Does vitamin D affect sarcopenia with insulin resistance in aging?

There are many studies investigating nutritional factors that affect both sarcopenia and muscle formation. According to extensive research, protein has an essential role in muscle formation. More recently, vitamin D has emerged as an important factor that regulates muscle metabolism. However, studies and research of association between 25-Hydroxyvitamin D (25(OH)D) status and components of homeostasis model assessment of insulin resistance ( HOMA-IR) in older are limited. Nineteen studies were found through a search of electronic databases and were subjected to a meta-analysis to investigate the differences in serum levels of 25(OH)D and HOMA-IR between patients with controls and sarcopenia. The random-effects standardized mean difference (SD) and 95% confidence interval (CI) were calculated as the effect size. Nineteen studies with 19,528 participants (5,081 with sarcopenia and 14,447 without) were analyzed. Sarcopenic participants had significantly lower serum levels of 25(OH) D (SD =1.163; 95% CI 0.514, 1.812; p<0.001; I-2=99.652%) and HOMA-IR (SD=-2.040; 95% CI -3.376, -0.705; p<0.005; I-2=99.837%) than controls. It has been reiterated that sarcopenia may be related serum levels of 25(OH) D and HOMA-IR. This relationship needs to be clarified by future longitudinal studies.