Parental history of diabetes is associated with increased cardiovascular risk factors

Serum insulin concentrations are higher in persons with a positive parental history of diabetes than in persons without such a history. Since hyperinsulinemia is associated with both an increased prevalence of hypertension and an atherogenic pattern of serum lipids and lipoproteins, we hypothesized that among nondiabetic persons, a parental history of diabetes would be associated with an atherogenic pattern of cardiovascular risk factors. In the San Antonio Heart Study, a population-based study of cardiovascular disease and diabetes, we examined 549 nondiabetic persons with a parental history of diabetes and 1167 nondiabetic persons without such a history. Compared to persons without a parental history of diabetes, those with such a history had a more atherogenic pattern of cardiovascular risk factors, including higher body mass index, higher systolic and diastolic blood pressures, higher serum insulin and triglyceride concentrations, and lower levels of high density lipoprotein cholesterol. After adjustment for serum insulin concentration, body mass index, and waist-to-hip ratio, the differences in lipids, lipoproteins, and blood pressure between the two parental history groups were no longer statistically significant. Since persons with a parental history of diabetes are more likely to be prediabetics, the present results suggest that prediabetics have an increased risk of coronary heart disease even before they become diabetic. This phenomenon may help explain why the duration of clinical diabetes is only weakly associated with the risk of coronary heart disease. If prediabetic persons are characterized by an atherogenic pattern of risk factors (possibly caused by obesity and hyperinsulinemia), the duration of the prediabetic phase may contribute to the risk of coronary heart disease as much as, if not more than, the duration of the subsequent diabetes itself.