Dr. Elizabeth Barrett-Connor, who founded and led a 47-year-long study that identified sex differences in the risk factors for major diseases of aging, died on June 9 at her home in the La Jolla section of San Diego. She was 84.

The cause was cerebral small vessel disease, her daughter, Caroline Connor, said.

Dr. Barrett-Connor’s project was called the Rancho Bernardo Study of Healthy Aging, named for the San Diego suburb where its more than 6,000 participants had originally lived. It was begun in the early 1970s as part of a dozen group studies on preventing heart disease.

The study led to insights into the biology of diabetes, cardiovascular disease, bone health and menopause.

Dr. Barrett-Connor, then an associate professor at the University of California, San Diego, was the only one who kept the study going beyond its initial funding — for decades. It was testament to her persistence and ability to get things done on a shoestring, said a former colleague, Cedric Garland, a professor emeritus at the university.