Association between total bilirubin and sarcopenia in people with type 2 diabetes: The KAMOGAWA-A study

Bilirubin is associated with vascular complications in diabetes. However, the correlation between bilirubin and sarcopenia or muscle strength has not been investigated. This study aimed to investigate the association between total bilirubin and skeletal muscle mass index (SMI), hand grip strength (HGS), and sarcopenia in patients with type 2 diabetes. This cross-sectional study included 1,108 patients with type 2 diabetes from three hospitals in Japan. Multiple and logistic regression analyses were used to examine the relationships between total bilirubin and SMI, HGS, and sarcopenia. Of the participants, 473 (43%) were women. The median (interquartile range) age, and glycated hemoglobin were 67 (59-73) years, and 7.4 (6.7-8.6) %, respectively. The median SMIs for women and men were 6.32 (5.73-7.04) kg/m² and 7.53 (7.02-8.19) kg/m², respectively. The median HGS for women and men were 21.5 (17.5-25.0) kg and 36.0 (30.0-41.5) kg, respectively. Sarcopenia was present in 11% and 12% of women and men, respectively. No correlation was observed between total bilirubin and SMI in both sexes. No significant association was observed between total bilirubin and HGS in men, whereas a positive correlation was observed in women (β = 0.18, p = 0.01). Total bilirubin was negatively associated with sarcopenia in women (odds ratio = 0.80, 95% confidence interval: 0.64-0.98, interaction p = 0.02). The total bilirubin was significantly associated with HGS and sarcopenia in women with type 2 diabetes. Total bilirubin may serve as a useful indicator of sarcopenia in Japanese women.