Association of Light‐Intensity Physical Activity With Lower Cardiovascular Disease Risk Burden in Rheumatoid Arthritis

Abstract

Objective: To characterize physical activity (PA) in individuals with rheumatoid arthritis (RA) and determine the associations between PA participation in light to moderate intensities and cardiovascular risk factors, disability, and disease activity. Methods: Cross-sectional study using data from two RA cohorts. PA was measured using an accelerometry-based activity monitor, and characterized as minutes/day in sedentary (≤1 metabolic equivalent-MET), very light (1.1–1.9 METs), light (2–2.9 METs), and moderate activities (≥3 METs). Cardiovascular markers included body mass index, blood pressure, insulin resistance, and lipid profile. Disability and disease activity were measured with the Health Assessment Questionnaire (HAQ) and Disease Activity Score-28 (DAS-28), respectively. Associations between PA at each intensity and health-markers were assessed by multiple linear regression models adjusted by age, sex, and cohort. Results: Ninety-eight subjects (58 ± 9 years, 85% female) were included. Subjects spent 9.8 hours/day being sedentary, 3.5 hours/day in very light PA, 2.1 hours/day in light PA and 35 minutes/day in moderate PA. Only 17% were physically active (≥150 minutes/week of moderate PA in 10-minute bouts). Regression models showed that very light, light and moderate PA were inversely associated with most cardiovascular risk factors, the HAQ, and DAS-28 scores (R2Δrange: .04 to .52, p <.05). The associations between PA and cardiovascular markers were either equivalent or stronger at very light- and light-intensities as compared to moderate-intensity. Conclusions: Individuals with RA are mostly active at very light and light intensities. PA at these intensities associate favorably with cardiovascular markers, and lower disability and disease activity in RA.

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

“…In a cross-sectional study, Khoja et al, (2016) reported SB measured by the SWA, to be inversely related to disease activity score in a group of RA patients [63]. However, as with all crosssectional studies, the causal direction of this association cannot be determined.…”

“…This underestimation was suggested to be due to the elevated resting energy expenditure observed in this patient population, relative to healthy adults in which the proprietary-SWA-algorithms tested were developed [61]. As such, these findings support the thesis that inaccuracies in sedentary time estimation may arise when studies in RA employ SB algorithms derived from calibration studies in healthy adults (e.g.,<100cpm - Table 3) [59,60,62,63]. [59,72].…”

“…accelerometer vs. activPAL), the manner in which sedentary behaviour is defined and subsequently quantified (e.g.,<100cpm (equating to ≤1.5 METS), vs. ≤1 MET vs. time sitting/lying) and the data collection protocol (e.g., inclusion vs. exclusion of sleep time) (Table 4). However, a lack of detailed reporting with regards to sedentary measurement/analysis protocols within studies, means the extent to which each of these factors may contribute towards differing sedentary time estimates in RA is difficult to establish [59,63,64,74,75].…”

“…Several recent studies have sought to examine health related correlates of sedentary behaviour for people living with RA, including associations with disease activity, physical function, muscle density, bone mass, and cardiovascular risk [59,63,[70][71][72]75].…”

“…Khoja et al (2016) also reported detrimental associations of SB with a number of cardiovascular risk factors (i.e., body-mass-index, blood pressure, insulin resistance, cholesterol), as well as functional disability in RA [63]. However, given that sedentary behaviour was defined as activities ≤1 MET in this study, conclusions could not be drawn concerning the relevance of common sedentary behaviours requiring 1-1.5 METS (e.g., sitting and reading a book or newspaper) for CV risk and other specific outcomes.…”