1. In this study, physical activity, compared to a health education program, did not result in significant improvements from baseline in global or domain-specific cognitive function in sedentary adults aged 70-89 years.
2. There was also no significant difference in the incidence of mild cognitive impairment (MCI) or dementia between the physical activity group and health education program group.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Maintaining a moderate level of physical activity throughout one’s life is known to decrease rates of heart disease, obesity, diabetes, and a host of other ailments. However, the effect of physical activity on cognitive function in old age remains unclear, with prior studies showing mixed results. Consequently, the authors of this trial, the Lifestyle Interventions and Independence for Elders (LIFE) trial, studied the effect of physical activity versus health education in sedentary older adults at risk for mobility disability but who were able to walk 400 meters.
It was found that, among sedentary older adults, a 24-month moderate-intensity physical activity program compared to a health education program did not result in improvements from baseline in global or domain-specific cognitive function. There was also no significant difference in the incidence of mild cognitive impairment (MCI) or dementia between the physical activity group and health education program group. This study was strengthened by its status as the largest randomized clinical trial studying physical activity in sedentary adults, a large sample size, and high follow-up rates. It is limited by doubt as to whether the level of activity was enough to result in a change in cognitive function. Further, the study was not able to show whether both interventions were indeed able to maintain, as opposed to improve, cognitive function. Future studies will need to investigate the utility of these interventions over a longer time period and to assess their abilities to maintain cognitive function.
In-Depth [randomized controlled trial]: This study evaluated 1635 participants aged 70-89 from February 2010 until December 2011. A total of 818 were randomized to the physical activity group and 817 to the health education group. The mean Digit Symbol Coding (DSC) task scores (range 0-133) at follow-up were not different between the two groups (46.26 points in the physical activity group and 46.28 points in the health education group; mean difference -0.01 points, 95%CI -0.80 to 0.77 points; p = 0.97). The mean Hopkins Verbal Learning Test (HVLT-R) scores (range 0-12) were also not different between the groups (7.22 words for physical activity group vs. 7.25 for the health education group; mean difference -0.03 words, 95%CI -0.29 to 0.24; p = 0.84). There was no significant difference between groups in MCI or dementia incidence; 13.2% of the physical activity group developed MCI or dementia compared to 12.1% of the health education group.
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