Different contributions of insulin resistance and beta-cell dysfunction in overweight Israeli Arabs with IFG and IGT.

BACKGROUND: Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are both intermediate stages that exist between normal glucose tolerance and overt type 2 diabetes. Epidemiological studies demonstrated that the two categories define distinct populations. In this study, we examined the contributions of insulin resistance and beta-cell dysfunction to both states in overweight subjects of Arab origin. METHODS: Twelve subjects with isolated IFG, 10 with isolated IGT, and 20 with IFG and IGT (combined glucose in tolerance-CGT) were compared with 30 subjects with normal glucose tolerance (NGT) subjects; all were of Arab origin and were overweight or obese. Different indices for insulin resistance and beta-cell function were calculated from oral glucose tolerance (OGTT) values. RESULTS: Subjects with isolated IFG and CGT were more obese and had significantly higher values of insulin resistance than subjects with isolated IGT and NFG. There was no significant difference between the insulin resistance in subjects with isolated IGT and that in subjects with NGT. Indices of beta cell function were severely reduced among subjects with isolated IGT and CGT when compared with those with both isolated IFG and NGT, while subjects with isolated IFG had similar beta-cell indices to subjects with NGT. CONCLUSION: These data demonstrate that beta-cell dysfunction and insulin resistance contribute differently to the pathogenesis of IFG and IGT among overweight Arab subjects.

Association of high body mass index with low age of disease onset among Arab women with type 2 diabetes in a primary care clinic.

BACKGROUND: Type 2 diabetes is usually associated with obesity, and both conditions are frequently detected in the Arab population in Israel. Recent studies have demonstrated that diabetes can be prevented by a change in lifestyle. OBJECTIVE: To assess the prevalence of diabetes in an Arab community, the contribution of obesity to diabetes development, and the therapeutic potential of a preventive program. METHODS: Data were obtained from the medical files of diagnosed diabetes patients attending a primary care clinic in an Arab village in northern Israel. RESULTS: Type 2 diabetes was diagnosed in 323 patients of whom 63% were women. The prevalence of diabetes below age 65 years was significantly higher among women than men. Diabetic women were younger than men at diagnosis (48.27 vs. 59.52 years respectively) and were found to have higher body mass index (34.35 vs. 30.04 respectively) at diagnosis. The age at diagnosis of diabetes was strongly correlated with BMI (r = 0.97, P < 0.0001). CONCLUSIONS: Women of Arab origin are at higher risk of developing type 2 diabetes compared to men. Obesity in women seems to be associated with higher diabetes risk as well as earlier appearance of the disease. Therefore, they will have the disease for longer and, consequently, will be at higher risk for complications.