Daily step count linked to dementia risk
A daily total of 3,800 to 9,800 steps was tied to lower dementia risk, longitudinal data from the U.K. Biobank showed.
The optimal dose of daily steps -- the value with the highest dementia risk reduction -- was 9,826 steps (HR 0.49, 95% CI 0.39-0.62).
The minimal step dose -- the point at which dementia risk was half of the maximum reduction -- was 3,826 steps per day (HR 0.75, 95% CI 0.67-0.83), the researchers reported in JAMA Neurology
Step intensity mattered. The optimal cadence dose for the highest 30 minutes of the day was 112 steps per minute (HR 0.38, 95% CI 0.24-0.60).
A key finding was that higher step intensity -- a 'mere' 112 steps/min in a 30-minute epoch -- had the greatest impact on reducing dementia incidence in this cohort (62% vs 50% risk reduction for 9,800 daily steps), and that this observation was made in analyses that also adjusted for total steps.
The study assessed daily step count from wrist-worn accelerometers for 78,430 people 40 to 79 years old in the U.K. Biobank cohort from February 2013 to December 2015. Researchers evaluated total number of daily steps, whether steps were incidental (less than 40 steps per minute) or purposeful (40 or more steps per minute), and peak 30-minute cadence (average steps/minute for the 30 highest minutes of the day, which were not necessarily consecutive).
This study represents an important contribution to step count-based recommendations for dementia prevention.