Population risk of cardiovascular disease: The Minnesota Heart Survey

A decline in age-adjusted ischemic cardiovascular disease mortality has been observed in the United States during the past two decades. Among the leading explanatory hypotheses is improvement in the major known risk factors for heart attack and stroke in the general population, specifically hypertension, smoking, and lipid levels. To better understand risk factor trends, the Minnesota Heart Survey (MHS) began systematic risk factor surveys of the Minneapolis-St Paul population in 1980, (population 1.99 million). The metropolitan area was divided into 704 subareas (clusters) of approx. 1000 households each, utilizing geographic boundaries. In a two-stage cluster sampling technique, 40 subareas were randomly chosen and mapped. Approximately 8.75% of households were chosen from each subarea and selected residents age 25-74 years invited to participate. A total 4451 individuals participated in 1980-1982. The response rate for a home interview was 81.9 and 84.4% for a subsequent survey center visit, producing an overall response of 69.1%. The age and sociodemographic characteristics of the survey participants were similar to those found in the 1980 census. The prevalence of hypertension was 18.3% in this population with 76.0% taking medications and 65.0% controlled. Total cholesterol and HDL-cholesterol levels demonstrated age and sex differences similar to those reported elsewhere. Current smoking of cigarettes was equally prevalent in men (34.5%) and women (33.5%) although more men were former smokers (35.2 vs 20.6%). Comparison of the MHS with the National HANES II data (1976-1980) indicates lower regular cigarette smoking among Minnesota males, with similar rates in females. Minnesota residents had better control of high blood pressure.