Nov. 22, 2010 -- Children whose parents divorced grow up to have twice the stroke risk of adults whose parents stayed together, a Canadian study finds.
The association between childhood experience of parental divorce and stroke cannot be explained by other factors linked to stroke risk: education, household income, obesity, smoking status, alcohol use, inactivity, mental health, or adverse childhood experiences such as abuse.
So what's the explanation? That's what University of Toronto gerontologist Esme Fuller-Thompson, PhD, and colleagues would like to know.
"We can only say there is an association between parental divorce and adult stroke, and that a lot of the pathways we considered key mediators of stroke are not correct," Fuller-Thompson tells WebMD. "Neither health behaviors nor depression nor adult socioeconomic status can explain the stroke risk we saw."
The Canadian researchers took advantage of data from the 2005 Canadian Community Health Survey of more than 13,000 residents of the provinces of Saskatchewan and Manitoba.
Fuller-Thompson's team was investigating the link between childhood physical abuse and health outcomes. They included parental divorce as one of the childhood stresses they wanted to evaluate. Indeed, they found that divorce was more common in families in which there was abuse.
"When we looked at adult risk of stroke, we found the association was not with abuse but parental divorce during childhood," Fuller-Thompson says. "We guessed, this association would go away if we controlled for healthy behavior -- there is some evidence that children of divorced parents are more likely to smoke and to drink."
Instead of making the association go away, controlling for health behavior and other factors only strengthened the link between childhood experience of divorce and adult stroke.
Despite the increased risk, the vast majority of adults whose parents divorced did not have strokes.
"Let's make sure we don’t have mass panic by telling people that every mother who divorces gives her child a stroke," Fuller-Thompson says. "We don't know divorce causes stroke, we just know this association exists. It could be a lot of things."
One theory is that exposure to stress during childhood may change the physiology of how a person responds to stress in adulthood. That remains to be explored.
Meanwhile, Fuller-Thompson notes that times have changed and divorce may not have the same effect on today's children as it did on the people in the Canadian study.
"Many of these adults experienced their parents' divorce in the 1950s, when the consequences and ramifications of divorce were different than they are today," she says. "So even if divorce experienced in childhood did cause their increased risk of stroke, it does not mean the risk is still there for children whose parents divorce today."
Fuller-Thompson reported the findings in a presentation to the annual meeting of the Gerontological Society of America, held Nov. 19-23 in New Orleans.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.