Dramatic 10-year rise in diabetes incidence

The pre-eminent health problem of next century

A dramatic increase in the rate of diabetes occurred between 1987 and 1996, suggesting a major public health crises looming in the 21st century, according to statistics presented at the American Diabetes Association's 58th Annual Scientific Sessions in Chicago.

"The incidence of Type II diabetes rose rapidly by 9% per year over the decade ending in 1996," says Michael P. Stern, MD, professor of medicine at the University of Texas Health Science Center in San Antonio. The percentage of new cases that developed over each successive eight-year interval during that decade rose from 5.7% to 15.7% among Mexican Americans and from 2.6% to 9.4% among non-Hispanic whites.

Possible dire consequences

Stern says that if the trends he has tracked in San Antonio are any indication, there are dire nationwide implications. "Because diabetes and obesity are major risk factors for cardiovascular disease - and both are increasing - this escalation may well eventually blunt or reverse the decline in heart disease that has been under way in the United States since the 1960s," he says.

The study focused on Type II diabetes and was based on results from the San Antonio Heart Study, a prospective epidemiologic study evaluating the incidence and risk factors for heart disease and diabetes that has been under way since 1979. A random sample of 5,100 men and women were enrolled between 1979 and 1988.

Baseline tests included height, weight, blood pressure, lipid levels, measures of adiposity, blood glucose levels, and electrocardiograms.

"Even after controlling for such risk factors as obesity, age, gender, ethnicity, and socioeconomic status, the trend for a rapid rise in diabetes incidence remained," says Stern.

Although the diabetes escalation may be due in part to the fact that the American population is getting older and fatter, Stern says that is not the whole explanation. He speculates on two other possibilities:

1. decline in physical activity, a risk factor that was not included in the analysis because of the difficulty in getting a good measure of such activity;

2. undefined changes in the American diet, such as an increased intake in fat.

Stern notes that deaths due to cardiovascular disease have steadily declined by about 50% since the 1960s in the general population, a reduction variously attributed to a decline in some risk factors among Americans (such as cholesterol levels, hypertension, and cigarette smoking) as well as to advanced heart disease treatment methods.

"Our findings suggest that diabetes and obesity are likely to emerge as the pre-eminent public health problems in the near future and will likely have a significant impact on the rate of cardiovascular disease mortality, potentially bringing recent reductions to a grinding halt," Stern says.