Minnesota Heart Survey - Risk Factor Survey (MHS)

BACKGROUND:

Cardiovascular disease mortality rates, especially for myocardial infarction and stroke, have fallen markedly over the past several decades in all race, sex, and age groups in the United States. Between 1966 and 1986, the combined death rate for all cardiovascular diseases declined by 42 percent. In 1986, the death rate for coronary heart disease was 55 percent of what it had been in 1966, and cerebrovascular disease was 42 percent of what it had been in 1966. The decline is assumed to be related to several factors including improved medical care and risk factor modification for elevated blood lipids, cigarette smoking, and hypertension. The Minnesota Heart Survey provide trends (1970-2002) in coronary heart disease deaths out-of-hospital, in hospitalization rates, case fatality and survivorship for myocardial infarction and stroke in the metropolitan area.

DESIGN NARRATIVE:

Between 1979 and 1999, R01HL23727 supported mortality surveillance and morbidity surveillance. Beginning in FY 2000, R01HL65755 supports the morbidity and mortality surveillance and R01HL23727 supports the risk factor survey.

Mortality Surveillance: The mortality surveillance was a continuation of a surveillance study performed by the investigators since 1960 for the state of Minnesota. Mortality data for hypertension, stroke, coronary heart disease, and all cardiovascular renal disease were monitored for the Twin City metropolitan area with a total population of two million. Age, sex, area, location of death and cause-specific death rates were followed. Trends in cancer, diabetes, and other non-cardiovascular disease were examined. Case fatality rates, including one- and five-year survivorships were determined and related to coronary heart disease mortality trends.

Morbidity Surveillance: All discharges from the seven-county area hospitals with acute and chronic myocardial heart disease and stroke listed among the discharge diagnoses were recorded using Professional Standards Review Organization data tapes. A ten percent random sample of all recorded diagnoses were validated yearly by abstracting data from hospital records. Each year's validation sample of definite and probable cases of myocardial infarction and stroke formed a cohort to be followed for mortality for one year after the onset of the disease event. Individual hospitals and the Professional Standards Review Organization in the area provided data on the total numbers of coronary care unit admissions and coronary artery bypass operations for each year. Beginning in August 1988, a registry was established for all new incident cases of coronary heart disease at the University of Minnesota Hospital and the Ramsey County Hospital. In 1989, twelve hospitals were part of the myocardial infarction registry.

Risk Factor Surveillance: Population samples, aged 25-74 years, are recruited and measured for blood pressure, serum cholesterol, serum high density lipoprotein cholesterol, cigarette smoking, diet, physical activity, height, weight, health attitudes and beliefs, and coronary prone behavior. Surveys were completed in 1980-1982 and 1984-1985. The third survey conducted in 1990-1992 included the Willett Food Frequency Questionnaire and bioimpedance measurements. A nested case-control study using the 1980-1982 risk factor cohort examined the baseline cardiovascular disease risk factor differences between coronary heart disease in cases and controls.

The study was renewed in the year 2000 under R01HL23727 to conduct a population survey of 4,000 adults, ages 25 to 84 in 2000-2002, to detect current trends in cardiovascular disease risk factors, including serum lipids, blood pressure, cigarette smoking prevalence, dietary fat intake, obesity, diabetes, physical inactivity, fibrinogen, and serum vitamin E. Cohort and ecological analyses will be used to link secular trends in risk factors to morbidity and mortality from coronary heart disease, congestive heart failure, and stroke. A total of 1,000 children and adolescents, ages 8-17, will also be surveyed using youth-specific measurement instruments where appropriate.