Physical activity attenuates or even eliminates the risk of all‐cause dementia associated with aging in older adults: A population‐based cohort study

Abstract

AbstractBackgroundFrom 2016 to 2040 the number of people with all‐cause dementia in the United Kingdom is expected to increase by 57%, while 70% percent of it is due to a higher life expectancy. It is meaningful to examine whether physical activity could mitigate the risk of all‐cause dementia associated with aging in older adults. We aimed to examine the overall and age‐stratified effect of physical activity on the risk of all‐cause dementia in older adults.MethodOlder adults aged 50 or more participants of the English Longitudinal Study of Aging (ELSA) were followed during a 17‐years follow‐up, between 2002 and 2019. Physical activity was accessed using a self‐reported, validated questionnaire in each wave (2002‐2019). Participants were classified as inactive, low, or moderate‐to‐high levels of physical activity. Medical diagnosis of dementia was asked in each wave for either the cohort member or by a proxy interview with family or caregivers. Additionally, the Informant Questionnaire on Cognitive Decline in the Elderly was used to determine the presence of all‐cause dementia (cut‐off = 3.5).ResultData from 8,270 older adults were analyzed (55.6% women; mean [SD] age, 63.9 [9.7]). Over a 17‐year follow‐up, 7.8% (95%: 7.3 to 8.4) were diagnosed with all‐cause dementia. For each year increased in age, the odds of all‐cause dementia increased 6.1% (95%CI: 5.1% to 7.1%). On the other hand, participants engaging in low (OR: 0.27; 95%CI: 0.22 to 0.33) or moderate‐to‐high level (OR: 0.12; 95%CI: 0.09 to 0.16) of physical activity had lower odds of incidence of all‐cause dementia through the follow‐up period. Participants aged 80 or over who engaged in a moderate‐to‐high level of physical activity had a lower risk of all‐cause dementia than inactive adults aged between 50‐69 years. Results were sustained after sensitive analysis to reduce the impact of reverse causality.ConclusionAlthough aging is the strongest risk factor for all‐cause dementia, physical activity could eliminate the risk associated with aging in older adults. Public health policies should consider that for older adults, engaging in physical activity below recommended levels may be an accessible and achievable strategy to prevent all‐cause dementia.