Serum Total Bilirubin Predicts Five-year Incidence Of The Metabolic Syndrome And Its Diagnostic Components

Background and Objectives:Oxidative stress and low-grade chronic inflammation are closely related to metabolic syndrome.It was found bilirubin could inhibit the lipid peroxidation and ameliorate oxidative stress,therefore,bilirubin has been proposed as an endogenous antioxidant that could decrease the incidence of cardiovascular diseases.Recently it was reported bilirubin was associated with presence of metabolic syndrome.The aim is to study if baseline bilirubin can predict five-year incidence of metabolic syndrome.Method: A total of 1263 people subjects(men 25.7%)with and mean age of 41.7±14.9 years old undergoing the health checkup were retrieved from a university hospital of Dalian in 2009 as a baseline and in 2014 as endpoint.Demographic and laboratory data were collected from database.The indices include gender,age,medical history(hypertension and diabetes),body mass index(BMI),systolic blood pressure(SBP),diastolic blood pressure(DBP),total bilirubin(Tbil),alanine aminotransferase(ALT),Aspartate transaminase(AST),fasting blood glucose(FBG),Triglyceride(TG),cholesterol(TC),Low density lipoprotein cholesterol(LDL-C)and High density lipoprotein(HDL-C).Serum Tbil at the year of 2009 was used as the baseline level,and were subdivided into four groups according to the ascending order of quartile,namely 0 ?mol/L ? Q1 < 8.9 ?mol/L,8.9 ?mol/L ? Q2 < 11.5 ?mol/L,11.5 ?mol/L ? Q3 < 14.7 ?mol/L,and Q4 ? 14.7?mol/L.The metabolic syndrome(MS)was diagnosed according to the definition of the 2013 version of CDS Guidelines for Prevention and Treatment of Type 2 Diabetes in China,but the waist circumference was replaced by BMI,and dysglycemia was replaced with FBG.Cross sectional analysis was first undertaken to study the association of bilirubin and presence of MS and its components,five-year incidence of MS and its components were predicted using baseline Tbil.Statistics was analyzed by SPSS software(IBM,ver 22.0).Results:1.The serum Tbil of the male was higher than that of the female,and the difference was significant(X2=45.972,P=0.000);The serum Tbil increased gradually with an increase in the mean of age,HDL-C and DBP significantly(P<0.05)and a decrease in the mean of FBG and TG(P>0.05);The BMI,FBG and TG in the group Q1(with a low level of Tbil)was higher than the other groups and the HDL-C was lower than the outer groups.For the group Q1(with a low level of Tbil),the prevalence of MS has been higher than the other groups.With an increase of Tbil level,the prevalence of MS gradually decreased.2.The prevalence and incidence of MS were significantly higher in males than in females(P=0.000)at baseline and in follow-up 5 years.At baseline,the mean of age,SBP,DBP,FBG,TG,TC,LDL-C,ALT,AST,UA in MS group were significantly higher than those in non-MS group(P=0.000)and the mean of HDL-C was significantly lower than that of non MS group(P=0.000).After 5-year follow-up,there was a higher baseline SBP,DBP,FBG,TG,ALT,UA,and a lower HDL-C in the people that developed MS during the follow up period compared with those people who remained free from developing MS(P<0.05).3.Multi factor Logistic regression analysis: The logistics regression analysis in MS,obesity,hypertension(HTN),Hyperglycemia,Hypertriglyceridemia,low HDL-C(2009)and baseline Tbil(2009)has been conducted respectively.With the age and gender as the control variable,it was found that the baseline Tbil was an independent risk factor for MS and its components.With the increase of Tbil,the risk of MS and its diagnosis components gradually decreased.The risks of the MS(OR=2.467;95%CI:1.435-4.241),obesity(OR=2.249;95%CI:1.452-3.485),hyperglycemia(OR=1.961;95%CI:1.149-3.344),hypertriglyceridemia(OR=2.781;95%CI:1.798-4.303),low HDL-C(OR2.099;95%CI:1.383-3.185)were highest in the group Q1(with a low level of Tbil),and the difference was statistically significant.Following up for 5 years(2014),the OR values of the hyperglycemia and low HDL-C were gradually decreased with the increase of the baseline Tbil.The baseline Tbil level was the independent influencing factor of MS,hypertension(HTN)and low HDL-C.The incidence of the MS(OR=2.459;95%CI:1.119-5.404),HTN(OR=1.825;95%CI:1.064-3.132),low HDL-C(OR=2.613;95%:1.329-5.139)were highest in the group Q1(with a low level of Tbil),and the difference was statistically significant.Conclusion: The male subjects were featured by a higher prevalence of metabolic syndrome than the female.The prevalence of metabolic syndrome is related to the serum Tbil.Individuals with low serum Tbil had a higher incidence of metabolic syndrome.Therefore,the serum Tbil may predict incidence of metabolic syndrome.