Men with a high BMI at lower risk of rheumatoid arthritis

9 Sep

A research team from Sweden – publishing in the journal Rheumatology – says that a high body mass index in men may reduce the risk of rheumatoid arthritis, though the same cannot be said for women.
[X-ray of person suffering from arthritis]
Researchers suggest a high BMI may protect men against rheumatoid arthritis, though this is not the case for women.

Dr. Carl Turesson, a physician with the Department of Rheumatology at Malmö University Hospital in Sweden and an affiliate with the Division of Rheumatology at the Mayo Clinic College of Medicine in Rochester, MN, told Medical News Today that “it is a general observation that abdominal obesity is seen more often in men.”

It is the kind of fat development in men with high body mass index (BMI), the researchers suggest, that could be protective against the development of rheumatoid arthritis (RA). This is because men with high BMI, compared with women, develop more abdominal obesity, or visceral fat.

“Abdominal fat produces different types of signal molecules, which may affect the development of inflammation,” Dr. Tuersson told us, adding that this is something that needs to be studied further.

The study wanted to investigate the impact of overweight and obesity on the risk of RA. The team used two large population-based health surveys – the Malmo Diet Cancer Study (MDCS) and the Malmo Preventative Medicine Program (MPMP), involving a total of 50,705 participants – drawing data from 383 subjects.

From these, the team found that men with a BMI over 25 kg/m2 were estimated to be 63% less likely to develop RA in the MDCS, and 40% less likely to develop the condition in the MPMP.

The study used World Health Organization (WHO) definitions of overweight and obesity. Overweight was defined as BMI of 25-30 kg/m2, while obesity was defined as a BMI greater than 30 kg/m2.

As smoking is negatively associated with obesity in men, the results were adjusted for this.

“This is relevant, since smoking is a known risk factor for RA, and smokers on average have a lower BMI,” Dr. Tuersson told MNT. “However, the effect of BMI in men remained statistically significant in analysis adjusted for smoking.”

Association between BMI and RA should be further studied in a US population

Dr. Turesson told MNT that he felt a similar study should be carried out in a US population:

“The distribution of BMI is different and relevant exposures, such as diet, differ to some extent from our Scandinavian study populations. Previous studies from the US have focused on the relation between obesity and RA in women.”

In 2005, an estimated 1.5 million American adults aged 18 and above had RA. Incidence rises with age, peaking with people aged 65-74 years (89 per 100,000).

MNT recently reported on a study suggesting that people who develop arthritis may be more likely to fall into poverty – particularly women who develop the condition.

Written by Jonathan Vernon

Copyright: Medical News Today

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