To investigate (1) the amount of self-reported time spent sedentary among a large cohort of persons with rheumatoid arthritis (RA), and (2) the contribution of sedentary time to explain perceived health and activity limitation in RA beyond that of previously known correlates. This cross-sectional study used data from a postal questionnaire and the Swedish Rheumatology Quality registers (SRQ). The International Physical Activity Questionnaire was used to assess sedentary time (sitting) and moderate, vigorous and walking activity (MVPA). Sociodemographics, pain, fatigue, fear-avoidance beliefs, anxiety/depression, disease duration, MVPA and sedentary time were included in multiple regression models with perceived health (Visual Analogue Scale 0-100) and activity limitation (Stanford Health Assessment Questionnaire) as dependent variables.
Results: In all 3152 (59%) of 5391 persons identified as eligible from the SRQ, responded to the questionnaire. 2819 individuals with complete data on all study variables were analysed. Mean time (SD) spent sedentary was 257 (213) minutes per day. Sedentary time did not contribute significantly to explain perceived health and only minimally to explain activity limitation. Instead, variation was mainly explained by pain; for perceived health (Beta = 0.780, p < 0.001) and for activity limitation (Beta = 0.445, p < 0.001).The results indicate a non-significant role of sedentary time and a need for increased focus on pain in the management of RA. Future studies should use prospective designs and objective assessment methods to further investigate the associations between sedentary time and health outcomes in persons with RA.
Keywords: Disability; Health; Multiple regression; Rheumatoid arthritis; Sedentary time; Sitting.