Associations between level and change in physical function and brain volumes.

Area of Science:

• Neuroscience
• Gerontology
• Public Health

Background:

• Physical function is positively associated with cognitive outcomes.
• Mechanisms linking physical function and brain structure require detailed elucidation.
• This study investigates brain structure in relation to physical function in older adults.

Purpose of the Study:

• To examine the associations between brain structure and physical function in community-dwelling older adults.
• To assess both contemporaneous physical function and changes in physical function over three years.
• To explore the relationship between brain volumetric measurements and physical function.

Main Methods:

• Utilized data from the Lothian Birth Cohort 1936 (N=694).
• Assessed brain structure using MRI at age 73, measuring intracranial volume, brain tissue, ventricles, grey matter, normal-appearing white matter, and white matter lesions.
• Measured physical function at ages 70 and 73 via 6-meter walk, grip strength, and forced expiratory volume, deriving a 'physical function factor'.

Main Results:

• Higher physical function at ages 70 and 73 correlated with larger total brain tissue and white matter volumes, and smaller ventricular and white matter lesion volumes.
• Physical function measures declined across the three-year interval (p<0.001).
• Decline in physical function was associated with smaller white matter volume (p<0.01), but not other brain volumetric measures.

Conclusions:

• Physical function is related to brain volumes in older adults.
• Declining physical function is associated with reduced white matter tissue.
• Further research is needed to understand the bidirectional mechanisms between physical function and brain structure.