Regardless of their biological sex, people with more traditional feminine personality traits have a harder time recovering after a heart attack than those with more traditionally masculine traits, a study led by McGill University researchers shows.

In fact, a person's gender identity was found to be a better predictor of suffering recurrent acute coronary syndrome (ACS) and major adverse cardiac events (MACE) such as heart attacks than their biological sex.

ACS is the general term for a group of conditions in which blood flow in the coronary arteries is decreased or blocked, preventing the heart muscle from functioning properly.

"The study means that gender also matters in terms of explaining differences between men and women," the study's lead author, Dr. Louise Pilote, told CBC Montreal's Daybreak.

Pilote is also the director of the McGill University Health Centre's General Internal Medicine division. 

The study was published in the current issue of the Journal of the American College of Cardiology.

1,000 patients surveyed

The study looked at about 1,000 people from across Canada, aged 18 to 55, who had been hospitalized for ACS between January 2009 and April 2013.

The participants were asked to fill out a detailed survey about their gender roles, to determine where they fall on a spectrum between traditionally masculine or feminine.

For example, the survey asked respondents the number of hours they spent carrying out household chores and taking care of children, as well as their salary.

Both men and women with traits traditionally associated with women had a higher incidence of a second heart attack within 12 months after their first one.

Anxiety could play role

The study didn't answer why the risk of repeated heart attacks among more participants with more feminine traits was higher. 

However, this same group also showed a higher incidence of anxiety, and Pilote said this could be one explanation.

"For example, financial difficulties or the need to manage housework, childcare and work may represent a daily burden, and chronic anxiety may result," Pilote said.

The study's authors hope their findings will lead more researchers to consider gender roles along with biological sex when studying diseases between men and women.