We've all been told that smoking can increase our risk of lung disease. But new research shows that our reproductive hormones may also play a role, particularly if you're a woman.
Chronic obstructive pulmonary disease, or COPD, refers to a group of diseases that cause airflow blockage and other problems related to breathing, including emphysema and chronic bronchitis. According to the U.S. Centers for Disease Control and Prevention, 16 million Americans live with COPD, with significantly more women being affected than men.
Specifically, women tend to develop severe COPD at younger ages than men, and non-smoking related cases of COPD are more likely to be found in women. This has led researchers to believe that female hormones may have some role in the discrepancy but, until recently, previous research into this area has been limited.
However, in a new study, published in the journal Thorax, researchers from the University of Queensland have used 27 observational studies to pool data from more than 850,000 women in 12 countries to examine the potential links between various reproductive factors and the development of COPD.
The women's health was monitored for an average of 11 years across all studies, during which 10,737 individuals developed COPD. And these cases appeared to be associated with the women's reproductive health.
To start, the age at which the women had started their periods was a significant predictor of their risk of developing COPD. This followed a U-shaped curve, with both early and late periods coming with an increased risk of COPD. Those who started menstruating at or before the age of 11 were 17 percent more likely to develop COPD, while those who started menstruating after the age of 16 saw a 24 percent higher risk.
Women with children were significantly more likely to develop the disease than those without, as were those who had experienced infertility or miscarriage.
Early-onset menopause (before the age of 40) was also associated with a 69 percent higher risk of COPD compared with those experiencing menopause between 50 and 51. By contrast, those who went through menopause at or after the age of 54 saw a 21 percent lower risk of developing the condition.
"The overall effect of estrogen might differ depending on the timing," the authors write to explain their results. "In the early or middle reproductive stage, long or higher accumulated exposure to estrogen would be detrimental to the lung, leading to a higher risk of COPD among women with early menarche or multiple live births.
"In the later stage, estrogen may be protective, since earlier age at menopause or [ovary removal] (indicates shorter exposure to estrogen) were associated with a higher risk of COPD."
However, while the pool of participants is large, these findings are purely observational and do not prove that estrogen exposure can cause COPD. Moreover, the authors point to various other factors—such as autoimmune disease, air pollution, and being underweight—that could also increase COPD risk.
While more research is needed to confirm these links, the study shines a light on how reproductive histories can affect our overall health, and offers new insights to medical professionals to support women's health.
Uncommon Knowledge
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About the writer
Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
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