According to a study published in the International Journal of Chronic Diseases, women who have never smoked tobacco have a higher prevalence of COPD diagnosis compared to never-smoking men. In addition, African American women have an even greater prevalence, report researchers from the University of Toronto.

The study found less than one in 20 (4.4%) never-smokers over the age of 50 reported having a diagnosis of COPD. Black women had the highest prevalence of COPD at (7.0%), followed by white women (5.2%), white men (2.9%), and black men at (2.4%).

“Consistent with our hypotheses, we find that sex/gender and race are associated with COPD prevalence but that the relationships are uniquely influenced by [socioeconomic position],” researchers wrote. “Specifically, we show that women (both black and white) have higher odds of COPD than men. This finding is consistent with prior research and the hypothesis that females have an increased susceptibility to COPD due to an interaction of sex-related biological causes and gender-associated structural factors.”

Researchers concluded that the study demonstrated, among never-smokers, black women have higher odds of COPD than white women but that socioeconomic position appears to explain the difference. “This finding contradicts an earlier study using the NHANES that found no age-adjusted black/white differences in the odds of self-report of physician-diagnosed COPD among never-smoking women,” researchers wrote.