Weak handgrip in older adults is linked to a higher risk for depression ― while a stronger handgrip may have protective benefits, new research suggests.
In a study of more than 115,000 adults, there was a significant association between stronger handgrip, up to 40 kg in men and 27 kg in women, and lower depression risk.
Investigators add that there was a “dose-response” association between physical strength and risk for depression.
“Being physically strong may serve as a preventive factor for depression in older adults, but this is limited to a maximum specific threshold for men and women,” Ruben Lopez-Bueno, PhD, Department of Physical Medicine and Nursing, University of Zaragoza, Spain, and colleagues write.
The findings were published online December 5 in The British Journal of Psychiatry.
Easy, Fast, Reliable
Depression is a major public health problem, and studies “aimed at examining preventive factors to tackle the increase in depression are required,” the investigators write.
They add that a “growing body of research” is examining the link between depression and muscle strength, with handgrip as an estimator, in healthy middle-aged and older adults.
Handgrip strength is an “easy-to-use, fast and reliable indicator of both sarcopenia (age-related loss of muscle mass) and dynapenia (age-related loss of muscle strength), both of which have been associated with depression,” the researchers note.
It is plausible that there is a “regulatory role of skeletal muscle on brain function affecting this condition,” they add.
They note that exercise seems to play a “key role” because it can improve muscle strength as well as muscle mass, downregulate systemic inflammation, and improve neuroplasticity, neuroendocrine, and oxidative stress responses.
Previous studies have relied either on cross-sectional or prospective cohort models and have focused mostly on a specific country, “not accounting for time-varying changes of both handgrip strength and relevant covariables.”
Moreover, previous evidence has been mixed regarding the “extent to which handgrip strength levels may associate with lower risk of depression, with study results ranging from weak to strong associations,” the investigators write.
So “higher-quality research with representative samples from different countries is required to better clarify the strength of such an association and to confirm directionality,” they add.
SHARE Data
To fill this gap, the researchers turned to data from waves 1, 2, 4, 5, 6, and 7 of the Survey of Health, Ageing and Retirement in Europe (SHARE). This encompassed 115,601 individuals aged 50 years and older (mean age, 64.3 years; 54.3% women) residing in European countries and Israel (24 countries total).
Data from wave 3 were not used because handgrip measures were not used in that wave. In the other waves, a handheld dynamometer was used to measure handgrip strength.
The participants were divided into tertiles of handgrip strength, with the “first third” being the lowest tertile of strength and the “final third” representing the highest strength.
All participants were followed for a median of 7.3 years (792,459 person-years), during which 26.1% experienced a risk for depression, as reflected by scores on the EURO-D 12-item scale.
The investigators set the time scale as the months from study entry until either a first depression onset or the end of follow-up.
Covariates that the researchers accounted for included gender, age, education, country, body mass index, physical inactivity, smoking, alcohol consumption, whether living with a partner, wave of inclusion, chronic diseases, consumption of prescribed drugs, and fruit and vegetable consumption.
The researchers used two models: the first adjusted for gender and age at time of the interview, and the second adjusted for all confounders.
In the model that was adjusted only for gender and age, greater handgrip strength was associated with a significantly reduced risk for depression among participants in the second, third, and the final third in comparison with the first third (hazard ratio [HR], 0.65; 95% CI, 0.63 – 0.68; and HR, 0.50; 95% CI, 0.48 – 0.53, respectively).
The associations remained consistent in the fully adjusted model, although risk for depression was slightly attenuated in the second and final thirds compared with the first third (HR, 0.76; 95% CI, 0.71 – 0.81; and HR, 0.64; 95% CI, 0.59 – 0.69, respectively).
When the researchers conducted analyses using restricted cubic spline modeling, they found a significant association for each kilogram increase of handgrip strength and depression, up to 40 kg in men and 27 kg in women (HR, 1.39; 95% CI, 1.08 – 1.71; and HR, 1.28; 95% CI, 1.05 – 1.55, respectively).
There was no greater reduction in depression risk in those with handgrip strength above those values.
Potential Depression Screen
The investigators suggest several explanations for their findings. For example, handgrip strength has “been used as an overall indicator of health status, including sarcopenia,” they write.
Adults with sarcopenia have been found to be at greater risk for depression because of reduced muscle strength, since neurotrophins are produced by skeletal muscle, among other tissues, and are associated with improvement in mood.
From a psychological point of view, “being physically strong may lead to a sensation of psychological wellbeing,” the researchers write.
Moreover, being physically active “across the lifespan also promotes structural and functional changes in the brain, benefiting cognitive functioning and reducing the risk of neurodegeneration,” they write.
This can be important because aging adults with cognitive impairments can also experience neuromuscular impairments that “presumably will contribute to becoming weaker,” they note.
Overall, the findings “warrant strength training programmes aimed at older adults to reduce depression risk,” the investigators write. Clinicians “may consider using the observed handgrip strength thresholds to screen for potential depression risk in older adults,” they add.
Protective Factor?
Commenting for Medscape Medical News, Julian Mutz, PhD, postdoctoral research associate at the Social, Genetic and Developmental Psychiatry Centre, King’s College, London, United Kingdom, said the study “provides further evidence that physical strength may be a protective factor against depression in older adults.”
This confirms a “plethora of cross-sectional and longitudinal studies,” including one recently conducted by Mutz’s group.
The design of the current study “allowed the authors to address a number of key limitations of previous studies, for example, by including repeated measurements of grip strength and adjustment for potential confounding factors over time,” said Mutz, who was not involved with the research.
Additionally, “an important contribution of this study is that the authors show that higher grip strength is only associated with a lower risk of depression up to a specific threshold,” he noted.
“The clinical implication of this finding is that only individuals with grip strength below this threshold are at a higher risk of depression. These individuals especially may benefit from interventions aimed at increasing physical strength,” Mutz said.
The SHARE data collection has been funded by the European Commission and by DG Employment, Social Affairs and Inclusion. Additional funding was obtained from the German Ministry of Education and Research, the Max Planck Society for the Advancement of Science, and the US National Institute on Aging. Lopez-Bueno is supported by the European Union – Next Generation EU. The other investigators and Mutz have reported no relevant financial relationships.
Br J Psych. Published online December 5, 2022. Full article
Batya Swift Yasgur, MA, LSW, is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to numerous medical publications, including Medscape and WebMD, and is the author of several consumer-oriented health books as well as Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom (the memoir of two brave Afghan sisters who told her their story).
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