[Gender differences in autoimmune diseases illustrated by rheumatoid arthritis].

Many autoimmune diseases like rheumatoid arthritis (RA) show gender differences. RA is triggered by an interaction between genetic, hormonal, environmental and behavioural factors. 75% of cases are women under the age of 60; lover the age 60 the gender ratio is 1:1. Different genotypes predispose for RA. Pregnancy often suppresses RA, as does oral contraception. Lactation, smoking (w), BMI > 30, heavy vibrations and certain dust particles (m) may trigger RA, while the effect of male hormones is uncertain. Future prevention should focus on environment, behavioural factors and genetic profiling.