Epidemiology of Insulin and Dehydroepiandrosterone Sulfate and Coronary Heart Disease Mortality

BACKGROUND:

In 1972, the Multiple Risk Factor Intervention Trial began recruiting 12,866 men, ages 35 to 57, selected for elevation of one or more risk factors but free from coronary heart disease and followed them for an average of seven years after randomization to a risk factor modification group or to a control group referred to their own physicians for treatment. The serum from MRFIT had been stored since 1972. Detailed follow-up for the cohort was completed through 1985 and was extended through 1988 using the National Death Index.

The role of insulin as a major risk factor for atherosclerosis resurfaced in the 1980s and was the subject of much research at the basic science, clinical, and epidemiological levels. The MRFIT serum data base probably was the only remaining such serum bank in the United States that could test the relationship between insulin levels and coronary heart disease mortality that included detailed measurements of other major cardiovascular risk factors, as well as both baseline and two-hour post-load glucose levels in a predominantly non-diabetic population.

DHEAS is the most abundant circulating steroid hormone in man and is readily converted to DHEA which is a potent non-competitive inhibitor of glucose-6-phosphate dehydrogenase, the rate limiting enzyme of the pentose cycle. Several studies suggest a key role of DHEAS in obesity, lipid metabolism, cellular proliferation, and atherosclerosis. Barrett-Connor in 1986 reported that low levels of this hormone were a risk factor for cardiovascular disease in men. Other studies report that administration of DHEAS to laboratory animals appears to delay aging, prevent obesity, and lower serum cholesterol levels.

DESIGN NARRATIVE: