Afro-Caribbeans have low mortality rates from coronary heart disease, despite a high prevalence of diabetes mellitus. We examined 1166 Afro-Caribbean and European men and women aged 40-64 years in a community survey in London, UK. Prevalence of glucose intolerance (combining impaired glucose tolerance, new and known diabetes) was 31% in Afro-Caribbeans and 14% in Europeans (p < 0.001). In men, the prevalence of probable coronary heart disease was 6% in Afro-Caribbeans and 13% in Europeans (p < 0.01). Triglyceride was lower in Afro-Caribbeans than Europeans; in men, HDL cholesterol was higher. Afro-Caribbean men were less centrally obese, while Afro-Caribbean women were more centrally obese than their European counterparts. Fasting and 2-h insulin levels were higher in Afro-Caribbeans than Europeans. Glucose intolerance was associated with high triglyceride, low HDL cholesterol and central obesity in European but not in Afro-Caribbean men. In Europeans, fasting triglyceride was 1.49 mmol/l in normoglycaemic and 1.89 mmol/l in glucose intolerant men (p < 0.05), in Afro-Caribbean men triglyceride was 1.08 and 1.22 mmol/l, respectively. Waist hip ratio was 0.94 in normoglycaemic, and 0.98 in glucose intolerant European men (p < 0.001). In Afro-Caribbean men, waist hip ratio was 0.93 in both groups. At each level of insulin, glucose or central obesity, triglyceride was lower in Afro-Caribbean men and women than in Europeans. We speculate that despite high insulin levels, Afro-Caribbeans have a favourable lipoprotein pattern which persists in the presence of glucose intolerance, and may be related to body fat distribution.(ABSTRACT TRUNCATED AT 250 WORDS)