People with gastrointestinal or urogenital infections in the 2 years prior to answering a questionnaire had significantly lower odds of having rheumatoid arthritis in a Swedish population-based case-control study, Dr. Maria E. C. Sandberg and her associates reported.
Gastroenteritis, urinary tract infections, and genital infections were significantly associated with a lower likelihood of having rheumatoid arthritis. Prostatitis, a much less common disease, had a protective effect at a similar magnitude, but a smaller sample size meant the association was not statistically significant. No association was found for sinusitis, tonsillitis, and pneumonia.
The sites of infections that conferred a decreased risk in the study were primarily infected with gram-negative bacteria, while the sites in which infections did not confer a decreased risk were primarily infected with gram-positive bacteria, the researchers noted.
The investigators noted that the findings “could be particularly interesting in light of emerging data implicating that the microbiome in the gut may play a role in RA pathogenesis since mucosal sites are exposed to a high load of bacterial antigens and may thus represent the site of initiation or modification of inflammation in RA.”
Read the full article published online Feb. 4 in Annals of the Rheumatic Diseases (doi:10.1136/annrheumdis-2014-206493).
