Familial aggregation of medial arterial calcification in Pima Indians with and without diabetes

OBJECTIVE - Little is known about medial arterial calcification (MAC) other than its association with age, sex, diabetes, and diabetes complications Familial aggregation of this disorder was studied to determine the importance of potential genetic factors and to assess whether such familial aggregation was independent of that of diabetes. RESEARCH DESIGN AND METHODS - Members of 1,256 Pima Indian nuclear families with 3,339 offspring were examined radiologically for MAC of the feet. Multiple logistic regression analyses were used to compare the presence of the disorder in a parent with the presence of MAC in an offspring and to determine whether familial aggregation of MAC was independent of parental diabetes. RESULTS - Controlled for age, sex, diabetes, serum cholesterol, and blood pressure, offspring of one parent with MAC had 3.3 (95% CI 1.5-7.6) times the odds of MAC as did offspring of parents without MAC, and offspring with both parents affected had an even higher risk (odds ratio, 8.1; 95% CI 3.4-18.8). Controlled for offspring age and sex and for parental age and diabetes, parental MAC was associated with the disorder in offspring (P < 0.001), but the effect of parental diabetes on MAC in the offspring was not significant when controlled for parental MAC (P = 0.36). Furthermore, offspring of nondiabetic parents with MAC, controlled for age, sex, diabetes, and diabetes duration, had 1.7 (95% CI 0.9-3.1) times the odds of MAC than did offspring of diabetic parents with MAC. CONCLUSIONS - Independent of parental age and diabetes and offspring age, sex, diabetes, and diabetes complications, parental MAC confers an increased risk of MAC in offspring. These findings suggest that the factors responsible for the Familial clustering of MAC may be different from those for diabetes.