Leisure time physical activity and dementia risk: a dose-response meta-analysis of prospective studies

Background There is considerable evidence of the favourable role of more physical activity (PA) in fighting against dementia. However, the shape of the dose–response relationship is still unclear. Objective To quantitatively investigate the relationship between dementia and PA. Design PubMed, EMBASE, Ovid and the Cochrane Library were searched for prospective studies published from 1 January 1995 to 15 October 2016. Two types of meta-analyses were performed with a focus on the dose–response relationship using two stage generalised least squares regression. Results The primary analysis exhibited a dose–response trend for all-cause dementia (ACD), Alzheimer’s disease (AD) but not for vascular dementia (VD). In the dose–response analysis, either ACD (p trend <0.005; p non-linearity =0.87) or AD (p trend <0.005; p non-linearity =0.10) exhibited a linear relationship with leisure time PA (LTPA) over the observed range (0–2000 kcal/week or 0–45 metabolic equivalent of task hours per week (MET-h/week)). Specifically, for every 500 kcal or 10 MET-h increase per week, there was, on average, 10% and 13% decrease in the risk of ACD and AD, respectively. Conclusions We have reported, for the first time, the dose–response relationship between LTPA and dementia, further supporting the international PA guideline from the standpoint of dementia prevention.