Accelerometer Measures of Activity and Dementia Risk
Unsurprisingly, given other data on exercise and aging, researchers here show that greater activity correlates with a reduced risk of suffering dementia. The data in this study comes from accelerometer devices, counting steps and intensity. The introduction of accelerometers over the past few decades has led to a considerable improvement in the quality of epidemiological data relating to physical activity, particularly the relationship between low levels of activity and health. Any increment above being sedentary provides a meaningful improvement, relative to the harms done by inactivity, but the optimal level of activity is somewhat higher than that.
Step-based recommendations may be appropriate for dementia-prevention guidelines. However, the association of step count and intensity with dementia incidence is unknown. This study examined the dose-response association between daily step count and intensity and incidence of all-cause dementia among adults in the UK. This was a UK Biobank prospective population-based cohort study (February 2013 to December 2015) with 6.9 years of follow-up (data analysis conducted May 2022). A total of 78,430 of 103,684 eligible adults aged 40 to 79 years with valid wrist accelerometer data were included. Registry-based dementia was ascertained through October 2021.
We found no minimal threshold for the beneficial association of step counts with incident dementia. Our findings suggest that approximately 9,800 steps per day may be optimal to lower the risk of dementia. We estimated the minimum dose at approximately 3,800 steps per day, which was associated with 25% lower incident dementia. This finding suggests that population-wide dementia prevention might be improved by shifting away from the least-active end of the step-count distributions. Unlike previous studies investigating mortality outcomes, our analyses highlight the importance of stepping intensity for preventing dementia. Both purposeful steps and peak 30-minute cadence (i.e. an indicator of overall best natural effort in a free-living environment) were associated with lower risks of dementia.