COPD is a complex disease that affects patients in both developed and developing countries around the world. Historically considered a men's disease, the prevalence and mortality of COPD has increased more rapidly in women than in men during the past two decades.

The review, published in Translational Research, examines potential reasons for this increase. The change has been largely attributed to the changing smoking trends during the last 50 years -- for instance, in developing countries, the prevalence of female smokers is predicted to increase to 20 percent by 2025, up from only nine percent in 2000. Other environmental risk factors, such as exposures to occupational dusts or chemicals and air pollution, may be a cause due to women entering into historically male jobs.

Newer evidence also suggests that men and women differ in susceptibility to smoking, possibly because of hormonal mechanisms -- female sex hormones have been known to influence airway function, and during childhood, girls experience a larger reduction in lung function than boys when exposed to either tobacco smoke or environmental air pollution. Additionally, the clinical presentation, comorbidities and disease perception of COPD may vary between the genders and may ultimately influence treatment decisions and strategies.

"Over my 30 years of treating patients, I've seen the number of women with COPD increase dramatically to where they now outnumber the number of men with COPD in my practice," said Mannino, professor and chair of Preventive Medicine and Environmental Health at the UK College of Public Health. "Women with COPD are particularly at risk for certain complications, such as osteoporosis."