May 14 (HealthDay News) -- Being well-educated can lengthen your life span, according to new study.

The research, published in the May 14 issue of PLoS ONE, shows that the gap in overall death rates between Americans with less than a high school education and college graduates increased rapidly from 1993 to 2001.

The widening resulted from significant drops in mortality from all causes among the most educated men (totaling 36 percent in black men and 25 percent in white men over the study period). This came in great part to decreases in their death rates from HIV infection, cancer and heart disease.

In contrast, the all-cause death rate rose among people with less than a high school education. The greatest annual percent increase was among white women who did not complete high school (3.2 percent per year), but it was also notable (0.7 percent per year) in white women who had completed high school.

"This study finds the socioeconomic inequalities in mortality rates are not only failing to drop, they are actually increasing in the U.S.," Dr. Otis W. Brawley, chief executive officer of the American Cancer Society, said in a prepared statement. "People with less education have fewer financial resources, less access to health insurance or stable employment, and less health literacy. As a result, while the death rate among the most educated Americans is dropping dramatically, we're seeing a real lack of progress or even worsening trends in the least educated persons. The gap between the best and worst off in the country is actually getting wider."

Researchers made their findings studying data from the National Vital Statistics System and the death certificate information of more than 3.5 million people who died between 1993 and 2001.

The study backs a previous one, published in the April issue of PLoS Medicine, that shows life expectancies across the United States are neither rising steadily nor uniformly. In that study of death rates between 1983 and 1999, mortality rates increased for women in many poor counties, while overall life expectancy disparities worsened between certain geographical areas and racial groups across the country.

SOURCE: Public Library of Science, news release, May 13, 2008