Sleep disturbance as a moderator of the association between physical activity and later pain onset among American adults aged 50 and over: evidence from the Health and Retirement Study

• Published in: BMJ open 2020-06, Vol.10 (6), p.e036219-e036219
• Main Authors: Whibley, Daniel, Guyer, Heidi M, Swanson, Leslie M, Braley, Tiffany J, Kratz, Anna L, Dunietz, Galit Levi
• Format: Article
• Language: English
• Subjects: Adults; Aged; Aged, 80 and over; Aging; Arthritis; Body mass index; Chronic Pain - epidemiology; Chronic Pain - etiology; Diabetes; Ethnicity; Exercise; Female; Health care; Humans; Interviews as Topic; Lung diseases; Male; Middle Aged; Older people; Pain; Population; Prospective Studies; Public Health; Retirement; Sleep; Sleep Wake Disorders; United States - epidemiology
• ISSN: 2044-6055; 2044-6055
• DOI: 10.1136/bmjopen-2019-036219

To examine whether sleep disturbance modifies the association between physical activity and incident pain. Prospective population-based study. Health and Retirement Study. 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). 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. Troublesome pain. 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). The beneficial association of physical activity on reduced likelihood of later pain was only observed in persons who endorsed low levels of sleep disturbance.