Universal drug coverage might help partly close the gap between the rich and the poor when it comes to diabetes complications, a new Canadian study suggests.

Researchers found that much of the income gap in heart risks among diabetic adults disappeared after the age of 65 - the age at which universal drug coverage kicks in for Canadians.

Canada has universal healthcare, but when it comes to medications, people younger than 65 either pay out-of-pocket or have private drug coverage through work - similar to Americans their age.

In the new study of more than 600,000 Ontario residents with diabetes, researchers found that lower-income people had higher risks of heart attack, stroke and death. But the disparity largely disappeared after age 65.

The findings, reported in the journal Diabetes Care, do not prove that universal drug coverage erased the income gap.

But there is no other obvious factor that would explain the “sudden shift” at age 65, said lead researcher Dr. Gillian L. Booth, of the University of Toronto and St. Michael’s Hospital in Ontario.

“This also fits in with what’s been seen in other studies,” Booth said in an interview.

Research has shown that a growing number of people with diabetes cannot afford their medications - which include not only drugs to control blood sugar, but also those for high blood pressure, High cholesterol and other problems that commonly go hand-in-hand with diabetes.

Another study in Ontario also found a widening gap in death rates between the rich and poor with diabetes - but the trend is mainly among people younger than 65.

“I feel confident that expanding drug coverage could help save some lives,” Booth said.

Her team’s findings are based on health records for 606,051 Ontario adults who were followed over six years. During that time, over 48,000 of those people were hospitalized for a heart attack or stroke, and just over 111,000 died of any cause.

Booth’s team found that among people younger than 65, those in the bottom 20 percent for income had a higher rate of heart attack, stroke and death: just over two percent per year, versus 1.4 percent among the wealthiest 20 percent.

Even when the researchers considered certain other factors - like people’s history of heart problems before the study - low income was still linked to a 51 percent higher risk.

But when the researchers looked at older adults, the gap between the rich and poor was much smaller: the lowest-income group had a 12-percent higher risk of heart attack, stroke or death than the most affluent group.