Effects of Gilbert syndrome on cardiovascular disease risk reduction: a systematic review

Gilbert syndrome is a human genetic disorder which affects bilirubin metabolism in the liver and results in unconjugated hyperbilirubinemia. While considered a benign condition with only occasional jaundice and possible alterations of metabolism of certain drugs, Gilbert syndrome can reduce cardiovascular disease (CVD) risk. The objective of this review was to summarize the evidence on the potential effect of Gilbert Syndrome on reducing CVD risk via lowering cholesterol and/or lipid levels in the body and is associated with other protective mechanisms which are related to higher blood levels of unconjugated bilirubin.

A systematic review of articles returned from the online database PubMed was conducted using search terms: "Gilbert syndrome", "reduced cardiovascular disease risk", "cardiovascular disease", "cholesterol", and "lipid level".

After filtering using the exclusion criteria and removing duplicates, eight articles were identified for the review. This review found that CVD risk was lower for people with Gilbert syndrome when compared to unaffected individuals. The reduced CVD risk was theorized to be due to elevated unconjugated bilirubin levels which lead to reduced concentrations of lipids, reduced inflammation biomarkers, decreased ABCA1 protein, increased serum antioxidant capacity expression, decreased BMI, and lower triglyceride levels.

Individuals with Gilbert syndrome have a reduced CVD risk. Given that Gilbert syndrome reduces CVD risk in individuals and that Gilbert syndrome results in elevated serum levels of unconjugated bilirubin; elevation of unconjugated bilirubin could serve as a biomarker to monitor CVD risk reduction in the general population.