Gene-Environment Interactions in Rheumatoid Arthritis Autoimmunity Disease Severity

Rheumatoid Arthritis (RA) is a systemic inflammatory disease affecting over 2 million people in the U.S. alone, a condition characterized by progressive joint destruction, significant work-related disability and accelerated mortality. While the precise cause of RA is unknown, it is clear that the disease does not result from a single heritable factor or single environmental exposure. Of the many environmental exposures that have been studied, cigarette smoking is the factor most consistently shown to be associated with RA onset. In addition to its role in disease susceptibility, recent studies have found that smoking, along with genetic factors, contribute to RA-related autoimmunity and disease severity. Moreover, studies to date looking at disease severity in RA have exclusively involved women of Caucasian/European ancestry. This is an important distinction since although RA is more common in women, smoking appears to be most closely linked to RA risk in men. Additionally, the burden of other smoking-related illnesses appears to be greatest among non-Caucasian populations. For this reason and because smoking rates and prevalence of risk-alleles differ in ethnic/racial minorities (i.e. SE and GSTM1-null polymorphism), further studies are needed to define the association of smoking and possible gene-smoking interactions and their role in autoimmunity and disease severity in these understudied populations.