Standardized comparison of glucose intolerance in West African-origin populations of rural and urban Cameroon, Jamaica, and Caribbean migrants to Britain

OBJECTIVE - To compare the prevalence of glucose intolerance in genetically similar African-origin populations within Cameroon and from Jamaica and Britain. RESEARCH DESIGN AND METHODS - Subjects studied were from rural and urban Cameroon or from Jamaica, or were Caribbean migrants, mainly Jamaican, living in Manchester, England. Sampling bases included a local census of adults aged 25-74 years in Cameroon, districts statistically representative in Jamaica, and population registers in Manchester. African- Caribbean ethnicity required three grandparents of this ethnicity. Diabetes was defined by the World Health Organization (WHO) 1985 criteria using a 75- g oral glucose tolerance test (2-h ≥ 11.1 mmol/l or hypoglycemic treatment) and by the new American Diabetes Association criteria (fasting glucose ≥7.0 mmol/l or hypoglycemic treatment). RESULTS - For men, mean BMIs were greatest in urban Cameroon and Manchester (25-27 kg/m2); in women, these were similarly high in urban Cameroon and Jamaica and highest in Manchester (27- 28 kg/m2). The age-standardized diabetes prevalence using WHO criteria was 0.8% in rural Cameroon, 2.0% in urban Cameroon, 8.5% in Jamaica, and 14.6% in Manchester, with no difference between sexes (men: 1.1%, 1.0%, 6.5%, 15.3%, women: 0.5%, 2.8%, 10.6%, 14.0%), all tests for trend P < 0.001. Impaired glucose tolerance was more frequent in Jamaica. CONCLUSIONS - The transition in glucose intolerance from Cameroon to Jamaica and Britain suggests that environment determines diabetes prevalence in these populations of similar genetic origin.