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Physical activity and amyloid beta in middle‐aged and older adults: A systematic review and meta‐analysis
Author(s) -
RodriguezAyllon Maria,
ArroyoAvila Cristina,
AlvarezOrtega Miriam,
MolinaGarcia Pablo,
SolisUrra Patricio,
MolinaHidalgo Cristina,
Erickson Kirk I,
EstebanCornejo Irene
Publication year - 2021
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.057736
Subject(s) - meta analysis , medicine , randomized controlled trial , observational study , systematic review , psycinfo , dementia , physical therapy , psychological intervention , gerontology , medline , disease , psychiatry , political science , law
Background Alzheimer’s disease is the main cause of dementia in the world. Particularly, amyloid beta (Aβ) plaques are the primary hallmarks of this disease. Previous research has shown that higher levels of physical activity might be associated with lower levels of Aβ accumulation. However, a synthesis of evidence is needed to confirm or refute this hypothesis. The aim of the present study is to determine the overall effect of physical activity on Aβ by conducting a systematic review and meta‐analysis of available randomized clinical trials and interventions, and to systematically synthesize observational evidence on the association between physical activity and Aβ in middle‐aged and older adults. Method A systematic search of 5 electronic databases (PubMed, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trials and SportDiscuss) was performed from inception to 1 st of April 2020. Studies were eligible if they included physical activity and Aβ data (i.e., any Aβ isoform measured by Positron Emission Tomography ‐PET‐, blood samples or lumbar puncture) in adults aged 45 years or older. Meta‐analyses were performed to examine the effect of physical activity on Aβ in randomized controlled trials (RCTs) and non‐RCTs (i.e., quasi‐experimental studies). Result A total of 26 articles were included in this systematic review: 6 RCTs, 2 non‐RCTs, 4 prospective longitudinal studies, and 14 cross‐sectional studies. Of the 8 intervention studies, 5 were included in the meta‐analysis. In brief, the overall effect of physical activity on Aβ in middle aged and older adults was not significant (pooled SMD= ‐0.12; 95% CI ‐0.40 to 0.016; I 2 =3%). Additionally, 19 observational associations were synthesized in this systematic review. Overall, there was an unclear association between physical activity and Aβ at any of its isoforms (11 of 19 studies, 58%)]. Conclusion Due to the small number of intervention studies included in the meta‐analysis (5 intervention studies) and the controversial findings provided by the observational studies, more studies are needed to understand the role of physical activity on Aβ in middle‐aged and older adults.