Correlation analysis of serum bilirubin and sleep disorders in patients with Parkinson's disease

Abstract

Objective To explore correlation between serum bilirubin and sleep disorders in Parkinson's disease (PD) patients. Methods Total 79 PD cases from He'nan Provincial People's Hospital, and 77 age and sex matched controls were recruited from October 2021 to October 2022. The Unified Parkinson Disease Rating ScaleⅢ(UPDRSⅢ) was used to evaluate motor symptoms, modified Hoehn⁃Yahr staging was used to evaluate disease severity, Rapid Eye Movement Sleep Behavior Disorder Questionaire⁃ Hong Kong (RBDQ ⁃HK) was used to access the severity of rapid eye movement sleep behavior disorder (RBD), Pittsburgh Sleep Quality Index (PSQI) was used to access the sleep quality, and Epworth Sleepiness Scale (ESS) was used to access the occurrence of excessive daytime sleepiness (EDS). The levels of serum total bilirubin (TBIL), indirect bilirubin (IBIL) and direct bilirubin (DBIL) were measured. Results Seventy⁃nine PD patients were divided into the early PD group (n = 47) and middle⁃late PD group (n = 32). The levels of TBIL (Z = 4.988, P = 0.000; Z = 3.917, P = 0.000), IBIL (Z = 4.860, P = 0.000; Z = 3.827, P = 0.000) and DBIL (Z = 4.054, P = 0.000; Z = 3.468, P = 0.002) in the early PD group and middle⁃late PD group were lower than those in the control group. Correlation analysis showed serum TBIL levels were negatively correlated with PSQI score (r = ⁃ 0.310, P = 0.006) and ESS score (r = ⁃ 0.254, P =0.027), serum IBIL levels were negatively correlated with PSQI score (r = ⁃ 0.284, P = 0.013), serum DBIL levels were negatively correlated with RBDQ⁃HK score (r = ⁃ 0.244, P = 0.034), PSQI score (r = ⁃ 0.288, P = 0.012) and ESS score (r = ⁃ 0.295, P = 0.010). Conclusions Serum bilirubin in PD patients were lower than those in the control group inferring that a decrease in serum bilirubin might be a potential mechanism for the occurrence of PD. The lower serum bilirubin was, the more severe sleep disorders in PD patients were.

DOI: 10.3969/j.issn.1672⁃6731.2023.08.011