Research On Relationship Between Serum Bilirubin Level And Asymptomatic Intracranial Atherosclerotic Stenosis

Background:Intracranial artery stenosis(ICAS)refers to the stenosis of large arteries caused by atherosclerosis,inflammation,dissection and other factors.Many studies have found that people with asymptomatic intracranial atherosclerotic stenosis(aICAS)have a significantly increased risk of ischemic stroke.According to reports,men,turtlenecks,dyslipidemia,history of diabetes,hypertension,and ischemic heart disease are independent risk factors for aICAS.But the literature research on aICAS-related protective factors is relatively lacking.Bilirubin is the end product of heme catabolism in the systemic circulation.It is often regarded as a metabolic waste harmful to the nervous system,can damage the central nervous system,and affects motor function(15),auditory function(16),cognition and Intelligence.High non-conjugated bilirubinemia indicates hemolytic disease,and hyper-conjugated bilirubinemia often indicates hepatobiliary diseases.However,in recent decades,many studies have shown that bilirubin may have a protective effect on blood vessels.Mechanisms include antioxidant effects,anti-inflammatory responses,and direct effects on cell signaling.However,the correlation between bilirubin and asymptomatic intracranial atherosclerotic stenosis(aICAS)has not yet been fully elucidated.Objective:The main purpose of this study is to investigate the serum bilirubin(including total bilirubin,direct bilirubin and indirect bilirubin),aICAS and moderate to severe asymptomatic intracranial atherosclerotic stenosis(m-saICAS).And through subgroup analysis,further explore the correlation between serum bilirubin and aICAS in the elderly,and assess whether bilirubin is a possible independent protective factor for intracranial large blood vessels.Methods:This study is based on the "Kongcun Town aICAS Study."Through questionnaire interviews,clinical examinations,and laboratory tests,baseline data on relevant demographics and risk factors was collected.After the initial screening of aICAS population using transcranial ultrasound Doppler(TCD),the diagnosis of aICAS was finally confirmed by magnetic resonance angiography(MRA).According to the concentration from low to high,the first-50%of the total bilirubin,direct bilirubin and indirect bilirubin concentrations were defined as the low concentration group,and the 50%of the population after each type of bilirubin concentration was defined as High concentration group.Binary logistic regression and linear logistic regression were used to analyze the association between bilirubin and aICAS or m-salCAS.Results:This study finally included 2013 subjects with an average age of 57.59 years(±10.33),of which 1056 women(52.46%).We found that high concentrations of total bilirubin,direct bilirubin and indirect bilirubin groups are protective factors of alCAS and m-saICAS.In the subgroup analysis,no statistical correlation was found between total bilirubin,direct bilirubin and indirect bilirubin in the young and middle-aged population(≤60 years old)and aICAS.In the elderly population(>60 years),after adjusting for related confounding factors,it was found that total bilirubin,direct bilirubin,and indirect bilirubin are independent protective factors of aICAS(p<0.05).Summary and conclusions:Total bilirubin,direct bilirubin,and indirect bilirubin might be independent protective factors for aICAS and moderate-to-severe aICAS in rural-dwelling Chinese people,especially among older participants aged≥60 years.