Effect of a 24-month physical activity intervention vs health education on cognitive outcomes in sedentary older adults: the LIFE randomized trial

Authors: SINK, KAYCEE - Wake Forest University; ESPELAND, MARK - Wake Forest University; CASTRO, CYNTHIA - Stanford University; CHURCH, TIMOTHY - Pennington Biomedical Research Center; COHEN, RON - University Of Florida; DODSON, JOHN - New York University; GURALNIK, JACK - University Of Maryland; HENDRIE, HUGH - Indiana University; JENNINGS, JANINE - Wake Forest University; KATULA, JEFFERY - Wake Forest University; LOPEZ, OSCAR - University Of Pittsburgh; MCDERMOTT, MARY - Northwestern University; PAHOR, MARCO - University Of Florence; REID, KEIRAN - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; RUSHING, JULIA - Wake Forest University; VERGHESE, JOE - Albert Einstein College Of Medicine; RAPP, STEPHEN - Wake Forest University; WILLIAMSON, JEFF - Wake Forest University

Submitted to: Journal of the American Medical Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2015
Publication Date: 8/25/2015
Citation: Sink, K.M., Espeland, M.A., Castro, C.M., Church, T., Cohen, R., Dodson, J.A., Guralnik, J., Hendrie, H.C., Jennings, J., Katula, J., Lopez, O.L., McDermott, M.M., Pahor, M., Reid, K.F., Rushing, J., Verghese, J., Rapp, S., Williamson, J.D. 2015. Effect of a 24-month physical activity intervention vs health education on cognitive outcomes in sedentary older adults: the LIFE randomized trial. Journal of the American Medical Association. 314(8):781-790.

Interpretive Summary: There is suggestive evidence from large research studies that participating in physical activity can benefit cognitive function in older adults. However, strong evidence for the benefit of physical activity on cognitive function is lacking, especially from definitive research studies such as randomized controlled trials. The purpose of this study was to examine in older adults whether a 2-year physical activity program results in better cognitive function or lower risk of dementia compared to a health education program. A total of 1,635 community-dwelling older persons at risk for mobility-disability and aged 70-89 years participated in this multicenter study. At each of the 8 clinical sites involved in the study, participants were randomly assigned to a structured, moderate-intensity physical activity (PA) program (n = 818) that included walking, resistance training, and flexibility exercises or to a health education program (n = 817) consisting of educational workshops and upper extremity stretching exercises. The main findings of this study showed that there was little cognitive change in either study group. Over time, mild cognitive impairment or dementia occurred in 13.2% of participants randomized to physical activity and 12.1% of participants randomized to health education. Overall, this study demonstrated that, in sedentary older adults who experienced little cognitive decline over a 2 year period, the LIFE physical activity intervention was not better than health education at maintaining cognitive function. However, it is possible that both physical activity and the health education control were cognitively protective.

Technical Abstract: Importance: Epidemiologic evidence suggests that physical activity benefits cognition, but results from randomized trials are limited and mixed. Objective: To determine whether a 24-month physical activity program results in better cognitive function, lower risk of mild cognitive impairment (MCI) or dementia, or both, compared with a health education program. Design, Setting, and Participants: A randomized clinical trial, the Lifestyle Interventions and Independence for Elders (LIFE) study, enrolled 1635 community-living participants at 8 US centers from February 2010 until December 2011. Participants were sedentary adults aged 70 to 89 years who were at risk for mobility disability but able to walk 400 m. Interventions: A structured, moderate-intensity physical activity program (n = 818) that included walking, resistance training, and flexibility exercises or a health education program (n = 817) of educational workshops and upper-extremity stretching. Main Outcomes and Measures: Prespecified secondary outcomes of the LIFE study included cognitive function measured by the Digit Symbol Coding (DSC) task subtest of the Wechsler Adult Intelligence Scale (score range: 0-133; higher scores indicate better function) and the revised Hopkins Verbal Learning Test (HVLT-R; 12-item word list recall task) assessed in 1476 participants (90.3%). Tertiary outcomes included global and executive cognitive function and incident MCI or dementia at 24 months. Results: At 24 months, DSC task and HVLT-R scores (adjusted for clinic site, sex, and baseline values) were not different between groups. The mean DSC task scores were 46.26 points for the physical activity group vs 46.28 for the health education group (mean difference, -0.01 points [95% CI, -0.80 to 0.77 points], P = .97). The mean HVLT-R delayed recall scores were 7.22 for the physical activity group vs 7.25 for the health education group (mean difference, -0.03 words [95% CI, -0.29 to 0.24 words], P = .84). No differences for any other cognitive or composite measures were observed. Participants in the physical activity group who were 80 years or older (n = 307) and those with poorer baseline physical performance (n = 328) had better changes in executive function composite scores compared with the health education group (P = .01 for interaction for both comparisons). Incident MCI or dementia occurred in 98 participants (13.2%) in the physical activity group and 91 participants (12.1%) in the health education group (odds ratio, 1.08 [95% CI, 0.80 to 1.46]). Conclusions and Relevance: Among sedentary older adults, a 24-month moderate-intensity physical activity program compared with a health education program did not result in improvements in global or domain-specific cognitive function.