A chronic inflammatory disease of the immune system, rheumatoid arthritis (RA) has been linked to a combination of genetic and environmental factors.
Aspects of lifestyle may explain as much as 40 percent of the risk. Cigarette smoking has consistently been found to play a role in RA's development. The role of nutritional factors is less certain. Studies have suggested the protective benefits of eating fish, the dangers of drinking coffee, and a reduction in disease risk for women who enjoy alcohol in moderation. Such associations, however, are still wide open to debate and further research.
Recently, a team of British researchers found that a diet lacking in fruit, especially varieties high in vitamin C, increases the risk of inflammatory arthritis, a common early sign of RA, as much as three-fold. Building on this compelling finding, they set out to investigate the association of other dietary habits with the onset of RA. Their results, published in the December 2004 issue of Arthritis & Rheumatism, indicate a high level of red meat consumption as an independent risk factor for inflammatory arthritis.
Led by Professors Alan Silman and Deborah Symmons at the University of Manchester, the team drew its subjects from a large, established research sample--over 25,000 men and women between the ages of 45 and 75 enrolled in the European Prospective Investigation of Cancer in Norfolk, England. Within this population, 88 new patients with inflammatory arthritis, affecting at least two major joints, were identified.
Nearly 40 percent of these patients satisfied the American College of Rheumatology criteria for RA at baseline. The patients were then matched, for age, sex, and body mass index, with 176 controls. At the study's onset, each participant completed a detailed 7-day food diary, with advance instruction on measuring food portions to help them be as specific as possible in recording their intake. Each participant also supplied information on his or her past and present status as a smoker.