Men with a high body mass index (BMI) may have a lower risk of developing rheumatoid arthritis (RA), a new study suggests.
Scientists in Sweden analysed data from 383 patients who were included in two large population-based health surveys. Results showed that in men, being overweight or obese at inclusion in the health survey was associated with a reduced risk of subsequent development of RA. There was no such association in women, the researchers said.
The findings were based on the Malmo Diet Cancer Study (MCDS) and Malmo Preventative Medicine Program (MPMP) data sets.
After the results were adjusted for smoking, which is negatively associated with obesity in men, those men with a BMI over 25kg/m2 were estimated to be 63% less likely to develop RA in the MDCS, and 40% less likely in the MPMP.
Addressing the question of why a high BMI would reduce the risk of men developing RA in the future, the scientists suggested that a high BMI more often reflects increased abdominal obesity or visceral fat in men compared with women, and this could help protect against the development of RA.
The researchers have previously described a connection between high BMI and hormones, where metabolic pathways related to the adipose tissue and hormone-related factors could have a protective effect against RA, Oxford University Press noted.
Lead author Carl Turesson said that there was no substantial difference between the effect of obesity on the risk of RA versus the effect of being overweight. “However, a differential effect of very high BMI cannot be ruled out,” he added.
The study features in the journal Rheumatology, which is published by Oxford University Press.