A lonely middle and old age could bring higher odds for a stroke, new data suggests.

A 12-year study of people over 50 found that those who experienced chronic loneliness were 56% more likely to have a stroke, versus those who said they weren't lonely.

“Loneliness is increasingly considered a major public health issue. Our findings further highlight why that is,” said study lead author Yenee Soh, a research associate in social and behavioral sciences at the Harvard School of Public Health.

“Especially when experienced chronically, our study suggests loneliness may play an important role in stroke incidence, which is already one of the leading causes of long-term disability and mortality worldwide," she said in a Harvard news release.

The findings were published June 24 in the journal eClinicalMedicine.

The study looked at data from the Health and Retirement Study (HRS) from 2006 through 2018. As they entered the study, more than 12,000 people over 50 who had no history of stroke prior to joining the study were asked questions from a standard test to gauge their levels of loneliness. About 8,900 of the participants were asked the same questions again in 2010.

A total of 1,237 strokes occurred among the group over the 12 years of the study, including 601 strokes among the participants who had been surveyed about loneliness at two time periods.

Soh's group placed folks into four categories of loneliness based on their survey answers: "consistently low”; “remitting” (those who scored high at baseline and low at follow-up); “recent onset” (those who scored low at baseline and high at follow-up); and “consistently high” (those who scored high at both baseline and follow-up).

People in the "consistently high" group had a 56% higher odds of having a stroke versus those in the "consistently low" group, the research showed, even after accounting for other psychological factors such as depression and isolation.

Any form of loneliness observed over the study period was tied to a higher risk for stroke, but there was no clear pattern of risk for folks whose loneliness came and went -- suggesting that it's long-term, chronic loneliness that's the main source of danger.

“Repeat assessments of loneliness may help identify those who are chronically lonely and are therefore at a higher risk for stroke," Soh said. "If we fail to address their feelings of loneliness, on a micro and macro scale, there could be profound health consequences."

“Importantly, these interventions must specifically target loneliness, which is a subjective perception and should not be conflated with social isolation," she added.