Grip strength buffers the harmful association between multimorbidity and depression among middle-aged and older adults

Background: Grip strength (GS) is associated to both multimorbidity and depression, however its possible moderating effect is unknown. This study aimed to investigate GS moderating effect on the association between multimorbidity and depression. Methods: Data from SHARE wave 8 was used. Participant were 41457 middle-aged and older adults (17954 men) from 18 European countries. A regression analysis was conducted for the moderating effect of sex- and agespecific GS quartiles (W) on the association between number of chronic diseases (X1) or multimorbidity (X2) and depression symptoms (Y). Results: More chronic diseases were associated with greater depressive symptomatology (men: B = 0.39, 95 % CI: 0.35, 0.42; women: B = 0.42, 95 % CI: 0.39, 0.45). On the other hand, being in a higher GS quartile was associated with fewer depression symptoms, and this association was stronger the higher the quartile was. Having a higher GS represented a decrease in depression symptoms associated with multimorbidity for men (quartile 1: B = 0.85, 95 % CI = 0.74, 0.95 vs. quartile 4: B = 0.49, 95 % CI = 0.38, 0.61) and women (quartile 1: B = 1.08, 95 %CI = 0.97, 1.19 vs. quartile 4: B = 0.59, 95 %CI: 0.47, 0.70). Conclusions: Strategies aiming to reduce the impact of multimorbidity on mental health should promote musclestrengthening physical activity among middle-aged and older adults.