Background/Purpose: Epidemiological evidence indicates that sedentary behaviour, or “too much sitting”, is associated with poor health outcomes in the general population, including elevated systemic inflammation. In addition, regularly breaking up sitting with light-intensity physical activities – such as standing or walking (i.e., sedentary breaks), is proposed to confer positive effects on systemic inflammation, and the experience of bodily pain. Importantly, these relationships are observed to be independent of engagement in moderate-to-vigorous physical activity.

We propose sedentary behaviour may contribute to the progression of pertinent RA outcomes, and particularly those with an inflammatory origin (e.g., joint pain). However, these associations may be bi-directional in nature, and sedentary behaviour may represent a consequence, as well as a cause of RA outcomes. The aim of this study is therefore to explore potential bi-directional associations between sedentary behaviour patterns (sitting, standing, sedentary breaks), with self-reported pain in RA.

Methods: Patients with RA (n = 62, Mean age = 56 ± 13 years) were recruited to this study lasting 8-days. On Day 1, patients completed validated questionnaires to assess their experience of pain over the preceding 2-weeks (Mcgill Pain Questionnaire-Short Form). Following this, they were given an activPAL (accelerometer enabled posture sensor) to wear for the next 7-days to assess their sitting time (min/day), standing time (min/day) and frequency of sedentary breaks (number/day). On Day 8, participants completed the same pain questionnaire as on Day 1, but were asked to report their experience of pain over the previous 7-days.

Linear regressions examined the relationship between pain on Day 1 (independent variable) with sedentary behaviour patterns over the subsequent week (sitting, standing, sedentary breaks – dependent variables) [Model 1]. Next, the association between sedentary behaviour patterns (in the preceding 7-days – independent variables) and pain on Day 8 were investigated [Model 2]. Finally, to investigate directionality Model 2 was further adjusted for reported pain on Day 1 [Model 3].

Results: Pain on Day 1 significantly predicted time spent sitting in the subsequent 7-days (Model 1; ß = .27, p <.05), but was not significantly linked to standing or sedentary breaks. Time spent sitting was significantly linked to the experience of pain on Day 8 (Model 2; ß = 26, p <.05), but no relationships were demonstrated between standing and sedentary breaks with this outcome. The association between sitting time and pain on Day 8, was no longer significant following adjustment for baseline (Day 1) pain (ß = .06, p = .52).

Conclusion: This is the first study to explore the potential bi-directional associations between sedentary behaviour patterns and pain in RA. Results suggest that sitting time may represent a consequence, rather than a cause of joint pain in these patients. However, the observed association between “too much sitting” throughout the week and subsequent pain (Day 8), may point to the potential of interventions targeting sitting time for minimising the risk of recurrent joint pain.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/bi-directional-associations-between-too-much-sitting-and-self-reported-pain-in-patients-with-rheumatoid-arthritis/