A prospective study of the association of grip strength and sleep status with depressive symptoms

INTRODUCTION: Depressive symptoms represent a major public health concern among middle-aged and older adults. Grip strength, a key indicator of physical frailty and biological ageing, and sleep disturbance, a recognised precursor of depression, have been independently linked to mental health outcomes. However, their combined effect on depressive symptoms remains unexplored. This study aimed to examine the association between grip strength levels, sleep status and their combined effects on the risk of depressive symptoms in middle-aged and older adults. METHOD: This prospective cohort study included 16,395 participants from the Survey of Health, Ageing and Retirement in Europe, followed from 2006 to 2017. Logistic regression and generalised estimating equations were used to examine associations. RESULTS: During follow-up, 5241 participants (31.97%) developed depressive symptoms, with higher incidence in females (58.98%). After adjusting for covariates, both low grip strength (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.02-1.23) and sleep disturbance (OR 1.66, 95% CI 1.50-1.84) were independently associated with elevated risk of depressive symptoms. A synergistic effect was observed: individuals with both low grip strength and sleep disturbance had 1.87 times higher risk (95% CI 1.60-2.17) compared to those with high grip strength and no sleep disturbance. Sex- and agestratified analyses revealed stronger associations in males and older adults (≥70 years). CONCLUSION: Low grip strength and sleep disturbance are independently and synergistically associated with risk of depressive symptoms. Screening for both factors may help identify high-risk individuals for targeted preventive interventions.