Physical activity reverted the increased risk of dementia associated with cardiovascular risk factors: findings a population‐based cohort study

Abstract

AbstractBackgroundCardiovascular risk factors are associated with a higher risk of dementia. However, whether physical activity could revert this increased risk remains uncertain. We analyzed the effect of physical activity on the risk of dementia stratified by cardiovascular risk factors.MethodsData from baseline (2002‐2003) to wave 9 (2018‐2019) of the English Longitudinal Study of Ageing (ELSA) were analyzed (n = 6,021). The wave that dementia was first detected after baseline was defined as the event time. Self‐reported physical activity (inactive, low, moderate, high) at baseline was measured using a validated questionnaire. Smoking, excessive alcohol consumption, hypertension, diabetes, and obesity were analyzed as cardiovascular risk factors. Participants with simultaneous presence of 2+ risk factors were classified with a high cardiovascular risk for dementia. Socioeconomic, behavioral, and health variables were added in the Cox proportional hazard regression model as possible confounders. The incidence and the risk of dementia for physical activity, cardiovascular risk factors, and their interaction were calculated.ResultBetween baseline and wave 9, 6.21% (95% confidence interval [CI]: 5.63 to 6.85) of the participants were diagnosed with dementia. Participants with 2+ cardiovascular risk factors had a higher risk of dementia (hazard ratio [HR]: 1.31; 95%CI: 1.04, 1.63) than low‐risk adults. Physical activity level was inversely associated with the risk of incident dementia in participants who were smokers (p for linear trend = 0.027), had hypertension (p for linear trend = 0.015), and obesity (p for linear trend = 0.014). Low physical activity level (e.g., engaging in moderate‐intensity physical activity once per week) reduced the risk of dementia in participants with hypertension (HR: 0.41; 95%CI: 0.24, 0.70), and obesity (HR: 0.37; 95%CI: 0.21, 0.67). Physical activity attenuated the increased risk of incident dementia provoked by accumulated cardiovascular risk factors. High risk participants with low (HR: 0.51; 95%CI: 0.29, 0.88), moderate (HR: 0.38; 95%CI: 0.21, 0.67) and high (HR: 0.46; 95%CI: 0.22, 0.98) physical activity level had lower risk of dementia than the high risk, inactive group. Sensitivity analyses confirmed the above‐mentioned findings.ConclusionPhysical activity starting at moderate‐intensity activities once per week attenuated the increased risk of dementia associated with cardiovascular risk factors in older adults.