Associations between serum total bilirubin levels and the prevalence of metabolic syndrome in elderly Chinese males

Metabolic syndrome (MetS) is a complex cluster of metabolic abnormalities. Serum total bilirubin (TB) is a potent endogenous antioxidant and cytoprotectant. This study aimed to investigate the associations between serum TB levels within the physiological range and the prevalence of MetS and its components in elderly Chinese men. A cross-sectional study involved 430 male participants aged ≥ 65 years. Participants were stratified into quartiles based on serum TB levels. The diagnosis of MetS was based on the criteria of the Chinese Diabetes Society. Serum TB levels were significantly lower in the MetS group than in the non-MetS group. An inverse trend was observed between TB levels and the number of concurrent metabolic abnormalities. After adjusting for confounders such as age, liver function, and renal function, higher physiological TB levels were independently associated with a lower prevalence of MetS, hypertension, dyslipidemia, and diabetes. No significant association was found with obesity. Stratified analysis by TB quartiles showed a gradual decrease in the prevalence of MetS and its components with increasing TB levels. In elderly Chinese men, higher physiological levels of serum total bilirubin are inversely associated with the prevalence of MetS, hypertension, dyslipidemia, and diabetes, suggesting a potential protective role of bilirubin against these metabolic diseases.