Here’s Why More Women Are Affected by Asthma Than Men

Like other chronic illnesses, such as migraines and arthritis, women have a far greater chance of developing asthma than men. In fact, women are twice as likely to have the respiratory condition, which can make breathing a struggle. Now, thanks to new research out of Vanderbilt University and Johns Hopkins, we have a better idea why.

Turns out, hormones may be behind this difference in asthma diagnoses. But before you go blaming women’s hormones for anything else, know that estrogen is actually not making things worse. Testosterone, it turns out, has the ability to reduce lung inflammation.

“When we started this study, we really thought that ovarian hormones would increase inflammation, more so than testosterone making it better,” senior author Dawn Newcomb of the Vanderbilt University Medical Center says in a statement. “I was surprised to see that testosterone was more important in reducing inflammation.”

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So here’s the deal: Prior to puberty, boys have asthma at a rate of approximately 1.5 times higher than girls. But then after puberty, once the sex hormones kick in, that trend reverses, making women twice as likely to develop the condition than men. But then, after menopause, rates of asthma in women begin to decline.

Of course, there are many factors that play into asthma, including a person’s environment, exposure to allergens and contracting viral infections, but researchers now are adding hormones to that list.

For the study, Newcomb and her coauthors focused on a specific type of lung cell that makes proteins that causes inflammation and mucus production in the lungs, making it harder to breathe. After collecting and analyzing blood samples, the researchers found that people with asthma had more of this type of lung cell and that asthmatic women had more than asthmatic men.

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The scientists added hormones created in the ovaries — like estrogen and progesterone — to these lung cells, but didn’t notice a significant change in the protein responsible for lung inflammation. But when they added testosterone, it resulted in reduced production of the asthma-causing protein.

While this helps explain the fluctuating rates of asthma between men and women before, during and after puberty, it’s only one of many components contributing to asthma. And given that for many people, presence of hormones isn’t something we control, it’s important to take care of ourselves and limit exposure to environmental causes like secondhand smoke whenever possible.