Gender-specific incidence of autoimmune diseases from national registers

• The overall incidence of 32 autoimmune diseases is 60% higher in women than in men.
• Half of the specific autoimmune diseases show female predominance.
• The rest of specific autoimmune diseases showed no difference or male predominance.

BackgroundIt is widely believed that autoimmune diseases affect predominantly in women, but the available evidence came from case control study with potential selection and recall bias. We aimed to examine the gender-specific incidence of autoimmune diseases by using national wide registers in Sweden.MethodsSwedish Hospital Discharge Register and Outpatient Register were used to identify a set of autoimmune diseases between 1987 and 2010. Gender-specific incidence rate was standardized directly according to the Swedish age distribution in 2000.ResultsA total of 403,757 individuals were diagnosed with autoimmune diseases between 1987 and 2010 in Sweden. The overall incidence of 32 autoimmune disease was 60% higher in women than men. Female predominance was noted in 18 specific diseases, whereas the rest of them showed no difference or male predominance. The age of onset was different between men and women in 27 autoimmune diseases.ConclusionsOur study suggested that the classical view of female predominance of autoimmune diseases may be far from striking than previously believed. Further studies are needed to examine whether there is true difference between men and women.