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OBJECTIVE: The present study aims to evaluate the performance of the Diabetes Risk Index (DRI), a metabolomic index based on lipoprotein particles and branched chain amino acids, on the incidence of newly developed hypertension in a large community dwelling cohort.METHODS: The DRI was calculated by combining 6 lipoprotein parameters [sizes of very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL), concentrations of large VLDL, small LDL, and large HDL particles], and the concentrations of valine and leucine. DRI scores were estimated in 4169 participants from the PREVEND prospective cohort. Cox proportional hazards regression was used to evaluate the association of DRI scores with incident hypertension.RESULTS: During a median follow-up of 8.6 years, 924 new hypertension cases were ascertained. In analyses adjusted for age and sex, there was a significant association between DRI and incident hypertension with a hazard ratio (HR) per 1 SD increase of 1.45 (95% CI 1.36,1.54; p < 0.001). After additional adjustment for traditional risk factors, the HR remained significant (HRadj 1.21, 95% CI 1.10, 1.33, p CONCLUSION: Higher DRI scores were associated with an increased risk of incident hypertension. Such association was independent of traditional clinical risk factors for hypertension.

Background & aims Lipoprotein Z (LP-Z) is an abnormal free cholesterol (FC)-enriched low density lipoprotein (LDL)-like particle discovered from patients with cholestatic liver disease. This study aims to define the diagnostic value of LP-Z in alcoholic hepatitis (AH) and interrogate the biology behind its formation. Approach & results We measured serum levels of LP-Z using nuclear magnetic resonance spectroscopy, a well-established clinical assay. Serum levels of LP-Z were significantly elevated in four AH cohorts compared to control groups, including heavy drinkers and cirrhosis. We defined a Z-index, calculated by the ratio of LP-Z to total apolipoprotein B-containing lipoproteins, representing the degree of deviation from normal very low density lipoprotein (VLDL) metabolism. A high Z-index was associated with 90-day mortality independent from the Model for End-Stage Liver Disease and provided added prognosticative value. Both a Z-index ≤0.6 and a decline of Z-index by ≥ 0.1 in two weeks predicted 90-day survival. RNAseq analyses of liver tissues demonstrated an inverse association in the expression of enzymes responsible for the extrahepatic conversion of VLDL to LDL and AH disease severity, which was further confirmed by the measurement of serum enzyme activity. To evaluate whether the FC in LP-Z could contribute to the pathogenesis of AH, we found significantly altered FC levels in liver explant of AH patients. Furthermore, FC in reconstituted LP-Z particles caused direct toxicity to human hepatocytes in a concentration-dependent manner, supporting a pathogenic role of FC in LP-Z. Conclusions Impaired lipoprotein metabolism in AH leads to the accumulation of LP-Z in the circulation, which is hepatotoxic from excessive FC. A Z-index ≤ 0.6 predicts 90-day survival independent from conventional biomarkers for disease prognostication.

Background In the failing heart, energy metabolism is shifted towards increased ketone body oxidation. Nevertheless, the association of beta-hydroxybutyrate (beta-OHB) with development of heart failure (HF) remains unclear. We investigated the association between plasma beta-OHB and the risk of HF in a prospective population-based cohort. Design Plasma beta-OHB concentrations were measured in 6134 participants of the PREVEND study. Risk of incident HF with reduced (HFrEF) or preserved (HFpEF) ejection fraction was estimated using multivariable-adjusted Cox regression models. Results During median follow-up for 8.2 years, 227 subjects were diagnosed with HF (137 with HFrEF; 90 with HFpEF). Cox regression analyses revealed a significant association of higher beta-OHB concentrations with incident HF (HR per 1 standard deviation increase, 1.40 (95% CI: 1.21-1.63; P

BackgroundLipoprotein Insulin Resistance Index (LP-IR) and Diabetes Risk Index are novel spectroscopic multimarkers of insulin resistance and type 2 diabetes risk. As the Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) randomized trials have previously demonstrated the ability of exercise training to improve traditional markers of insulin action, the aim of this study was to examine the effects of exercise amount, intensity, and mode on LP-IR and the Diabetes Risk Index.MethodsA total of 503 adults with dyslipidemia [STRRIDE I (n = 194), STRRIDE AT/RT (n = 139)] or prediabetes [STRRIDE-PD (n = 170)] were randomized to control or one of 10 exercise interventions, ranging from doses of 8–23 kcal/kg/week; intensities of 50–75% V̇O2peak; and durations of 6–8 months. Two groups included resistance training and one included dietary intervention (7% weight loss goal). Fasting plasma samples were obtained at baseline and 16–24 h after the final exercise bout. LP-IR, the Diabetes Risk Index, and concentrations of the branched chain amino acids valine and leucine were determined using nuclear magnetic resonance spectroscopy. LP-IR and the Diabetes Risk Index scores range from 0–100 and 1–100, respectively (greater scores indicate greater risk). Paired t-tests determined significance within groups (p < 0.05).ResultsAfter training, six exercise groups significantly improved LP-IR (ranging from −4.4 ± 8.2 to −12.4 ± 14.1), and four exercise groups significantly improved the Diabetes Risk Index (ranging from −2.8 ± 8.2 to −8.3 ± 10.4). The most beneficial interventions for both LP-IR and the Diabetes Risk Index were low amount/moderate intensity aerobic, aerobic plus resistance, and aerobic plus diet.SummaryMultiple exercise interventions improved LP-IR and the Diabetes Risk Index. In those with dyslipidemia, adding resistance to aerobic training elicited a synergistic effect on insulin resistance and type 2 diabetes risk. In individuals with prediabetes, combining a dietary intervention and weight loss with aerobic training resulted in the most robust type 2 diabetes risk improvement.

Background: Lipoprotein particles with abnormal compositions, such as lipoprotein X (LP-X) and lipoprotein Z (LP-Z), have been described in cases of obstructive jaundice and cholestasis. The study objectives were to: (1) develop an NMR-based assay for quantification of plasma/serum LP-Z particles, (2) evaluate the assay performance, (3) isolate LP-Z particles and characterize them by lipidomic and proteomic analysis, and (4) quantify LP-Z in subjects with various liver diseases. Methods: Assay performance was assessed for linearity, sensitivity, and precision. Mass spectroscopy was used to characterize the protein and lipid content of isolated LP-Z particles. Results: The assay showed good linearity and precision (2.5–6.3%). Lipid analyses revealed that LP-Z particles exhibit lower cholesteryl esters and higher free cholesterol, bile acids, acylcarnitines, diacylglycerides, dihexosylceramides, lysophosphatidylcholines, phosphatidylcholines, triacylglycerides, and fatty acids than low-density lipoprotein (LDL) particles. A proteomic analysis revealed that LP-Z have one copy of apolipoprotein B per particle such as LDL, but less apolipoprotein (apo)A-I, apoC3, apoA-IV and apoC2 and more complement C3. LP-Z were not detected in healthy volunteers or subjects with primary biliary cholangitis, primary sclerosing cholangitis, autoimmune hepatitis, or type 2 diabetes. LP-Z were detected in some, but not all, subjects with hypertriglyceridemia, and were high in some subjects with alcoholic liver disease. Conclusions: LP-Z differ significantly in their lipid and protein content from LDL. Further studies are needed to fully understand the pathophysiological reason for the enhanced presence of LP-Z particles in patients with cholestasis and alcoholic liver disease.

Objective: Evaluate the ability of a newly developed diabetes risk score, the Diabetes Risk Index (DRI), to predict incident type 2 diabetes mellitus (T2D) in a large adult population. Methods: The DRI was developed by combining the Lipoprotein Insulin Resistance Index (LP-IR), calculated from 6 lipoprotein subspecies and size parameters, and the branched chain amino acids, valine and leucine, all of which have been shown previously to be associated with future T2D. DRI scores were calculated in a total of 6134 nondiabetic men and women in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) Study. Cox proportional hazards regression was used to evaluate the association of DRI scores with incident T2D. Results: During a median follow-up of 8.5 years, 306 new T2D cases were ascertained. In analyses adjusted for age and sex, there was a significant association between DRI scores and incident T2D with the hazard ratio (HR) for the highest versus lowest quartile being 12.07 (95% confidence interval: 6.97&ndash, 20.89, p &lt, 0.001). After additional adjustment for body mass index (BMI), family history of T2D, alcohol consumption, diastolic blood pressure, total cholesterol, triglycerides, HDL cholesterol and HOMA-IR, the HR was attenuated but remained significant (HR 3.20 (1.73&ndash, 5.95), p = 0.001). Similar results were obtained when DRI was analyzed as HR per 1 SD increase (HR 1.37 (1.14&ndash, 1.65), p &lt, 0.001). The Kaplan&ndash, Meier plot demonstrated that patients in the highest quartile of DRI scores presented at higher risk (p-value for log-rank test &lt, 0.001). Conclusions: Higher DRI scores are associated with an increased risk of T2D. The association is independent of clinical risk factors for T2D including HOMA-IR, BMI and conventional lipids.

Objective: Examine the effects of amount, intensity, and mode of exercise training on type 2 diabetes (T2D) risk. Methods: A total of 531 men and women with dyslipidemia [STRRIDE I (n=222), STRRIDE AT/RT (n=142) or prediabetes [STRRIDE-PD (n=167)] were randomized to control group or one of 10 exercise interventions, ranging from doses of 8-22 kcal/kg/week; intensities of 50-75% V?O2peak; and duration of 6-9 months. Two groups included resistance training and one included dietary intervention (weight loss goal of 7%). Fasting plasma samples were obtained at baseline and 16-24 h after last exercise bout. The Diabetes Risk Index (DRI) and its components—Lipoprotein Insulin Resistance Index (LP-IR) and branched chain amino acids (BCAA) valine and leucine—were determined by NMR spectroscopy. DRI scores range from 1-100, the latter representing those at greatest T2D risk. Paired t-tests determined significance within groups (p Results: The inactive control group did not significantly change DRI score. After training, four of ten exercise groups significantly improved DRI scores, ranging from -2.8 ± 8.2 to -8.3 ± 10.4. In STRRIDE AT/RT, only the aerobic-plus-resistance group significantly improved DRI. In STRRIDE-PD, the moderate-intensity-plus-diet group had a greater DRI change than the other exercise-only moderate intensity groups. Reductions in DRI appeared to be driven largely by decreases in insulin resistance (LP-IR) but not dysmetabolism (BCAA), except for the moderate-intensity-plus-diet group, which exhibited a reduction in both. Conclusions: Multiple exercise interventions led to improvements in DRI scores. Results provide compelling evidence that adding resistance to aerobic training elicits a synergistic effect on insulin resistance and T2D risk. In individuals with prediabetes, incorporating dietary intervention with aerobic training results in the most robust improvement in T2D risk. Disclosure L.M. Ross: None. C.A. Slentz: None. I.Y. Shalaurova: None. J.D. Otvos: Employee; Self; LabCorp. M.A. Connelly: Employee; Self; LabCorp. C.W. Bales: None. J.A. Houmard: None. W.E. Kraus: None. Funding National Institutes of Health (R01HL057354, R01DK081559, T32HL007101)

BACKGROUND: Early assessment of insulin resistance may be a way of identifying patients at risk as well as monitoring treatments that increase insulin sensitivity and reduce the risk of developing type II diabetes mellitus (T2DM).OBJECTIVE: The objective of the study was to evaluate the ability of the Lipoprotein Insulin Resistance Index (LP-IR) to predict incident T2DM in a large cohort.METHODS: LP-IR scores were calculated using 6 lipoprotein particle concentrations and sizes measured by nuclear magnetic resonance spectroscopy. In total, 5977 nondiabetic men and women were included. Cox proportional hazards regression was used to evaluate the association of LP-IR scores with incident T2DM.RESULTS: LP-IR scores were closely associated with insulin resistance, assessed by homeostatic model assessment of insulin resistance (r = 0.51; P CONCLUSION: LP-IR may be a convenient way to assess insulin resistance and T2DM risk, as well as to monitor preventative treatments. (C) 2018 National Lipid Association. All rights reserved.

Introduction: Lipoprotein Insulin Resistance Index (LP-IR) is a novel spectroscopic multimarker linked to future diabetes risk. We recently assessed changes in LP-IR across the three STRRIDE trials, where on average, STRRIDE exercise interventions improved LP-IR. In the present study, we sought to determine if there were effects of gender, race, and glucose tolerance on LP-IR responses across the STRRIDE trials. Methods: A total of 461 adults with dyslipidemia (STRRIDE I and STRRIDE AT/RT) or prediabetes (STRRIDE-PD) were randomized to one of 7 exercise interventions, ranging from doses of 8-22 kcal/kg/week (KKW); intensities of 50-75% VO 2peak ; and durations of 6-9 months. Six groups included aerobic exercise, two groups included resistance training, and one group included dietary intervention (weight loss goal of 7%). Fasting blood samples were obtained at both baseline and 16-24 h after the final exercise bout. In STRRIDE-PD only (n=165), subjects completed oral glucose tolerance tests and were categorized into normal (NGT) and impaired glucose tolerance (IGT) groups at baseline. NMR spectroscopy was performed at LabCorp to determine LP-IR score (comprised of six lipoprotein subclass and size parameters). LP-IR score ranges from 0 (most insulin sensitive) to 100 (most insulin resistant). Irrespective of intervention group, we assessed change in LP-IR in three stratified analyses: by gender, race, and baseline glucose tolerance category. Paired t-tests determined whether the post- minus pre- intervention change scores within each group were significant (p Results: At baseline, women had lower LP-IR scores compared to men (47.8 ± 22.3 vs 62.6 ± 21.5; p Conclusion: There were significant baseline differences in LP-IR among gender, racial, and glucose tolerance groups. However, after adjusting for these baseline differences, there were similar beneficial responses to exercise in this marker of insulin resistance.

Background: Quantifying mildly elevated ketone bodies is clinically and pathophysiologically relevant, especially in the context of disease states as well as for monitoring of various diets and exercise regimens. As an alternative assay for measuring ketone bodies in the clinical laboratory, a nuclear magnetic resonance (NMR) spectroscopy-based test was developed for quantification of &beta, hydroxybutyrate (&beta, HB), acetoacetate (AcAc) and acetone. Methods: The ketone body assay was evaluated for precision, linearity and stability and method comparisons were performed. In addition, plasma ketone bodies were measured in the Insulin Resistance Atherosclerosis Study (IRAS, n = 1198, 373 type 2 diabetes mellitus (T2DM) subjects). Results: &beta, HB and AcAc quantified using NMR and mass spectrometry and acetone quantified using NMR and gas chromatography/mass spectrometry were highly correlated (R2 = 0.996, 0.994, and 0.994 for &beta, HB, AcAc, acetone, respectively). Coefficients of variation (%CVs) for intra- and inter-assay precision ranged from 1.3% to 9.3%, 3.1% to 7.7%, and 3.8% to 9.1%, for &beta, HB, AcAc and acetone, respectively. In the IRAS, ketone bodies were elevated in subjects with T2DM versus non-diabetic individuals (p = 0.011 to &le, 0.001). Age- and sex-adjusted multivariable linear regression analysis revealed that total ketone bodies and &beta, HB were associated directly with free fatty acids (FFAs) and T2DM and inversely with triglycerides and insulin resistance as measured by the Lipoprotein Insulin Resistance Index. Conclusions: Concentrations of the three main ketone bodies can be determined by NMR with good clinical performance, are elevated in T2DM and are inversely associated with triglycerides and insulin resistance.

Objectives Plasma branched-chain amino acid (BCAA) levels, measured on nuclear magnetic resonance (NMR) metabolomics research platforms or by mass spectrometry, have been shown to be associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We developed a new test for quantification of BCAA on a clinical NMR analyzer and used this test to determine the clinical correlates of BCAA in 2 independent cohorts. Design and methods The performance of the NMR-based BCAA assay was evaluated. A method comparison study was performed with mass spectrometry (LC-MS/MS). Plasma BCAA were measured in the Insulin Resistance Atherosclerosis Study (IRAS, n = 1209; 376 T2DM subjects) and in a Groningen cohort (n = 123; 67 T2DM subjects). In addition, carotid intima media thickness (cIMT) was measured successfully in 119 subjects from the Groningen cohort. Results NMR-based BCAA assay results were linear over a range of concentrations. Coefficients of variation for inter- and intra-assay precision ranged from 1.8–6.0, 1.7–5.4, 4.4–9.1, and 8.8–21.3%, for total BCAA, valine , leucine , and isoleucine , respectively. BCAA quantified from the same samples using NMR and LC-MS/MS were highly correlated (R 2 = 0.97, 0.95 and 0.90 for valine, leucine and isoleucine). In both cohorts total and individual BCAA were elevated in T2DM (P = 0.01 to ≤0.001). Moreover, cIMT was associated with BCAA independent of age, sex, T2DM and metabolic syndrome (MetS) categorization or alternatively of individual MetS components. Conclusions BCAA levels, measured by NMR in the clinical laboratory, are elevated in T2DM and may be associated with cIMT, a proxy of subclinical atherosclerosis.

Background: Gut microbiota-related metabolites, trimethylamine-N-oxide (TMAO), choline, and betaine, have been shown to be associated with cardiovascular disease (CVD) risk. Moreover, lower plasma betaine concentrations have been reported in subjects with type 2 diabetes mellitus (T2DM). However, few studies have explored the association of betaine with incident T2DM, especially in the general population. The goals of this study were to evaluate the performance of a newly developed betaine assay and to prospectively explore the potential clinical associations of betaine and future risk of T2DM in a large population-based cohort. Methods: We developed a high-throughput, nuclear magnetic resonance (NMR) spectroscopy procedure for acquiring spectra that allow for the accurate quantification of plasma/serum betaine and TMAO. Assay performance for betaine quantification was assessed and Cox proportional hazards regression was employed to evaluate the association of betaine with incident T2DM in 4336 participants in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. Results: Betaine assay results were linear (y = 1.02X − 3.75) over a wide range of concentrations (26.0−1135 µM). The limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ) were 6.4, 8.9, and 13.2 µM, respectively. Coefficients of variation for intra- and inter-assay precision ranged from 1.5−4.3% and 2.5−5.5%, respectively. Deming regression analysis of results produced by NMR and liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS) revealed an R2 value of 0.94 (Y = 1.08x − 1.89) and a small bias for higher values by NMR. The reference interval, in a cohort of apparently healthy adult participants (n = 501), was determined to be 23.8 to 74.7 µM (mean of 42.9 ± 12.6 µM). In the PREVEND study (n = 4336, excluding subjects with T2DM at baseline), higher betaine was associated with older age and lower body mass index, total cholesterol, triglycerides, and hsCRP. During a median follow-up of 7.3 (interquartile range (IQR), 5.9−7.7) years, 224 new T2DM cases were ascertained. Cox proportional hazards regression models revealed that the highest tertile of betaine was associated with a lower incidence of T2DM. Hazard ratio (HR) for the crude model was 0.61 (95% CI: 0.44−0.85, p = 0.004). The association remained significant even after adjusting for multiple clinical covariates and T2DM risk factors, including fasting glucose. HR for the fully-adjusted model was 0.50 (95% CI: 0.32−0.80, p = 0.003). Conclusions: The newly developed NMR-based betaine assay exhibits performance characteristics that are consistent with usage in the clinical laboratory. Betaine levels may be useful for assessing the risk of future T2DM.

Introduction: Metabolic Vulnerability Index (MVX) is a novel spectroscopic multimarker of mortality risk. MVX reflects components of nutrition and systemic inflammation status and is hypothesized to enhance disease and mortality risk stratification. As Studies Targeting Risk Reduction Interventions through Defined Exercise (STRRIDE) has previously demonstrated the ability of aerobic exercise training to improve traditional markers of cardiometabolic health, we hypothesized that aerobic exercise intervention also would result in beneficial changes in the components of MVX. Methods: Participants (n=222, previously sedentary, overweight men and women with mild to moderate dyslipidemia from STRRIDE) were randomized to either a 6-month control group or to one of three supervised aerobic exercise groups for 8-months: 1) low amount moderate intensity (LM): 14 kcal/kg/wk at 40-55% VO 2peak ; 2) low amount vigorous intensity (LV): 14 kcal/kg/wk at 65-80% VO 2peak ; 3) high amount vigorous intensity (HV): 21 kcal/kg/wk at 65-80% VO 2peak . Blood samples were obtained after an overnight fast at both baseline and study completion (16-24 hr after the final training bout for exercisers). Nuclear magnetic resonance spectroscopy was performed on the Vantera ® clinical analyzer at LabCorp to determine MVX score. MVX has two components: inflammation index [INFX; combined concentrations of GlycA and small HDL particle subspecies (diameters < 9 nm)] and metabolic malnutrition index (MALNX; combined concentrations of total branched chain amino acids and ketone bodies). MVX, INFX, and MALNX are all scaled from 1 (lowest risk) to 100 (highest risk). Paired t-tests determined whether the post- minus pre- intervention change scores within each group were significant (p Results: The inactive control group did not exhibit significant changes in any of the multimarkers. After 8-months of exercise training, the LM group experienced significant decreases in all three scores: INFX (-2.1 ± 5.2), MALNX (-3.1 ± 11.3), and MVX (-3.9 ± 9.1). The LV group significantly decreased their INFX score (-1.5 ± 3.8), yet significantly increased MALNX (2.2 ± 6.8). The HV group significantly decreased their INFX (-1.6 ± 4.8) and MVX scores (-1.9 ± 5.6). For the LM group, the beneficial changes in MALNX and MVX were significantly greater than the LV group. Conclusion: Aerobic exercise improved components of the novel risk-prediction multimarker MVX, with the LM group displaying the best responses across all three scores. As ongoing research investigates the clinical utility of these mulitmarkers, this study provides evidence for the ability of exercise intervention to beneficially change MVX score.

Background: Low circulating magnesium (Mg) is associated with an increased risk of developing type 2 diabetes mellitus (T2DM). We aimed to study the performance of a nuclear magnetic resonance (NMR)-based assay that quantifies ionized Mg in EDTA plasma samples and prospectively investigate the association of Mg with the risk of T2DM. Methods: The analytic performance of an NMR-based assay for measuring plasma Mg was evaluated. We studied 5747 subjects free of T2DM at baseline in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study. Results: Passing&ndash, Bablok regression analysis, comparing NMR-measured ionized Mg with total Mg measured by the Roche colorimetric assay, produced a correlation of r = 0.90, with a slope of 1.08 (95% CI: 1.00&ndash, 1.13) and an intercept of 0.02 (95% CI: &minus, 0.02&ndash, 0.08). During a median follow-up period of 11.2 (IQR: 7.7&ndash, 12.0) years, 289 (5.0%) participants developed T2DM. The association of NMR-measured ionized Mg with T2DM risk was modified by sex (Pinteraction = 0.007). In women, we found an inverse association between Mg and the risk of developing T2DM, independent of adjustment for potential confounders (HR: 1.80, 95% CI: 1.20&ndash, 2.70). In men, we found no association between Mg and the risk of developing T2DM (HR: 0.90, 95%: 0.67&ndash, 1.21). Conclusion: Lower NMR-measured plasma ionized Mg was independently associated with a higher risk of developing T2DM in women, but not in men.

Background: Lipoprotein particle sizes and concentrations are characteristically altered in patients with insulin resistance (IR) or type 2 diabetes mellitus (T2DM). This study assessed the ability of an IR score, based on nuclear magnetic resonance (NMR)-derived lipoprotein information, to detect IR in otherwise healthy individuals.Lipoprotein subclass and size information were evaluated for strength of association with IR, as measured by homeostasis model assessment of insulin resistance (HOMA-IR) in the Multi-Ethnic Study of Atherosclerosis (MESA). To increase the likelihood of identifying subjects with IR, six lipoprotein measures were combined into a single algorithm. The resulting assay [Lipoprotein Insulin Resistance Index (LP-IR)] was developed using HOMA-IR in 4972 nondiabetic subjects from MESA and verified independently using glucose disposal rates (GDRs) measured during hyperinsulinemic-euglycemic clamps in 56 insulin-sensitive, 46 insulin-resistant, and 46 untreated subjects with T2DM.LP-IR exhibited stronger associations with HOMA-IR (r=0.51) and GDR (r=-0.53) than each of the individual lipoprotein parameters as well as the triglycerides/high-density lipoprotein cholesterol (TGs/HDL-C) ratio (r=0.41 and -0.44, respectively). In MESA, associations between the LP-IR score and HOMA-IR were strong in men (r=0.51), women (r=0.52), European Americans (r=0.58), African Americans (r=0.48), Chinese Americans (r=0.49), and Hispanic Americans (r=0.45). When LP-IR was categorized by HOMA-IR and either body mass index (BMI) or fasting plasma glucose (FPG), subgroups were revealed whose LP-IR scores were high (≥ 50), despite having normal BMIs (24 kg/m(2)) or FPG (100 mg/dL).LP-IR scores had strong associations with multiple measures, HOMA-IR, and GDR, the former being more reflective of hepatic and the latter of peripheral insulin sensitivity, and may represent a simple means to identify individuals with IR.

The amount of cholesterol per low-density lipoprotein (LDL) particle is variable and related in part to particle size, with smaller particles carrying less cholesterol. This variability causes concentrations of LDL cholesterol (LDL-C) and LDL particles (LDL-P) to be discordant in many individuals.LDL-P measured by nuclear magnetic resonance spectroscopy, calculated LDL-C, and carotid intima-media thickness (IMT) were assessed at baseline in the Multi-Ethnic Study of Atherosclerosis, a community-based cohort of 6814 persons free of clinical cardiovascular disease (CVD) at entry and followed for CVD events (n = 319 during 5.5-year follow-up). Discordance, defined as values of LDL-P and LDL-C differing by ≥ 12 percentile units to give equal-sized concordant and discordant subgroups, was related to CVD events and to carotid IMT in models predicting outcomes for a 1 SD difference in LDL-C or LDL-P, adjusted for age, gender, and race.LDL-C and LDL-P were associated with incident CVD overall: hazard ratios (HR 1.20, 95% CI [CI] 1.08-1.34; and 1.32, 95% CI 1.19-1.47, respectively, but for those with discordant levels, only LDL-P was associated with incident CVD (HR 1.45, 95% CI 1.19-1.78; LDL-C HR 1.07, 95% CI 0.88-1.30). IMT also tracked with LDL-P rather than LDL-C, ie, adjusted mean IMT of 958, 932, and 917 microm in the LDL-PLDL-C discordant, concordant, and LDL-PLDL-C discordant subgroups, respectively, with the difference persisting after adjustment for LDL-C (P = .002) but not LDL-P (P = .60).For individuals with discordant LDL-C and LDL-P levels, the LDL-attributable atherosclerotic risk is better indicated by LDL-P.

Background— Changes in conventional lipid risk factors with gemfibrozil treatment only partially explain the reductions in coronary heart disease (CHD) events experienced by men in the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT). We examined whether measurement of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle subclasses provides additional information relative to CHD risk reduction. Methods and Results— This is a prospective nested case-control study of 364 men with a new CHD event (nonfatal myocardial infarction or cardiac death) during a 5.1-year (median) follow-up and 697 age-matched controls. Nuclear magnetic resonance (NMR) spectroscopy was used to quantify levels of LDL and HDL particle subclasses and mean particle sizes in plasma obtained at baseline and after 7 months of treatment with gemfibrozil or placebo. Odds ratios for a 1-SD increment of each lipoprotein variable were calculated with adjusted logistic regression models. Gemfibrozil treatment increased LDL size and lowered numbers of LDL particles (−5%) while raising numbers of HDL particles (10%) and small HDL subclass particles (21%). Concentrations of these LDL and HDL particles achieved with gemfibrozil were significant, independent predictors of new CHD events. For total LDL and HDL particles, odds ratios predicting CHD benefit were 1.28 (95% CI, 1.12 to 1.47) and 0.71 (95% CI, 0.61 to 0.81), respectively. Mean LDL and HDL particle sizes were not associated with CHD events. Conclusions— The effects of gemfibrozil on NMR-measured LDL and HDL particle subclasses, which are not reflected by conventional lipoprotein cholesterol measures, help to explain the demonstrated benefit of this therapy in patients with low HDL cholesterol.

Background: The sex differential in coronary heart disease (CHD) risk, which is not explained by male/female differences in lipid and lipoprotein concentrations, narrows with age. We examined whether this differential CHD risk might, in part, be attributable to the sizes of lipoprotein particles or concentrations of lipoprotein subclasses.Methods: We analyzed frozen plasma samples from 1574 men and 1692 women from exam cycle 4 (1988–1990) of the Framingham Offspring Study. Nuclear magnetic resonance (NMR) spectroscopy was used to determine the subclass concentrations and mean sizes of VLDL, LDL, and HDL particles. Concentrations of lipids and apolipoproteins were measured by standard chemical methods.Results: In addition to the expected sex differences in concentrations of triglycerides, LDL-cholesterol, and HDL-cholesterol, women also had a lower-risk subclass profile consisting of larger LDL (0.4 nm) and HDL (0.5 nm) particles. The sex difference was most pronounced for HDL, with women having a twofold higher (8 vs 4 μmol/L) concentration of large HDL particles than men. Furthermore, similar to the narrowing of the sex difference in CHD risk with age, the observed male/female difference in HDL particle size also decreased with age. Although lipoprotein particle sizes were highly correlated with lipid and lipoprotein concentrations, the sex differences in the mean sizes of lipoprotein particles persisted (P Conclusions: Women have a less atherogenic subclass profile than men, even after accounting for differences in lipid concentrations.

Lipoprotein subclass analyses may facilitate coronary heart disease (CHD) risk stratification and provide insight into the cardioprotective benefits of statins (3-hydroxymethylglutaryl-coenzyme A reductase inhibitors). This study evaluated the influence of pravastatin on lipoprotein subclass profiles to determine whether subjects with predominantly large LDL (LDL size >20.5 nm) or small LDL (LDL size < or =20.5 nm) at baseline differ in responsiveness to drug treatment. Frozen plasma specimens were analyzed from a subset of participants in the Pravastatin Limitation of Atherosclerosis in the Coronaries (PLAC-I) trial at baseline and after treatment for 6 months with pravastatin (n=154) or placebo (n=138). Lipids were measured by standard chemical methods and lipoprotein subclasses by nuclear magnetic resonance (NMR) spectroscopy. Pravastatin-induced changes in lipid levels were similar in subjects with large or small LDL at baseline. Levels of the most abundant LDL subclass were preferentially lowered by pravastatin, resulting in an increase in average LDL size for those with a predominance of small LDL. High-risk CHD subjects with small LDL particles gain at least as much pharmacological benefit from pravastatin as those with large LDL, as evidenced by reductions in the numbers of total and small LDL particles, and increases in average LDL and HDL particle size.