Smoking and occupational exposure to vapor, gas, dust, and fumes (VGDF) increases rheumatoid factor (RF) levels for male patients with rheumatoid arthritis (RA), according to results published in BMJ Open.
The study included men who fulfilled 2010 American College of Rheumatology/European League Against Rheumatism RA diagnostic criteria (n=726). The researchers followed participants from February 2015 through August 2016.
Of all participants, 75% (n=546) had been exposed to VGDF for >1 year, and 77% (n=561) had been smokers. Only 8% of participants (n=58) had no exposure to VGDF and had never smoked.
There was a significant difference between participants who had never smoked and were unexposed to VGDF compared with participants who had never smoked but had been exposed to VGDF (median RF, 24 vs 36; P =.03). This difference became even more significant when nonsmoking, VGDF-unexposed participants were compared with nonsmoking participants with ≥2 years of VGDF exposure (median RF, 24 vs 57; P =.02).
The results also showed a significant difference in RF levels between smokers unexposed to VGDF compared with smokers who were exposed to VGDF (median RF, 71 vs RF 95; P =.04). Again, this effect was even more pronounced when comparing unexposed smokers with smokers who had ≥2 years VGDF exposure (median RF, 71 vs RF 113; P =.01). Researchers also observed a significant difference in RF titre between nonsmoking participants with ≥2 years of VGDF exposure and smokers with >2 years of VGDF exposure (median RF, 57 vs 113; P=.02).
Murphy D, Bellis K, Hutchinson D. Vapour, gas, dust and fume occupational exposures in male patients with rheumatoid arthritis resident in Cornwall (UK) and their association with rheumatoid factor and anti-cyclic protein antibodies: a retrospective clinical study [published online May 17, 2018]. BMJ Open. doi: 10.1136/ bmjopen-2018-021754