Is muscle weakness the new smoking? Grip strength associated with accelerated biological aging

Abstract: Muscle weakness characterized by grip strength is associated with accelerated biological aging, a new study reports.

Source: University of Michigan

Everyone ages at a different pace. That’s why two 50-year-olds, despite living the same number of years, can have different biological ages — meaning that a host of internal and external factors have caused them to age at different rates with different levels of risk of disease and early death.

Lifestyle choices, such as diet, smoking and disease, contribute to the acceleration of biological age beyond chronological age. In other words, your body ages faster than expected.

And for the first time, researchers have found that muscle weakness characterized by grip strength, a proxy for overall strength capacity, is associated with accelerated biological aging.

Specifically, the weaker your grip strength, the older your biological age, according to results published in Journal of Cachexia, Sarcopenia and Muscle.

Michigan Medicine researchers modeled the relationship between biological age and grip strength in 1,274 middle-aged and older adults using three “age-accelerating clocks” based on DNA methylation, a process that provides a molecular biomarker and estimator of the pace of aging. The watches were originally modeled after various studies examining diabetes, cardiovascular disease, cancer, physical disability, Alzheimer’s disease, inflammation and early mortality.

The results reveal that both older men and women showed an association between a weaker grip and an acceleration of biological age in DNA methylation clocks.

“We know that muscle strength is a predictor of longevity and that frailty is a powerful predictor of disease and mortality, but for the first time we have found strong evidence of a biological link between muscle weakness and an actual acceleration in biological age. ” said Mark Peterson, PhD, lead author of the study and associate professor of physical medicine and rehabilitation at the University of Michigan.

“This suggests that if you maintain muscle strength throughout life, you can protect against many common diseases associated with aging. We know that smoking, for example, can be a strong predictor of disease and mortality, but now we know that muscle weakness could be the new smoking.”

The real strength of this study was in the 8- to 10-year follow-up, in which lower grip strength predicted faster biological aging measured up to a decade later, said Jessica Faul, Ph.D., MPH, study co-author and research associate at the Institute for Social Research. MIND.

Previous studies have shown that poor grip strength is an extremely strong predictor of adverse health events. One study even found it to be a better predictor of cardiovascular events, such as myocardial infarction, than systolic blood pressure, a clinical marker for heart disease. Peterson and his team have previously shown a strong association between frailty and chronic disease and mortality across populations.

This evidence, along with recent findings from their study, Peterson says, shows the potential for clinicians to embrace the use of grip strength as a way to screen individuals for future risks of functional decline, chronic disease, and even early mortality.

“Testing grip strength would allow for the possibility of designing interventions to delay or prevent the onset or progression of these ‘age-related’ adverse health events,” he said.

“We asked that clinicians start using grip strength in their clinics and only in geriatrics has this type been incorporated. However, few people use this, even though we’ve seen hundreds of publications showing that grip strength is a really good measure of health.”

The researchers say future research is needed to understand the link between grip strength and accelerated aging, including how inflammatory conditions contribute to age-related frailty and mortality.

Previous studies have shown that chronic inflammation during aging – known as “inflammation” – is a significant risk factor for mortality among the elderly. This inflammation is also associated with lower grip strength and may be a significant predictor of the pathway between lower grip strength and disability and chronic disease multimorbidity.

In addition, Peterson says, studies need to focus on how lifestyle and behavioral factors, such as physical activity and diet, can affect grip strength and accelerate aging.

“Healthy eating habits are very important, but I think regular exercise is the most critical thing someone can do to stay healthy throughout life,” he said. “We can show it with a biomarker like DNA methylation age, and we can also test it with a clinical trait like grip strength.”

Additional authors include Stacey Collins, MA, Helen CS Meier, Ph.D., MPH, Alexander Brahmsteadt, MD, all of the University of Michigan.

About this news about aging and muscle strength research

Author: Noah Fromson
Source: University of Michigan
Contact: Noah Fromson – University of Michigan
Picture: Image credited to Justine Ross, Michigan Medicine

Original research: Open access.
“Grip strength is inversely related to the acceleration of DNA methylation age” by Mark D. Peterson et al. Journal of Cachexia, Sarcopenia and Muscle

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Abstract

Grip strength is inversely related to the acceleration of DNA methylation age

Background

There is a large body of evidence linking muscle weakness, as determined by poor grip strength, to a number of negative health outcomes associated with aging. Given these connections, grip strength has been labeled a “biomarker of aging”; however, the pathways linking grip strength to negative health outcomes are unclear. The aim of this study was to determine whether grip strength is associated with measures of DNA methylation (DNAm) aging acceleration.

Methods

Middle-aged and elderly people from the waves of the Health and Retirement Study from 2006 to 2008 with a follow-up of 8-10 years were included. Cross-sectional and longitudinal regression modeling was performed to examine the association between normalized grip strength (NGS) and three measures of DNA age acceleration, adjusting for cell composition, sociodemographic variables, and smoking. Longitudinal modeling was also completed to examine the association between change in absolute grip strength and acceleration of DNA aging. The three DNAm clocks used to estimate age acceleration include the established DunedinPoAm, PhenoAge and GrimAge clocks.

the results

There was a strong and independent cross-sectional association between NGS and DNAm age acceleration for men using DunedinPoAm (β: -0.36; P < 0.001), PhenoAge (β: -8.27; P = 0.01) and GrimAge (β: −4.56; P = 0.01) hours and for women using DunedinPoAm (β: −0.36; P < 0.001) and GrimAge (β: −4.46; P = 0.01) hours. There was also an independent longitudinal association between baseline NGS and DNAm age acceleration for men (β: -0.26; P < 0.001) and women (β: −0.36; P < 0.001) using the DunedinPoAm clock and only for women using PhenoAge (β: −8.20; P < 0.001) and GrimAge (β: −5.91; P < 0.001) hours. Longitudinal modeling revealed a strong association between change in grip strength from wave 1 to wave 3 independently associated with PhenoAgeAA (β: -0.13; 95% CI: -0.23, -0.03) and GrimAgeAA (β: - 0.07; 95% CI: −0.14, −0.01) only in men (both P < 0.05).

Findings

Our findings provide some initial evidence of accelerated aging among men and women with lower NGS and strength loss over time. Future research is needed to understand the extent to which DNA age mediates the association between grip strength and chronic disease, disability, and mortality.