Obesity, Diabetes, and Hyperlipidemia in a Central Australian Aboriginal Community With a Long History of Acculturation

Abstract

Objective— To determine the age- and sex-specific prevalence of diabetes and to examine associations between related anthropometric and metabolic abnormalities in an Aboriginal community in central Australia with a long history of acculturation. Research Design and Methods— We used a cross-sectional survey of 353 adults > 15 yr of age (87% response rate) and measured the following parameters: weight, height, circumferences of waist and hips; glucose, insulin, cholesterol, triglyceride, and high-density lipoprotein cholesterol in fasting plasma; and plasma glucose and insulin 2 h after 75 g oral glucose. Results— The prevalence of diabetes was 29.6% in survey participants > 35 yr of age and 5.3% in those < 35 yr of age. Impaired glucose tolerance also occurred with higher frequency in those > 35 yr of age (14.8 vs. 4.7%). Of those > 35 yr of age, 75% of the women and 51% of the men were overweight or obese, with a body mass index ≥ 25 kg/m2. A large insulin response to oral glucose was evident, with the upper tertile of the 2-h insulin response six times higher than the lower tertile (113 ± 43 vs. 19 ± 8 mU/L). Hyperinsulinemia showed a strong, positive association with impaired glucose tolerance, body mass index, waist-to-hip ratio, cholesterol, and triglyceride levels and a negative association with high-density lipoprotein cholesterol levels. Cholesterol levels were on average 0.5 mM higher in men than in women. Deteriorations in carbohydrate and lipid metabolism occurred before 40 yr of age: diabetes, body mass index, waist-to-hip ratio, and fasting triglycerides and cholesterol concentrations peaked and high-density lipoprotein cholesterol concentrations reached their nadir at the end of the fourth decade. Conclusions— These data suggest that any intervention programs developed to prevent or reduce diabetes prevalence in this population should be targeted at adolescents and young adults.