Dr. Lewis Kuller, a top epidemiologist and a leading figure in preventive cardiology, died on Oct. 25, in a Pittsburgh hospital. He was 88.

In his career of more than 60 years, he studied risk factors for cardiovascular disease through a breadth of clinical trials, much of that time as chairman of the epidemiology department at the University of Pittsburgh School of Public Health.

In the 1970s and ‘80s, Dr. Kuller was the chief investigator in the 10-year Multiple Risk Factor Intervention Trial, colloquially known as “Mr. Fit.” It involved nearly 13,000 men between the ages of 35 and 57, and focused on reducing the risks of heart disease through aggressive intervention by treating blood pressure and high cholesterol and counseling cigarette smokers.

In the 1980s and continuing for nearly 25 years, Dr. Kuller was the architect of a trial called the Healthy Women Study, which demonstrated that menopause was a risk factor for cardiovascular disease.

In 1985, Dr. Kuller’s “Mr. Fit” study became a cause célèbre when an advertisement published in 25 newspapers and magazines by the R.J. Reynolds tobacco company used it to say that the study had failed to find a clear link between smoking and heart disease.

Dr. Kuller told The Washington Post that the study did not test the link because the evidence on the connection was a long-settled scientific issue. In response to the Reynolds ad, Dr. Kuller told The Post, “It’s like an ad that says, ‘Eat a carcinogen — we need more time to think about the issue.’”