A study of nearly 9,600 American adults has found that the force of a single hand squeeze on a dynamometer tracks with the risk of dying from any cause over the following years, more closely than several more complicated measures of grip strength that researchers have tried to build around it. Adults in the weakest fifth of grip strength faced roughly double the mortality risk of everyone else, a gap researchers say holds up across age groups and both sexes.
Comparing five ways to measure grip strength
Researchers at Qingdao University in China used data from the 2011–2014 cycle of the National Health and Nutrition Examination Survey, the long-running federal survey that combines interviews, physical exams and laboratory tests, to compare five different ways of expressing grip strength. Two were absolute measures: the average handgrip strength across both hands, and the single highest reading recorded. Three were relative measures that adjust the raw squeeze for body size: grip strength divided by body mass index, grip strength divided by height squared, and maximum grip divided by body weight. The point of the comparison was to settle which version, if any, does the best job of forecasting death.
How NHANES tested nearly 9,600 adults
Participants aged 20 and older, examined as part of the National Health and Nutrition Examination Survey, squeezed a digital handheld dynamometer as hard as possible while standing, alternating hands across three trials each, with at least a minute of rest between squeezes. After excluding people who were pregnant or had missing grip strength, body mass index or mortality data, 9,583 adults remained in the analysis, with a mean age of 47.4 and just under half men. Deaths were tracked through the National Death Index to the end of 2019, a median follow-up of 6.75 years during which 805 participants died.
The mortality gap tied to grip strength
Weaker grip was consistently linked to a higher risk of death, according to the study, published in Scientific Reports. Every 5-kilogram drop in average handgrip strength was associated with a 36 per cent higher hazard of death in men and a 49 per cent higher hazard in women, after adjusting for age, race, education, income, smoking, drinking, exercise habits and chronic conditions including hypertension, diabetes, cardiovascular disease and cancer. The weakest 20 per cent of grip strength, defined separately by sex and body mass index, carried roughly double the mortality risk of everyone else: a hazard ratio of 2.20 in men and 2.52 in women. Comparing the lowest quartile of grip strength with the highest showed a similarly steep gap, on the order of a twofold increase in hazard, regardless of which grip measurement was used.
Why simple grip strength outpredicted the adjusted versions
When the researchers compared how well each of the five measures actually predicted death, using statistical tools that score prediction accuracy, average handgrip strength and grip strength divided by height squared performed best and were statistically indistinguishable from each other. Maximum grip strength ranked close behind. The two measures adjusted for body mass index or body weight performed measurably worse. That runs counter to an intuitive assumption that accounting for a person’s size should sharpen the prediction; the authors argue that in this dataset, the raw force someone can generate said more about their underlying health than any ratio built from it did. Using a receiver operating characteristic curve, a standard way of scoring how well a measurement separates people who died from people who did not, average handgrip strength and grip divided by height squared each scored 0.714, edging out maximum grip strength at 0.712; a separate concordance statistic put both at 0.860. The researchers also tested a third low-grip definition, a reference cutoff calculated from a person’s age, sex, height and weight, which was tied to a 91 per cent higher mortality hazard in men but lost statistical significance for women once every covariate was included, a sex difference the study flags as unexplained.
How the finding compares with earlier research
The pattern fits earlier work despite differences in scale. A meta-analysis of 42 studies covering more than 3 million participants found that all-cause mortality risk rose 16 per cent for every 5-kilogram decrease in grip strength, a smaller effect than the 36 to 49 per cent seen in this NHANES sample, though still in the same direction. The relationship in the new analysis was non-linear, meaning risk did not climb at a constant rate as grip strength fell, and results were largely unaffected when researchers excluded people who died within the first year of follow-up or who already had cancer or cardiovascular disease when their grip was measured, a step meant to rule out reverse causation from existing illness.
What the association does not establish
The study is observational, so it can show that weaker grip strength is linked to a higher risk of death without proving that low grip strength itself causes it. Grip strength is widely understood as a marker of overall muscle function and physical frailty rather than a distinct disease process, and the researchers found that once cognitive function was factored in among older adults, the size of the association shrank or disappeared in some models, suggesting overlapping decline in strength and cognition partly explains the link at older ages. The authors describe grip strength as a cheap, fast screening signal worth tracking in clinical settings rather than a standalone diagnosis, and they note that a single measurement in a survey cannot capture how a person’s strength is changing over time, which other research suggests may matter as much as the raw number.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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