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The association of grip strength with depressive symptoms and cortisol in hair: A cross‐sectional study of older adults
Author(s) -
Smith Lee,
Firth Joseph,
Grabovac Igor,
Koyanagi Ai,
Veronese Nicola,
Stubbs Brendon,
Soysal Pinar,
Yang Lin,
Jackson Sarah E.
Publication year - 2019
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.13497
Subject(s) - medicine , grip strength , confounding , depression (economics) , cross sectional study , body mass index , hand strength , chronic stress , comorbidity , physical therapy , pathology , economics , macroeconomics
Background Low handgrip strength has been shown to be associated with higher levels of depressive symptoms. One area of mental health that is understudied in relation to grip strength is chronic stress, which can exist independently to depression, or as a comorbidity or precursor to this condition. The present study examined cross‐sectional associations between grip strength, an established marker of physical function, and (a) depressive symptoms and (b) chronic stress utilizing hair cortisol concentrations, while accounting for multiple pertinent confounding variables. Method Data were used from wave 6 (2012/13) of the English Longitudinal Study of Aging, a panel study of older (≥50 years) community‐dwelling men and women. Grip strength was measured in kg using a hand‐held dynamometer. Depressive symptoms were assessed using the 8‐item Center for Epidemiologic Studies Depression scale. Hair cortisol concentrations (pg/mg) were determined from samples of scalp hair and log‐transformed for analysis to correct skewness. Associations of grip strength with depressive symptoms and hair cortisol concentration were tested using linear regression models adjusted for age, sex, ethnicity, wealth, smoking status, physical activity, body mass index, limiting long‐standing illness, arthritis, diabetes, and hair treatment. Results The sample comprised of 3741 participants (mean age 68.4 years, 66.4% female). After adjustment for age and sex, grip strength was significantly and negatively associated with both depressive symptoms ( B = −0.038, SE = 0.004, P < 0.001) and hair cortisol ( B = −0.003, SE = 0.001, P = 0.029). However, in the fully‐adjusted models, both associations were attenuated and only the association with depressive symptoms remained statistically significant ( B = −0.015, SE = 0.004, P < 0.001; hair cortisol B = −0.002, SE = 0.001, P = 0.088). Conclusion In a large sample of older adults in England, grip strength was negatively associated with depressive symptoms. Results were inconclusive regarding the association between grip strength and chronic stress. Further research examining the longitudinal relationships between muscular strength and specific aspects of mental health, while also exploring the neurobiological mechanisms underlying these associations, is warranted before recommendations for policy and practice can be made.