Identifying risk factors for diabetes in first degree relatives of non-insulin dependent diabetic patients

Glucose tolerance test data on 794 first-degree relatives of diabetics in pedigrees ascertained through non-insulin dependent diabetes mellitus from southeastern Michigan were used to identify risk factors for diabetes. The general risk factors, age and obesity, were important in predicting diabetes at initial visit, although the predicted risk curves were very different for males and females. In predicting diabetes at initial visit, the number of affected sibs contributed more to the logistic regression than did the number of affected parents. Among a group of 393 individuals who were followed up for a mean of eight years, the initial glucose tolerance test response was the best single predictor of being diabetic on follow-up. These results suggest there may be a strong within-generational component which influences both the quantitative test response and the risk to diabetes. This component may reflect environmental factors influencing glucose tolerance among sibs and, as such, should be considered when studying the genetics of diabetes.