Highlights of the article
- Men and women differ with respect to biological, physiological, and genetic COPD manifestations
- Experts point to the ongoing problem of gender bias that exists in COPD prevalence, with more women than men being diagnosed.
- A sex-stratified genome-wide association study provides a clue to the COPD sexual dimorphism.
Chronic obstructive pulmonary disease (COPD) is a type of lung disease that slowly robs its sufferer of the ability to breathe normally. It is the fourth leading cause of death in the world. In 2012, more than 3 million people died of COPD, accounting for 6% of global deaths. Primarily it is associated with tobacco use and smoking, and secondarily with inhalation of occupational and environmental pollutants.
From a historical point of view, COPD was labeled as “man’s disease” mainly because men smoke more and partly because they had higher occupational chemicals exposure than women. However, emerging data from around the world indicate that COPD among women has reached comparable levels to men, with an estimation that the number will continue to climb. There is also an increase in hospitalization and death rate among women than in men. These changes in COPD burden in the past decades has brought a paradigm shift from men to women and recognizes that women are also at significant risk of COPD.
Women Exhibit Different COPD Symptoms Then Men
According to the COPD International Survey, women were more likely to report severe dyspnea (shortness of breath) despite significantly fewer years of smoking than age-matched males. Even younger women with fewer years of smoking reported having greater dyspnea than older men with more years of smoking. There are more anxiety and depression and worse symptom-related quality of life in COPD women than their male counterparts. Female smokers also have a higher risk of early-onset severe COPD than male smokers. Bronchial spasm, which is a risk factor for lung function decline, is easily triggered in women than in men suffering from COPD.
Gender-Specific Differences Make Women More Vulnerable To Lung Damage than Men
Women have smaller lungs and airways than men, and therefore smoking the same amount of tobacco as men result in greater exposure for women.
The inflammatory response in the lungs of women differs from male smokers. Pro-inflammatory mediator like leptin is associated with an increased prevalence of COPD in women but not in men.
The female sex hormone ‘estrogen’ is known to play a role in maintaining lung elasticity that keeps the airway open. Accordingly, airway obstruction is more in postmenopausal women than in premenopausal women. Adolescent girls who are exposed to smoke or air pollution demonstrates greater reductions in lung function than boys. Estrogen also alters the nicotine (present in cigarette and tobacco smoke) breakdown in the body and worsens lung damage.
COPD in a mother increases the risk of COPD in a daughter who smokes, emphasizing the involvement of the X chromosome.
Studies have also shown that bronchioles (branches of airways) have thicker walls and smaller lumen in female patients providing clues for increased lung damage in females than in male patients.
Sexual Dimorphism Lies In Genes
Hardin and colleagues, through their recent sex-based, genome-wide research suggested that COPD among women is associated with the changes in the gene CELSR1 involved in lung development. The changes in this gene (genetic variants) impair lung structure and proper development, thus increasing susceptibility to COPD.
There is a great concern for physicians on whether men and women should be treated differently due to varied differences. According to current treatment guidelines, there hasn’t yet any specific gender-based treatment guidelines available. Although COPD is not a curable disease, it is a manageable disease with medications and lifestyle changes.
