Researchers say their findings challenge a widely held assumption that women are simply more vulnerable to cigarette smoke than men.
Women aged 40 years and older are significantly more likely to suffer from chronic obstructive pulmonary disease than men – despite smoking less on average – a US study has found.
Researchers analysed data from the 2020 National Health Interview Survey and discovered that 7.8% of women reported having COPD, compared to 6.5% of men. This higher rate occurred even though women were less likely to have smoked cigarettes and, when they had typically had lower lifetime tobacco exposure than men.
The findings, published BMJ Open Respiratory Research, challenge a widely held assumption that women’s increased vulnerability to COPD comes from being more sensitive to the harmful effects of tobacco. Instead, the study suggests that other, often overlooked factors may be driving the trend.
The researchers pointed to possible culprits like indoor air pollution from home heating, cooking fuels and cleaning or beauty products – many of which are more commonly used by women. Certain jobs dominated by women, such as housekeeping or salon work, may also increase exposure to lung irritants.
Past global studies have shown that burning wood or coal indoors is a major risk factor for COPD. Even in the US, heating homes with coal has been linked to COPD in non-smokers. One Canadian study found that this kind of exposure raised COPD risk for women who had never smoked but not for those who had – suggesting indoor pollution may sometimes be overshadowed by smoking in research.
Using advanced statistical analysis to account for factors such as smoking history and demographics, the latest study found that women still had a 47% higher risk of developing COPD compared to men.
The findings raised important questions about how gender-related biological, environmental or healthcare factors may influence lung health, the researchers said.
While smoking remains a leading cause of COPD, experts say more research is needed to understand why women appear to be more vulnerable to the disease.
“Compared with men, women have more early-onset severe COPD, more severe dyspnoea, more frequent exacerbations and worse quality of life for a given percent decrease in airflow on spirometry,” the authors wrote.
“Women with COPD are younger on average and have a lower average pack- year smoking exposure than men.
“This has raised the question of whether women are more susceptible to cigarette smoke. Indeed, prior work has suggested that the dose-response relationship between smoking and COPD may vary by gender, with a more rapid decline in airflow seen in women.
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“However, other studies have shown no difference in the progression of airflow obstruction by gender. Only very limited research has focused on COPD in adults who have never smoked cigarettes but overall suggests higher rates of COPD among women compared with men.”
The study examined responses from 12,638 women and 10,390 men aged 40 years and older, with demographics reflective of the U.S. population. Participants were evenly spread across their 40s, 50s, and 60s, with fewer respondents in older age groups. However, more women than men were over the age of 80, and more women reported living in poverty based on family income.
When it came to tobacco use, women reported lower rates of cigarette, cigar, pipe and smokeless tobacco use, but had similar rates of e-cigarette use compared to men.
“Our findings refine prior estimates of COPD among those without a smoking history and re-emphasise the high burden of COPD in women, underscoring the need for thoughtful efforts to prevent, diagnose and treat their disease,” the authors concluded.
“Additionally, our research raises uncertainty about the common assumption that increased vulnerability to cigarette smoke is driving the gender divide in COPD.”
