Why Women Experience More Autoimmune Disease Than Men

Category: Research & Health Insights
Estimated read time: 4–5 minutes

Original Sources

• Nature article on autoimmune sex differences — Nature
  👉 https://www.nature.com/articles/d41586-024-00267-6 (#Autoimmune sex differences) Nature

• Women generally mount stronger immune responses — PubMed
  👉 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9386672/ Frontiers

• Sex differences in autoimmunity mechanisms — PubMed
  👉 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980266/ PMC

• Genetics & hormone influences on immune response — Autoimmune Institute
  👉 https://www.autoimmuneinstitute.org/articles/how-sex-genetics-influence-autoimmunity/ autoimmuneinstitute.org

• NIH overview of sex differences in autoimmune disease — NIH
  👉 https://www.nih.gov/news-events/nih-research-matters/understanding-sex-differences-autoimmune-disease National Institutes of Health (NIH)

• Johns Hopkins overview on autoimmune disease — Hopkins Medicine
  👉 https://www.hopkinsmedicine.org/health/wellness-and-prevention/autoimmune-disease-why-is-my-immune-system-attacking-itself Wikipedia

What is an autoimmune disease?

Autoimmune diseases happen when the immune system mistakenly attacks the body’s own healthy cells and organs instead of defending against real threats like infections. There are more than 80 autoimmune conditions, including lupus, multiple sclerosis, rheumatoid arthritis and thyroiditis.

Across these diseases, women are disproportionately affected; about 80% of diagnosed cases occur in females worldwide.

Why the imbalance?

1. Immune system strength

Women’s immune systems are generally more active and reactive than men’s. This helps them fight infections more effectively, but that same heightened activity also raises the risk of misdirected immune attacks on their own tissues.

Higher levels of humoral (antibody) and cell-mediated immune responses in women mean the immune system is more likely to overreact, which is one of the hallmarks of autoimmune disease.

2. Genetics — the X chromosome

Women have two X chromosomes, while men have one X and one Y. Many immune-related genes are located on the X chromosome, so women’s cells have a larger set of immune regulatory genes to work with. 

To prevent double doses of X-chromosome genes, one X chromosome is normally “switched off” in each cell. However, processes such as X-inactivation can be imperfect, and recent research suggests this can sometimes confuse the immune system and trigger autoimmunity.

3. Hormones and immune regulation

Sex hormones like estrogen, progesterone and testosterone influence how the immune system works:

• Estrogen tends to activate immune responses, boosting antibody production and inflammation pathways, which can increase autoimmune risk.

• Testosterone generally suppresses immune activity, which may be one reason men have lower autoimmunity rates overall.

These hormonal effects begin at puberty, change during pregnancy and shift again at menopause, which may explain why autoimmune diseases often first appear during reproductive years.

Pregnancy & immune memory

Pregnancy changes a woman’s immune system dramatically to support the developing foetus. After pregnancy, the immune system doesn’t simply “reset”, and some researchers believe this prolonged immune adaptation may contribute to an increased autoimmune burden later in life.

Environmental & lifestyle factors

Researchers also suspect that environmental exposures (e.g., infections, microbiome changes, diet and stress) interact with genetic and hormonal factors to influence autoimmune risk. These interactions are complex and still under study.

Conditions that are more common in women

Most autoimmune diseases disproportionately affect women, such as:

• Systemic lupus erythematosus (SLE), up to 9 times more common in women

• Sjogren’s syndrome, thyroiditis and rheumatoid arthritis, several times more common in women

Not all autoimmune diseases follow this pattern; for example, some conditions, like certain liver diseases, occur more often in men, but the overall trend is clear.

What this means for women’s health

While the exact causes are still being studied, scientists agree that autoimmune disease risk is shaped by the intersection of hormones, genetics, immune response and environmental factors.

This doesn’t mean every woman will develop autoimmunity, but awareness of these biological trends helps researchers tailor prevention, diagnosis and treatment strategies that consider sex as a fundamental biological variable.

SHE takeaway

Women’s stronger and more complex immune systems are a double-edged sword, giving enhanced protection against infections, yet also raising the risk of immune misfires that lead to autoimmune disease. Knowing why this happens is an important step toward better research, better care, and better health outcomes for everyone.

Medical Disclaimer:
This article is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare professional with concerns about your health.