Sedentary behaviour in rheumatoid arthritis: definition, measurement and implications for health

Abstract

Rheumatoid Arthritis (RA) is a chronic autoimmune disease characterised by high gradeinflammation, and associated with elevated cardiovascular risk, rheumatoid-cachexia and functional impairment. Sedentary behaviour is linked to heightened inflammation, and is highly pervasive in RA -likely as a result of compromised physical function and persistent fatigue. This high sedentarity may exacerbate the inflammatory process in RA, and hold relevance for disease-related outcomes. The aim of this narrative review is to provide an overview of the definition, measurement and health relevance of sedentary behaviour in the context of RA. Contradictions are highlighted with regards to the manner in which sedentary behaviour is operationalized, and the significance of sedentary behaviour physiology for disease-outcomes in RA is outlined. The advantages and disadvantages of sedentary behaviour measurement approaches are also discussed. Against this background, we summarise studies that have reported sedentary behaviour and its health correlates in RA, and propose directions for future research.

Physical activity in rheumatoid arthritis: relationship to cardiovascular risk factors, subclinical atherosclerosis, and disease activity

“…Rheumatoid arthritis (RA) is associated with an excess risk for cardiovascular disease (CVD), attributable partly to traditional cardiovascular risk factors (1)(2)(3) and partly to the systemic inflammation present in RA (2,4). An insufficient level of physical activity has also been presented as a contributory factor to the CVD morbidity in RA (5)(6)(7)(8). Physical activity, defined as 'any bodily movement produced by skeletal muscles that results in energy expenditure' (9), is strongly protective against CVD morbidity and mortality in the general population, and has the potential of affecting cardiovascular risk factors (10,11) as well as inflammation (12).…”

Correlates of sedentary behaviour and light physical activity in people living with rheumatoid arthritis: protocol for a longitudinal study

“…It has been reported that people living with RA typically spend long periods of time sedentary, 3,29,30 and recent accelerometry studies suggest people with this condition can spend up to 9 waking hours sedentary per day. 31,32 On the basis of emerging evidence for the association between SB and inflammation, Fenton and Kitas 29 hypothesised that high levels of SB in RA may exacerbate already elevated systemic inflammation in these patients, and contribute to the progression of RA outcomes. Akin to this proposition, Fenton et al 31 summarised results of non-RA studies, demonstrating the adverse links between SB with inflammation and chronic diseases with an inflammatory component (e.g., CVD, type 2 diabetes), underlining the relevance of these findings for RA.…”

“…31,32 On the basis of emerging evidence for the association between SB and inflammation, Fenton and Kitas 29 hypothesised that high levels of SB in RA may exacerbate already elevated systemic inflammation in these patients, and contribute to the progression of RA outcomes. Akin to this proposition, Fenton et al 31 summarised results of non-RA studies, demonstrating the adverse links between SB with inflammation and chronic diseases with an inflammatory component (e.g., CVD, type 2 diabetes), underlining the relevance of these findings for RA. That is, as evidence for the associations between SB, inflammation and poor health continues to accumulate, it is important to evaluate the role of SB as an independent risk factor for disease outcomes in RA -a population experiencing compromised health and at high risk of comorbidity.…”

“…Finally, the majority of studies that identify associations between SB and health outcomes in RA are cross-sectional, posing a challenge when inferring a causal direction of these associations. 31 As such, research is required to address these methodological limitations, and generate important knowledge regarding the consequences of SB in RA for inflammatory burden and related RA outcomes. It is also essential that high quality studies investigate the potential benefits of LPA participation for people living with RA, in order to elucidate the potential relevance of interventions that focus on displacing SB with LPA.…”

“…Specifically, studies should accurately define and conceptualise SB, and follow recommended protocols that utilise validated measures (subjective and objective) to measure sedentariness and its correlates in RA. 31 Additionally, future research studies should seek to further explore the 'sedentary-inflammation hypothesis', 31 which postulates cyclical relationships between SB, inflammation and adverse health outcomes in RA. Finally, interventions assessed by Randomised Controlled Trials must be developed, implemented and evaluated, to definitively test the relationships in this study in order to infer causality.…”