Sex differences in rheumatoid arthritis: more than meets the eye.

Abstract

Sex differences in the prevalence of autoimmune diseases such as rheumatoid arthritis (RA) are well described, but the literature is not as clear about sex differences in RA disease course and prognosis. A recent study from a very large cross-sectional international cohort demonstrated slightly worse levels of disease activity and function in female patients with RA, compared with men. These findings are discussed in the context of our evolving knowledge of sex differences in the expression of this prototypic autoimmune disease, both in terms of the actual disease activity level, the effects that the disease has on physical function, and our ability accurately to measure these aspects.

Figure 1

X-linked genetic factors, hormonal factors, and exposures that may be different for men and women could all influence the prevalence of autoimmune diseases as well as their severity. The latter aspect is, however, also influenced by many more factors, including differences in the treatments given, the response to treatments, the subjective experience of the disease, and the instruments used to measure the disease. The thick arrows indicate established associations and the thin arrows putative associations.