Researchers have sought to discover whether there is a plausible link between obesity and the development of rheumatoid arthritis (RA), with 2 large US studies finding no such evidence and 2 European studies showing significant evidence to suggest
the link.
A recent study investigated the influence of obesity on the development of RA to determine whether obesity is a possible risk factor that could help to explain the annual increase in the incidence of RA in the United States since 1995, after a 4-decade decline (Crowson CS, et al. Arthritis Care Res [Hoboken]. 2013;65:71-77).
The study included 1626 patients who were evenly split between patients having RA (N = 813) and controls (N = 813), with approximately 30% of each group classified as obese (body mass index of ≥30 kg/m2) at the index date. The patients who were classified as obese were found to have a higher risk of developing RA during the study period (odds ratio, 1.24; 95% confidence interval, 1.01-1.53). Furthermore, the investigators found that the incidence of RA rose by an increment of 9.2 per 100,000 among women, and obesity accounted for 52% of this increase (4.8 per 100,000).
The results of this study suggest that obesity is associated with a modest risk for the development of RA, which may account for some of the rise in the prevalence of obesity.
Although the mechanisms by which obesity may put patients at risk for RA are mostly unknown, this study suggests that, in addition to the environmental elements that are known to be risk factors, the association between obesity and chronic inflammation, as well as their influence on the development of RA, should be further investigated.