Association Of Vigorous-intensity Physical Activity With The Risk Of Dementia

Abstract

PURPOSE: To investigate whether a higher percentage of vigorous-intensity physical activity (VPA) to total moderate-to-vigorous intensity PA (MVPA) is associated with a lower risk of dementia. METHODS: Participants were 348,616 men and women aged 56 ± 8 yrs who completed a baseline examination from 2006-2010 in the UK Biobank study. Participants who reported no MVPA or with dementia at baseline were excluded. Participants reported time spent in moderate-intensity PA (MPA) and VPA per week, and the weighted percentage of VPA to total MVPA was calculated as (VPA min/wk*2)/(MPA min/wk + [VPA min/wk*2]). Participants were categorized into groups based on 0% (reference), >0-30%, >30-60%, or > 60% VPA out of total MVPA. Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of incident all-cause dementia (according to hospital inpatient records and death registry) by VPA groups. In a joint analysis, participants were categorized into one of four groups based on meeting the guidelines of ≥150 min/wk of MVPA or not and reporting any VPA (>0 min/wk) or not. Models were adjusted for age, sex, race, education, Townsend deprivation index, body mass index, comorbidities, smoking, alcohol consumption, familial dementia, and total MVPA (not in joint analysis). RESULTS: During an average follow-up of 11 yrs, 3,266 (0.9%) participants developed dementia. Compared to 0% VPA, the HRs (95% CIs) were 0.75 (0.68-0.83), 0.81 (0.74-0.89), and 0.89 (0.81-0.98) for the >0-30%, >30-60%, or > 60% VPA groups, respectively, after adjusting for the confounders including MVPA. In the joint analysis, compared to those who did “<150 min/wk and no VPA”, the HRs (95% CIs) for dementia were 0.91 (0.80-1.04), 1.01 (0.90-1.13), and 0.84 (0.77-0.92) for those who did “<150 min/wk with VPA”, “≥150 min/wk and no VPA”, and “≥150 min/wk with VPA”, respectively, after adjusting for the confounders. CONCLUSION: Among individuals who engage in MVPA, performing at least some weekly VPA, particularly in combination with meeting the PA guidelines, may help reduce the risk of dementia. These results suggest that intensity of PA may influence underlying mechanisms (e.g., vascular aging) that contribute to dementia. This research has been conducted using the UK Biobank resources under application number 43528.