Objectives: Elderly persons with low muscle mass (LMM) or sarcopenia are prone to frailty and functional decline. This study aimed to investigate the relationship between serum selenium level and skeletal muscle mass in community-dwelling elderly.
Design: Cross-sectional observational study.
Setting and participants: A total of 327 elderly Taipei citizens (mean age 71.5 ± 4.7 years) were recruited from the community.
Measurements: Skeletal muscle mass was measured by bioelectrical impedance analysis. LMM was defined by low skeletal muscle index (SMI: muscle mass (kg)/[height (m)](2)). All participants were further divided into quartiles by serum selenium level and the risk for LMM among these quartiles was examined using multivariate logistic regression analyses. Estimated serum selenium levels for the LMM group vs the normal group and estimated SMI in the quartiles of serum selenium were computed by least square method in linear regression models.
Results: The estimated mean (±standard deviation) of serum selenium level was significantly lower in the LMM group compared with the normal group after adjusting for confounders (1.01 ± 0.03 μmol/L vs 1.14 ± 0.02 μmol/L, P < .001). After adjusting for age, sex, lifestyle, and physical and metabolic factors, the odds ratios (95% confidence interval, P value) of LMM in the bottom, second, and third selenium quartile groups were 4.62 (95% CI 2.11-10.10, P < .001), 2.30 (95% CI 1.05-5.03, P < .05) and 1.51 (95% CI 0.66-3.46, P = .327), respectively, compared with the top quartile group of serum selenium level. The least square mean of SMI increased with the quartiles of serum selenium (P < .001).
Conclusions: This is the first study to demonstrate that low serum selenium is independently associated with low muscle mass in the elderly. The causality and underlying mechanism between selenium and low muscle mass or sarcopenia warrant further research.
Keywords: Skeletal muscle mass; bioelectrical impedance analysis; elderly; selenium.