Relationships between 25(OH)D concentration, sarcopenia and HOMA-IR in postmenopausal Korean women

<p><b>Objective:</b> Sarcopenia and insulin resistance are common co-morbidities in the elderly and are known to be associated with vitamin D deficiency. However, no previous studies have investigated interactions between all three of these factors. We aimed to investigate the relationship between 25-hydroxyvitamin D concentration, sarcopenia, and insulin resistance in postmenopausal Korean women.</p> <p><b>Methods:</b> This study used data from the Korea National Health and Nutrition Examination Survey 2008–2011. Participants were 3744 postmenopausal Korean women. Sarcopenia was defined as appendicular skeletal muscle mass divided by body weight >1 standard deviation below the mean for women aged 20–40 years. The serum 25-hydroxyvitamin D and fasting insulin levels were measured, and insulin resistance was calculated using the formula: fasting plasma glucose (mg/dl) × fasting insulin (mIU/l)/405.</p> <p><b>Results:</b> We found a strong inverse association between 25-hydroxyvitamin D concentration and sarcopenia in postmenopausal Korean women (<i>p</i> = 0.0009). There was also a significant association between sarcopenia and insulin resistance, independent of vitamin D and obesity status (<i>p</i> < 0.0001). However, there was no significant association between 25-hydroxyvitamin D concentration and insulin resistance. In the subgroup analysis, insulin resistance was found to be determined by sarcopenic rather than vitamin D status.</p> <p><b>Conclusions:</b> Sarcopenia was associated with both insulin resistance and 25-hydroxyvitamin D concentration in postmenopausal Korean women, regardless of obesity status. However, 25-hydroxyvitamin D concentration was not associated with insulin resistance. Sarcopenia is therefore of greater clinical importance due to its close relationship with insulin resistance.</p>