Autoimmune thyroid disease in rheumatoid arthritis: a global perspective.

Objective. To determine the prevalence and impact of autoimmune thyroid disease (AITD) in patients with rheumatoid arthritis (RA). Methods. Eight-hundred patients were included. The association between AITD and RA was analyzed was analyzed by bivariate and multivariate analysis. In addition, a literature review was done focusing on geographical variations. Results. In our cohort the prevalence of AITD was 9.8% while the presence of antibodies was 37.8% for antithyroperoxidase enzyme (TPOAb) and 20.8% for antithyroglobulin protein (TgAb). The presence of type 2 diabetes, thrombosis, abnormal body mass index, and a high educational level was positively associated with AITD. The literature review disclosed a geographical variation of AITD in RA ranging from 0.5% to 27%. Autoantibody prevalence ranges from 6% to 31% for TgAb, 5% to 37% for TPOAb, and from 11.4% to 32% for the presence of either of the two. Conclusion. AITD is not uncommon in RA and should be systematically assessed since it is a risk factor for developing diabetes and cardiovascular disease. These results may help to further study the common mechanisms of autoimmune diseases, to improve patients' outcome, and to define public health policies. An international consensus to accurately diagnose AITD is warranted.

Autoimmune disease and gender: plausible mechanisms for the female predominance of autoimmunity.

A large number of autoimmune diseases (ADs) are more prevalent in women. The more frequent the AD and the later it appears, the more women are affected. Many ideas mainly based on hormonal and genetic factors that influence the autoimmune systems of females and males differently, have been proposed to explain this predominance. These hypotheses have gained credence mostly because many of these diseases appear or fluctuate when there are hormonal changes such as in late adolescence and pregnancy. Differences in X chromosome characteristics between men and women with an AD have led researchers to think that the genetic background of this group of diseases also relates to the genetic determinants of gender. These hormonal changes as well as the genetic factors that could explain why women are more prone to develop ADs are herein reviewed.