BOSTON, Dec. 25 (UPI) -- People without health insurance experience a dramatic improvement in their health once they become eligible for Medicare at age 65, a U.S. study reveals.

"This study provides strong evidence about how health improves when people gain insurance coverage," Dr. John Ayanian, senior author and professor of healthcare policy and medicine at Harvard Medical School and Brigham and Women's Hospital, said in a news release.

Study results are to appear in the Wednesday issue of the Journal of the American Medical Association.

Results indicate that for every 100 uninsured people with heart disease or diabetes before age 65, "we found that with Medicare coverage they had 10 fewer major cardiac complications, such as heart attacks or heart failure, than expected by age 72," Ayanian said.

Researchers analyzed Health and Retirement Study data collected from 7,233 participants every two years from 1992 through 2004, and examined their health from ages 55 to 72. Researchers said 5,006 were continuously insured, while 2,227 were either persistently or intermittently uninsured until they qualified for Medicare at age 65.