How much more common are autoimmune diseases in women?
The short answer is that women are roughly twice as likely as men to be diagnosed with an autoimmune disease. A large 2024 study using electronic health records from six major US medical systems found that 63% of people diagnosed with an autoimmune disease were female, meaning women were almost twice as likely as men to receive such a diagnosis [2]. This finding is echoed by a 2025 German study of over 73 million insured individuals, which reported that 67% of all autoimmune disease patients were female [1]. Both are among the largest studies of their kind, and their agreement strengthens the conclusion.
For some individual diseases, the female predominance is even more dramatic. The German study found that autoimmune thyroiditis was nearly 6 times more common in women (prevalence ratio 5.92), primary biliary cirrhosis was 5.6 times more common, and systemic lupus erythematosus (SLE) was 5.15 times more common [1]. These ratios mean that for every man diagnosed with lupus, about 5 women are. However, not all autoimmune diseases follow this pattern: type 1 diabetes and ankylosing spondylitis were actually more common in men in that same study [1].
Why are women more affected?
Researchers believe the answer lies in a combination of biological factors, including sex hormones, genetics, and immune system differences. A 2024 review paper summarizes that key drivers include sex hormones (like estrogen), immune-related genes on the X chromosome (of which women have two copies), and sex-specific effects of environmental factors like viruses or toxins that can trigger autoimmunity [4]. Another 2022 review highlights that sex chromosomes and gonadal hormones alter immune responses in fundamental ways, which helps explain why women mount stronger immune reactions overall — a strength that can unfortunately also increase the risk of the immune system attacking the body's own tissues [6].
The influence of hormones is particularly visible around puberty. A study of children and adolescents with autoimmune thyroid disease found that the female predominance became much more pronounced after the onset of puberty, suggesting that reproductive hormones play a triggering role [5]. Interestingly, that same study found that among children who already had one autoimmune disease, boys were actually more likely than girls to develop a second autoimmune condition [5]. This nuance shows that while women are at higher overall risk, the relationship between sex and autoimmunity is not simple.
Are there autoimmune diseases that are more common in men?
Yes, the pattern is not universal. The large German study found that men were more likely than women to be diagnosed with type 1 diabetes (1.37 times more common), ankylosing spondylitis (1.40 times more common), and Guillain-Barré syndrome (1.31 times more common) [1]. Myasthenia gravis showed no sex difference at all [1]. This means that while the overall trend strongly favors women, the direction and magnitude of the sex difference depend on the specific disease.
Even within diseases that predominantly affect women, the course of the disease can differ between sexes. A 2023 study of 417 lupus patients (366 women, 51 men) found that while women were far more numerous, men tended to develop the disease later in life and had a higher rate of early organ damage [3]. This suggests that being male may not protect against severe disease, even if it lowers the odds of getting it in the first place.
About These Sources
This answer is built on 6 peer-reviewed studies — published from 2020 to 2025, 3 from 2024 or later, 4 in Q1 journals, collectively cited 346 times — selected as the most relevant from 12 studies that passed quality screening, drawn from 80 papers retrieved from a database of over 500 million.
Sources used in this answer
Sex-specific and regional differences in the prevalence of diagnosed autoimmune diseases in Germany, 2022
In a 2022 German study of over 73 million insured individuals, 67% of autoimmune disease patients were female; autoimmune thyroiditis was nearly 6 times more common in women, while type 1 diabetes and ankylosing spondylitis were more common in men.
Estimation of prevalence of autoimmune diseases in the United States using electronic health record data
Using electronic health records from 6 US medical systems (2011-2022), this study found that 63% of autoimmune disease patients were female, and women were nearly twice as likely as men to be diagnosed with an autoimmune disease.
Gender differences in SLE: report from a cohort of 417 Caucasian patients
In a cohort of 417 Caucasian lupus patients (366 women, 51 men), men had later disease onset and higher early damage accrual, but women were far more numerous overall.
Mechanisms underlying sex differences in autoimmunity
This review identifies key mechanisms for sex differences in autoimmunity: sex hormones, X-chromosome immune genes, epigenetic effects, and mitochondrial damage from viruses or toxins that increase autoantibodies.
Gender Differences at the Onset of Autoimmune Thyroid Diseases in Children and Adolescents
In 382 children with autoimmune thyroid disease, females predominated overall, but the sex difference emerged after puberty; among those with additional autoimmune diseases, males had a higher relative prevalence.
Sex Differences in Immunity
This review summarizes strong epidemiological evidence that sex is a key biological variable in immunity, influencing autoimmunity, viral infection severity (e.g., COVID-19), and cancer immunotherapy responses.