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 this news organization, Julian Mutz, PhD, postdoctoral research associate at the Social, Genetic and Developmental Psychiatry Centre, King’s College, London, 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 Dr. 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 Dr. 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,” Dr. 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 U.S. National Institute on Aging. Dr. Lopez-Bueno is supported by the European Union – Next Generation EU. The other investigators and Dr. Mutz have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.