Association of Serum Bilirubin Levels With Sarcopenia in Patients With Type 2 Diabetes: a Cross-Sectional Study in China

Background: The prevalence of sarcopenia increased in type 2 diabetes mellitus (T2DM). Elevated oxidative stress and inflammation played important roles in the pathogenesis of diabetic sarcopenia. Bilirubin had been confirmed to possess potential anti-oxidative activity. This study aimed to explore the relationship between bilirubin and sarcopenia in patients with T2DM. Methods: A total of 251 patients (124 men and 127 postmenopausal women) with T2DM aged ≥ 50 years were recruited. Levels of serum total bilirubin (TBIL), direct bilirubin (DBIL) and indirect bilirubin (IBIL) were measured. Muscle mass was measured by dual-energy X-ray absorptiometry (DXA). The relationships between serum bilirubin levels and appendicular skeletal muscle mass index (SMI) were assessed using a Pearson correlation analysis and multiple linear regression analysis in men and women, respectively. Multiple logistic regression analysis was used to evaluate the association of the highest quartile of serum bilirubin levels with sarcopenia.Results: TBIL (r =0.211, p = 0.019) and IBIL (r =0.249, p = 0.005) were positively associated with SMI in men, but not in women. After multiple adjustment in multiple linear regression analysis, TBIL (p = 0.023) and IBIL (p = 0.012) were also significantly associated with SMI in men. In multiple logistic regression analysis, the highest quartile of IBIL showed a decreased OR for sarcopenia (OR=0.243, P = 0.009) in men. Conclusions: Both of TBIL and IBIL were positively associated with muscle mass in men with T2DM. IBIL might have a stronger protective effect on the occurrence of sarcopenia in men with T2DM.