Does vitamin D affect sarcopenia with insulin resistance in aging?

Area of Science:

• Gerontology
• Nutritional Science
• Metabolic Health

Background:

• Sarcopenia, characterized by muscle loss, is a growing concern in aging populations.
• Protein is crucial for muscle formation, while vitamin D regulates muscle metabolism.
• Limited research exists on the association between 25-hydroxyvitamin D (25(OH)D) status and insulin resistance markers in older adults.

Purpose of the Study:

• To investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and homeostasis model assessment of insulin resistance (HOMA-IR) in individuals with and without sarcopenia.
• To synthesize existing evidence through a meta-analysis.

Main Methods:

• A meta-analysis was conducted on 19 studies identified through electronic database searches.
• Included 19,528 participants: 5,081 with sarcopenia and 14,447 without.
• Calculated random-effects standardized mean difference (SD) and 95% confidence intervals (CI) for effect size.

Main Results:

• Sarcopenic participants exhibited significantly lower serum 25(OH)D levels (SD =1.163; 95% CI 0.514, 1.812; p<0.001).
• Sarcopenic individuals also showed significantly higher HOMA-IR (SD=-2.040; 95% CI -3.376, -0.705; p<0.005).
• High heterogeneity was observed (I2=99.652% for 25(OH)D and I2=99.837% for HOMA-IR).

Conclusions:

• Sarcopenia is associated with lower serum 25(OH)D levels and higher HOMA-IR in older adults.
• These findings suggest a potential link between vitamin D status, insulin resistance, and sarcopenia.
• Further longitudinal studies are recommended to elucidate this relationship.