Of the various simple measures that correlate with mortality and risk of age-related disease, grip strength remains a relatively good option, even in this modern era of epigenetic clocks. Illustrative of this point, researchers here show a correlation between grip strength and epigenetic age data in a sizable study population. The degree to which an individual suffers from the chronic inflammation of aging may be an important determinant of this relationship. Inflammation disrupts tissue function throughout the body, and maintenance of muscle mass and strength is one of the aspects of health negatively affected by unresolved inflammatory signaling.
Researchers modeled the relationship between biological age and grip strength of 1,274 middle aged and older adults using three "age acceleration clocks" based on DNA methylation, a process that provides a molecular biomarker and estimator of the pace of aging. The clocks were originally modeled from various studies examining diabetes, cardiovascular disease, cancer, physical disability, Alzheimer's disease, inflammation, and early mortality. Results reveal that both older men and women showed an association between lower grip strength and biological age acceleration across the DNA methylation clocks. The real strength of this study was in the eight to 10 years of observation, in which lower grip strength predicted faster biological aging measured up to a decade later.
Past studies have shown that low grip strength is an extremely strong predictor of adverse health events. One study even found that it is a better predictor of cardiovascular events, such as myocardial infarction, than systolic blood pressure - the clinical hallmark for detecting heart disorders. Researchers have previously shown a robust association between weakness and chronic disease and mortality across populations. This evidence coupled with the recent findings shows potential for clinicians to adopt the use of grip strength as a way to screen individuals for future risk of functional decline, chronic disease and even early mortality.
Future research is needed to understand the connection between grip strength and age acceleration, including how inflammatory conditions contribute to age-related weakness and mortality. Previous studies have shown that chronic inflammation in aging - known as "inflammaging" - is a significant risk factor for mortality among older adults. This inflammation is also associated with lower grip strength and may be a significant predictor on the pathway between lower grip strength and both disability and chronic disease multimorbidity.