What really matters in heart disease outcomes, researchers are saying, may be gender roles, not biological sex.
Just about any medical study will note different effects for men and women. Gender differences theory applied to a recent study of differences in the risk of heart attacks between men and women, however, found that gender is a more important factor than sex.
Researchers at 13 university departments of medicine, nursing, exercise science, epidemiology, and public health across Canada looked at the medical records of 273 women and 636 men between the ages of 18 and 55 who had been hospitalized for acute coronary syndrome (which is essentially symptoms of heart attack with or without damage to the heart muscle) between 2011 and 2013. They used the records and a patient questionnaire to determine the relationship between sex (whether someone is male or female) and gender (whether one fulfills the roles associated with men or women in society) and MACE, the probability of major adverse coronary events (another hospitalization for acute coronary syndrome, a heart attack, admission to hospital for a stent or bypass, or death) in the 12 months after hospitalization for acute coronary syndrome.
The researchers found that gender was more important than sex in predicting who would go back to the hospital for heart problems after a first episode of acute coronary syndrome. Specifically, Canadians who fulfilled female gender roles were 350% more likely to be readmitted to the hospital for a second round of treatment for acute coronary syndrome as Canadians who fulfilled male gender roles.
What is female "gender"?
Female gender fulfills social expectations of women in society.
Female gender, like male gender, is not all or nothing. The researchers used a 17-point scale to distinguish female and male gender roles.
The researchers' questionnaire reflected traditional gender norms with questions such as "Are you responsible for most of the child rearing activities in your family?" and "Are you the primary wage earner in your family?" but these were at least a place to start. Although the idea that the male gender role is to earn money and the female gender role is to take care of children is outdated, it at least gave the researchers a way to see if more than just biological sex plays a role in heart health outcomes.
The researchers found that 3% of men and 3% of women had to be readmitted to hospital in 12 months for heart issues, but a greater degree of femininity was associated with a greater risk of disease. "Feminine" people had a 5% rate of recurrence of heart disease while "masculine" people had about a 2% rate of recurrence.
What does this mean?
It shows us that a binary understanding of sex, without an understanding of sex roles, is too limited in understanding the differences of men and women in health processes. There will always be hard and fast objective differences between men and women, but it may be the harder to define gender differences that may matter most in health and disease.
Pelletier R, Khan NA, Cox J, et al. Sex Versus Gender-Related Characteristics: Which Predicts Outcome After Acute Coronary Syndrome in the Young?. J Am Coll Cardiol. 2016;67(2):127-135. doi:10.1016/j.jacc.2015.10.067.