Diabetes in the Melanesian and Indian peoples of Fiji: a study of risk factors.

Epidemiological risk factor patterns for diabetes mellitus determined by hemoglobin A1 and fasting blood glucose criteria were compared in the biethnic (Melanesian and Indian) nation of Fiji. The 2 diagnostic criteria elicited essentially similar risk factor patterns in Indians but ranking of predictors was altered in Melanesians. By either criterion age was a dominant risk factor for diabetes in both ethnic groups with age2 a predictor in Indians of elevated hemoglobin A1 (chi 2 = 7.8, P less than 0.005) and fasting blood glucose (chi 2 = 25.3, P less than 0.0001). Age- and sex-adjusted prevalence of diabetes was higher in Indians than in Melanesians [RR = 2.5 (1.9-3.3)]. A positive family history was associated with increased risk of diabetes in both ethnic groups by the hemoglobin A1 criterion [pooled RR = 2.3 (2.0-2.6)] but was not significant in Melanesians under the fasting blood glucose criterion. A positive family history was a strong predictor of severe hyperglycemia in both ethnic groups. The relative risk for diabetes was greater in females [1.5 (1.2-9.1)], with no ethnic difference. There was no urban-rural difference in either ethnic group. The similar risk factor patterns for diabetes diagnosed by hemoglobin A1 and severe hyperglycemia suggest that elevated hemoglobin A1 may constitute a useful screening test for 'high risk' diabetic subjects.