0·9%), slightly more common in urban Negroes (1·4%), but very common in Caucasians (16·5%); prevalences in Coloured and Indian groups were low (1·7 and 2·9%). Rural Negroes had a far larger fibre-intake, greater frequency of defaecation, and much shorter transit-time; yet, in the four ethnic groups in urban areas, despite wide differences in appendicectomy-prevalence, data on these variables were similar. Differences in other aspects of the bowel milieu intérieur must therefore be sought. Corresponding studies were made on 1325 Caucasian pupils in Homes; their diet is less sophisticated (in respect of fibre, sugar and fat-intakes) than that of the general population. Pupils had slightly greater defaecation-frequency, lesser transit-time, and an appendicectomy-incidence only 23% of that of an appropriate control-group. The conclusion is reached that the causes of appendicitis are wholly environmental.