Transitional Dynamics of Sarcopenia and Associations of Nutritional Indices with State Transitions in Chinese aged ≥ 50

Vitamin D and muscle health: insights from recent studies

PURPOSE OF REVIEW

The purpose of this review is to critically evaluate the effects of vitamin D on muscle mass and physical/muscle function in middle-aged and older adults, based on recent human studies, including cross-sectional, observational, and intervention studies. Vitamin D, beyond its well established role in bone health, has shown potential in influencing muscle physiology, making it a nutrient of interest in the context of sarcopenia and related chronic conditions.

RECENT FINDINGS

The review states how vitamin D affects muscle function, emphasizing its role in muscle cell proliferation, differentiation, and key signaling pathways. Additionally, the review of recent human studies revealed an inconsistent relationship between vitamin D and sarcopenia and related indices, with mixed results regarding muscle mass and strength. Variability in supplementation dose, duration, and baseline 25-hydroxyvitamin D levels may contribute to these inconsistencies.

SUMMARY

While animal studies indicate vitamin D's effectiveness in muscle growth, cross-sectional, observational, and intervention studies do not show clear benefits of maintaining efficient vitamin D levels on muscle mass or function in humans. Although vitamin D impacts muscle health, it is insufficient alone, emphasizing the need for a multifaceted approach to sarcopenia prevention and management.

The geriatric nutrition risk index is longitudinally associated with incident Sarcopenia: evidence from a 5-year prospective cohort

BACKGROUND

Previous studies investigating the association between the geriatric nutrition risk index (GNRI) and sarcopenia either lacked longitudinal evidence or narrowly focused on specific populations.

AIMS

We aimed to reveal longitudinal associations of GNRI with sarcopenia risk in community-dwelling Chinese. We also investigated interaction effects of potential factors on such associations.

METHODS

We included participants aged ≥ 50 years with sufficient data from the WCHAT study who did not have sarcopenia at baseline and completed sarcopenia assessment during follow-up. GNRI was calculated according to the formula based on serum albumin, height and weight. Sarcopenia was diagnosed according to the 2019 AWGS consensus. Longitudinal associations between GNRI and sarcopenia were estimated by logistic regression with GNRI as either a continuous or categorical variable by tertiles, using generalized estimating equations (GEE) as sensitivity analyses. Subgroup analyses by potential covariates were conducted to detect interaction effects.

RESULTS

A total of 1907 participants without baseline sarcopenia were finally included, of whom 327 (17.1%) developed incident sarcopenia during 5-year follow-up. After controlling for confounders, sarcopenia risk decreased with each one standard deviation increase in GNRI (ORadjusted=0.36, 95% CI 0.31-0.43), and it also decreased successively from the lowest (< 111.2) through middle (111.2-117.7) to the highest (≥ 117.8) tertile of the GNRI level (P for trend < 0.001). Similar results were yielded by GEE. Such associations generally remained robust across subgroups with distinct characteristics, while significant differences were observed between different age groups (≥ 65 vs. <65 years) (interaction P-value < 0.05).

CONCLUSION

GNRI is longitudinally associated with sarcopenia risk with possibly age-specific differences in association magnitude, which holds implications for policymakers to conduct population-based risk assessment.

Longitudinal associations between social support and sarcopenia: findings from a 5-year cohort study in Chinese aged ≥50 years

OBJECTIVES

We aimed to investigate longitudinal associations of overall social support and its sub-domains with risk of sarcopenia and its related traits in community-dwelling Chinese aged ≥ 50 years. We also explored interaction effects of potential factors on such associations.

DESIGN

A prospective cohort study.

SETTING

Community-based setting in western China.

PARTICIPANTS

We included participants aged ≥50 years with complete information necessary for analysis from the WCHAT study who did not have sarcopenia at baseline (2018) and had sufficient data for sarcopenia assessment during 2021-2023.

MEASUREMENTS

Exposures included overall social support, subjective support, objective support and support utilization, which were assessed with the Social Support Rating Scale. Outcomes included sarcopenia, low muscle mass (LMM), low muscle strength and low physical performance, which were diagnosed with the 2019 AWGS consensus. Longitudinal associations between the exposures and outcomes were estimated by logistic regression, with generalized estimating equations (GEE) as sensitivity analyses. Subgroup analyses by potential covariates were conducted to detect interaction effects.

RESULTS

A total of 1905 participants were finally included in the analytic sample, of whom 326 (17.1%) developed incident sarcopenia during 5-year follow-up. After controlling for confounders, higher degree of overall social support (OR = 0.87, 95%CI 0.76-0.99), subjective support (OR = 0.88, 95%CI 0.77-0.99) and support utilization (OR = 0.87, 95%CI 0.77-0.99) correlated with lower sarcopenia risk, among which higher support utilization degree was indicative of lower risk for LMM (OR = 0.88, 95%CI 0.79-0.98). GEE further revealed that overall support degree was negatively associated with risk for sarcopenia (OR = 0.86, 95%CI 0.76-0.98) and LMM (OR = 0.87, 95%CI 0.77-0.99). Objective support was neither significantly associated with sarcopenia nor its traits. No significant interaction effect was observed between overall support and the concerned confounders on sarcopenia (interaction P-value > 0.05).

CONCLUSION

Overall social support degree was negatively associated with sarcopenia risk, possibly primarily through affecting muscle mass rather than muscle strength or physical performance, and such an association remained robust across subgroups with distinct characteristics. This holds implications for policymakers to conduct population-based risk assessment, and supportive strategies against sarcopenia should focus on enhancing subjective support and support utilization rather than objective support alone.