A Polygenic Risk Score for Hand Grip Strength Predicts Muscle Strength and Proximal and Distal Functional Outcomes...

Area of Science:

• Genetics
• Gerontology
• Physiology

Background:

• Hand grip strength (HGS) is a key indicator of overall muscle strength and health in aging populations.
• Genetic factors play a role in determining individual differences in muscle strength.

Purpose of the Study:

• To compute a polygenic risk score (PRS) for HGS.
• To investigate the predictive value of PRS for muscle strength, functional capacity, and disability in older women.

Main Methods:

• Utilized genomewide association study summary statistics for HGS from the Pan-UK Biobank.
• Calculated PRS for HGS in the Finnish Twin Study on Aging (N=429 women, ages 63-76).
• Assessed HGS, knee extension strength, ankle plantarflexion strength, functional capacity (gait and dual-task tests), and activities of daily living (ADL/IADL) disabilities.

Main Results:

• PRS for HGS independently explained 6.1% of variation in measured HGS and significant portions of variation in knee extension (5.4%) and ankle plantarflexion strength (1.2%).
• PRS for HGS also accounted for 0.1%-1.5% variation in functional capacity tests.
• Higher PRS for HGS was associated with a reduced likelihood of ADL/IADL disabilities (OR=0.74-0.76).

Conclusions:

• Older women with a genetic predisposition for lower muscle strength exhibited significantly lower strength compared to those with a predisposition for higher strength.
• PRS for HGS is systematically associated with overall muscle strength and functional outcomes requiring muscle strength.