Environmental factors and the outcome of rheumatoid arthritis.

The outcome of rheumatoid arthritis (RA) is influenced by both genetic and non-genetic (environmental) factors. Treatment is the most important environmental factor which influences RA outcome. This chapter considers non-treatment environmental influences on the outcome of RA. There is evidence that socio-economic factors (such as level of formal education and area of residence), smoking, diet and psychological factors may affect the levels of pain and physical disability experienced by RA patients. More work is needed in order to understand the mechanisms underlying these associations. Smoking may also adversely affect radiological outcome in the longer term. It is possible that pregnancy may improve the outcome of RA. Contrary to popular lay opinion, there is no evidence that the weather has any influence on RA.