Hand grip strength: a phenotype suitable for identifying genetic variants affecting mid- and late-life physical...

Area of Science:

• Gerontology
• Human Genetics
• Physiology

Background:

• Declining physical functioning in later life is a significant public health concern, impacting morbidity, functional independence, and quality of life.
• Identifying genetic factors influencing physical functioning is crucial for understanding aging processes and developing targeted interventions.
• Previous research on genetic influences on physical functioning has been limited to specific populations and a few genetic variants.

Purpose of the Study:

• To investigate the heritability of hand grip strength as a phenotype for physical functioning in a large, population-based sample.
• To assess the suitability of hand grip strength for genetic studies aimed at identifying variants affecting mid- and late-life physical function.

Main Methods:

• A population-based study of 1,757 Danish twin pairs aged 45-96 years.
• Measurement of hand grip strength as a proxy for overall physical functioning.
• Heritability estimation using classical twin study methods.

Main Results:

• Hand grip strength demonstrated a substantial heritability of 52% (95% CI, 48-55%) in the studied population.
• The study identified a sufficient number of dizygotic twin pairs (28 discordant, 77 concordant) for powerful genetic analyses using extreme sib pairs.
• Hand grip strength is strongly associated with muscular functioning and predicts incident disability.

Conclusions:

• Hand grip strength is a highly heritable phenotype, making it suitable for genetic research into physical functioning.
• Genetic factors play a significant role in maintaining physical functioning capacity in mid- and late-life.
• Further genetic studies utilizing hand grip strength can identify specific genetic variants impacting physical aging.