Lower grip strength and insufficient physical activity can increase depressive symptoms among middle-aged and older European adults: a longitudinal study

OBJECTIVES: The present study aimed to identify the gender-specific trajectories of grip strength using group-based trajectories, explore the interaction between grip strength and physical activity on depression, and investigate the association of physical activity with the change in depression by different grip strength groups among middle-aged and older European adults. METHODS: A total of 14,098 participants aged 50 years or older from the Survey of Health, Ageing and Retirement in Europe 2007–2019 were included in this study. Group-based trajectory modeling was used to identify the low, middle and high group of grip strength by gender. Generalized estimated equations were fitted to analyze the interaction effect. The data of wave 2-wave 5 and wave 2-wave 7 were chosen to conduct sensitivity analyses. RESULTS: Significant interactions between grip strength group and physical inactivity were found (x(2) (interaction) = 11.16, P = 0.004). Significant interactions between physical inactivity and time on depression were identified in low (x(2) (interaction) = 27.83, P < 0.001) and moderate (x(2) (interaction) = 23.67, P < 0.001) grip strength, but a similar result was not found in high grip strength (x(2) (interaction) = 4.39, P = 0.495). Participants in the physical inactivity group had higher depression scores in the low and moderate grip strength groups. Sensitivity analyses yield almost similar results. CONCLUSIONS: Grip strength and physical inactivity interact with depression. Lower grip strength and insufficient physical activity can increase depressive symptoms. People with lower grip strength and physical inactivity should pay special attention to the prevention of depression. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-03392-x.