Women who are overweight or obese, particularly those who acquire the excess weight by late adolescence, have an elevated risk for developing rheumatoid arthritis (RA), analysis of data from two prospective studies showed.
While there was a nonsignificant trend for increased risk for RA among all overweight or obese women (P=0.068), there was a 35% higher risk among those with body mass index (BMI) values of 25 or higher at age 18 (HR 1.35, 95% CI 1.11-1.64, P=0.002), according to Bing Lu, MD, DPH, and colleagues from Harvard University’s medical and public health schools in Boston.
In addition, the risk among those women for developing seropositive RA — generally considered more severe — increased by almost 50% (HR 1.49, 95% CI 1.08-2.06, P<0.001), the researchers reported online in Annals of the Rheumatic Diseases.
Obesity contributes to the development of multiple disease states, including osteoarthritis and diabetes, and the latest research shows obesity linked to arthritis in women.
“One pathway by which obesity may increase the risk of several diseases is via systemic inflammation. Adipose tissue secretes proinflammatory adipocyte-derived cytokines, or adipokines, into the circulation,” explained Lu and colleagues.
However, previous studies examining the relationship between obesity and RA have had conflicting results, and the researchers suggested that risk factors may differ according to age at disease onset.
“Given the recent rapid increase in the prevalence of obesity, this risk factor appears to have a significant impact on the incidence of RA and may account for a large proportion of the recent increase in incidence of RA among women,”
Adipocytes can produce inflammatory markers such as tumor necrosis factor, interleukin-6, and C-reactive protein, which have been detected in individuals with preclinical disease.