Low-density-lipoprotein cholesterol concentrations and risk of incident diabetes: epidemiological and genetic insights from the Framingham Heart Study.

AIMS/HYPOTHESIS: Statins and niacin (nicotinic acid) reduce circulating LDL-cholesterol (LDL-C) levels by different mechanisms. Yet, both increase the risk of diabetes mellitus. Our objective was to relate blood LDL-C concentrations and a genetic risk score (GRS) for LDL-C to the risk of incident diabetes in individuals not treated with lipid-modifying therapy. METHODS: We evaluated participants of the Framingham Heart Study who attended any of Offspring cohort examination cycles 3-8 and Third Generation cohort examination cycle 1 (N =14,120 person-observations, 6,011 unique individuals; mean age 50 ± 11 years, 56% women), who were not treated with lipid-modifying or antihypertensive medications and who were free from cardiovascular disease at baseline. Incident diabetes was assessed at the next examination. RESULTS: The GRS was significantly associated with LDL-C concentrations (sex- and age-adjusted estimated influence 0.24, p < 0.0001). On follow-up (mean 4.5 ± 1.5 years), 312 individuals (2.2%) developed new-onset diabetes. In multivariable models, a higher LDL-C concentration was associated with lower risk of diabetes (OR per SD increment 0.81, 95% CI 0.70, 0.93, p = 0.004). The GRS was associated with incident diabetes in a similar direction and of comparable magnitude (OR per SD increment 0.85, 95% CI 0.76, 0.96, p = 0.009). CONCLUSIONS/INTERPRETATION: Among individuals not treated with lipid-modifying therapy low LDL-C concentrations were associated with increased diabetes risk. These observations may contribute to our understanding of why lipid-lowering treatment may cause diabetes in some individuals. Additional studies are warranted to elucidate the molecular mechanisms underlying our observations.

The relation of red blood cell fatty acids with vascular stiffness, cardiac structure and left ventricular function: the Framingham Heart Study.

Polyunsaturated fatty acids have been associated with beneficial influences on cardiovascular health. However, the underlying mechanisms are not clear, and data on the relations of polyunsaturated fatty acids to subclinical disease measures such as vascular stiffness and cardiac function are sparse and inconclusive. In a large community-based cohort, we examined the relations of omega-3 and other fatty acids to a comprehensive panel of vascular function measures (assessing microvascular function and large artery stiffness), cardiac structure and left ventricular function. Red blood cell (RBC) membrane fatty acid composition, a measure of long-term fatty acid intake, was assessed in participants of the Framingham Offspring Study and Omni cohorts and related to tonometry-derived measures of vascular stiffness and to a panel of echocardiographic traits using partial correlations. Up to n=3055 individuals (56% women, mean age 66 years) were available for analyses. In age- and sex-adjusted models, higher RBC omega-3 content was moderately associated (p≤0.002) with several measures of vascular stiffness and function in a protective direction. However, after multivariable adjustment, only an association of higher RBC omega-3 content with lower carotid-femoral pulse wave velocity (a measure of aortic stiffness) remained significant (r = -0.06, p=0.002). In secondary analyses, higher linoleic acid, the major nutritional omega-6 fatty acid, was associated with smaller left atrial size, even after multivariable adjustment (r = -0.064, p<0.001). In conclusion, in our cross-sectional community-based study, we found several associations consistent with the notion of protective effects of omega-3 and linoleic acid. The clinical significance of these modest associations remains to be elucidated.

Long-term risk of cardiovascular events across a spectrum of adverse major plasma lipid combinations in the Framingham Heart Study.

BACKGROUND: Blood levels of high low-density lipoprotein cholesterol (LDL-C), high triglycerides (TG), and low high-density lipoprotein cholesterol (HDL-C) have been associated with increased risk of cardiovascular disease (CVD). The long-term comparative CVD risk associated with these 3 major lipid classes in various combinations is, however, unknown. METHODS: A total of 3,501 participants of the Framingham Offspring Study (mean age 51 ± 10 years, 56% women) without CVD at baseline were followed up for incident CVD between 1987 and 2011. Participants were grouped according to baseline lipid values into 8 distinct categories to compare the prognostic significance of values within an optimal range to Third Report of the National Cholesterol Educational Program-defined high LDL-C (> 130 mg/dL), high TG (> 150 mg/dL), and/or low HDL-C (< 40 mg/dL) in various combinations using multivariable-adjusted Cox regression models. RESULTS: On follow-up (median 20.2 years), 724 (21%) had new-onset CVD. Adjusted for confounders and compared with the group with optimal lipid values, hazards ratios and population-attributable risks (PARs) were as follows: isolated low HDL-C, 1.93 (95% CI 1.37-2.71), PAR = 3.1%; isolated high LDL-C, 1.28 (1.03-1.59), PAR 6.4%; isolated high TG, 1.35 (0.91-1.98), PAR = 1.1% (not significant); low HDL-C and high LDL-C, 1.82 (1.33-2.49), PAR = 3.9%; low HDL-C and high TG, 1.74 (1.28-2.37), PAR = 3.9%; high LDL-C and high TG, 1.52 (1.12-2.07), PAR = 6.4%; and high LDL-C, high TG and low HDL-C 2.28 (1.73-3.02), PAR = 7.5%. CONCLUSIONS: Aside from isolated hypertriglyceridemia, low levels of HDL-C, high levels of LDL-C, and high levels of TG in any combination were associated with increased risk of CVD.

Changes in erythrocyte membrane trans and marine fatty acids between 1999 and 2006 in older Americans.

Over the last several years, national programs to lower the content of industrially produced (IP) C18:1 and C18:2 trans fatty acids in foods have been implemented, but whether this has resulted in lower blood trans fatty acid levels is unknown. Likewise, an increased perception of the health benefits of fish oils rich in EPA and DHA may have resulted in an increase in consumption and blood levels of these fatty acids. To explore these issues, we analyzed the changes in RBC fatty acid composition between the 7th (1998-2001) and 8th (2005-2007) examination cycles in a random sample of the Framingham Offspring cohort. This was a retrospective cohort study of 291 participants from whom blood was drawn at both examinations and for whom complete covariate data were available. Overall, the proportion of trans fatty acids in RBC changed by -23% (95% CI: -26 to -21%). RBC EPA+DHA proportions increased by 41% (95% CI: 31 to 52%) in 38 individuals who were taking fish oil supplements at examination 8, but in 253 participants not taking fish oil, the proportion of RBC EPA+DHA did not change. In conclusion, in a random subsample of Framingham Offspring participants with serial observations over 6.7 y, the proportion of trans fatty acids in RBC decreased. Those of EPA+DHA increased in people taking fish oil supplements. These changes could potentially translate into a lower risk for cardiovascular disease.

Insulin resistance and the relationship of a dyslipidemia to coronary heart disease: the Framingham Heart Study.

OBJECTIVE: The goal of this study was to examine the effect of insulin resistance (IR) in subjects without diabetes on the relationship of a dyslipidemia with high triglycerides and low high-density lipoprotein cholesterol (HDL-C) to the development of coronary heart disease (CHD). METHODS AND RESULTS: Lower and higher fasting plasma HDL-C and triglyceride concentrations (defined at the study population median) and presence or absence of IR (defined by upper quartile Homeostatic Model Assessment values) were related to the development of myocardial infarction or CHD death in Framingham Heart Study participants without diabetes or a history of CHD (n=2910) attending the 1991 to 1995 examination. During follow-up (mean, 14 years), 128 participants experienced an incident CHD event. With Kaplan-Meier plots, the incidence of CHD was significantly greater with than without IR at either the lowest HDL-C or the highest triglycerides (P<0.001). In multivariable Cox models adjusted for major CHD risk factors, including waist circumference, only subgroups with IR had a significantly higher incidence of CHD. Compared with a reference group without IR and with higher-than-median HDL-C or lower-than-median triglycerides, the hazard ratio (HR) for incident events was significant with only IR and a lower HDL-C (HR 2.83, P<0.001) or higher triglycerides (HR 2.50, P<0.001). These findings were similar in men and women. CONCLUSIONS: In this community-based sample exclusive of diabetes, incident CHD risk associated with plasma HDL-C or triglycerides was significantly increased only in the presence of IR.

Common genetic variation in multiple metabolic pathways influences susceptibility to low HDL-cholesterol and coronary heart disease.

A low level of HDL-C is the most common plasma lipid abnormality observed in men with established coronary heart disease (CHD). To identify allelic variants associated with susceptibility to low HDL-C and CHD, we examined 60 candidate genes with key roles in HDL metabolism, insulin resistance, and inflammation using samples from the Veterans Affairs HDL Intervention Trial (VA-HIT; cases, n = 699) and the Framingham Offspring Study (FOS; controls, n = 705). VA-HIT was designed to examine the benefits of HDL-raising with gemfibrozil in men with low HDL-C (≤40 mg/dl) and established CHD. After adjustment for multiple testing within each gene, single-nucleotide polymorphisms (SNP) significantly associated with case status were identified in the genes encoding LIPC (rs4775065, P < 0.0001); CETP (rs5882, P = 0.0002); RXRA (rs11185660, P = 0.0021); ABCA1 (rs2249891, P = 0.0126); ABCC6 (rs150468, P = 0.0206; rs212077, P = 0.0443); CUBN (rs7893395, P = 0.0246); APOA2 (rs3813627, P = 0.0324); SELP (rs732314, P = 0.0376); and APOC4 (rs10413089, P = 0.0425). Included among the novel findings of this study are the identification of susceptibility alleles for low HDL-C/CHD risk in the genes encoding CUBN and RXRA, and the observation that genetic variation in SELP may influence CHD risk through its effects on HDL.

Association of circulating cholesteryl ester transfer protein activity with incidence of cardiovascular disease in the community.

BACKGROUND: Plasma high-density lipoprotein cholesterol concentration is related inversely to the risk of cardiovascular disease (CVD). Inhibiting cholesteryl ester transfer protein (CETP) activity raises high-density lipoprotein cholesterol and may be cardioprotective, but an initial clinical trial with a CETP inhibitor was stopped prematurely because of increased CVD in treated patients, raising concerns about this approach. Data relating circulating CETP concentrations to CVD incidence in the community are conflicting. METHODS AND RESULTS: Plasma CETP activity was measured in 1978 Framingham Heart Study participants (mean age, 51 years; 54% women) who attended a routine examination in 1987-1990 and were free of CVD. On follow-up (mean, 15.1 years), 320 participants experienced a first CVD event (fatal or nonfatal coronary heart disease, cerebrovascular disease, peripheral vascular disease, or heart failure). In multivariable analyses adjusted for standard risk factors including high-density lipoprotein cholesterol, plasma CETP activity was related inversely to the incidence of CVD events (hazard ratio for activity, at or above the median of 0.72; 95% confidence interval, 0.57 to 0.90; P=0.004 [compared with below median]; hazard ratio per SD increment, 0.86; 95% confidence interval, 0.76 to 0.97; P=0.01). The inverse association of CETP activity with CVD incidence remained robust in time-dependent models updating standard risk factors every 4 years and was maintained in analyses of incident "hard" CVD events (myocardial infarction, stroke, or heart failure). CONCLUSIONS: In our prospective investigation of a community-based sample, lower plasma CETP activity was associated with greater CVD risk. These observations, if confirmed, challenge the concept that CETP inhibition may lower CVD risk.

Relations of lipid concentrations to heart failure incidence: the Framingham Heart Study.

BACKGROUND: The relations of lipid concentrations to heart failure (HF) risk have not been elucidated comprehensively. METHODS AND RESULTS: In 6860 Framingham Heart Study participants (mean age, 44 years; 54% women) free of baseline coronary heart disease, we related high-density lipoprotein cholesterol (HDL-C) and non-HDL-C to HF incidence during long-term follow-up, adjusting for clinical covariates and myocardial infarction at baseline and updating these at follow-up examinations. We evaluated dyslipidemia-specific population burden of HF by calculating population attributable risks. During follow-up (mean of 26 years), 680 participants (49% women) developed HF. Unadjusted HF incidence in the low (<160 mg/dL) versus high (> or =190 mg/dL) non-HDL-C groups was 7.9% and 13.8%, respectively, whereas incidence in the high (> or =55 [men], > or =65 [women] mg/dL) versus low (<40 [men], <50 [women] mg/dL) HDL-C groups was 6.1% and 12.8%, respectively. In multivariable models, baseline non-HDL-C and HDL-C, modeled as continuous measures, carried HF hazards (confidence intervals) of 1.19 (1.11 to 1.27) and 0.82 (0.75 to 0.90), respectively, per SD increment. In models updating lipid concentrations every 8 years, the corresponding hazards (confidence intervals) were 1.23 (1.16 to 1.31) and 0.77 (0.70 to 0.85). Participants with high baseline non-HDL-C and those with low HDL-C experienced a 29% and 40% higher HF risk, respectively, compared with those in the desirable categories; the population attributable risks for high non-HDL-C and low HDL-C were 7.5% and 15%, respectively. Hazards associated with non-HDL-C and HDL-C remained statistically significant after additional adjustment for interim myocardial infarction. CONCLUSIONS: Dyslipidemia carries HF risk independent of its association with myocardial infarction, suggesting that lipid modification may be a means for reducing HF risk.

Multiple biomarkers for the prediction of first major cardiovascular events and death.

BACKGROUND: Few investigations have evaluated the incremental usefulness of multiple biomarkers from distinct biologic pathways for predicting the risk of cardiovascular events. METHODS: We measured 10 biomarkers in 3209 participants attending a routine examination cycle of the Framingham Heart Study: the levels of C-reactive protein, B-type natriuretic peptide, N-terminal pro-atrial natriuretic peptide, aldosterone, renin, fibrinogen, D-dimer, plasminogen-activator inhibitor type 1, and homocysteine; and the urinary albumin-to-creatinine ratio. RESULTS: During follow-up (median, 7.4 years), 207 participants died and 169 had a first major cardiovascular event. In Cox proportional-hazards models adjusting for conventional risk factors, the following biomarkers most strongly predicted the risk of death (each biomarker is followed by the adjusted hazard ratio per 1 SD increment in the log values): B-type natriuretic peptide level (1.40), C-reactive protein level (1.39), the urinary albumin-to-creatinine ratio (1.22), homocysteine level (1.20), and renin level (1.17). The biomarkers that most strongly predicted major cardiovascular events were B-type natriuretic peptide level (adjusted hazard ratio, 1.25 per 1 SD increment in the log values) and the urinary albumin-to-creatinine ratio (1.20). Persons with "multimarker" scores (based on regression coefficients of significant biomarkers) in the highest quintile as compared with those with scores in the lowest two quintiles had elevated risks of death (adjusted hazard ratio, 4.08; P<0.001) and major cardiovascular events (adjusted hazard ratio, 1.84; P=0.02). However, the addition of multimarker scores to conventional risk factors resulted in only small increases in the ability to classify risk, as measured by the C statistic. CONCLUSIONS: For assessing risk in individual persons, the use of the 10 contemporary biomarkers that we studied adds only moderately to standard risk factors.

Cardiovascular events with increased lipoprotein-associated phospholipase A(2) and low high-density lipoprotein-cholesterol: the Veterans Affairs HDL Intervention Trial.

OBJECTIVE: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), a proinflammatory enzyme that predominantly circulates with low-density lipoprotein (LDL), has been shown in general populations to predict cardiovascular (CV) events. We sought to determine whether increased Lp-PLA(2) would also predict CV events in the absence of high LDL-cholesterol (LDL-C), in a population with low high-density lipoprotein-cholesterol (HDL-C). METHODS AND RESULTS: Plasma Lp-PLA(2) activity was measured at baseline and after 6 months on-trial in 1451 men with low HDL-C (mean, 32 mg/dL) and low LDL-C (mean 110 mg/dL), randomized to either placebo or gemfibrozil therapy in the Veterans Affairs HDL Intervention Trial (VA-HIT). Over a quartile range of increasing Lp-PLA(2) there was a significant increase in LDL-C and decrease in HDL-C (P < 0.0001), and an increased percentage of myocardial infarction (MI), stroke, or CHD death (P=0.03 for trend). In Cox models, adjusted for major CV risk factors, a 1-SD increase in Lp-PLA(2) was associated with a significant increase in CV events (hazard ratio [HR] 1.17 95% CI 1.04 to 1.32). Although gemfibrozil reduced Lp-PLA(2) only modestly (6.6%), at higher levels of Lp-PLA(2) gemfibrozil produced a significant reduction in CV events. CONCLUSIONS: In VA-HIT, a population with low HDL-C and LDL-C, high Lp-PLA(2) independently predicted CV events that were reduced by gemfibrozil.

Usefulness of the triglyceride-high-density lipoprotein versus the cholesterol-high-density lipoprotein ratio for predicting insulin resistance and cardiometabolic risk (from the Framingham Offspring Cohort).

Increased triglycerides (TG) and decreased high-density lipoprotein (HDL) cholesterol are key metabolic abnormalities in patients with insulin resistance (IR) states, including diabetes mellitus. The TG/HDL cholesterol ratio was advocated as a simple clinical indicator of IR, but studies yielded inconsistent results. The total cholesterol/HDL cholesterol ratio was widely used to assess lipid atherogenesis, but its utility for assessing IR or its associated coronary heart disease (CHD) risk was unknown. TG/HDL cholesterol and total cholesterol/HDL cholesterol ratios were related to IR (top quartile of the homeostasis model assessment-IR) in 3,014 patients (mean age 54 years; 55% women). Logistic regression was used to construct receiver-operator characteristic curves for predicting IR, with lipid ratios as predictors. Multivariable Cox regression was used to evaluate whether adjusting for lipid ratios attenuated the association of IR with CHD. Cross sectionally, age- and gender-adjusted correlations of IR were 0.46 with TG/HDL cholesterol ratio and 0.38 with total/HDL cholesterol ratio. IR prevalence increased across tertiles of lipid ratios (p <0.0001). The area under the receiver-operator characteristic curves for predicting IR with TG/HDL cholesterol ratio was 0.745, slightly higher than that for total/HDL cholesterol ratio (0.707; p <0.001 for comparison). On follow-up (mean 6.4 years), 112 patients experienced initial CHD events. IR was associated with CHD risk (multivariable-adjusted hazards ratio 2.71, 95% confidence interval 1.79 to 4.11), which remained significant even after adjustment for lipid ratios. In conclusion, our observations suggested that the TG/HDL cholesterol ratio was an imperfect surrogate for IR and its associated CHD risk, and it was only slightly better than the total/HDL cholesterol ratio for this purpose.

Relation of gemfibrozil treatment and high-density lipoprotein subpopulation profile with cardiovascular events in the Veterans Affairs High-Density Lipoprotein Intervention Trial.

The significant cardiovascular disease (CVD) event reduction in the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT) could not be fully explained by the 6% increase in high-density lipoprotein (HDL) cholesterol with the fibrate gemfibrozil. We examined whether measurement of HDL subpopulations provided additional information relative to CVD risk reduction. The HDL subpopulations were characterized by 2-dimensional gel electrophoresis in subjects who were treated with gemfibrozil (n = 754) or placebo (n = 741). In this study, samples obtained at the 3-month visit were used; and data were analyzed prospectively using CVD events (coronary heart disease death, myocardial infarction, or stroke) during the 5.1 years of follow-up. Analyses in the gemfibrozil arm showed that subjects with recurrent CVD events had significantly higher prebeta-1 and had significantly lower alpha-1 and alpha-2 HDL levels than those without such events. Prebeta-1 level was a significant positive predictor; alpha-1 and alpha-2 levels were significant negative risk factors for future CVD events. alpha-2 level was superior to HDL cholesterol level in CVD-risk assessment after adjustment for established risk factors. Gemfibrozil treatment was associated with 3% to 6% decreases in the small, lipid-poor prebeta-1 HDL and in the large, lipid-rich alpha-1 and alpha-2 HDL and with increases in the small alpha-3 (3%) and prealpha-3 (16%) HDLs. Although the use of gemfibrozil has been associated with reduction in CVD events in VA-HIT, HDL subpopulation analysis indicates that gemfibrozil-mediated improvement in CVD risk might not be the result of its effects on HDL. It is quite possible that much of the cardiovascular benefits of gemfibrozil are due to a much wider spectrum of effects on metabolic processes that is not reflected by changes in blood lipids and HDL subpopulations.

Gamma glutamyl transferase and metabolic syndrome, cardiovascular disease, and mortality risk: the Framingham Heart Study.

OBJECTIVE: To determine whether serum gamma-glutamyl transferase (GGT) predicts cardiovascular disease (CVD) morbidity and mortality, accounting for temporal changes in known CVD risk factors and C-reactive protein (CRP). METHODS AND RESULTS: In 3451 Framingham Study participants (mean age 44 years, 52% women) we examined the relations of GGT with CVD risk factors, and prospectively determined the risk of new-onset metabolic syndrome, incident CVD, and death. GGT was positively associated with body mass index, blood pressure, LDL cholesterol, triglycerides, and blood glucose in cross-sectional analysis (P<0.005). On follow-up (mean 19 years), 968 participants developed metabolic syndrome, 535 developed incident CVD, and 362 died. The risk of metabolic syndrome increased with higher GGT (multivariable-adjusted hazard ratio [HR] per SD increment log-GGT, 1.26 [95%CI; 1.18 to 1.35]). Adjusting for established CVD risk factors (as time-dependent covariates updated quadriennially) and baseline CRP, a 1-SD increase in log-GGT conferred a 13% increase in CVD risk (P=0.007) and 26% increased risk of death (P<0.001). Individuals in the highest GGT quartile experienced a 67% increase in CVD incidence (multivariable-adjusted HR 1.67, 95%CI; 1.25 to 2.22). CONCLUSIONS: An increase in serum GGT predicts onset of metabolic syndrome, incident CVD, and death suggesting that GGT is a marker of metabolic and cardiovascular risk.

Increased small low-density lipoprotein particle number: a prominent feature of the metabolic syndrome in the Framingham Heart Study.

BACKGROUND: Levels of LDL cholesterol (LDL-C) are frequently not elevated in individuals with the metabolic syndrome (MetSyn). However, the atherogenic potential of LDL may depend on the number and size of LDL particles in addition to the cholesterol content of LDL. METHODS AND RESULTS: We examined the sex-specific cross-sectional relations of small LDL particle number (determined by nuclear magnetic resonance spectroscopy) to the presence of MetSyn and its components in 2993 Framingham Heart Study participants (mean age, 51 years; 53% women) without cardiovascular disease (CVD) and the relations of small LDL particle number to CVD incidence in people with MetSyn. The MetSyn (> or =3 of 5 traits as defined by the National Cholesterol Education Adult Treatment Panel III) was present in 27% of men and 17% of women. In both sexes, small LDL particle number increased from 0 to 5 MetSyn traits, a pattern partly accounted for by strong correlations between small LDL particle number and serum triglycerides (r=0.61, P<0.0001) and HDL-C (r=-0.55, P<0.0001). Compared with participants without the MetSyn, those with the MetSyn had a higher CVD event rate. However, among participants with the MetSyn, CVD rates were similar for groups with an elevated versus a lower number of small LDL particles (defined by the sex-specific median). CONCLUSIONS: Small LDL particle number is elevated in the MetSyn, increases with the number of MetSyn components, and most prominently is correlated with triglycerides and HDL-C. Whereas increased small LDL particle number identified the MetSyn with high sensitivity, a higher small LDL particle number was not associated with greater CVD event rates in people with the MetSyn.

Low-density lipoprotein and high-density lipoprotein particle subclasses predict coronary events and are favorably changed by gemfibrozil therapy in the Veterans Affairs High-Density Lipoprotein Intervention Trial.

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.

Genome-wide association with select biomarker traits in the Framingham Heart Study.

BACKGROUND: Systemic biomarkers provide insights into disease pathogenesis, diagnosis, and risk stratification. Many systemic biomarker concentrations are heritable phenotypes. Genome-wide association studies (GWAS) provide mechanisms to investigate the genetic contributions to biomarker variability unconstrained by current knowledge of physiological relations. METHODS: We examined the association of Affymetrix 100K GeneChip single nucleotide polymorphisms (SNPs) to 22 systemic biomarker concentrations in 4 biological domains: inflammation/oxidative stress; natriuretic peptides; liver function; and vitamins. Related members of the Framingham Offspring cohort (n = 1012; mean age 59 +/- 10 years, 51% women) had both phenotype and genotype data (minimum-maximum per phenotype n = 507-1008). We used Generalized Estimating Equations (GEE), Family Based Association Tests (FBAT) and variance components linkage to relate SNPs to multivariable-adjusted biomarker residuals. Autosomal SNPs (n = 70,987) meeting the following criteria were studied: minor allele frequency > or = 10%, call rate > or = 80% and Hardy-Weinberg equilibrium p > or = 0.001. RESULTS: With GEE, 58 SNPs had p < 10(-6): the top SNPs were rs2494250 (p = 1.00*10(-14)) and rs4128725 (p = 3.68*10(-12)) for monocyte chemoattractant protein-1 (MCP1), and rs2794520 (p = 2.83*10(-8)) and rs2808629 (p = 3.19*10(-8)) for C-reactive protein (CRP) averaged from 3 examinations (over about 20 years). With FBAT, 11 SNPs had p < 10(-6): the top SNPs were the same for MCP1 (rs4128725, p = 3.28*10(-8), and rs2494250, p = 3.55*10(-8)), and also included B-type natriuretic peptide (rs437021, p = 1.01*10(-6)) and Vitamin K percent undercarboxylated osteocalcin (rs2052028, p = 1.07*10(-6)). The peak LOD (logarithm of the odds) scores were for MCP1 (4.38, chromosome 1) and CRP (3.28, chromosome 1; previously described) concentrations; of note the 1.5 support interval included the MCP1 and CRP SNPs reported above (GEE model). Previous candidate SNP associations with circulating CRP concentrations were replicated at p < 0.05; the SNPs rs2794520 and rs2808629 are in linkage disequilibrium with previously reported SNPs. GEE, FBAT and linkage results are posted at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite. CONCLUSION: The Framingham GWAS represents a resource to describe potentially novel genetic influences on systemic biomarker variability. The newly described associations will need to be replicated in other studies.

Plasma phosphatidylcholine docosahexaenoic acid content and risk of dementia and Alzheimer disease: the Framingham Heart Study.

BACKGROUND: Docosahexaenoic acid (DHA) is an abundant fatty acid in the brain. In the diet, DHA is found mostly in fatty fish. The content of DHA has been shown to be decreased in the brain and plasma of patients with dementia. OBJECTIVE: To determine whether plasma phosphatidylcholine (PC) DHA content is associated with the risk of developing dementia. DESIGN, SETTING, AND PARTICIPANTS: A prospective follow-up study in 899 men and women who were free of dementia at baseline, had a median age of 76.0 years, and were followed up for a mean of 9.1 years for the development of all-cause dementia and Alzheimer disease. MAIN OUTCOME MEASURES: Plasma PC fatty acid levels were measured at baseline. Cox proportional regression analysis was used to assess relative risks of all-cause dementia and Alzheimer disease according to baseline plasma levels. RESULTS: Ninety-nine new cases of dementia (including 71 of Alzheimer disease) occurred during the follow-up. After adjustment for age, sex, apolipoprotein E epsilon4 allele, plasma homocysteine concentration, and education level, subjects in the upper quartile of baseline plasma PC DHA levels, compared with subjects in the lower 3 quartiles, had a relative risk of 0.53 of developing all-cause dementia (95% confidence interval, 0.29-0.97; P=.04) and 0.61 of developing Alzheimer disease (95% confidence interval, 0.31-1.18; P=.14). Subjects in the upper quartile of plasma PC DHA levels had a mean DHA intake of 0.18 g/d and a mean fish intake of 3.0 servings per week (P<.001) in a subset of 488 participants. We found no other significant associations. CONCLUSION: The top quartile of plasma PC DHA level was associated with a significant 47% reduction in the risk of developing all-cause dementia in the Framingham Heart Study.

The L162V polymorphism at the peroxisome proliferator activated receptor alpha locus modulates the risk of cardiovascular events associated with insulin resistance and diabetes mellitus: the Veterans Affairs HDL Intervention Trial (VA-HIT).

BACKGROUND: The Veterans Affairs HDL Intervention Trial (VA-HIT) showed that gemfibrozil, which activates peroxisome proliferator-activator receptor alpha (PPARalpha), significantly reduced the risk of cardiovascular (CV) events in men with low HDL cholesterol (< 40 mg/dl) and established coronary heart disease. Treatment was particularly beneficial in those with insulin resistance (IR) or diabetes mellitus (DM). We hypothesized that the association between a functional polymorphism at the PPARA locus (L162V) and the risk of a CV event, as well as response to fibrate therapy, might be greatest in those with either IR or DM (DM/IR) in VA-HIT. METHODS AND RESULTS: A total of 827 men (placebo, n = 413; gemfibrozil, n = 414) from the VA-HIT were genotyped. This population included a high proportion of subjects with DM/IR. In VA-HIT, the PPARA V162 allele was associated with reduced levels of HDL cholesterol and the presence of DM/IR at baseline. It was also associated with reduced risk of CV events in those with DM/IR but not in those with neither (DM/IR *PPARA genotype, P = 0.005). Among subjects with DM/IR, treatment with gemfibrozil reduced CV events in non-carriers from 29.9 to 17.8% and carriers of the V162 allele from 14.7 to 4.8%. In contrast, carriers of the V162 allele with no DM/IR who were treated with gemfibrozil experienced significantly more CV events than did those who received placebo (20.6% versus 13.6%; P = 0.01). CONCLUSIONS: The effect of the L162V polymorphism at the PPARA locus on CV risk depends on the presence of DM/IR. Among subjects treated with gemfibrozil, the V162 allele was associated not only with reduced CV risk in subjects with DM/IR, but also with significantly increased CV risk in the absence of these traits, identifying this genetic variant as a potential marker for predicting which subjects may have a favorable response to fibrate therapy.

LpA-I, LpA-I:A-II HDL and CHD-risk: The Framingham Offspring Study and the Veterans Affairs HDL Intervention Trial.

OBJECTIVE: We tested the hypothesis that concentrations of LpA-I and/or LpA-I:A-II HDL subclasses are significantly associated with CHD prevalence and recurrent cardiovascular events. METHODS: LpA-I levels were determined by differential electroimmunoassay in male participants with (n = 169) and without CHD (n = 850) from the Framingham Offspring Study (FOS) and in male participants with CHD from the placebo arm of the Veterans Affairs HDL Intervention Trial (VA-HIT) (n = 741). Data were analyzed cross-sectionally (FOS) and prospectively (VA-HIT) and were adjusted for established lipid and non-lipid CHD risk factors. RESULTS: We observed slightly but significantly higher LpA-I levels in CHD cases compared to all or to HDL-C-matched controls and slightly but significantly higher LpA-I:A-II levels in CHD cases compared to HDL-C-matched controls it the FOS. Neither LpA-I nor LpA-I:A-II levels were significantly different between groups with and without recurrent cardiovascular events in the VA-HIT. No significant differences were observed in LpA-I and LpA-I:A-II levels in low HDL-C (< or = 40 mg/dl) subjects with CHD (VA-HIT, n = 711) and without CHD (FOS, n = 373). Plasma LpA-I concentration had a positive correlation with the large LpA-I HDL particle (alpha-1) but no correlation with the small LpA-I HDL particle (prebeta-1). LpA-I:A-II concentration had a positive correlation with the large (alpha-2) and an inverse correlation with the small (alpha-3) LpA-I:A-II HDL particles. CONCLUSION: Our data do not support the hypothesis that CHD prevalence (FOS) or recurrence of cardiovascular events (VA-HIT) are associated with significant reductions in the concentrations of LpA-I and/or LpA-I:A-II HDL subclasses.

Value of high-density lipoprotein (HDL) subpopulations in predicting recurrent cardiovascular events in the Veterans Affairs HDL Intervention Trial.

OBJECTIVE: To test the hypothesis whether determination of high-density lipoprotein (HDL) subpopulations provides more power to predict recurrent cardiovascular disease (CVD) events (nonfatal myocardial infarction, coronary heart disease death, and stroke) than traditional risk factors in the Veterans Affairs HDL Intervention Trial (VA-HIT). METHODS AND RESULTS: Apolipoprotein A-I (apoA-I)-containing HDL subpopulations were quantitatively determined by nondenaturing 2D gel electrophoresis. Hazard ratios of recurrent CVD events were calculated by comparing VA-HIT subjects with (n=398) and without (n=1097) such events. Subjects with new CVD events had significantly lower HDL-C, apoA-I, and large cholesterol-rich HDL particle (alpha-1, alpha-2, pre-alpha-1, and pre-alpha-2) levels, significantly higher triglyceride, and small poorly lipidated HDL particle (pre-beta-1 and alpha-3) levels than subjects without such events. Multivariate analyses indicated that alpha-1 and alpha-2 particle levels were significant negative risk factors, whereas alpha-3 level was a significant positive risk factor for new CVD events. Pre-beta-1 level was a significant risk factor for new CVD events only in univariate analysis. A forward selection model indicated that alpha-1 was the most significant risk factor for recurrent CVD events among HDL particles. CONCLUSIONS: An altered HDL subpopulation profile marked with low alpha-1 and alpha-2 levels and a high alpha-3 level in coronary heart disease patients indicated an elevated risk for new CVD events. Moreover, alpha-1 and alpha-2 levels were superior to HDL-C levels in risk assessment in patients with low HDL-C in VA-HIT.