DuPont Company Study
Background / Introduction:
Pell and D’Alonzo of the giant DuPont corporation reported one of the earliest CVD epidemiological studies of a large industrial cohort, mainly of men prior to retirement at age 65.
Method / Population:
Among about 100,000 employees, half production workers, the investigators calculated age-specific coronary incidence rates by birth cohort based on company medical records.
Study results were first reported in 1961 with only 653 events, when the investigators were able to demonstrate a few findings of early interest: the much greater frequency in men, which difference decreased with age; the first report that executive class employees had significantly less risk than lower-salaried, and that non-specific electrocardiographic findings were predictive. Otherwise, the early findings confirmed those of the cohorts of other industrial and general populations about the significance of CVD risk factors.
The later report in 1985 was based on more than 6000 coronary events and produced the major contribution of the DuPont Study, demonstrating for the first time:
- a 28 percent decreased incidence (rather than mortality) of coronary heart disease (from 3.1 to 2.3 per 1000 in the 25 years up to 1982).
- a sharp decrease in early case-fatality rates following by several years the fall in incidence.
- that lowered CVD incidence due to risk factor change accounted for the major part of the decline in CVD mortality, but improved cardiac care also contributed.
- that higher-paid worker classes fared better.
Conclusions / Discussion:
The large numbers, long duration of follow-up, and the ability to define incidence and case-fatality provided the first clear evidence that incidence was declining and that both risk factor change and coronary care were involved. (HB)
Pell, S and D’Alonzo, CA. Immediate mortality and five-year survival of employed men with a first myocardial infarction. New England Journal of Medicine 1964; 270: 915-922
Pell, S and Fayerweather, WE. Trends in the incidence of myocardial infarction and in associated mortality and morbidity in a large employed population. 1957-1983. New England Journal of Medicine 1985; 312: 1005-1011.