Serum trace element levels and their associations with handgrip strength: a cross-sectional study among non-diabetic older adults in Germany.

Handgrip strength is an important marker of health status and is influenced by modifiable risk factors, including dietary intake. Trace elements (TE) copper, iron, iodine, manganese, selenium, and zinc are involved in physiological processes relevant to muscle function. However, the individual and interactive effects of these TE on handgrip strength have not been investigated in community-dwelling non-diabetic older adults. We performed a cross-sectional analysis within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort, comprising 1432 participants (median age 67 years, 59% female). Serum TE levels were measured using inductively coupled plasma tandem mass spectrometry, and handgrip strength was measured using a dynamometer. Associations between TE and handgrip strength were investigated with multivariable regression models. Interactions and non-linear effects were assessed using Bayesian Kernel Machine Regression (BKMR). Higher serum manganese levels were inversely associated with handgrip strength in multivariable linear regression models (β -0.011, 95% CI -0.019; -0.003). In logistic regression analyses, higher serum manganese levels were associated with higher odds of having low strength (OR per SD 1.25, 95% CI 1.10-1.48), and higher serum selenium levels were associated with lower odds of having low strength (0.83, 0.70-0.97). We did not observe any association between other TE and handgrip strength. BKMR analyses did not indicate strong interactive effects of TE on handgrip strength. Our findings indicate that higher serum manganese levels are associated with lower handgrip strength, and lower serum selenium levels are associated with higher odds of having low strength among community-dwelling non-diabetic older adults.