GlycA Levels Independently Predict Coronary Artery Calcium Incidence and Progression in the ELSA-Brasil Cohort (Brazilian Longitudinal Study of Adult Health).

Atherosclerosis is an inflammatory disease. Coronary artery calcium (CAC) is a marker of atherosclerotic disease events and mortality risk. Increased GlycA, an emerging marker of inflammation, is associated with a higher risk for coronary artery disease (CAD). However, there is conflicting evidence on whether GlycA predicts subclinical CAD progression. We hypothesized that GlycA can predict subclinical CAC incidence/progression in healthy participants. We included 2,690 ELSA-Brasil cohort participants without cardiovascular/chronic inflammatory disease not receiving statin therapy who had GlycA levels measured and 2 interval CAC assessments between 2010 and 2018. Multivariable logistic and linear regression models were computed to evaluate GlycA as a predictor of CAC incidence and progression. CAC incidence required a baseline CAC of 0. CAC progression required a baseline CAC >0. The mean age of participants was 48.6 ± 7.7 years, 56.7% were women, and 54.6% and 16.1% (429 of 2,690) were White and Black, respectively. The mean CAC interscan period was 5.1 ± 0.9 years, the mean GlycA level was 414.7 ± 65 µmol/L, and the incidence of CAC was 13.1% (280 of 2,129). The GlycA level odds ratio for CAC incidence was 1.002 (95% confidence interval 1.0005 to 1.005, p = 0.016), adjusted for demographics, lifestyle, a family history of early CAD (≤60 years), lipids, and co-morbidities. The GlycA (≤p25 vs ≥p75) odds ratio for CAC progression (Berry definition) was 1.77 (95% confidence interval 1.07 to 2.96, p = 0.03) in a similar multivariable-adjusted model. Higher GlycA levels were associated with CAC incidence and progression in a healthy Brazilian cohort.

GlycA as a Novel Biomarker of Systemic Inflammation in Hypothyroidism.

Background: GlycA is a novel glycoprotein biomarker of systemic inflammation and cardiovascular risk. Our objective was to assess the levels of GlycA in individuals with hypothyroidism. We also explored whether levothyroxine (LT4)-treated patients had different levels of GlycA, with attention to thyrotropin (TSH) levels. Methods: We performed a cross-sectional analysis, using baseline data from the ELSA-Brasil cohort study. We included only participants with serum TSH and GlycA levels measurements, using magnetic resonance spectroscopy (n = 4745). We excluded individuals with endogenous hyperthyroidism and those using drugs impacting thyroid function. Participants not taking LT4 and whose serum TSH was 0.4-4.0 mIU/L were classified as euthyroid (EU) and those with elevated TSH as undiagnosed hypothyroidism (UH). For those on LT4 (n = 345), adequacy of treatment was defined as TSH within the reference range. Those with TSH <0.4 mIU/L were considered over-treated (OT), and those >4.0 mIU/L, under-treated (UT). Both (UT+OT) were considered inadequately treated (IT). Group comparisons were performed by Kruskal-Wallis, adjusted Chi-square, and the post hoc Dunn test. Additional subgroup analysis were performed in patients with circulating thyroperoxidase antibodies (TPO-Ab+). Respective multivariable analyses were performed to evaluate the relationship between thyroid-related variables and GlycA levels (Generalized Linear Model), as well as an abnormal GlycA (>400 µmol/L; Logistic Binary Regression). Results: The prevalence rate of UH was 9.8% (467/4745) and, among those on LT4, only 61.7% (213/345) were adequately treated (AT). GlycA levels were higher in IT in comparison to EU (429 vs. 410 µmol/L, p < 0.01) but did not differ between UH (413 µmol/L) and euthyroidism. However, the subgroup analysis of those TPO-Ab+ showed that not only those with IT, but also those with UH, had higher levels of GlycA in comparison to euthyroidism (423 and 424 vs. 402 µmol/L, p = 0.04). This association between higher levels of GlycA and IT was maintained even in multivariable analysis (odds ratio 1.53, confidence interval 1.03 to 2.31) Lower levels of GlycA were detected in AT (405 µmol/L,) compared with OT (432 µmol/L, 0.04) and UT (423 µmol/L, p = 0.02). Conclusions: Patients with IT, both OT and UT, had higher GlycA levels, which may be associated with low-grade systemic inflammation and, possibly, increased cardiovascular risk.

Combined Association of Novel and Traditional Inflammatory Biomarkers With Carotid Artery Plaque: GlycA Versus C-Reactive Protein (ELSA-Brasil).

Elevated levels of glycoprotein acetylation (GlycA) and C-reactive protein (CRP) have been associated with carotid artery plaque (CAP). However, it is not yet established if elevations in both inflammatory biomarkers provide incremental association with CAP. This study aimed evaluate the cross-sectional association of high CRP and GlycA with CAP at baseline participants from the ELSA-Brasil adult cohort. Participants with information on CRP, GlycA, and CAP with neither previous cardiovascular disease nor CRP >10 mg/L were included. High GlycA and CRP were defined as values within upper quintile and >3 mg/L, respectively. Participants were classified into 4 groups: 1. nonelevated CRP/GlycA (reference group); 2. elevated CRP alone; 3. elevated GlycA alone; and 4. both elevated. The analysis included 4,126 participants with median age of 50 years-old, being 54.2% of women. Prevalence of CAP was 36.1%. Participants with high CRP had the highest frequency of obesity, whereas participants with high GlycA presented higher cardiovascular risk factor burden and were more likely to have CAP than the reference group (odds ratio [OR] 1.39, 95% confidence interval [CI] 1.11 to 1.73), persisting after multivariable adjustment (OR 1.37, 95% CI 1.02 to 1.83). Participants with both elevated CRP and GlycA were more likely to have CAP in crude (OR 1.35, 95% CI 1.10 to 1.65) but not in adjusted models. The findings suggest potential different biologic pathways between inflammation and carotid atherosclerosis: high GlycA was associated with CAP whereas high CRP was more associated with obesity.

The association between triglyceride-rich lipoproteins, circulating leukocytes, and low-grade inflammation: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Experimental studies have linked triglyceride-rich lipoproteins (TRLs) to inflammation, but the extent of this phenomenon in vivo has not been completely elucidated. OBJECTIVE: We investigated the association between TRL subparticles and inflammatory markers (circulating leukocytes, plasma high-sensitivity C-reactive protein [hs-CRP], and GlycA) in the general population. METHODS: This was a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). TRLs (number of particles per unit volume) and GlycA were measured by nuclear magnetic resonance spectroscopy. The association between TRLs and inflammatory markers was determined by multiple linear regression models adjusted for demographic data, metabolic conditions, and lifestyle factors. Standardized regression coefficients (beta) with 95% confidence intervals are reported. RESULTS: The study population comprised 4,001 individuals (54% females, age 50 ± 9 years). TRLs, especially medium and large subparticles, were associated with GlycA (beta 0.202 [0.168, 0.235], p<0.001 for total TRLs). There was no association between TRLs and hs-CRP (beta 0.022 [-0.011, 0.056], p = 0.190). Medium, large, and very large TRLs were associated with leukocytes, with stronger connections with neutrophils and lymphocytes than monocytes. When TRL subclasses were analyzed as the proportion of the total pool of TRL particles, medium and large TRLs were positively related to leukocytes and GlycA, whereas smaller particles were inversely associated. CONCLUSIONS: There are different patterns of association between TRL subparticles and inflammatory markers. The findings support the hypothesis that TRLs (especially medium and larger subparticles) may induce a low-grade inflammatory environment that involves leukocyte activation and is captured by GlycA, but not hs-CRP.

Substantially elevated TSH, not traditional clinical subclinical thyroid disorder groupings, are associated with smaller LDL-P mean size: ELSA-Brasil.

BACKGROUND: LDL appears to drive atherogenesis in overt hypothyroidism, but in subclinical dysfunction, its role is not completely elucidated. OBJECTIVE: The aim of this study was to evaluate subfractions of LDL in subclinical (SC) thyroid disorders. METHODS: Individuals were divided into three groups by baseline thyroid function (SC hypothyroidism, euthyroidism, and SC hyperthyroidism). LDL particle (LDL-P) subfractions were analyzed by Nuclear Magnetic Resonance (NMR) spectroscopy. The association between LDL-P subfractions and thyroid groups and quintiles was evaluated by linear regression models. RESULTS: We evaluated 3304 participants (54.1% women, 51.2% white, mean age 50.6 ± 8.7 years). In the univariate analysis, small LDL particle concentrations (SLDL-P) were not different between SC hypo- and hyperthyroidism compared to euthyroid individuals (p = 0.485 and p = 0.314, respectively). Large LDL-P (LDL-P) levels also did not differ in SC hyperthyroidism and SC hypothyroidism compared to euthyroidism (p = 0.698 and 0.788 respectively). Intermediate LDL-P levels were not different across the groups. These numbers did not materially change in multivariate analysis. However, we also analyzed LDL subfractions according to quintiles of TSH. We showed that in the higher TSH quintile LDL subfractions presented a significantly smaller mean size of LDL subfractions compared to the first quintile. CONCLUSIONS: SC thyroid disorders are not associated with significant changes in LDL-P subfractions measured by NMR spectroscopy. However, it seems that the LDL mean size decreases as TSH levels increase, which may represent a more atherogenic lipid profile.

Branched-chain amino acids predict incident diabetes in the Brazilian Longitudinal Study of Adult Health - ELSA-Brasil.

AIMS: To evaluate the role of branch chain amino acid (BCAA) concentrations as a predictor for incident type 2 diabetes (DM). METHODS: Participants from ELSA-Brasil without diabetes at baseline and followed for 3.9 ± 0.6 years were included in the analysis. The determinations of BCAA (valine, leucine, isoleucine) were performed by proton nuclear magnetic resonance spectroscopy. Cardiometabolic profile and incidence of DM were evaluated according to quartiles of BCAA at baseline, stratified by sex. RESULTS: From 3,828 participants (56% female, 50.5 ± 8.7 years) 299 (8.5%) were diagnosed with DM. For both sexes, a worsening of cardiometabolic profile was observed across increasing BCAA quartiles. In survival analysis, incidence rates of DM for the entire period were highest in participants in the third and fourth quartile of BCAA (log Rank analysis < 0.001 for both sexes). In Cox regression analysis, for men, the HR (95%CI) for risk of DM was 2.24 (1.24-4.03) for those from the fourth quartile of BCAA, while in women it was 1.94 (1.07-3.50), comparing to first quartile of BCAA after adjustments for age, BMI, physical activity, family history of DM, pre-diabetes, blood pressure, total cholesterol and HOMA-IR. CONCLUSIONS: Higher levels of BCAA were independently predictors of DM.

Increased particle size of triacylglycerol-enriched remnant lipoproteins, but not their plasma concentration or lipid content, augments risk prediction of incident type 2 diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes prevention requires the accurate identification of those at high risk. Beyond the association of fasting serum triacylglycerols with diabetes, triacylglycerol-enriched remnant lipoproteins (TRLs) more accurately reflect pathophysiological changes that underlie progression to diabetes, such as hepatic insulin resistance, pancreatic steatosis and systemic inflammation. We hypothesised that TRL-related factors could improve risk prediction for incident diabetes. METHODS: We included individuals from the Brazilian Longitudinal Study of Adult Health cohort. We trained a logistic regression model for the risk of incident diabetes in 80% of the cohort using tenfold cross-validation, and tested the model in the remaining 20% of the cohort (test set). Variables included medical history and traits of the metabolic syndrome, followed by TRL-related measurements (plasma concentration, TRL particle diameter, cholesterol and triacylglycerol content). TRL features were measured using NMR spectroscopy. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). RESULTS: Among 4463 at-risk individuals, there were 366 new cases of diabetes after a mean (±SD) of 3.7 (±0.63) years of follow-up. We derived an 18-variable model with a global AUROC of 0.846 (95% CI: 0.829, 0.869). Overall TRL-related markers were not associated with diabetes. However, TRL particle diameter increased the AUROC, particularly in individuals with HbA1c <39 mmol/mol (5.7%) (hold-out test set [n = 659]; training-validation set [n = 2638]), but not in individuals with baseline HbA1c 39-46 mmol/mol (5.7-6.4%) (hold-out test set [n = 233]; training-validation set [n = 933]). In the subgroup with baseline HbA1c <39 mmol/mol (5.7%), AUROC in the test set increased from 0.717 (95% CI 0.603, 0.818) to 0.794 (95% CI 0.731, 0.862), and AUPRC in the test set rose from 0.582 to 0.701 when using the baseline model and the baseline model plus TRL particle diameter, respectively. TRL particle diameter was highly correlated with obesity, insulin resistance and inflammation in those with impaired fasting glucose at baseline, but less so in those with HbA1c <39 mmol/mol (5.7%). CONCLUSIONS/INTERPRETATION: TRL particle diameter improves the prediction of diabetes, but only in individuals with HbA1c <39 mmol/mol (5.7%) at baseline. These data support TRL particle diameter as a risk factor that is changed early in the course of the pathophysiological processes that lead to the development of type 2 diabetes, even before glucose abnormalities are established. Graphical abstract.

Unfavorable Triglyceride-rich Particle Profile in Subclinical Thyroid Disease: A Cross-sectional Analysis of ELSA-Brasil.

Subclinical thyroid disorders have been associated with atherosclerosis and increased cardiovascular risk. As triglyceride-rich lipoprotein particles (TRLPs) have recently emerged as a casual factor for atherogenesis, the aim of this study was to evaluate the relationship between subclinical hypo- and hyperthyroidism and TRLP subfractions. We selected 5066 participants from the ELSA-Brasil cohort with available data of thyroid function and lipid profile measured by nuclear magnetic resonance (NMR) spectroscopy. Individuals were divided into 3 groups by baseline thyroid function (subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism). Triglyceride-rich lipoprotein particle subfractions were analyzed through NMR spectroscopy. To examine the association between TRLP subfractions and thyroid function, we conducted univariate and multivariate linear regression models adjusted for demographic characteristics, body mass index, diabetes, smoking status, and alcohol use. Of 3304 individuals, 54% were women, with a mean age of 50.6 ± 8.7 years, 51% white, and 53% with at least a college education. Of these individuals, 92% were euthyroid, whereas 6.8% had subclinical hypothyroidism and 1.2% had subclinical hyperthyroidism. The univariate linear regression showed that very small TRLPs (P = 0.026) and very large TRLPs (P = 0.008) were statistically increased in subclinical hypothyroidism when compared with euthyroidism. In subclinical hyperthyroidism, there was a reduction in total TRLPs (P = 0.003), seemingly driven by reduced very small TRLPs (P = 0.067). The findings were confirmed when adjusted for demographic characteristics, as well as comorbidities. This study suggests that subclinical hypothyroidism is associated with very small and very large TRLPs, which are related to an unfavorable atherogenic profile. Subclinical hyperthyroidism is associated to lower very small TRLPs.

Differences in HDL particle size in the presence of subclinical thyroid dysfunctions: The ELSA-Brasil study.

BACKGROUND AND AIMS: Thyroid dysfunction is related to several lipid abnormalities. There is no consensus about concentration of high-density lipoprotein (HDL) in different studies. The aim of this report is to evaluate HDL particle (HDL-P) subfractions across a spectrum of thyroid functions in a Brazilian population. METHODS: Individuals were divided into three groups by baseline thyroid function (subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism). HDL-P subfractions were analyzed by Nuclear Magnetic Resonance (NMR) spectroscopy. To examine the association between HDL-P subfractions and thyroid function, we used univariate and multivariate linear regression models adjusted for demographic characteristics, comorbidities, lifestyle factors, and traditional lipid measurement (HDL-C, LDL-C and triglycerides). RESULTS: Of 3304 participants, 54.1% were women, 51.2% white, with mean age 50.6 ± 8.7 years. HDL-C and triglycerides levels (p = 0.032 and p = 0.016, respectively) were higher in the SC hypothyroid group. There were no statistically significant differences in total cholesterol levels and LDL-C levels. In univariate analysis, small HDL-P subfractions were significantly lower in subclinical hypothyroidism (p = 0.026) whereas intermediate HDL-P were higher in subclinical hyperthyroidism (p = 0.049), compared to euthyroidism. After adjustment for demographic data, SC hypothyroidism was still statistically associated with lower levels of small HDL-P. After adjusting for comorbidities, lifestyle factors, and traditional lipid measurements, SC hypothyroidism had an established association with lower levels of small HDL-P while SC hyperthyroidism was associated with lower levels of large HDL-P. CONCLUSIONS: In this large cohort from a Brazilian population, subclinical hypothyroidism was associated with lower small HDL-P subfractions, and subclinical hyperthyroidism with lower large HDL-P subfractions and higher intermediate HDL-P subfractions.

Relationship between TSH Levels and the Advanced Lipoprotein Profile in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PURPOSE/AIMS: The relationship between thyroid-stimulating hormone (TSH) and lipoprotein subfractions by Vertical Auto Profile (VAP) is unclear. We aimed to evaluate lipoprotein profiles according to TSH levels in euthyroid individuals.Material and Methods: Cross-sectional analysis of 3,525 participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) with no previous thyroid disease and who were not on lipid-lowering medication. Total-cholesterol and its fractions, lipoprotein subfractions, triglycerides, and triglyceride-rich lipoprotein cholesterol [TRL-C (VLDL1+2-C, VLDL3-C, IDL-C)] were determined by VAP. Associations between TSH quintiles and lipoprotein subfractions were evaluated by crude and adjusted linear regression models.Results: For the total sample, significant beta-coefficients in full adjusted models for the 5th quintile of TSH (compared to 1st) were found for the following VAP lipids and lipoproteins: IDL-C (ß: 0.90; 0.11 to 1.69); VLDL-C (ß: 2.80; 1.51 to 4.08), triglycerides (ß: 18.66; 8.07 to 29.25), non-HDL-C (ß: 4.63; 0.50 to 8.75 mg/dl), TRL-C (ß:1.93;0.70 to 3.17), VLDL3-C (ß: 1.04; 0.50 to 1.57), as well as, TC/HDL-C (ß: 0.15; 0.03 to 0.26) and TG/HDL-C ratio (ß: 0.49;0.21 to 0.77). In women, similar results were found for VLDL-C, triglycerides, non-HDL-C, TRL-C, VLDL3-C, TC/HDL-C and TG/HDL-C-ratios. In men, we also found positive associations between the highest quintile of TSH with VLDL-C, triglycerides, VLDL3-C and TG/HDL-C.Conclusions: In the ELSA-Brasil, the highest TSH levels were mostly positively associated with lipoprotein levels, particularly TG, TRL and their remnants. Notwithstanding, our findings suggest that TSH levels within the normal range have little impact on the atherogenic profile.

Changes in lipoprotein subfractions following menopause in the Longitudinal Study of Adult Health (ELSA-Brasil).

INTRODUCTION: It is unclear how aging and menopause-induced lipid changes contribute to the elevated cardiovascular risk in menopausal women. We examined the association between lipid profiles and menopausal status and duration of menopause in the Longitudinal Study of Adult Health (ELSA-Brasil). METHODS: This is a cross-sectional analysis of baseline data from women in the ELSA-Brasil, stratified by duration of menopause into 5 groups: pre-menopause, <2 years, 2-5.9 years, 6-9.9 years and ≥10 years of menopause, excluding menopause <40 years or of non-natural cause; also excluded were women using lipid-lowering drugs or hormone replacement. Comparisons were performed using ANOVA with Bonferroni correction. Associations of menopause categories and time since menopause with lipid variables obtained by vertical auto-profile were tested using multiple linear regression. RESULTS: From 1916 women, postmenopausal groups had unadjusted higher total cholesterol, LDL-c, real LDL-c, IDL-c, VLDL-c, triglycerides, non-HDL-c, VLDL3-c, triglyceride-rich lipoprotein remnants (TRL-c) and buoyant LDL-c concentrations than pre-menopausal women, with no difference among postmenopausal groups. In multiple linear regression, duration of menopause <2 years was significantly associated with TRL-c [7.21 mg/dL (95% CI 3.59-10.84)] and VLDL3-c [2.43 mg/dL (95%CI 1.02-3.83)]. No associations of menopausal categories with HDL-c or LDL-c subfractions were found, and nor were associations of time since menopause with lipid subfractions. CONCLUSIONS: In a large sample of Brazilian women, deterioration of the lipid profile following menopause was confirmed, which could contribute to the increased cardiovascular risk. Our findings suggest a postmenopausal elevation in triglyceride-rich lipoprotein remnants. How lipoprotein subfractions change after the onset of menopause warrants investigation in studies with appropriate designs.

High-density Lipoprotein-cholesterol Subfractions and Coronary Artery Calcium: The ELSA-Brasil Study.

BACKGROUND: Although elevated high-density lipoprotein cholesterol (HDL-C) is considered protective against atherosclerotic cardiovascular disease, no causal relationship has been demonstrated. HDL-C comprises a group of different subfractions that might have different effects on atherosclerosis. Our objective was to investigate the association between HDL-C subfractions with the coronary artery calcium (CAC) score. METHODS: We included 3,674 (49.8 ± 8.3 years, 54% women) participants from the ELSA-Brasil study who had no prior history of CVD and were not currently using lipid-lowering medications. We measured the fasting lipoprotein cholesterol fractions (in mmol/l) by a zonal ultracentrifugation method (VAP). We analyzed the independent predictive values of total HDL-C, HDL2-C, and HDL3-C subfractions and in the HDL2-C/HDL3-C ratio using linear regression to predict Ln(CAC+1) and logistic regression to predict the presence of CAC. RESULTS: Overall 912 (24.8%) of the participants had CAC>0, and 294 (7.7%) had CAC>100. The mean total HDL-C, HDL2-C, and HDL3-C were: 1.42 ± 0.37, 0.38 ± 0.17 and 1.03 ± 0.21 mmol/l, respectively. Individuals with CAC>0 had lower levels of total HDL-C as well as of each subfraction (p < 0.001). When adjusted for age, gender, smoking, hypertension, alcohol use, physical activity, and LDL-C, we observed an inverse association between HDL-C and its subfractions and CAC (p < 0.05). However, by adding triglycerides in the adjustment, neither total HDL-C nor its subfractions remained independently associated with the presence or extent of CAC. CONCLUSION: In this cross-sectional analysis, neither the total HDL-C nor its subfractions (HDL2-C and HDL3-C, as well as HDL2-C/HDL3-C ratio) measured by VAP are independently associated with the presence or extent of coronary calcification.

Impact of improved low-density lipoprotein cholesterol assessment on guideline classification in the modern treatment era-Results from a racially diverse Brazilian cross-sectional study.

BACKGROUND: The Martin/Hopkins low-density lipoprotein cholesterol equation (LDL-CN) was previously demonstrated as more accurate than Friedewald LDL-C estimation (LDL-CF) in a North American database not able to take race into account. OBJECTIVES: We hypothesized that LDL-CN would be more accurate than LDL-CF and correlate better with LDL particle number (LDL-P) in a racially diverse Brazilian cohort. METHODS: We performed a cross-sectional analysis of 4897 participants in the Brazilian Longitudinal Study of Adult Health, assessing LDL-CF and LDL-CN accuracy via overlap with ultracentrifugation-based measurement among clinical guideline LDL-C categories as well as mg/dL and percent error differences. We analyzed by triglyceride categories and correlated LDL-C estimation with LDL-P. RESULTS: LDL-CN demonstrated improved accuracy at 70 to <100 and <70 mg/dL (P < .001), with large errors ≥20 mg/dL about 9 times more frequent in LDL-CF at LDL-C <70 mg/dL, mainly due to underestimation. Among individuals with LDL-C <70 mg/dL and triglycerides ≥150 mg/dL, 65% vs 100% of ultracentrifugation-based low-density lipoprotein cholesterol calculation fell within appropriate categories of estimated LDL-CF and LDL-CN, respectively (P < .001). Similar results were observed when analyzed for age, sex, and race. Participants at LDL-C <70 and 70 to <100 mg/dL with discordantly elevated LDL-CN vs LDL-CF had a 58.5% and 41.5% higher LDL-P than those with concordance (P < .0001), respectively. CONCLUSIONS: In a diverse Brazilian cohort, LDL-CN was more accurate than LDL-CF at low LDL-C and high triglycerides. LDL-CN may avoid underestimation of LDL-C and better reflect atherogenic lipid burden in low particle size, high particle count states.

RTNduals: an R/Bioconductor package for analysis of co-regulation and inference of dual regulons.

MOTIVATION: Transcription factors (TFs) are key regulators of gene expression, and can activate or repress multiple target genes, forming regulatory units, or regulons. Understanding downstream effects of these regulators includes evaluating how TFs cooperate or compete within regulatory networks. Here we present RTNduals, an R/Bioconductor package that implements a general method for analyzing pairs of regulons. RESULTS: RTNduals identifies a dual regulon when the number of targets shared between a pair of regulators is statistically significant. The package extends the RTN (Reconstruction of Transcriptional Networks) package, and uses RTN transcriptional networks to identify significant co-regulatory associations between regulons. The Supplementary Information reports two case studies for TFs using the METABRIC and TCGA breast cancer cohorts. AVAILABILITY AND IMPLEMENTATION: RTNduals is written in the R language, and is available from the Bioconductor project at http://bioconductor.org/packages/RTNduals/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RTNsurvival: an R/Bioconductor package for regulatory network survival analysis.

MOTIVATION: Transcriptional networks are models that allow the biological state of cells or tumours to be described. Such networks consist of connected regulatory units known as regulons, each comprised of a regulator and its targets. Inferring a transcriptional network can be a helpful initial step in characterizing the different phenotypes within a cohort. While the network itself provides no information on molecular differences between samples, the per-sample state of each regulon, i.e. the regulon activity, can be used for describing subtypes in a cohort. Integrating regulon activities with clinical data and outcomes would extend this characterization of differences between subtypes. RESULTS: We describe RTNsurvival, an R/Bioconductor package that calculates regulon activity profiles using transcriptional networks reconstructed by the RTN package, gene expression data, and a two-tailed Gene Set Enrichment Analysis. Given regulon activity profiles across a cohort, RTNsurvival can perform Kaplan-Meier analyses and Cox Proportional Hazards regressions, while also considering confounding variables. The Supplementary Information provides two case studies that use data from breast and liver cancer cohorts and features uni- and multivariate regulon survival analysis. AVAILABILITY AND IMPLEMENTATION: RTNsurvival is written in the R language, and is available from the Bioconductor project at http://bioconductor.org/packages/RTNsurvival/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Composite acute phase glycoproteins with coronary artery calcification depends on metabolic syndrome presence - The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Inflammation has been weakly associated with coronary artery calcium (CAC) in the overall population. However, it is currently unknown whether this varies according to the cardio-metabolic profile. We evaluated the association between GlycA, a unique composite biomarker of pro-inflammatory acute phase glycoproteins, high sensitivity C-reactive protein (hsCRP), uric acid, and their composite values (composite inflammation) in the overall population and strata according to cardiovascular risk. METHODS: This is a cross-sectional study of 3753 Sao Paulo site participants of the ELSA-Brasil cohort that were free of cardiovascular/chronic inflammatory disease and not taking statins or allopurinol. We measured GlycA by nuclear magnetic resonance spectroscopy. For each biomarker quartile (Qs), we ran adjusted logistic and linear regression for CAC>0 and CAC score. RESULTS: In the overall analysis, the 4th vs. 1st GlycA Q odds ratio (OR) for CAC>0 was 1.53 (95% CI: 1.18, 1.98, p trend<0.001) adjusted for demographics and lifestyle, but null after adding metabolic syndrome (MS) components, OR 1.14 (95% CI: 0.86, 1.51, p trend=0.140). Likewise, for continuous CAC values there was no difference across GlycA Qs in the fully adjusted analysis. Similarly, hsCRP, uric acid, and composite inflammation were not associated with CAC>0 or CAC score. In stratified analysis, GlycA was associated with CAC>0 in No-MS individuals, standardized (SD) OR 1.23 (95% CI: 1.08, 1.40); but not in MS individuals, SD OR 1.01 (95% CI: 0.89, 1.15) (p interaction 0.037). We found similar interaction in stratified analysis for continuous CAC on composite inflammation. CONCLUSIONS: GlycA and composite inflammation are associated with CAC among low cardiovascular risk individuals (No-MS), but not otherwise. GlycA and composite biomarkers may better represent sources of inflammation apart from visceral obesity and traditional cardiovascular risk factors, which may have relevant effect on CAC accumulation in low cardiovascular risk individuals.

Diabetes alters the association between high-density lipoprotein subfractions and carotid intima-media thickness: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

INTRODUCTION: High-density lipoprotein cholesterol comprises a group of heterogeneous subfractions that might have differential effects on atherosclerosis. Moreover, prior investigations suggest that the presence of diabetes (T2D) modifies the impact of some subfractions on atherosclerosis. In this study, we aimed to evaluate the association between high-density lipoprotein cholesterol subfractions and carotid intima-media thickness in the baseline assessment of the Brazilian Longitudinal Study of Adult Health participants from the São Paulo investigation centre. METHODS: We evaluated 3930 individuals between 35 and 74 years without previous cardiovascular disease not using lipid-lowering drugs. High-density lipoprotein cholesterol subfractions (HDL2-C and HDL3-C) were measured by vertical ultracentrifugation (vertical auto profile). The relationship between each high-density lipoprotein cholesterol subfraction and carotid intima-media thickness was analysed by multiple linear regression models. RESULTS: Total high-density lipoprotein cholesterol, as well as HDL2-C and HDL3-C, was negatively associated with carotid intima-media thickness after adjustment for demographic data (all p < 0.001) and traditional risk factors (all p < 0.05). When stratified by T2D status, the HDL2-C/HDL3-C ratio showed a negative association with carotid intima-media thickness in participants with T2D ( p = 0.032), even after fully controlling for confounding variables, including total high-density lipoprotein cholesterol. CONCLUSION: HDL2-C, HDL3-C and HDL2/HDL3-C ratio are inversely associated with carotid intima-media thickness after adjustment for traditional risk factors. Association of the HDL2-C/HDL3-C ratio is modified by the presence of diabetes, being more pronounced in diabetic individuals.

Association between high-density lipoprotein subfractions and low-grade inflammation, insulin resistance, and metabolic syndrome components: The ELSA-Brasil study.

BACKGROUND: High-density lipoprotein cholesterol (HDL-C) can be divided into subfractions, which may have variable effects in atherogenesis. The results about the association between HDL-C subfractions and risk factors for cardiovascular disease are mixed. OBJECTIVE: The objective of this study was to analyze the association between HDL-C subfractions and each metabolic syndrome component, homeostasis model assessment-estimated insulin resistance (HOMA-IR) and C-reactive protein (CRP). METHODS: Four thousand five hundred thirty-two individuals between 35 and 74 years old without previous manifest cardiovascular disease not using fibrates were enrolled. HDL-C subfractions were separated by vertical ultracentrifugation (vertical auto profile-in mg/dL) into HDL2-C and HDL3-C. HDL2-C/HDL3-C ratio, HOMA-IR, and high-sensitivity CRP were also included in the analysis. RESULTS: Mean age of participants was 51 ± 9 years, and 54.8% were women. In univariate analysis, HDL-C, HDL2-C, and HDL3-C were all inversely associated with each of the metabolic syndrome defining factors, HOMA-IR values, and serum CRP. We also observed a negative association between HDL2-C/HDL3-C ratio with the variables aforementioned even after adjusting for smoking, alcohol use, physical activity, and HDL-C levels (P < .01). CONCLUSION: HDL-C and its subfractions (HDL2-C and HDL3-C) are inversely associated with the defining features of metabolic syndrome, insulin resistance, and systemic inflammation. In addition, the HDL2-C/HDL3-C ratio measured by vertical auto profile is significantly associated with the former factors even after comprehensive adjustment for HDL-C and other confounding variables.

The relationship between migraine and lipid sub-fractions among individuals without cardiovascular disease: A cross-sectional evaluation in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Introduction Recent studies have explored the relationship between dyslipidemia and migraine in a cardiovascular context. Thus, we aimed to evaluate the possible association between lipids, lipoprotein subfractions and migraine according to aura symptoms in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Methods 1,560 women and 1,595 men, without CVD or lipid disorders requiring medication, underwent a baseline clinical assessment. Total-cholesterol and its sub-fractions (LDL, VLDL and HDL subclass cholesterol); triglycerides and triglyceride-rich lipoprotein cholesterol [TRL-C (VLDL1+2-C VLDL3-C + IDL-C)] were determined by vertical auto profile (VAP). We also calculated logarithmic LDL density ratio [LLDR = ln ((LDL3-C + LDL4-C)/(LDL1-C + LDL2-C))], T-Chol/HDL-C and triglycerides/HDL-C ratios. Odds ratios (OR) with 95% confidence intervals (CI) were obtained to evaluate the relationship between lipids tertiles and migraine for both sexes. Results Main findings revealed positive associations between migraine without aura (MO) and the highest tertiles of VLDL-C (OR, 1.61; 95%CI, 1.07-2.40) and TRL-C (OR, 1.55; 95% CI, 1.03-2.34) in women. In men, the highest tertile of VLDL3-C (OR, 3.87; 95%CI, 1.23-12.19) was positively associated with MO, as well. Conclusions In middle-aged participants without CVD or lipid disorders requiring medication, the worst lipid profile was determined by the highest levels of TRL-C and their cholesterol-rich remnants in migraineurs without aura for both sexes.

Association Between Smoking and Serum GlycA and High-Sensitivity C-Reactive Protein Levels: The Multi-Ethnic Study of Atherosclerosis (MESA) and Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Inflammation is suggested to be a central feature of atherosclerosis, particularly among smokers. We studied whether inflammatory biomarkers GlycA and high-sensitivity C-reactive protein are associated with cigarette smoking. METHODS AND RESULTS: A total of 11 509 participants, 6774 from the MESA (Multi-Ethnic Study of Atherosclerosis) and 4735 from ELSA-Brasil (The Brazilian Longitudinal Study of Adult Health) were included. We evaluated the cross-sectional association between multiple measures of smoking behavior and the inflammatory biomarkers, GlycA and high-sensitivity C-reactive protein, using regression models adjusted for demographic, anthropometric, and clinical characteristics. Participants were 57.7±11.1 years old and 46.4% were men. Never, former, and current smokers comprised 51.7%, 34.0%, and 14.3% of the population, respectively. Multivariable-adjusted mean absolute difference in GlycA levels (µmol/L) with 95% confidence interval (CI) were higher for former (4.1, 95% CI, 1.7-6.6 µmol/L) and current smokers (19.9, 95% CI, 16.6-23.2 µmol/L), compared with never smokers. Each 5-unit increase in pack-years of smoking was associated with higher GlycA levels among former (0.7, 95% CI, 0.3-1.1 µmol/L) and current smokers (1.6, 95% CI, 0.8-2.4 µmol/L). Among former smokers, each 5-year increase in time since quitting smoking was associated with lower GlycA levels (-1.6, 95% CI, -2.4 to -0.8 µmol/L) and each 10-unit increase in number of cigarettes/day was associated with higher GlycA among current smokers (2.8, 95% CI, 0.5-5.2 µmol/L). There were similar significant associations between all measures of smoking behavior, and both log-transformed GlycA and high-sensitivity C-reactive protein. CONCLUSIONS: Acute and chronic exposure to tobacco smoking is associated with inflammation, as quantified by both GlycA and high-sensitivity C-reactive protein. These biomarkers may have utility for the study and regulation of novel and traditional tobacco products.