OBJECTIVE: To examine whether sleep disturbance modifies the association between physical activity and incident pain. DESIGN: Prospective population-based study. SETTING: Health and Retirement Study. PARTICIPANTS: American adults aged ≥50 years who reported no troublesome pain in 2014 were re-assessed for pain in 2016. Of 9828 eligible baseline respondents, 8036 (82%) had complete follow-up data for adjusted analyses (weighted analysis population N=42 407 222). EXPOSURES: Physical activity was assessed via interview with questions about time spent in moderate and vigorous physical activity. Sleep disturbance, assessed using a modified form of the Jenkins Sleep Scale, was examined as a potential moderator. MAIN OUTCOME MEASURE: Troublesome pain. RESULTS: In weighted analyses, 37.9% of the 2014 baseline pain-free sample participated in moderate or vigorous physical activity once a week or less, with an overall mean Physical Activity Index Score of 9.0 (SE=0.12). 18.6% went on to report troublesome pain in 2016. Each one-point higher on the Physical Activity Index Score was associated with a reduced odds ratio (OR) of incident pain for those who endorsed sleep disturbance never/rarely (OR=0.97, 95% CI 0.94 to 0.99), but not for those who endorsed sleep disturbance sometimes (OR=0.99, 95% CI 0.97 to 1.01) or most of the time (OR=1.01, 95% CI 0.99 to 1.03). The analysis of possible interaction demonstrated that frequency of sleep disturbance moderated the physical activity and incident pain association (Wald test: p=0.02). CONCLUSIONS: The beneficial association of physical activity on reduced likelihood of later pain was only observed in persons who endorsed low levels of sleep disturbance.
Bibliographical noteFunding DW is supported by a Foundation Fellowship Versus Arthritis (Award
Contributors DW, HG, LMS, TJB, AK and GLD were involved in study conception
and design, and advised on the statistical analysis plan and interpretation of the
data. HG compiled the dataset and DW performed the statistical analysis. DW
drafted the manuscript. HG, LMS, TJB, AK and GLD reviewed the manuscript,
provided amendments and approved the final version. DW, HG and GLD had full
access to study data and take responsibility for its accuracy and the integrity of the analysis.
Data availability statement Data are available in a public, open access repository.
The dataset used for this study was generated from data products publicly released by the Health and Retirement Study (HRS): https://hrs.isr.umich.edu. The HRS is sponsored by the National Institute on Ageing (grant number NIA U01AG009740).
- older adults
- physical activity
- sleep disturbance