How sleep, physical activity, and sedentary behavior influence incident dementia risk

By Scott Cunningham, MD, PhD
Published June 15, 2022

Key Takeaways

  • Of 3 modifiable behaviors known to be associated with dementia, combining sleeping 7 h/d, moderate-to-high leisure-time physical activity (LTPA), and low-to-moderate sedentary time had the lowest risk of incident dementia.

Putting It Into Practice

The 2020 Report of the Lancet Commission concluded that modification of 12 modifiable risk factors could reduce the incidence of dementia by 40%.

Risk profiling is best achieved when the independent and combined effect of modifiable and non-modifiable risk factors are determined.

Why this study matters

Notwithstanding a cure, the global prevalence of dementia is expected to triple in the next 3 decades. Thus, prevention, risk reduction, and cognitive enhancement rely on an understanding of the modifiable cardiovascular and lifestyle risk factors.

Study design

Participants (n = 431,924) without dementia at the time of enrollment were recruited from the UK Biobank and followed for a median of 9 years.

The following data were collected and fitted with restricted cubic spine to determine linear and non-linear association with dementia: sleep duration; LTPA; and sedentary time.

Results and conclusion

Duration of sleep had a U-shaped association with dementia; 7 h of sleep per day had the lowest risk of dementia. LTPA had a curvilinear association with dementia, while sedentary time had a J-shaped association with dementia.

The risk of dementia was 17% lower in participants with high LTPA and 22% higher in participants with high sedentary time.

Each of the 3 modifiable behaviors had a non-linear association with brain structures corresponding to dementia.

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