Using previous studies and trials, a review examined the differences in COPD between men and women.
The researchers found that both environmental and biological risk factors could account for the growing number of women with COPD. Women's lungs may be more sensitive to smoking, for example.
According to this review, women may also report different symptoms than men and could be more at risk for complications like osteoporosis.
"Talk to your doctor about quitting smoking."
David Mannino, MD, of the University of Kentucky, led this review on chronic obstructive pulmonary disease, or COPD.
COPD is a lung disease characterized by poor airflow, shortness of breath and coughing. COPD patients' airways do not function properly because their lung tissues have broken down, often in response to irritants like cigarette smoke or air pollution.
According to this review, COPD used to occur primarily in men, but it has appeared in women more frequently in the past 20 years.
Dr. Mannino and colleagues used previous research and studies to summarize what is currently known about gender differences in COPD.
The first National Health and Nutrition Examination Survey, or NHANES I, took place from 1971-1975 and reported that 50.8 per 1,000 women and 108.1 per 1,000 men had COPD.
By the time NHANES III was administered from 1988-1994, only 74.3 per 1,000 men reported COPD. However, for women, the number jumped to 58.2 per 1,000 women.
According to the authors of this review, tobacco consumption and environmental factors may account for some of the increase in COPD among women. In developing countries, the percentage of female smokers is expected to more than double by 2025 from 9 percent in 2000.
Additionally, these authors suggested that women may be more susceptible to cigarette smoke than men. The National Emphysema Treatment Trial found that women generally smoked less than men, but experienced comparable levels of lung damage.
Biological factors could also play a role, according to these researchers. The review claimed that female sex hormones influence the way airways function in a way that could make women more susceptible to lung damage from smoke.
The researchers also suggested that genetics could affect a woman's risk of developing COPD. According to the review, 15 percent of COPD patients were nonsmokers; of this group, 80 percent were women.
Men and women also experienced different COPD symptoms, the review showed. The authors referenced several cross-sectional studies on patients with COPD that indicated that women were more likely to report shortness of breath, but less likely to report phlegm symptoms.
The authors noted that gender differences in symptom presentation could be due to social and cultural factors rather than biological factors.
There were gender differences in the other health conditions that COPD patients develop as well. The authors of this review referenced three studies that showed that women were less likely than men to have heart disease. One of the studies showed that women were more likely to also have osteoporosis, inflammatory bowel disease, reflux and depression.
Another study involving over 70,000 COPD patients showed that women were more likely to survive an acute exacerbation, or sudden worsening, of COPD. Several smaller studies have also suggested that men were more likely to die from COPD.
Treatment of COPD usually involves some combination of smoking cessation, prescription medications and pulmonary rehabilitation (exercise, nutrition counseling and education to help repair the lungs).
Some studies have shown differences in treatment between men and women; for example, women were less likely to quit smoking. However, the authors noted that the impact of gender on treatment was not clear.
The authors of the review concluded that gender significantly affects COPD development, both due to environmental and social factors and biological differences.
They called for more research to be done on the gender differences in COPD disease progression and treatment strategies.
This review was published in the October edition of Translational Research.
The authors did not disclose funding sources. The lead author has served on advisory boards and received research grants from various pharmaceutical companies.