The inflammatory reflex and risk for rheumatoid arthritis: a case-control study of human vagotomy

Recent data suggest remarkable effects of vagus stimulation (reduction) and vagotomy (exacerbation) on acute inflammation in rats, the so-called "inflammatory reflex". Its role in humans remains unknown. Therefore, the aim was to explore whether surgical vagotomy in humans would affect the risk of a prototype inflammatory disease, rheumatoid arthritis. This was a case-control study. Assessment of the relative risk (RR) of developing rheumatoid arthritis after surgical vagotomy during 1964-2001 in 63,092 prevalent rheumatoid arthritis cases versus 125,404 matched controls from the general population and in 2548 incident rheumatoid arthritis cases versus 24,357 matched controls from the general population, respectively, was done. For comparison, we assessed RRs for hospitalisation for gastric disorders not including vagotomy. Data on exposures and rheumatoid arthritis were retrieved from population-based and prospectively recorded Swedish registers. A pre-rheumatoid arthritis vagotomy was not significantly associated with an increased risk for rheumatoid arthritis (RR = 1.17, 95% CI 0.97 to 1.40). RRs in the same range were observed for several other pre-rheumatoid arthritis gastric conditions that do not include vagotomy (eg, gastric ulcer RR = 1.21, 95% 1.11 to 1.33). Vagotomy has no specific effect on the risk of developing rheumatoid arthritis in humans. Gastroduodenal ulcers occur more often than expected even before the occurrence of rheumatoid arthritis.