Family history of coronary heart disease is a stronger predictor of coronary heart disease morbidity and mortality than family history of non-insulin dependent diabetes mellitus.

The aim of this study was to compare the effect of family history of non-insulin dependent diabetes mellitus (NIDDM) and coronary heart disease (CHD) as risk factors for CHD morbidity and mortality. Altogether, 394 siblings of NIDDM probands and non-diabetic probands, with and without CHD, were followed for 8 years with respect to CHD events in a prospective population-based study. The baseline study was conducted from 1983 to 1985. Age- and sex-adjusted cumulative occurrence of CHD events was higher in the siblings of the probands with CHD and with NIDDM (13.1%; P = 0.037) and in the siblings of the probands with CHD and without NIDDM (15.4%; P = 0.054), compared with the siblings of the probands without NIDDM and without CHD (4.8%). The incidence of fatal CHD events tended to be higher in a group with a family history of NIDDM and CHD, but the trend was not statistically significant. In univariate logistic regression analyses, a family history of CHD was positively associated with cumulative occurrence of CHD events (odds ratio 2.53, P = 0.009), whereas a family history of NIDDM had no significant association (odds ratio 1.39, P = 0.312). After adjustment for age, sex, family history of NIDDM and major cardiovascular risk factors, the association between family history of CHD and cumulative occurrence of CHD events remained significant (odds ratio 2.25, P = 0.048). In conclusion, the present study indicates that a family history of CHD is a stronger predictor of future CHD events than a family history of NIDDM.