Diabetes Care, Vol 17, Issue 1 70-73, Copyright © 1994 by American Diabetes Association
South African Indians show a high prevalence of NIDDM and bimodality in plasma glucose distribution patterns
MA Omar, MA Seedat, RB Dyer, AA Motala, LT Knight and PJ Becker
Department of Medicine, University of Natal, Congella, South Africa.
OBJECTIVE--To determine the prevalence of diabetes mellitus and impaired
glucose tolerance (IGT) and to test for bimodality in the plasma glucose
distribution in South African Indians. RESEARCH DESIGN AND
METHODS--Subjects were selected by systematic cluster sampling in various
areas of Durban. They underwent a modified glucose tolerance test whereby
fasting and 2-h postglucose (75 g) plasma glucose levels were measured. The
program MIX was used to test for bimodality in the plasma glucose
distribution. RESULTS--We tested 2,479 subjects (1,441 women and 1,038
men). Based on the revised World Health Organization criteria, the crude
prevalence of diabetes mellitus was 9.8%, and the crude prevalence of IGT
was 5.8%; the age- and sex-adjusted prevalence was 13.0 and 6.9%,
respectively. IGT was significantly more common in men (7.6%) than in women
(4.4%). Obesity was a feature of both diabetes mellitus and IGT,
particularly in women. Both fasting and 2-h plasma glucose values did not
conform to a single normal distribution pattern in any age-group, whereas
unequivocal evidence of bimodality was seen in the 55- to 74-year age-group
of both sexes for fasting and 2-h glucose and also in the 2-h levels of men
in the 25- to 34-year age-group. CONCLUSIONS--This study has highlighted a
high prevalence of non-insulin-dependent diabetes mellitus in South African
Indians and bimodality in the plasma glucose distribution.