Comparison of 25-hydroxyvitamin D and bilirubin levels between patients with essential tremor and Parkinson’s disease

Abstract

Introduction: Differential diagnoses between essential tremor and Parkinson’s disease is challenging in some individuals, with both disorders sharing similarities. Considering these links, we hypothesized that both conditions have a similar profile for some antioxidant molecules, including 25-hydroxyvitamin D and bilirubin. Methods: Weperformed a cross-sectional study comparing serum levels of 25-hydroxyvitamin D and bilirubin in 31 ET patients, 38 PD, and 65 controls matched for age. We used the Fahn-Tolosa-Marin scale for the severity of tremors in the ET group. We used Hohen-Yahr and MDS-UPDRS part III scales in the PD group. In addition, we evaluated sociodemographiccharacteristics, including age, sex, ethnicity, years of study, duration of disease, and use of primidone.Results: We found no differences in serum levels for 25-hydroxyvitamin D or bilirubin subtype levels between the ET and PD groups. We found low levels of indirect bilirubin in the PD group compared to the controls. We did not find differences between ET and controls in all biomarkers of the study. Conclusion: ET and PD patients have similar profiles for 25-hydroxyvitamin D and bilirubin serum levels. The discovery of differences in oxidative stressbiomarkers in both conditions, mainly low-cost substances available clinically, can assist in the differential diagnosis and, in the future, prognostication and better therapy management.