AGE AND FAMILY RELATIONSHIP ACCENTUATE THE RISK OF INSULIN-DEPENDENT DIABETES-MELLITUS (IDDM) IN RELATIVES OF PATIENTS WITH IDDM

The international community of diabetologists is rapidly becoming invo lved in intervention trials aimed at preventing insulin-dependent diab etes in high risk relatives. Whereas age and relationship to a proband with insulin-dependent diabetes mellitus interacting with detected is let cell autoantibodies (ICA) are risk factors, their independent cont ribution to that risk remains unclear. In a prospective study of 6851 nondiabetic relatives of 2742 probands conducted between 1979-1993, we found age, but not relationship, to be a dramatic risk variable in IC A-positive persons as estimated by the Cox regression model. The 5-yr risk of insulin-dependent diabetes mellitus was 66% for those found to have ICA detectable before age 10 yr, falling progressively to less t han 16% for ICA-positive relatives over age 40 yr. In ICA-negative rel atives, age and relationship are independent prognostic variables.