Moderating Effect of Grip Strength in the Association between Diabetes Mellitus and Depressive Symptomatology

Diabetes mellitus and depression rank among the leading causes of disease burden and are present in the top ten causes of disability-adjusted life years worldwide. Numerous studies have shown that both depression and diabetes have a detrimental effect on the quality of life, and when they coexist, the effect is considerably worse. This study aimed to analyse how grip strength moderates the relationship between diabetes and depressive symptoms among middle-aged and older adults. In total, 41,701 participants (18,003 men) in wave 8 of the cross-sectional population-based Survey of Health, Ageing, and Retirement in Europe (2019/2020) data were studied. A dynamometer was used to test grip strength twice on each hand. Depressive symptoms were measured using the 12-item EURO-D scale. The relationship between diabetes and depressive symptoms is negatively moderated by grip strength (male: B = -0.03, 95% CI = -0.04, -0.03; female: B = -0.06, 95% CI = -0.07, -0.06). Furthermore, the significant zone grip strength moderation values for males and females were less than 48.7 kg and 38.9 kg, respectively. Muscular strength was a moderator of depressive symptoms, attenuating its association with diabetes. This supports the premise that physical activity, namely muscle-strengthening exercises, should be included in diabetes treatment programs.