(HealthDay News) – Obesity is linked with the risk of developing rheumatoid arthritis (RA), and seems to have contributed to the recent increase in incidence of the condition.

To investigate the influence of obesity on the incidence of RA, Cynthia S. Crowson, from the Mayo Clinic in Rochester, MN, and colleagues compared 813 patients with RA with 813 matched population-based controls. Medical records were reviewed to collect height, weight, and smoking status data. The incidence of RA in the absence of obesity was estimated using population attributable risk.

The researchers found that approximately 30% of each group were obese (body mass index ≥30kg/m²) at incidence/index date. Obesity correlated significantly with developing RA (odds ratio, 1.24; odds ratio, 1.53 after adjusting for smoking status). From 1985–2007, the incidence of RA rose by 9.2 per 100,000 women. Obesity was responsible for 4.8 per 100,000, or 52%, of the increase.

“Given the recent rapid increase in the prevalence of obesity, this risk factor appears to have a significant impact on the incidence of RA,” the authors write. “These findings suggest that unless the obesity epidemic is controlled, the incidence and prevalence of RA will continue to rise, leading to increasing demands for rheumatological care.”

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