Rheumatoid arthritis is an autoimmune disease that most likely is caused by an interaction of genetic and environmental factors. Researchers sought to determine a possible role of diet, in particular the mostly plant-based Mediterranean diet, which is thought to have anti-inflammatory properties. The researchers analyzed data on health and diet for 1,721 people with rheumatoid arthritis and 3,667 people without the disease. Results were published in Arthritis Research & Therapy
(September 2018). They found that 24 percent of those with rheumatoid arthritis and 28 percent of those without it highly adhered to the Mediterranean diet. High adherence reduced the chances of getting rheumatoid arthritis by 21 percent compared to low adherence, but only in men who had positive blood tests for rheumatoid factor and anti-cyclic citrullinated peptide, which are antibodies in most people with rheumatoid arthritis.