Moderate-to-Vigorous Physical Activity At Any Dose Reduces All-cause Dementia Risk Regardless Of Frailty Status

PURPOSE: Reaching the global moderate-to-vigorous physical activity (MVPA) recommendations (150 min/week) is difficult for older adults, particularly among those living with frailty and its associated risk of dementia. We examined the lowest amount of MVPA associated with reduced dementia risk among at-risk persons living with and without frailty enrolled in the UK Biobank (UKB) study. METHODS: MVPA was extracted from wrist-worn accelerometry in a subpopulation of the UKB study. A modified version of the physical frailty phenotype was used to define frailty. First-time dementia was identified using ICD-10 codes. Associations between physical activity patterns (including interactions with frailty) and incident dementia were analyzed using Cox regression models. MVPA was treated continuously and categorically across five levels to identify the lowest beneficial dose. Models were adjusted for demographics, frailty status, and comorbidities. RESULTS: This study included 89,667 adults (mean age 62 years, 56% women) with 735 participants developing dementia over an average of 4.4 years. Average weekly MVPA was 126 min. For each 1 standard deviation (123.2 MVPA min/week) higher MVPA, there was a 20% reduced risk of all-cause dementia (HR = 0.80, 95% CI: 0.71, 0.89). The HRs for engaging in 0-35 min, 35-70 min, 70-140 min and > 140 MVPA min/week were 0.59, 0.40, 0.36 and 0.28, respectively (all p values<0.05; Figure 1), compared to 0 MVPA min/week. All associations were similar across frailty status (interaction p value for all models>0.21). CONCLUSION: Our study suggests that engaging in any amount of MVPA reduces dementia risk, particularly when inactive. Further, we conclude that MVPA associations with dementia onset are not substantially modified by frailty status.Figure 1.: Categories of MVPA/week by Onset of First-Time DementiaAAW was supported by Grant Number K01 AG076967 from the National Institute on Aging, National Institutes of Health.