WASHINGTON, May 15 (UPI) -- The death gap between U.S. adults with less than high school education and those with college degrees increased rapidly from 1993 to 2001, a U.S. study said.

Epidemiologists at the American Cancer Society led by Ahmedin Jemal worked with scientists at the Centers for Disease Control and Prevention in Atlanta, using data from the National Vital Statistics System and death certificate information to analyze more than 3.5 million deaths from 1993 to 2001.

The study, published in the journal PLoS ONE, found the overall death rate from all causes decreased significantly during the time period among those with more than 16 years of education.

In contrast, the death rate increased in those with less than a high school education. The annual percent increase was largest among white women with less than 12 years of education, but was also statistically significant in white women who had completed high school.

The authors say the growing death gap was caused largely by an unprecedented decrease in the death rate among the most educated men, largely due to decreases in death rates from HIV, cancer and heart disease.