Arthritis Rheumatol: Does smoking and socioeconomic factors affect imaging results for mid-axis spinal arthritis?

The study looked at the relationship between smoking and imaging outcomes in patients with axSpA over a five-year time and assessed whether socioeconomic (SE) factors influenced these relationshipsincluded in axSpA patients from the DESIR queueAssessment of 4 imaging results by three central reviewers at baseline, 2 and 5 years (spinal X-rays (improved Stoker strong spinal scoliosis spinal score, mSASS); SIJ X-rays (improved New York grading, mNY) and spinal MRI (Canadian Spinal Arthritis Research Alliance score, SPARCC) and MRI-SIJCC (SPARCC)The explanatory variable of interest is the smoking status at the baselineThe interaction between smoking and SE factors (type of work (blue-collar vswhite-collar) and education level (low vs high) was first examined, and, if significant, analyzed at different levelsThe generalized estimation equation model is used and adjusted for the confounding factorsincluded 406 axSpA patients: 52 per cent of men, 40 per cent of smokers and 18 per cent blue-collarSmoking was independently associated with heavier inflammation of MRI-SIJ at each visit over a five-year period, an effect that was only seen in blue-collar (beta(95%CI: 5.41, 9.48) and low-education patients (beta(95% CI) (0.42, 4.88) patients (separate models)In all patients, smoking was also significantly associated with spinal inflammation (beta (95%CI: 1.69,2.93)) and SIJ damage (beta .95% CI: 0.57 (0.57,0.96)) regardless of SE and other potential confounding factorsfound a strong association between baseline smoking and MRI-SIJ inflammation at each visit during a five-year period in blue-collar or low-level axSpA patientsThese findings suggest that mechanical stress enhances the effect of smoking on axSpA axial inflammation