Why autoimmune diseases hit women harder—and what clinicians may be missing
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Many autoimmune diseases are more common in women during their reproductive years, and some conditions change during pregnancy or around menopause.
—Kristin Galetta, MD
More than 15 million people in the US have been diagnosed with an autoimmune disease, and the large majority of them are female.[]
Here’s a refresher of how autoimmune disease can impact your female patients.
Related: Could 'being too nice' raise autoimmune disease risk in women?Two X chromosomes
Among the various factors that may contribute to higher rates of autoimmune diseases among women, genetics may play a role.
As Kristin Galetta, MD, a board-certified neurologist at Stanford, explains, “Women have two X chromosomes, and some immune-related genes on the X chromosome escape the normal process of X-inactivation, where one of the two genes is suppressed to avoid duplicating information. This may contribute to differences in immune regulation.”
“Sex hormones are also important," Dr. Galetta said. "Estrogen generally enhances immune responses, whereas testosterone tends to have more immunosuppressive effects. These differences may help explain why women are more prone to many autoimmune diseases, although they don't explain everything.”
Across the lifespan, autoimmune diseases are more likely to impact women at specific stages, likely due to changes to hormones.
“Many autoimmune diseases are more common in women during their reproductive years,” Dr. Galetta said, “and some conditions change during pregnancy or around menopause. Estrogen tends to promote immune activation, although its effects are complex and can vary depending on the disease and the level of exposure. So hormones are clearly part of the picture, but they are not a simple on-off switch for autoimmunity.”
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In the US, 8% of the population lives with an autoimmune disease. Of these, roughly 80% are women. Researchers have identified more than 140 autoimmune disorders.[]
It is believed that hormones can impact each of these diseases in different ways.
“Some autoimmune diseases can improve while estrogen is high, such as rheumatoid arthritis, but lupus can actually flare because estrogen can, in a way, help the antibody-producing immune cells survive longer.” Kanika Monga, MD, a clinical rheumatologist in Houston, told MDLinx.
“Testosterone, on the other hand, is generally protective, and it is believed that men who develop autoimmune disease may have lower levels,” Dr. Monga said.
Specific autoimmune diseases are more likely to impact females than males. In systemic lupus erythematosus (SLE) and Sjorgen’s syndrome, up to 95% of patients are female.[] Arthritis and multiple sclerosis occur in females 60% more than in males.[]
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As well as hormones and the additional X chromosome in females, there are other factors that could contribute to the development of autoimmune diseases that differ between the sexes.[]
These include immune system responses, reproductive function, organ vulnerability, and the impact of environmental agents.[]
More generally, aside from genetics, factors believed to contribute to development of autoimmune disease include infections, smoking, certain medications, obesity, exposure to toxic agents, and already having an autoimmune disease.[]
While there is no cure for autoimmune diseases, and it is not always possible to prevent the onset of disease, Dr. Monga recommends counselling patients to focus on modifiable risk factors.
“It may be beneficial to focus on lowering modifiable risk factors when possible, such as quitting smoking, maintaining a healthy weight, staying active, and eating well,” she said.
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