Association Of Baseline Serum Bilirubin Or Percentage Change In Bilirubin Levels Over 8-year Of Observation With Incidence Of Metabolic Syndrome

Background and Objectives: Chronic low-grade inflammation and oxidative stress are closely associated with metabolic syndrome(MS).Bilirubin is considered an endogenous antioxidant.In individuals with Gilbert syndrome,bilirubin level is usually higher than 17.1?mol/L,but their mortality is less than half than that of general population.Previous retrospective studies reported that higher serum bilirubin concentrations were associated with low prevalence diabetes and its chronic complications,low incidence of cardiovascular disorders and mortality.Most of previous reports are retrospective in design,the aims of our study is to determine if baseline serum total bilirubin concentration and percentage change in bilirubin levels(PCB)are related to incident MS in healthy Chinese adults over 8-year of obseveation.Methods:A total of 1267 people subjects undergoing the health checkup were selected from a university hospital in 2009.After 8 years(2017),follow-up was performed on people with no metabolic syndrome at baseline in 2009.data of gender,age,family history,past medical history,related treatment,weight,height,systolic blood pressure(SBP),and diastolic blood pressure(DBP)were collected.Body mass index(BMI)was calculated as weight in kilogrammes divided by the square of height in metres(kg/m2).Fasting blood samples were taken to assess the level of Low density lipoprotein cholesterol(LDL-C),total cholesterol(TC),high density lipoprotein cholesterol(HDL-C),triglyceride(TG),total bilirubin(TB),uric acid(UA),alanine aminotransferase(ALT),aspartate transaminase(AST),fast blood glucose(FBG),hepatitis B viralsurface antigen(HBs Ag)and anti-hepatitis C viral antibody(anti-HCV).Baseline TB were divided into three groups according to the ascending order of tertiles as T1,T2 and T3.or percentage change in bilirubin levels(PCB)were divided into three groups according to the ascending order of tertiles as P1,P2 and P3.PCB was calculated according to the following formula: 100(%)×[2017 TB(?mol/l)–2009 TB(?mol/l)]/[2009 TB(?mol/l)].The metabolic syndrome(MS)was diagnosed according to the definition of the 2013 version of Chinese Guidelines for Prevention and Treatment of Type 2 Diabetes with central obesity replaced by BMI?25kg/m2 and dysglycemia as fasting serum glucose over 6.1 and history of diabetes.Cross-sectional study of association of TB with MS was analysed,and the association of baseline TB and PCB with incidence of MS over 8 years was analysed.SPSS software(version 22.0,IBM Co Ltd,Chicago,USA)was used for statistical analyses.Results:1.Both at Baseline(2009)MS and incident MS at 8-year(2017)follow-up,levels of age,FBG,BMI,SBP,DBP,FBG,UA,AST,TC,TG were higher,while the HDL-C was lower in subjects with MS than in those without MS(Ptrend<0.05).In 2009,TB was 12.31 ±4.66 ?mol/L in MS group and 12.45 ±4.91 ?mol/L in non-MS group.After8 years follow-up,the baseline TB of MS group was 11.87 ±5.68 ?mol/L,and that of non-MS group was 12.50 ±4.70?mol/L,but there was no significant difference(Ptrend>0.05).The overall prevalence of MS at baseline was 17.76%(men 38.8%,women 11.03%).The incidence of MS was 11.8%(men 24.3%,women 9.2%)over8-year follow-up in 2017.2.Spearman anlysis found TB were significantly positive correlation with age,ALT,AST and UA significantly(P<0.05),and non-significantly positive correlated with SBP,DBP,TC,TG,LDL-C,and negative correlated with FBG,BMI,HDL-C(Ptrend>0.05).3.Logistic regression found risk of MS were higher in TB level of T2(OR=1.712,95%CI: 1.061-2.763),and T1(OR=2.533,95%CI:1.551-4.137)compared with T3 level after adjusting for sex and age(Ptrend<0.05).4.The incident MS over 8 years of follow-up was also increased in baseline T2(OR=2.603,95%CI: 1.279-5.298)and T1(OR=2.892,95%CI:1.427-5.861)compared with T3 level after adjusting for sex and age(Ptrend<0.05).5.Logsitic regression showed higher(PCB)tertiles seemed associated with increases in the incident MS after 8 years after adjusting for sex and age,OR for P2 was 1.237(95%CI: 0.663-2.308),and for P3 was 1.331(95%CI:0.716-2.472)compared with P1,but the association was not significant(Ptrend>0.05).Conclusion:Men have higher TB than women.Lower TB is associated with higher prevalence of MS,and associated with higher incidence of MS in future,while higher PCB may be an indicator for prediction of incidence of MS,but future study with larger population is needed.