Florey,C.du V. (Dept.Clinical Epidemiology and Social Medicine, St.Thomas' Hospital Medical School, London, S.E.I, England), McDonald, H., McDonald J., and Miall, W. E. The prevalence of diabetes in a rural population of Jamaican adults. Int. J. Epid. 1972,1: 157–166. The prevalence of diabetes mellitus and significance of related variables are described for a rural Jamaican community. The population of the defined survey area was enumerated by private census and all 696 persons aged 25–64 were requested to participate. A response rate of 77.3 per cent was achieved. Blood samples were drawn after respondents had fasted and 1 hour after consumption of a 100 G glucose load (Glucola). Blood tests included blood glucose, serum cholesterol and trigtycerides. Anthropometric and blood pressure measurements, a 12 lead electrocardiogram and a PA chest X-ray were taken and a questionnaire administered to elicit the occurrence of effort pain. Persons with 1 hour blood glucose levels of 180 mg. per cent or more were requested to undergo a 3 hour glucose tolerance test. Age specific rates for diabetes rose to 14.5 per cent in males aged 45–54 and 17.0 per cent in females aged 55–64. The percentage distribution of 1 hour glucose is given by age and sex. No relationship between number of live births and 1 hour blood glucose was found. In a comparison between non-diabetics, newly diagnosed and previously known diabetics, known diabelics of both sexes had thicker infrascapular skinfolds, male new and known diabetics had higher cholesterol, and triglycerides increased from non-to known diabetics of both sexes. The validity of intersurvey comparison of diabetes rates is discussed and an alternative presentation of data is recommended. The lack of relationship between the diagnosis of diabetes and cardiovascular disease is also discussed.