Women who have never smoked are around 50% more likely than their male counterparts to develop chronic obstructive pulmonary disease (COPD), new research reveals.
Published in the journal BMJ Open Respiratory Research, the study challenges the belief that women are at higher risk of COPD than men because they are more vulnerable to the effects of cigarette smoke, which was previously thought to explain the disparity in COPD rates between sexes.
The research suggests that the extra burden of COPD in women should be considered when assessing respiratory illness in female patients, particularly in those patients who have never smoked.
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Despite significant reductions in the number of people who smoke in the last 50 years, COPD remains a leading cause of death in both the US and the UK.
Women tend to develop COPD at a younger age than men, and often experience more severe symptoms, prompting the suggestion that increased COPD rates in women are due to a heightened susceptibility to the effects of cigarette smoke.
To explore this further, the researchers analysed data from the 2020 US National Health Interview Survey (NHIS), both to try to understand potential links between the development of COPD and gender and to produce an updated estimate of the prevalence and impact of COPD. Over 32,000 people responded to the survey, including 12,638 women and 10,390 men. All participants were aged 40 or over and provided information on their smoking history, what tobacco products they used, and whether they vaped. The analyses were adjusted for sociodemographic covariates.
Overall, women were found to have a higher COPD prevalence (7.8%) than men (6.5%). This was despite their lower cigarette smoke exposure – women reported smoking fewer daily cigarettes than men, averaging around 18 compared with around 22, and to have done so for fewer years. And they were less likely than men to have started smoking before the age of 15, at around 19% compared with 28%.
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The prevalence of COPD was higher among women who had ever smoked than it was among men – at 16% compared with 11.5%. But it was also much higher among women than men who had never smoked – the prevalence of COPD was almost twice as high in women who had never smoked as it was in male never-smokers, at just over 3% compared with just over 1.5%.
In further analysis, women were found to have a 47% higher relative risk of being diagnosed with COPD, after accounting for other variables that could influence their risk.
And, crucially, the gender disparity persisted, irrespective of smoking history: among those who had never smoked, women were 62% more likely to be diagnosed with COPD than men, while among those who had ever smoked they were 43% more likely to have COPD.
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The researchers concluded: ‘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.’
