Effect of low serum total bilirubin levels (≤0.32 mg/dl) on risk of coronary artery disease in patients with metabolic syndrome

Bilirubin improves renal function by reversing the endoplasmic reticulum stress and inflammation in the kidneys of type 2 diabetic rats fed high-fat diet

Diabetic kidney disease (DKD), as a chronic diabetes-induced complication, is considered the most frequent leading cause of end-stage renal disease (ESRD). Regarding the observed protective effects of bilirubin, as a potential endogenous antioxidant/anti-inflammatory compound, against DKD progression, we planned to evaluate the effects of bilirubin administration on endoplasmic reticulum (ER) stress and inflammation in type 2 diabetic (T2D) rats fed high-fat diet (HFD). In this regard, thirty 8-week adult male Sprague Dawley rats were divided into five groups (n = 6). T2D and obesity were induced by streptozotocin (STZ) (35 mg/kg) and HFD (700 kcal/day), respectively. Bilirubin treatment was carried out for 6- and 14-week intervals (10 mg/kg/day), intraperitoneally. Then, the expression levels of ER stress-related genes (i.e. binding immunoglobulin protein (Bip), C/EBP homologous protein (Chop), and spliced x-box-binding protein 1 (sXbp1), as well as nuclear factor-κB (NF-κB) were analyzed using quantitative Real-time PCR experiments. Moreover, histopathological and stereological changes of kidney and its related structures were investigated for the studied rats. Bip, Chop, and NF-κB expression levels were significantly decreased under bilirubin treatment, while sXbp1 was up-regulated following the bilirubin administration. More interestingly, glomerular constructive damages seen in HFD-T2D rats, were considerably improved in the animals received bilirubin. Stereological assessments also revealed that bilirubin could desirably reverse the mitigation of kidney's total volume and its related structures, such as cortex, glomeruli, and convoluted tubules. Taken together, bilirubin has potential protective/ameliorative effects on DKD progression, especially through alleviating the renal ER stress and inflammatory responses in T2D rats with injured kidneys. In this era, clinical benefits of mild hyperbilirubinemia can be considered in human DKD.

High IgG4 serum concentration is associated with active Graves orbitopathy

BACKGROUND

The aim of the study was to evaluate the differences in clinical profile, laboratory parameters, and ophthalmological signs, and symptoms between patients with high IgG4 Graves orbitopathy and patients with normal IgG4 Graves orbitopathy.

METHODS

This was a prospective observational study. We recruited adult patients with Graves Orbitopathy(GO) referred to our clinic for further diagnostics and treatment. Eventually, 60 patients with GO were enrolled in the study. All patients underwent ophthalmological assessment, magnetic resonance imaging (MRI) of the orbits, and laboratory tests, including IgG4 serum concentration measurement. High IgG4 GO was diagnosed if the IgG4 concentration exceeded 135 mg/dl. We used both the clinical activity score (CAS) and magnetic resonance imaging (MRI) to assess the activity of GO. Eventually, active GO was defined according to MRI results.

RESULTS

Among 60 GO patients, 15 (25%) patients had elevated IgG4 levels. Patients in the high IgG4 group had a higher prevalence of active GO by MRI than patients with normal IgG4 (100% vs. 64.44%, P=0.006). They also had a higher eosinophile count in peripheral blood, a lower bilirubin level, a more frequent lower eyelid retraction, and a lower prevalence of glaucoma. There were no statistically significant differences between the groups in CAS. Patients with active GO, had higher median IgG4 level [89.95 (55.48; 171.1) vs 43.45 (32.48; 49.68) mg/dl, P<0.001]. The receiver operating characteristic (ROC) analysis for IgG4 as a marker of active GO revealed the following results: AUC 0.848 for the cut-off value of 54.2 mg/dl, sensitivity 79.5%, specificity 87.5%, positive predictive value 94.6%, negative predictive value 59.1%.

CONCLUSIONS

We demonstrated that IgG4 is a marker of GO activity. Certain differences in the clinical profile of patients with high IgG4 GO, and normal IgG4 GO were observed. More data is needed to establish whether patients with high IgG4 GO are GO patients with particularly active disease or actually represent a distinct clinical entity related to IgG4-Related Disease.

Role of bilirubin in the prognosis of coronary artery disease and its relationship with cardiovascular risk factors: a meta-analysis

Background

Bilirubin is a heme catabolism product with antioxidant, anti-inflammatory, and anti-apoptotic properties and is implicated in the prognosis of several diseases. This study evaluates the prognostic role of bilirubin in coronary artery disease (CAD) patients.

Methods

After identifying studies from the literature, meta-analyses were performed to achieve a) overall estimates of serum total bilirubin levels in patients with myocardial infarction (MI), non-MI CAD and healthy individuals; b) odds ratios (OR) of adverse outcomes between higher and lower total bilirubin levels; c) standardized mean difference (SMD) in total bilirubin levels in patients with high vs low CAD severity; and d) correlation between disease severity and total bilirubin. Metaregression analyses were performed to examine the relationship between cardiovascular risk factors and increasing quantiles of total bilirubin levels.

Results

Forty-three studies were identified. Pooled serum total bilirubin levels were 0.72 mg/dl [95% confidence interval (CI): 0.60, 0.83] in MI patients; 0.65 mg/dl [95% CI: 0.60, 0.69] in non-MI CAD patients; and 0.66 mg/dl [95% CI: 0.56, 0.75] in healthy individuals. Higher total bilirubin levels were associated with greater odds of adverse outcomes in MI patients (OR: 1.08 [95% CI: 0.99, 1.18]) but lower odds in non-MI CAD patients (OR: 0.80 [95%CI: 0.73, 0.88]). Compared to non-severe cases, total bilirubin levels were higher in patients with severe MI (SMD 0.96 [95% CI: − 0.10, 2.01]; p = 0.074) but were lower in severe non-MI CAD patients (SMD − 0.30 [95%CI: − 0.56, − 0.03]; p = 0.02). Total bilirubin levels correlated positively with MI severity (r = 0.41 [95% CI: 0.24, 0.59]; p < 0.01) but correlated negatively with non-MI CAD severity (r =  − 0.17 [95% CI: − 0.48, 0.14]; p = 0.28). Female sex was inversely associated with increasing quantiles of bilirubin (meta-regression coefficient: − 8.164 [− 14.531, − 1.769]; p = 0.016) in MI patients.

Conclusion

Prognostic role of bilirubin for CAD appears complicated, as different odds are observed for MI and non-MI CAD patients which weakens the case of causal involvement of bilirubin in CAD etiology or prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02899-w.

Association of Plasma Bilirubin Levels With Peripheral Arterial Disease in Chinese Hypertensive Patients: New Insight on Sex Differences

Background and aims: Previous studies have indicated that Plasma total bilirubin (TBiL) might play an essential role in peripheral arterial disease (PAD). However, the effects of different levels of TBiL on PAD development remain uncertain. We aimed to examine the TBiL and the prevalence of PAD among Chinese adults with hypertension, with particular attention paid to sex differences.

Methods: A total of 10,900 hypertensive subjects were included in the current study. The mean age of our study participants was 63.86 ± 9.25 years, and there were 5,129 males and 5,771 females. The outcome was peripheral arterial disease (PAD), defined as present when the ankle-brachial index (ABI) of either side was ≤0.90. The association between TBiL and PAD was examined using multivariate logistic regression analysis and the restricted cubic spline.

Results: Of 10,900 hypertensive participants, 350 (3.21%) had PAD, and the mean plasma total bilirubin was 14.66 (6.86) μmol/L. The mean TBiL was 15.67 μmol/L in men and 13.76 μmol/L in women. The smoothing curve showed that a U-shaped curve association existed between TBiL and the prevalence of PAD in Chinese adults with hypertension. When stratified by sex, TBiL was significantly U-shaped associated with PAD among men but not women. Among males, the inflection point was 11.48 μmol/L; to the left inflection point, the effect size and 95% CI were 0.08, 0.01, 0.66, respectively; to the right inflection point, OR, 5.16; 95% CI,1.64, 16.25.

Conclusions: We found an independent U-shaped association between TBiL and the prevalence of PAD among hypertensive subjects and a differential association between men and women. We further revealed a turning point by threshold effect analysis.

Dose-Response Association Between Bilirubin and Cardiovascular Disease: A Systematic Review and Meta-analysis

The association between bilirubin (BIL) and cardiovascular disease (CVD) remains controversial. We performed a meta-analysis of prospective studies to evaluate this association in the general population. We searched PubMed, EMBASE, Web of Science, Cochrane, and Scopus databases through to September 2021. The Newcastle-Ottawa Quality Assessment Scale was used to assess study quality. The pooled effect estimate was calculated by the fixed-effect model or random-effect model. We included 12 prospective studies (368 567 participants). The pooled risk ratio of CVD for the lowest vs highest groups of BIL levels was .75 (95% CI: .58-.97) with high heterogeneity (I² = 87.5%, P < .001). Similar associations were observed for coronary heart disease and stroke. We further performed a "dose-response" meta-analysis, and a significant U-shaped relationship between circulating (most values were serum bilirubin, but a few were plasma bilirubin) BIL and CVD (P < .01) was observed. The lowest risk of CVD events was observed in participants with a BIL of 17-20 µmol/L in serum and/or plasma. In conclusion, there was a U-shaped dose-response relationship between BIL and CVD, especially for men. Further studies are needed to confirm our findings and identify the mechanisms involved as well as any prognostic or therapeutic potential.

Association Between Bilirubin, Atazanavir, and Cardiovascular Disease Events Among People Living With HIV Across the United States

OBJECTIVE

Bilirubin is an antioxidant that may suppress lipid oxidation. Elevated bilirubin is associated with decreased cardiovascular events in HIV-uninfected populations. We examined these associations in people living with HIV (PLWH).

METHODS

Potential myocardial infarctions (MIs) and strokes were centrally adjudicated. We examined MI types: type 1 MI (T1MI) from atherosclerotic plaque instability and type 2 MI (T2MI) in the setting of oxygen demand/supply mismatch such as sepsis. We used multivariable Cox regression analyses to determine associations between total bilirubin levels and outcomes adjusting for traditional and HIV-specific risk factors. To minimize confounding by hepatobiliary disease, we conducted analyses limited to bilirubin values <2.1 mg/dL; among those with fibrosis-4 values <3.25; and among everyone. We repeated analyses stratified by hepatitis C status and time-updated atazanavir use.

RESULTS

Among 25,816 PLWH, there were 392 T1MI and 356 T2MI during follow-up. Adjusted hazard ratios for the association of higher bilirubin levels with T1MI were not significant. Higher bilirubin levels were associated with T2MI. By contrast, among PLWH on atazanavir, higher bilirubin levels were associated with fewer T2MI (hazard ratio 0.56:0.33-1.00). Higher bilirubin levels among those on atazanavir were associated with fewer T1MI combined with ischemic stroke.

LIMITATIONS

Analyses were conducted with total rather than unconjugated bilirubin.

CONCLUSIONS

Among PLWH, higher bilirubin levels were associated with T2MI among some subgroups. However, among those on atazanavir, there was a protective association between bilirubin and T2MI. These findings demonstrate different associations between outcomes and elevated bilirubin due to diverse causes and the importance of distinguishing MI types.

The Relationship Between Serum Bilirubin Levels and Peripheral Arterial Disease and Gender Difference in Patients With Hypertension: BEST Study

We evaluated the relationship between serum bilirubin levels and ankle-brachial index (ABI) to determine whether gender affected the relationship between bilirubin levels and peripheral arterial disease (PAD) in patients with hypertension. A total of 543 patients were included in our studies (78 patients with PAD and 465 without PAD). Peripheral arterial disease was defined as ABI <0.90 for either and/or both sides. Serum bilirubin levels were measured with a vanadate oxidation method by using fasting venous blood samples. Serum total bilirubin (TBiL) and direct bilirubin (DBiL) levels were higher in males compared with females (both P < .05). Total bilirubin and DBiL were significantly lower in the PAD group. After adjustment for cardiovascular risk factors, PAD was independently negatively related to TBiL and DBiL, with odds ratios (OR) 0.914 (95% confidence interval [CI]: 0.845-0.990) and 0.748 (95% CI: 0.572-0.977). In addition, there was a relationship between PAD and bilirubin levels (TBiL-OR = 0.884, 95% CI: 0.792-0.985; DBiL-OR = 0.621; 95% CI: 0.424-0.909) only in males but not in females. Future studies should further evaluate whether interventions that increase serum bilirubin levels will have a particular role in PAD prevention in males.

Serum Albumin, but not Bilirubin, is Associated with Diabetic Chronic Vascular Complications in a Chinese Type 2 Diabetic Population

To identify the factors associated with serum total bilirubin (STB) and determine whether STB is independently associated with diabetic retinopathy (DR) or diabetic kidney disease (DKD), 1,665 Chinese patients with type 2 diabetes (T2DM) (248 outpatients newly diagnosed with T2DM [NDM] and 1,417 inpatients previously diagnosed with T2DM [PDM]) were studied. Clinical and biochemical information was collected, and a single nucleotide polymorphism (rs6704078) of the UGT1A1 gene was genotyped in 1,059 individuals. Multiple linear regression showed that STB was associated with haemoglobin concentration, platelet count, and serum triglyceride concentration in NDM and PDM patients, and with serum albumin, duration of diabetes, and smoking in PDM patients. In patients with PDM, multiple logistic regression revealed that serum albumin was associated with DR (odds ratio [OR] = 0.92, 95% confidence interval [CI]: 0.87-0.96, p = 0.001) and DKD (OR = 0.93, 95% CI: 0.88-0.98, p = 0.005) after adjustment for STB, STB-related factors, and risk factors for DR and DKD. In addition, patients with the T allele of rs6704078 had higher STB (13.2 [10.4-17.9] μmol/L versus 11.8 (9.4-14.8) μmol/L; p < 0.001) and similar risks of DR or DKD to those without the T allele. Thus, serum albumin, but not STB, is associated with DR and DKD.

Biliverdin reductase and bilirubin in hepatic disease

The buildup of fat in the liver (hepatic steatosis) is the first step in a series of incidents that may drive hepatic disease. Obesity is the leading cause of nonalcoholic fatty liver disease (NAFLD), in which hepatic steatosis progresses to liver disease. Chronic alcohol exposure also induces fat accumulation in the liver and shares numerous similarities to obesity-induced NAFLD. Regardless of whether hepatic steatosis is due to obesity or long-term alcohol use, it still may lead to hepatic fibrosis, cirrhosis, or possibly hepatocellular carcinoma. The antioxidant bilirubin and the enzyme that generates it, biliverdin reductase A (BVRA), are components of the heme catabolic pathway that have been shown to reduce hepatic steatosis. This review discusses the roles for bilirubin and BVRA in the prevention of steatosis, their functions in the later stages of liver disease, and their potential therapeutic application.

Is there any relationship between serum levels of total bilirubin and the severity of erectile dysfunction?

OBJECTIVE

Recent studies have shown that atherosclerosis is associated with erectile dysfunction and the serum bilirubin level. In this study, the serum total bilirubin levels of patients with erectile dysfunction were measured to investigate the relationship between the levels of erectile dysfunction and total bilirubin.

METHODS

A total of 94 patients with erectile dysfunction were divided into three groups; severe erectile dysfunction (33 patients), moderate erectile dysfunction (31 patients), and mild erectile dysfunction (30 patients). In addition, a control group was formed with 31 healthy men. The International Index of Erectile Function-5 Questionnaire was used to measure the quality of erection in all the groups. The body mass index was calculated for all the participants. The serum glucose, low-density lipoprotein and high-density lipoprotein, cholesterol, triglyceride, total bilirubin, and total testosterone levels were also determined.

RESULTS

No statistically significant difference was observed between the groups in terms of the mean age, hypertension, smoking status, alcohol use, cardiovascular diseases, hepatobiliary disease, diabetes mellitus, and levels of total testosterone, low-density lipoprotein-cholesterol, and triglyceride. However, high-density lipoprotein, body mass index, and total bilirubin were significantly lower compared to the control group (p < 0.001). The serum total bilirubin level was found to be 0.41 ± 0.21 ng/dL in the severe erectile dysfunction, 0.43 ± 0.19 ng/dL in the moderate erectile dysfunction, and 0.48 ± 0.11 ng/dL in the mild erectile dysfunction groups (p < 0.001).

CONCLUSION

Considering the significant differences between the erectile dysfunction and control groups in terms of serum total bilirubin levels, a low level of bilirubin may have a role in the etiology of erectile dysfunction.

Relationship between serum bilirubin levels and cardiovascular disease

We tested the hypothesis that higher levels of bilirubin, a bile pigment with antioxidant properties, are associated with a decreased risk of cardiovascular disease (CVD). This study analyzed data from the Korean Health and Genome Study to examine the association between serum total bilirubin (TB) on CVD and CVD death. Serum TB was measured in a total of 8,844 subjects (4,196 males and 4,648 females) and evaluated for the development of new onset CVD from 2001 to 2012 (mean 8.1 years of follow-up). During the follow-up period, 689 cases of incident CVD (7.8%) were identified, and the prevalence of metabolic syndrome (MetS) at baseline was 26.1%. The prevalence of MetS decreased across bilirubin tertile categories. In addition to MetS itself, individual components of MetS significantly decreased with increased bilirubin tertiles. Moreover, the incidence of CVD decreased across bilirubin tertile categories. The hazard ratios (HRs) for developing coronary heart disease (CHD, HR 0.769, 95% CI 0.655–1.000) and CVD death (HR 0.513, 95% CI 0.267–0.985) was significantly lower in the highest tertile group (> 0.63 mg/dL) in comparison to the lowest tertile group (< 0.44 mg/dL) after adjusting for all confounding variables. In the present longitudinal study, a significant negative relationship was demonstrated between baseline bilirubin levels and incident CHD and CVD death.

Direct, indirect and total bilirubin and risk of incident coronary heart disease in the Dongfeng-Tongji cohort

BACKGROUND

Total bilirubin (TBIL) is known to be inversely associated with coronary heart disease (CHD) risk, however, whether this association is dose-response remains inconsistent and it is unclear which subtype of bilirubin is responsible for the potential protective effect.

METHODS

We included 12,097 participants who were free of CHD, stroke, cancer and potential liver, biliary and renal diseases at baseline from September 2008 to June 2010 and were followed-up until October 2013. Cox proportional hazards models were used to assess the hazard ratios (HR) and 95% confidence interval (95% CI) of bilirubin with incident CHD risk.

RESULTS

The adjusted HRs for incident CHD increased with increasing direct bilirubin (DBIL) (p for trend = .013). Participants within the highest quintile of DBIL had 30% higher risk of incident CHD compared to those in the lowest quintile (95% CI: 1.07, 1.58). In contrast, compared with subjects in the lowest quintile of TBIL, those in the third quintile had the lowest of 24% risk for CHD incidence (95% CI: 0.63, 0.92), which showed a U-shaped association (p for quadratic trend = .040).

CONCLUSIONS

DBIL was associated with a dose-response increased risk for CHD incidence. However, a U-shaped association existed between TBIL, indirect bilirubin and incident CHD risk. Key messages Direct bilirubin is independently associated with incident coronary heart disease (CHD) in a dose-response manner. A similarly consistent U-shaped association was found between total bilirubin, indirect bilirubin and incident CHD. The potential protective effect of total bilirubin within the normal range on incident CHD should be mainly attributed to mild-to moderate elevated levels of indirect bilirubin.

The associations between serum biomarkers and stenosis of the coronary arteries

Serum biochemical indices reflect dynamic physiological and pathophysiological processes within the body, the associations between these markers and the number of stenotic coronary arteries have been rarely studied. 627 healthy controls and 1,049 coronary heart disease (CHD) patients were sequentially recruited in our hospital. The association patterns between serum biochemical markers and the numbers of stenotic coronary arteries were evaluated in a cross-sectional manner. Upon binary multiple logistic regression analysis, the risk factor patterns differed by gender. Age, high-density lipoprotein cholesterol (HDL) and homocysteine (HCY) were common risk factors for CHD in both males and females. Upon ordinal multiple logistic regression analysis, age, low-density lipoprotein cholesterol (LDL) and lipoprotein (Lp) (a) increased, and HDL decreased, as the number of stenotic coronary arteries increased in male patients. Age and Lp(a) were positively associated with the number of stenotic coronary arteries and total bilirubin (TBil) was negatively associated with the number of stenotic coronary arteries in female patients. Age and Lp(a) were common risk factors positively associated with the number of stenotic coronary arteries in both male and female patients. HDL and LDL were male-specific risk factors and TBil was a female-specific risk factor for an increasing number of stenotic coronary arteries. In conclusion, serum biomarker levels correlated with the number of stenotic coronary arteries and showed gender different patterns.

Relationship between serum bilirubin concentrations and diabetic nephropathy in Shanghai Han's patients with type 1 diabetes mellitus

Background

Recent studies highlight a negative association between total bilirubin concentrations and albuminuria in patients with type 2 diabetes mellitus. Our study evaluated the relationship between bilirubin concentrations and the prevalence of diabetic nephropathy (DN) in Chinese patients with type 1 diabetes mellitus (T1DM).

Methods

A total of 258 patients with T1DM were recruited and bilirubin concentrations were compared between patients with or without diabetic nephropathy. Multiple stepwise regression analysis was used to examine the relationship between bilirubin concentrations and 24 h urinary microalbumin. Binary logistic regression analysis was performed to assess independent risk factors for diabetic nephropathy. Participants were divided into four groups according to the quartile of total bilirubin concentrations (Q1, 0.20–0.60; Q2, 0.60–0.80; Q3, 0.80–1.00; Q4, 1.00–1.90 mg/dL) and the chi-square test was used to compare the prevalence of DN in patients with T1DM.

Results

The median bilirubin level was 0.56 (interquartile: 0.43–0.68 mg/dL) in the DN group, significantly lower than in the non-DN group (0.70 [interquartile: 0.58–0.89 mg/dL], P < 0.001). Spearman’s correlational analysis showed bilirubin concentrations were inversely correlated with 24 h urinary microalbumin (r = -0.13, P < 0.05) and multiple stepwise regression analysis showed bilirubin concentrations were independently associated with 24 h urinary microalbumin. In logistic regression analysis, bilirubin concentrations were significantly inversely associated with nephropathy. In addition, in stratified analysis, from the first to the fourth quartile group, increased bilirubin concentrations were associated with decreased prevalence of DN from 21.90% to 2.00%.

Conclusion

High bilirubin concentrations are independently and negatively associated with albuminuria and the prevalence of DN in patients with T1DM.

Serum bilirubin concentrations and incident coronary heart disease risk among patients with type 2 diabetes: the Dongfeng-Tongji cohort

AIMS

Elevated serum bilirubin levels are associated with decreased coronary heart disease (CHD) risk in cross-sectional studies among diabetic patients, but prospective evidence is limited. We investigated the relationship of serum bilirubin levels with incident CHD risk among type 2 diabetes patients.

METHODS

In a prospective study of 2918 type 2 diabetes embedded in the Dongfeng-Tongji cohort, serum total bilirubin (TBil), direct bilirubin (DBil), and indirect bilirubin (IBil) were measured at baseline. Cox proportional hazards models were used to examine the association between serum bilirubin levels and CHD risk.

RESULTS

A total of 440 CHD cases were identified during 12,017 person-years of follow-up. Compared with extreme quartiles, the adjusted hazard ratio and 95% confidence interval of incident CHD were 0.74 (0.56-0.99) with P trend = 0.08 in IBil, while in TBil and DBil, the bilirubin-CHD associations were not significant. Moreover, serum TBil and IBil levels were interacted with drinking status on the risk of incident CHD (P interaction = 0.021 and 0.037, respectively), and the associations were evident in ever drinkers. In drinkers, when serum TBil or IBil concentrations increased 1 μmol/L, the CHD risk both decreased 6% (95% CIs 0.89-0.99 and 0.87-1.00, respectively).

CONCLUSIONS

Serum IBil levels were marginally related to decreased incident CHD risk among type 2 diabetes. Drinking could potentially enhance the associations of serum TBil and DBil levels with incident CHD risk.

Increment of serum bilirubin as an independent marker predicting new-onset type 2 diabetes mellitus in a Korean population

BACKGROUND AND AIMS

Several cross-sectional studies reported that serum bilirubin concentrations had an inverse association with type 2 diabetes mellitus (T2DM) prevalence. The aim of the current study was to investigate the relationship between percentage change in bilirubin levels (PCB) and incident risk of T2DM using a longitudinal model.

METHODS AND RESULTS

22,084 participants who received regular health check-ups between 2006 and 2012 were enrolled. Multivariable-adjusted Cox regression models were used to determine the hazard ratio (HR) of incident T2DM based on PCB. PCB was determined by subtracting baseline serum bilirubin level (BB) from the bilirubin level at the end of follow-up or a year before the last date of diagnosis, dividing by BB and multiplying by 100. Compared to non-diabetics, BB was lower in the diabetic group at the initial visit. There were 20,098 participants without T2DM at the initial visit; 1253 new cases occurred during follow-up. As PCB increased, T2DM incidence also increased (P < 0.001). After adjusting for confounders, the HR of incident T2DM in the highest PCB quartile was 2.08 (95% confidence interval [CI] 1.76-2.46). This trend remained significant when PCB was analyzed as a continuous variable (HR for 1-SD increment, 1.25; 95% CI 1.19-1.31). Additional analysis comparing the rate of PCB during the follow-up period revealed that the serum bilirubin level of the Incident T2DM group increased before T2DM development and decreased rapidly thereafter compared to others (P < 0.001).

CONCLUSIONS

Bilirubin level increment over time is associated with T2DM development.

Serum total bilirubin levels are negatively correlated with metabolic syndrome in aged Chinese women: a community-based study

We evaluated serum total bilirubin levels as a predictor for metabolic syndrome (MetS) and investigated the relationship between serum total bilirubin levels and MetS prevalence. This cross-sectional study included 1728 participants over 65 years of age from Eastern China. Anthropometric data, lifestyle information, and previous medical history were collected. We then measured serum levels of fasting blood-glucose, total cholesterol, triglycerides, and total bilirubin, as well as alanine aminotransferase activity. The prevalence of MetS and each of its individual component were calculated per quartile of total bilirubin level. Logistic regression was used to assess the correlation between serum total bilirubin levels and MetS. Total bilirubin level in the women who did not have MetS was significantly higher than in those who had MetS (P<0.001). Serum total bilirubin quartiles were linearly and negatively correlated with MetS prevalence and hypertriglyceridemia (HTG) in females (P<0.005). Logistic regression showed that serum total bilirubin was an independent predictor of MetS for females (OR: 0.910, 95%CI: 0.863-0.960; P=0.001). The present study suggests that physiological levels of serum total bilirubin might be an independent risk factor for aged Chinese women, and the prevalence of MetS and HTG are negatively correlated to serum total bilirubin levels.

Bilirubin in coronary artery disease: Cytotoxic or protective?

Bilirubin has traditionally been considered a cytotoxic waste product. However, recent studies have shown bilirubin to have anti-oxidant, anti-inflammatory, vasodilatory, anti-apoptotic and anti-proliferative functions. These properties potentially confer bilirubin a new role of protection especially in coronary artery disease (CAD), which is a low grade inflammatory process exacerbated by oxidative stress. In fact, recent literature reports an inverse relationship between serum concentration of bilirubin and the presence of CAD. In this article, we review the current literature exploring the association between levels of bilirubin and risk of CAD. We conclude that current evidence is inconclusive regarding the protective effect of bilirubin on CAD. A causal relationship between low serum bilirubin level and increased risk of CAD is not currently established.

Total Bilirubin Levels Predict Subclinical Atherosclerosis in Patients With Prediabetes

Bilirubin may have important antiatherosclerotic effects. Prediabetes (PD), the intermediate stage before diabetes mellitus, is associated with increased cardiovascular morbidity and mortality. We evaluated the relationship between serum bilirubin levels and carotid intima-media thickness (cIMT), as a surrogate marker of subclinical atherosclerosis, in patients with PD. We enrolled 170 consecutive patients with PD. The patients underwent ultrasonography to evaluate cIMT. The patients were divided into groups according to cIMT values (<0.9 vs ≥0.9 mm). The patients with cIMT ≥ 0.9 mm had significantly higher diastolic blood pressure, neutrophil-lymphocyte ratio (NLR), and glycated hemoglobin values compared with patients having cIMT < 0.9 mm, whereas total and direct bilirubin values were significantly lower in this group. Multivariate regression analyses revealed NLR and total bilirubin as the independent predictors of subclinical atherosclerosis. The present study demonstrated that NLR and lower total bilirubin levels were independent predictors of subclinical atherosclerosis in patients with PD. Simple measures such as NRL and total bilirubin may provide predictive information regarding the risk of cardiovascular disease in patients with PD.

Relationship between Cardiovascular Risk Score and Traditional and Nontraditional Cardiometabolic Parameters in Obese Adolescent Girls

Background

Since the cardiovascular (CV) risk score in the young population, children and adolescents, is underestimated, especially in developing countries such as Montenegro, where a strong interaction exists between the genetically conditioned CV risk and environmental factors, the purpose of this study was to estimate CV risk in apparently healthy adolescent girls. Moreover, we aimed to test some new, emerging CV risk factors and their interaction with the traditional ones, such as obesity. Precisely, we aimed to assess the impact of low bilirubin levels, as a routine biochemical parameter, as an additional risk factor for atherosclerotic disease in the adult phase.

Methods

Forty-five obese adolescent girls (mean age 17.8±1.22 years) and forty-five age- and sex-matched normal weight controls, all nonsmokers, were included. Anthropometric and biochemical parameters were measured. Cardiovascular Risk Score (CVRS) was calculated by adding the points for each risk factor (e.g. sex, HDL-c, non-HDL-c, blood pressure and fasting glycemia).

Results

A significant positive relationship between CVRS and ALT, hsCRP and TG/HDL-c, but an opposite relationship between CVRS and total bilirubin were found (P<0.001). Multiple linear regression analysis showed that higher waist circumference (WC) and LDL-c, but lower HDL-c were independent predictors of lower bilirubin values (adjusted R²=0.603, P<0.001).

Conclusions

Obese adolescent girls are at an increased risk of cardiovascular disease late in life. In addition to the traditional risk factors, total bilirubin may have the potential to discriminate between low and higher risk for cardiovascular disturbances in healthy adolescent girls.

Coronary Artery Disease in Patients With Disorders of Bilirubin Excretion

We aimed to determine the predictors of coronary artery disease (CAD) in patients with abnormal bilirubin excretion, that is, Gilbert syndrome, Crigler-Najjar syndrome, Dubin-Johnson syndrome, and Rotor syndrome. We analyzed data from the Healthcare Cost and Utilization Project (HCUP) of the Agency for Healthcare Research and Quality, Rockville, MD for the period 2009 to 2010. All patients ≥18 years of age with a primary diagnosis of "disorders of bilirubin excretion" [International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9CM) code 277.4] were included in the study. Primary outcome was to determine predictors of CAD in adult patients diagnosed with abnormal bilirubin excretion. We identified a total of 12,423 adult patients with bilirubin excretion disorder hospitalized during 2009-2010 (0.03% of all inpatient admissions). CAD was seen in 18% of patients, with a higher prevalence in men (21% in men vs. 13% in women, P < 0.0001). In multivariate logistic regression adjusted for demographic and traditional risk factors, hypertension [odds ratio (OR): 1.74; 95% confidence interval (CI), 1.33-2.27, P < 0.001], hyperlipidemia (OR: 2.49; 95% CI, 1.95-3.18, P < 0.001), diabetes (OR: 1.46; 95% CI, 1.12-1.91, P = 0.01), and age (OR: 1.05; 95% CI, 1.04-1.06, P < 0.001) were found to be independent predictors of CAD in adult patients with abnormal bilirubin excretion. Female sex (OR: 0.49; 95% CI, 0.36-0.65, P < 0.001) demonstrated an inverse association in predicting CAD. There was increased prevalence of CAD in our patient population with increased prevalence of cardiovascular risk factors. Age, diabetes mellitus, hypertension, and hyperlipidemia were found to be independent predictors of CAD.

Relationship between Serum Bilirubin and Left Ventricular Hypertrophy in Patients with Essential Hypertension

Background

Prospective studies have found low bilirubin levels were an important predictive factor of cardiovascular events. However, few have yet investigated possible association between serum bilirubin level and LVH in essential hypertension. The aim of the present study was to evaluate the relationship between serum bilirubin levels with LVH in newly diagnosed hypertension patients.

Methods

The present study evaluated the relationship between serum total bilirubin level and left ventricle hypertrophy (LVH) in newly diagnosed hypertensive patients with a sample size of 344. We divided subjects into LVH group (n=138) and non-LVH group (n=206). Physical examination, laboratory tests and echocardiography were conducted. The multivariate logistic regression model was used to verify the independent association between RDW and LVH.

Results

Our results found that patients with LVH had lower bilirubin levels than non-LVH ones. Stepwise multiple linear regression analysis showed total bilirubin level (B=-0.017, P=0.008) was negatively associated with left ventricle mass index (LVMI) even adjusting for some confounders. The multiples logistic regression found total bilirubin level was independently related with of LVH, as a protective factors (OR=0.91, P=0.010).

Conclusion

As a routine and quick laboratory examination index, serum bilirubin may be treated as novel marker for evaluating LVH risk in hypertensive patients. Cohort study with larger sample size are needed.