Are total bilirubin and high-sensitivity C-reactive protein independently associated with Type 2 diabetes mellitus in postmenopausal women?

Background

Various studies have reported contradictory results regarding the relationship of total bilirubin and high-sensitivity C-reactive protein levels (hsCRP) with diabetes mellitus Type 2 (DM2). Therefore, we aimed to examine which one of them could be more convenient for the estimation of DM2 risk in postmenopausal women.

Materials and Methods

A total of 150 healthy postmenopausal women (mean age 57[53-60] years) and 79 postmenopausal women with DM2 (mean age 66 [61-71] years) were enrolled in cross-sectional study. Examinees were recruited consecutively in the study during their regular check-up visit in the Primary Health Care Center in Podgorica, Montenegro, in a period from October 2012 to May 2016. Anthropometric measurements, biochemical parameters, and blood pressure were obtained. Multivariable logistic regression analysis was used to find the independent predictors for DM2 development in postmenopausal women.

Results

Age, waist circumference, and total bilirubin were the independent predictors for DM2 development in postmenopausal women (odds ratio [OR] =1.224, 95% confidence interval [CI] [1.117-1.341], P < 0.001; OR = 1.137, [95% CI = 1.036-1.215], P < 0.001, and OR = 0.727, [95% CI = 0.611-0.866], P < 0.001, respectively), whereas hsCRP lost its independent predictive role (OR = 1.155, [95% CI = 0.854-1.560], P = 0.349).

Conclusion

Unlike hsCRP, total bilirubin independently correlated with DM2 in postmenopausal women.

Association of circulating total bilirubin with the metabolic syndrome and type 2 diabetes: A systematic review and meta-analysis of observational evidence

OBJECTIVE

Emerging evidence suggests that bilirubin levels might be associated with the metabolic syndrome (MetS) and type 2 diabetes (T2D), although the nature of the association remains unclear.

DESIGN

This systematic review and meta-analysis investigated the relationship between total plasma bilirubin and the risk of MetS and T2D.

DATA SOURCES

Relevant studies were identified using five databases (Embase, Medline [Ovid], Web of Science, PubMed, Cochrane Central and Google Scholar), with the last search done on 21 October 2015. Study references were checked and authors contacted to identify additional studies.

STUDY SELECTION

Randomized controlled trials, and cohort, case-control and cross-sectional studies of adults examining the association between blood bilirubin levels and MetS and T2D were included, irrespective of language and date of publication. Abstract and full-text selection was done by two independent reviewers, with a third reviewer available in case of disagreement.

DATA EXTRACTION

Data were extracted by two independent reviewers using a predesigned data collection form.

MAIN OUTCOMES AND MEASURES

MetS and T2D.

METHODS

Summary estimates were obtained by random-effects meta-analysis.

RESULTS

Of the 2313 searched references, 16 observational studies (11 cross-sectional, two prospective, one that was both cross-sectional and prospective, two retrospective and one national survey) met our inclusion criteria. Overall, data were available for 175,911 non-overlapping participants, including 7414 MetS cases and 9406 T2D cases. In the meta-analysis of seven cross-sectional studies, the pooled odds ratio (95% confidence interval) for MetS in a comparison of extreme tertiles of serum bilirubin levels was 0.70 (95% CI: 0.62, 0.78), whereas no significant association was found for the pooled estimated relative risk between two prospective studies (0.57, 95% CI: 0.11, 2.94). The corresponding estimate was 0.77 (95% CI: 0.67, 0.87) for T2D from four cross-sectional studies.

CONCLUSION

The available evidence, mainly from cross-sectional studies, supports an inverse association of bilirubin levels with adverse metabolic outcomes. Large-scale prospective studies are now needed to establish whether bilirubin levels may be useful in the prevention of MetS and T2D.

Clinical significance of serum bilirubin and gamma-glutamyltransferase levels on coronary atherosclerosis assessed by multidetector computed tomography

BACKGROUND AND AIMS

Low bilirubin and high gamma-glutamyltransferase (GGT), which are endogenous markers of oxidative stress, confer a higher risk of cardiovascular disease (CVD). We investigated associations between serum concentrations of bilirubin, GGT and coronary atherosclerosis.

METHODS AND RESULTS

A cross-sectional analysis was performed on 1520 subjects who underwent multidetector computed tomography scans. Coronary atherosclerosis was assessed by coronary artery calcium score (CACS) and obstructive coronary artery disease (OCAD), was defined as the presence of coronary artery stenosis of ≥50%. Total bilirubin (TB) level was negatively correlated with CACS and coronary stenosis whereas GGT level was positively correlated with CACS in men. However, there was no correlation between TB, GGT levels and either CACS or coronary artery stenosis in women. In a multivariate-adjusted model, TB level was inversely associated with a CACS > 100 [odds ratio (OR) per log standard deviation (SD), 0.67; 95% confidence interval (CI), 0.52-0.87], and OCAD (OR per log SD, 0.77; 95% CI, 0.62-0.95) in men. By contrast, GGT level was positively associated with a CACS > 100 (OR per log SD, 1.35; 95% CI, 1.05-1.73) but not with OCAD. Adding TB and GGT to the conventional risk factors increased predictive accuracy for CACS > 100 (net reclassification improvement index [NRI] = 13.1%, P = 0.026; integrated discrimination index [IDI] = 0.024, P = 0.001) and for OCAD (NRI = 12.6%, P = 0.026; IDI = 0.010, P = 0.013).

CONCLUSIONS

Low TB and high GGT levels were concomitantly associated with coronary atherosclerosis in Korean men. Future studies are needed to elucidate the causal associations of TB and GGT with CVD.

Effect of exercise training and isoflavones on hepatic steatosis in overweight postmenopausal women

OBJECTIVES

Postmenopausal women are particularly inclined to an increased risk of developing non-alcoholic hepatic steatosis. The purpose of this study was to investigate whether adding isoflavone supplementation to exercise training could reduce the risk.

METHODS

In a 6-month, double-blind, randomized, controlled trial, 54 healthy overweight-to-obese (body mass index 28-40 kg/m2) postmenopausal women were randomly assigned to one of the following groups: (1) exercise and isoflavones (Ex-Iso; n = 26), (2) exercise and placebo (Ex-Pla; n = 28). Exercise training consisted of three weekly sessions of mixed training. We examined the plasma level of specific hepatic enzymes (alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase, and alkaline phosphatase) as a reflection of fatty liver along with the calculation of the fatty liver index. All measures were obtained at baseline and after the 6-month intervention.

RESULTS

Following the intervention, a lower fatty liver index (p <0.01; 29% in Ex-Iso, 18% in Ex-Pla) and plasma γ-glutamyltransferase (p <0.01; 22% in Ex-Iso, 16% in Ex-Pla) were observed in both groups, with a higher reduction in the Ex-Iso group. On the other hand, for all other hepatic enzymes, there was no change.

CONCLUSIONS

Our results show that exercise training appears to bring favorable changes in the plasma level of hepatic enzymes, possibly due to the lowering of liver fat content. While postmenopausal women can benefit from this intervention to decrease the risk of developing non-alcoholic hepatic steatosis, it seems that the addition of isoflavones to exercise training provides some additional effects to those provided by exercise alone.

Effect of different doses of aerobic exercise training on total bilirubin levels

Low serum bilirubin levels have been associated with increased risk for cardiovascular disease, and recent data suggest that lower body fat and reductions in weight are associated with higher bilirubin levels. However, it is unknown if exercise training can increase bilirubin levels and whether a higher dose of exercise will further increase bilirubin levels compared with a lower dose.

PURPOSE

The primary aim of our current report was to examine whether exercise dose affects bilirubin levels in obese postmenopausal women from the Dose-Response to Exercise in Women trial. In addition, we evaluated whether changes in fitness, insulin sensitivity, and waist circumference associated with exercise training were associated with change in bilirubin levels.

METHODS

Participants (n = 419) were randomized to the control group or to 4, 8, and 12 kcal·kg⁻¹·wk⁻¹ (KKW) of exercise training at an intensity of 50% of aerobic capacity. Total bilirubin levels were evaluated at baseline and at follow-up.

RESULTS

Exercise training significantly increased serum bilirubin levels only in the 12-KKW group (0.044 mg·dL⁻¹, P = 0.026) compared with the control group (0.004 mg·dL⁻¹). Subgroup analyses showed that there was a significant increase in bilirubin levels in participants in the 12-KKW group (0.076 mg·dL⁻¹) who were classified as insulin resistant (homeostatic model assessment for insulin resistance score > 2.6) compared with insulin-resistant control participants (0.018 mg·dL⁻¹, P = 0.028).

CONCLUSIONS

Our findings suggest that high doses of exercise training are necessary to significantly increase bilirubin levels in previously sedentary postmenopausal women and especially those with impaired glucose metabolism.