Muscle Strength and Later Incident Dementia and Related Mortality: The Cooper Center Longitudinal Study

Area of Science:

• Gerontology
• Neurology
• Exercise Science

Background:

• Investigating the link between physical health and cognitive decline is crucial for aging populations.
• Muscle strength is a key component of physical health, but its association with dementia remains under investigation.

Purpose of the Study:

• To explore the longitudinal relationship between muscle strength and the incidence of dementia.
• To examine the association between muscle strength and dementia-related mortality in community-dwelling adults.

Main Methods:

• A prospective cohort study of 7755 adults (aged 20-90) was conducted.
• Muscle strength was assessed using 1-repetition maximum bench and leg press, categorized into tertiles.
• Dementia incidence and mortality were tracked using Medicare claims and the National Death Index.

Main Results:

• A medium tertile of lower body strength showed a marginally significant reduction in all-cause dementia hazard (HR=0.86, CI=0.73-1.0) after controlling for risk factors and fitness.
• No significant associations were found between upper or lower body muscle strength and dementia-related mortality.
• The study included a predominantly White (97%) and male (86%) cohort with a mean age of 44 at baseline.

Conclusions:

• Muscle strength, encompassing both upper and lower body, did not demonstrate a significant association with dementia risk or related mortality.
• These findings suggest that after accounting for cardiovascular risk factors and cardiorespiratory fitness, muscle strength alone may not be a primary predictor of dementia outcomes.