Occupational physical activities and long-term functional and radiographic outcomes in patients with ankylosing spondylitis

Objective. We sought to identify specific occupational activities associated with functional limitations and radiographic damage in patients with longstanding ankylosing spondylitis (AS). Methods. We asked patients diagnosed with AS for >= 20 years to report all past occupations, which we mapped to specific physical activities using the Occupational Information Network, which is the US Department of Labor job classification database. For each occupation reported, we obtained ratings for 13 physical abilities of the worker and 13 aspects of the work environment or work tasks (work context) thought to be most relevant to patients with AS. Averages for each measure, weighted by the number of years in each job, were related to the degree of functional limitation as assessed by the Bath AS Functional Index (BASFI) and to the extent of spinal radiographic damage as assessed by the Bath AS Radiology Index for the spine (BASRI-s). Results. Among 397 patients, those with a history of jobs requiring dynamic flexibility (the ability to repeatedly bend, stretch, twist, or reach) had more functional limitations than those whose past jobs required little or no dynamic flexibility (adjusted mean BASFI score 48.3 in the top quartile versus 38.1 in all others). Those whose past jobs required more dynamic flexibility, extent flexibility, and exposure to whole body vibration also had significantly higher BASRI-s scores. Conclusion. Bending, twisting, and stretching are the occupational activities associated with greater functional limitations and radiographic damage in patients with longstanding AS. Exposure to whole body vibration was also associated with more radiographic damage.