Prevalence of glucose intolerance among Native Hawaiians in two rural communities. Native Hawaiian Health Research (NHHR) Project.

OBJECTIVE: To estimate prevalence of type 2 diabetes and impaired glucose tolerance (IGT) among a population of native Hawaiians in two rural communities. RESEARCH DESIGN AND METHODS: Prevalence of glucose intolerance was assessed in two rural communities by history (confirmed by record review) or with a 75-g oral glucose tolerance test according to World Health Organization criteria. Anthropometric and demographic data were also obtained. A short survey was used to estimate the prevalence of known diabetes among nonparticipants. Prevalence rates were adjusted using the standard world population of Segi. RESULTS: A total of 574 native Hawaiians age > or = 30 years participated. The crude prevalence of IGT and type 2 diabetes were 15.5 and 20.4%, respectively. Only IGT prevalence was significantly higher (P = 0.03) among women (18.7%) than among men (10.9%). Prevalence of glucose intolerance was significantly associated with BMI, waist circumference, and waist-to-hip ratio (WHR). After adjusting for age and BMI, waist circumference and WHR were significantly and independently associated with type 2 diabetes prevalence only among women. Prevalence of type 2 diabetes was not significantly associated with the percentage of Hawaiian ancestry after adjusting for age. CONCLUSIONS: This study observed a high prevalence of glucose intolerance associated with being overweight among native Hawaiians. Age-adjusted type 2 diabetes prevalence was four times higher than among the U.S. National Health and Nutrition Examination Survey (NHANES) II population. Prevalence was high despite high rates of admixture with other ethnic groups of Hawaii, suggesting that these other Asian and Pacific Island populations share similar susceptibility to type 2 diabetes risk.

The insulin resistance syndrome in native Hawaiians. Native Hawaiian Health Research (NHHR) Project.

OBJECTIVE: To investigate whether fasting hyperinsulinemia is associated with a clustering of cardiovascular disease (CVD) risk factors, manifesting as the insulin resistance syndrome (IRS), in a population of native Hawaiians. RESEARCH DESIGN AND METHODS: A total of 574 native Hawaiians > or = 30 years of age were examined for blood pressure, waist-to-hip ratio (WHR), BMI, oral glucose tolerance, and fasting lipid, insulin, and C-peptide concentrations. All statistical analyses (n = 384) excluded 190 individuals who had NIDDM or who were taking hypertension medication. Using logistic regression analysis, fasting insulin and C-peptide levels were compared with CVD risk factors (glucose intolerance, hypertension, central adiposity, elevated triglyceride levels, and low HDL cholesterol levels) after adjusting for age and obesity. RESULTS: Sixty-six percent of native Hawaiians were overweight or obese, and 70% were found to have central adiposity. Fasting insulin concentrations were correlated with BMI, WHR, blood pressure, and triglyceride, HDL cholesterol, and glucose concentrations. Fasting insulin was also significantly associated with an increasing number of CVD risk factors in each participant (P < 0.001). Fasting insulin and C-peptide concentrations were independently associated with glucose intolerance, high triglyceride levels, and low HDL cholesterol levels. However, only fasting C-peptide concentrations were independently associated with hypertension and central adiposity. Apparent differences in the correlates of fasting insulin and C-peptide may be related to multiple factors and warrant further evaluation. CONCLUSIONS: This study provides cross-sectional data confirming the existence of the IRS in native Hawaiians. However, further longitudinal studies are needed to examine the relationship of insulin resistance and/or surrogate markers to increased rates of NIDDM and CVD mortality in native Hawaiians.