Relationships between sarcopenic obesity and insulin resistance, inflammation, and vitamin D status: the Korean Sarcopenic Obesity Study

Summary Objective It has been suggested that insulin resistance, low‐grade inflammation and vitamin D deficiency are associated with obesity and sarcopenia. However, their relationships with sarcopenic obesity ( SO ) are unclear. We evaluated the impact of homoeostasis model assessment of insulin resistance ( HOMA ‐ IR ), high‐sensitivity C ‐reactive protein (hs CRP ) and 25‐hydroxyvitamin D (25[ OH ] D ) levels on SO in K orean adults. Study subject/measurements This study included 493 apparently healthy adults (180 men and 313 women) enrolled in the K orean S arcopenic O besity S tudy. S arcopenia was defined as a skeletal muscle mass index ( SMI ) of 1 SD below the sex‐specific mean value for a young reference group. Obesity was defined as a visceral fat area ( VFA ) ≥100 cm 2 . We classified the participants into four sarcopenia/obesity groups based on both SMI and VFA . Results The prevalence of SO was 17·8% in men and 24·9% in women. In women, the SO group had higher HOMA ‐ IR and hs CRP levels compared with the non‐ SO group. In men, the 25[ OH ] D levels were significantly lower in the SO group than the non‐ SO group. Both hs CRP and HOMA ‐ IR levels were negatively correlated with SMI and positively correlated with VFA in both men and women, whereas 25[ OH ] D levels were positively correlated with SMI in both men and women. Multiple binary logistic regression analysis showed that HOMA ‐ IR and 25[ OH ] D levels were independently associated with SO in men, while HOMA ‐ IR and hs CRP were significant factors predicting SO in women. Conclusion Insulin resistance, inflammation and vitamin D deficiency were associated with SO in a K orean adult population.