Kivimäki M, et al. - In this meta-analysis of 19 prospective observational cohort studies, researchers ascertained if physical inactivity is a risk factor for dementia, focusing on the role of cardiometabolic disease in this association, and reverse causation bias resulting from changes in physical activity during the preclinical (prodromal) phase of dementia. According to results, physical inactivity was non-significantly linked to dementia among people in whom cardiometabolic disease preceded dementia. Physical inactivity was not related to all-cause dementia or Alzheimer’s disease in analyses that addressed bias due to reverse causation, although an indication of excess dementia risk was noted in a subgroup of physically inactive people who developed the cardiometabolic disease.