Clustering of premature mortality in 1,761 insulin-dependent diabetics and their family members.

The clustering of premature mortality was investigated in 1,761 insulin-dependent diabetics and their family members from the Children's Hospital of Pittsburgh Insulin-Dependent Diabetes Mellitus Registry from 1950-1981. At follow-up, 5% of the mothers and 13% of the fathers were deceased. Life table analyses revealed that fathers of deceased diabetics were significantly more likely to die prematurely than fathers of living diabetics (18% vs. 8% at age 55 years; p = 0.02). A father-diabetic son concordance of mortality appeared to be responsible for this effect. A similar overall trend was observed for maternal mortality, although the difference was not statistically significant. Cause-specific analyses revealed that the increased paternal mortality was primarily the result of cardiovascular disease. Overall mortality rates of parents of deceased diabetics were higher than those of the general population, reaching statistical significance in the age group 35-44 years (p less than 0.05). Mortality among diabetic siblings was also examined. Diabetic siblings of deceased diabetics had a markedly increased risk of dying compared with diabetic siblings of living diabetics (p = 0.001). These findings indicate that premature mortality among both diabetic and nondiabetic relatives of diabetics clusters in families in which there is a deceased insulin-dependent diabetic, and suggest that the marked increase in mortality among persons with insulin-dependent diabetes may be partly under familial control.