Summary:
This study is a systematic review and meta-analysis of prospective cohort studies that examined the relationship between physical activity and the risk of developing Alzheimer’s disease. Dementia is recognised as a major global public health concern, particularly in ageing populations, and Alzheimer’s disease represents the most common type. Given the absence of highly effective pharmacological treatments that can prevent or reverse disease progression, attention has increasingly shifted toward lifestyle strategies that may delay onset or reduce risk. This study tracked physical activity levels and later development of Alzheimer’s disease over time. Additional analyses explored potential influences such as activity intensity, follow-up duration, and confounding factors including age, sex, education, genetic risk, cardiovascular conditions, and geographic differences. The review included 29 cohort studies involving over two million participants. Results indicated that higher levels of physical activity were associated with a lower risk of Alzheimer’s disease overall. Moderate and high levels of activity also showed clearer associations than low levels of activity. Overall, this study suggests that physical activity may be a modifiable lifestyle factor associated with reduced risk of Alzheimer’s disease, particularly when activity levels are moderate to vigorous. However, the authors note that the association may vary depending on follow-up duration and other influencing factors, and they recommend continued high-quality research to strengthen understanding on this topic.
Abstract:
Objective: Physical activity (PA) is beneficial in reductions of all-cause mortality and dementia. However, whether Alzheimer’s disease (AD) risk is modified by PA remains disputable. This meta-analysis aims to disclose the underlying relationship between PA and incident AD. Methods: Pubmed, Embase, Cochrane Library, and Web of Science were retrieved from inception to June 2023. Random-effects models were employed to derive the effect size, represented by hazard ratio (HR) and 95% confidence interval (CI). Results: Twenty-nine prospective cohort studies involving 2068,519 participants were included. The pooled estimate showed a favorable effect of PA on AD risk decline (HR 0.72, 95% CI 0.65–0.80). This association remained robust after adjusting for maximum confounders (HR 0.85, 95% CI 0.79–0.91). Subgroup analysis of PA intensity demonstrated an inverse dose-response relationship between PA and AD, effect sizes of which were significant in moderate (HR 0.85, 95% CI 0.80–0.93) and high PA (HR 0.56, 95% CI 0.45–0.68), but not in low PA (HR 0.94, 95% CI 0.77–1.15). Regardless of all participants or the mid-life cohort, the protection of PA against AD appeared to be valid in shorter follow-up (<15 years) rather than longer follow-up (≥15 years). In addition to follow-up, the robustness of the estimates persisted in supplementary meta-analyses, meta-regression analyses, and sensitivity analyses. Conclusion: PA intervention reduces the incidence of AD, but merely in moderate to vigorous PA with follow-up of less than 15 years, thus conditionally recommending the popularization of PA as a modifiable lifestyle factor to prevent AD.
Article Publication Date: 25/11/2023
DOI: 10.1016/j.arr.2023.102127
