Smoking does not protect patients with axial spondyloarthritis from attacks of uveitis

Acute anterior uveitis (AAU) is the the most common extra-axial manifestation in axial spondyloarthritis (axSpA) and can lead to visual impairment if untreated. Cross-sectional axSpA studies have consistently reported lower odds of AAU in current smokers than ex or never smokers,1 2 which is in contrast to higher AAU risk among smokers in the general population.3 One explanation for this apparent paradox is behaviour change; those with AAU may be more likely to quit smoking. However, this does not explain the higher odds of AAU in never smokers. Another possibility is that smoking is protective for AAU as it is for ulcerative colitis, which shares patho-aetiology with axSpA and AAU.4 If smoking is protective of AAU, it should also reduce the frequency of flares. We examined the impact of smoking status on the number of AAU episodes among patients with AAU.