A Bayesian network model for predicting cardiovascular risk

BACKGROUND AND OBJECTIVE

Cardiovascular diseases are the leading death cause in Europe and entail large treatment costs. Cardiovascular risk prediction is crucial for the management and control of cardiovascular diseases. Based on a Bayesian network built from a large population database and expert judgment, this work studies interrelations between cardiovascular risk factors, emphasizing the predictive assessment of medical conditions, and providing a computational tool to explore and hypothesize such interrelations.

METHODS

We implement a Bayesian network model that considers modifiable and non-modifiable cardiovascular risk factors as well as related medical conditions. Both the structure and the probability tables in the underlying model are built using a large dataset collected from annual work health assessments as well as expert information, with uncertainty characterized through posterior distributions.

RESULTS

The implemented model allows for making inferences and predictions about cardiovascular risk factors. The model can be utilized as a decision- support tool to suggest diagnosis, treatment, policy, and research hypothesis. The work is complemented with a free software implementing the model for practitioners' use.

CONCLUSIONS

Our implementation of the Bayesian network model facilitates answering public health, policy, diagnosis, and research questions concerning cardiovascular risk factors.

Association of BCAT2 and BCKDH polymorphisms with clinical, anthropometric and biochemical parameters in young adults

BACKGROUND AND AIM

Circulating amino acids are modified by sex, body mass index (BMI) and insulin resistance (IR). However, whether the presence of genetic variants in branched-chain amino acid (BCAA) catabolic enzymes modifies circulating amino acids is still unknown. Thus, we determined the frequency of two genetic variants, one in the branched-chain aminotransferase 2 (BCAT2) gene (rs11548193), and one in the branched-chain ketoacid dehydrogenase (BCKDH) gene (rs45500792), and elucidated their impact on circulating amino acid levels together with clinical, anthropometric and biochemical parameters.

METHODS AND RESULTS

We performed a cross-sectional comparative study in which we recruited 1612 young adults (749 women and 863 men) aged 19.7 ± 2.1 years and with a BMI of 24.9 ± 4.7 kg/m². Participants underwent clinical evaluation and provided blood samples for DNA extraction and biochemical analysis. The single nucleotide polymorphisms (SNPs) were determined by allelic discrimination using real-time polymerase chain reaction (PCR). The frequencies of the less common alleles were 15.2 % for BCAT2 and 9.83 % for BCKDH. The subjects with either the BCAT2 or BCKDH SNPs displayed no differences in the evaluated parameters compared with subjects homozygotes for the most common allele at each SNP. However, subjects with both SNPs had higher body weight, BMI, blood pressure, glucose, and circulating levels of aspartate, isoleucine, methionine, and proline than the subjects homozygotes for the most common allele (P < 0.05, One-way ANOVA).

CONCLUSION

Our findings suggest that the joint presence of both the BCAT2 rs11548193 and BCKDH rs45500792 SNPs induces metabolic alterations that are not observed in subjects without either SNP.

Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based?

The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S. Dietary Guidelines for Americans, the country's national nutrition policy, which recently reconfirmed its recommendation to limit saturated fats to 10% or less of total energy intake, based on insufficient and inconsistent evidence. Continuation of a cap on saturated fat intake also fails to consider the important effects of the food matrix and the overall dietary pattern in which saturated fatty acids are consumed.

Lifestyle interventions for the prevention and treatment of hypertension

Hypertension affects approximately one third of the world's adult population and is a major cause of premature death despite considerable advances in pharmacological treatments. Growing evidence supports the use of lifestyle interventions for the prevention and adjuvant treatment of hypertension. In this Review, we provide a summary of the epidemiological research supporting the preventive and antihypertensive effects of major lifestyle interventions (regular physical exercise, body weight management and healthy dietary patterns), as well as other less traditional recommendations such as stress management and the promotion of adequate sleep patterns coupled with circadian entrainment. We also discuss the physiological mechanisms underlying the beneficial effects of these lifestyle interventions on hypertension, which include not only the prevention of traditional risk factors (such as obesity and insulin resistance) and improvements in vascular health through an improved redox and inflammatory status, but also reduced sympathetic overactivation and non-traditional mechanisms such as increased secretion of myokines.

Mediterranean Diet Adherence Modulates Anthropometric Measures by TCF7L2 Genotypes among Puerto Rican Adults

BACKGROUND

Transcription factor 7-like 2 (TCF7L2) genetic variants that predispose individuals to type 2 diabetes (T2D) show inconsistent associations with anthropometric traits. Interaction between TCF7L2 genotypes and dietary factors may help explain these observations.

OBJECTIVE

We aimed to examine the potential modulation of TCF7L2-rs7903146 and rs12255372 on anthropometric markers by a Mediterranean diet (MedDiet).

METHODS

Cross-sectional analysis was conducted in 1120 participants (aged 45-75 y) of the Boston Puerto Rican Health Study. Anthropometric variables were measured, and polymorphisms were genotyped using standardized protocols. Diet was assessed using a validated FFQ. The MedDiet was defined based on adherence to 9 food and nutrient components using sex-specific population-based median cut-offs; high adherence was defined as meeting ≥4 components. Haplotypes were tested for association with obesity traits, independently and via interaction with the MedDiet.

RESULTS

TCF7L2-rs7903146 showed significant interaction with the MedDiet influencing BMI, weight, and waist circumference. The T risk-allele carriers (CT + TT) with a high MedDiet score had lower weight (77.3 ± 1.0 compared with CC 80.9 ± 1.0 kg; P = 0.013) and waist circumference (99.2 ± 0.9 compared with CC 102.2 ± 0.9 cm; P = 0.021), when compared with CC participants. A low MedDiet score resulted in no significant differences between genotypes. For TCF7L2-rs12255372, we found significant interactions with the MedDiet for weight (P-interaction = 0.034) and BMI (P-interaction = 0.036). The T allele carriers with a higher MedDiet score showed a trend of lower but no significant differences when compared with CC participants for BMI (P = 0.19), weight (P = 0.09), and waist circumference (P = 0.11). We found significant interactions between the 2 risk-carrying haplotypes and the MedDiet compared with the common haplotype (GC), with lower BMI (β ± SE, TT: -1.53 ± 0.68; P-interaction = 0.024), weight (TT: -4.16 ± 1.77; P-interaction = 0.019), and waist circumference (GT: -5.07 ± 2.50; P-interaction = 0.042) at a high MedDiet score.

CONCLUSION

Puerto Ricans with the TCF7L2-rs7903146 and rs12255372 T2D risk genotypes, although still high, had better anthropometric profiles when adhering to a MedDiet, suggesting that this diet may offset unfavorable genetic predisposition.

Weight gain prevention buffers the impact of CETP rs3764261 on high density lipoprotein cholesterol in young adulthood: The Study of Novel Approaches to Weight Gain Prevention (SNAP)

BACKGROUND AND AIMS

Two weight gain prevention strategies, one targeting small changes to diet and physical activity and a second targeting large changes, significantly reduced weight gain in young adulthood. We examined whether weight gain prevention blunts genetic risk for body weight increase and/or high density lipoprotein cholesterol (HDL-C) lowering over two years.

METHODS AND RESULTS

Participants were 524 male and female young adults (mean age = 28.2, SD = 4.3; mean BMI = 25.5, SD = 2.6). Obesity-related SNPs accounting for ≥ 0.04% of the variance were genotyped and combined into a genetic risk score. For HDL-C, SNPs within CETP, LIPC and FADS2 were genotyped. The obesity-related genetic risk score did not predict change in BMI independently or in interaction with treatment arm. However, consistent with the prior literature, each copy of the HDL-C risk, C, allele at CETP rs3764261 was associated with lower HDL-C at baseline. Moreover, significant interaction between SNP and treatment arm for change in HDL-C was observed (p = 0.02). In the control group, HDL-C change was dependent upon rs3764261 (p = 0.004) with C allele carriers showing a continued reduction in HDL-C. In contrast, within the two intervention groups, HDL-C increased on average with no differential effect of rs3764261 (p > 0.24). Notably, even among carriers of the CC genotype, small and large change arms were associated with increased HDL-C and the control arm a reduction (p = 0.013).

CONCLUSIONS

The C allele at CETP rs3764261 is a strong risk factor for low HDL-C in young adulthood but weight gain prevention may mitigate this risk. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE: clinicaltrials.gov Identifier: NCT01183689, https://clinicaltrials.gov/.

Interindividual Variability in Biomarkers of Cardiometabolic Health after Consumption of Major Plant-Food Bioactive Compounds and the Determinants Involved

Cardiometabolic disease, comprising cardiovascular diseases, type 2 diabetes, and their associated risk factors including metabolic syndrome and obesity, is the leading cause of death worldwide. Plant foods are rich sources of different groups of bioactive compounds, which might not be essential throughout life but promote health and well-being by reducing the risk of age-related chronic diseases. However, heterogeneity in the responsiveness to bioactive compounds can obscure associations between their intakes and health outcomes, resulting in the hiding of health benefits for specific population groups and thereby limiting our knowledge of the exact role of the different bioactive compounds for health. The heterogeneity in response suggests that some individuals may benefit more than others from the health effects of these bioactive compounds. However, to date, this interindividual variation after habitual intake of plant bioactive compounds has been little explored. The aim of this review is to provide an overview of the existing research that has revealed interindividual variability in the responsiveness to plant-food bioactive compound consumption regarding cardiometabolic outcomes, focusing on polyphenols, caffeine and plant sterols, and the identified potential determinants involved.

Identification and validation of seven new loci showing differential DNA methylation related to serum lipid profile: an epigenome-wide approach. The REGICOR study

Lipid traits (total, low-density and high-density lipoprotein cholesterol, and triglycerides) are risk factors for cardiovascular disease. DNA methylation is not only an inherited but also modifiable epigenetic mark that has been related to cardiovascular risk factors. Our aim was to identify loci showing differential DNA methylation related to serum lipid levels. Blood DNA methylation was assessed using the Illumina Human Methylation 450 BeadChip. A two-stage epigenome-wide association study was performed, with a discovery sample in the REGICOR study (n = 645) and validation in the Framingham Offspring Study (n = 2,542). Fourteen CpG sites located in nine genes (SREBF1, SREBF2, PHOSPHO1, SYNGAP1, ABCG1, CPT1A, MYLIP, TXNIP and SLC7A11) and 2 intergenic regions showed differential methylation in association with lipid traits. Six of these genes and 1 intergenic region were new discoveries showing differential methylation related to total cholesterol (SREBF2), HDL-cholesterol (PHOSPHO1, SYNGAP1 and an intergenic region in chromosome 2) and triglycerides (MYLIP, TXNIP and SLC7A11). These CpGs explained 0.7%, 9.5% and 18.9% of the variability of total cholesterol, HDL cholesterol and triglycerides in the Framingham Offspring Study, respectively. The expression of the genes SREBF2 and SREBF1 was inversely associated with methylation of their corresponding CpGs (P-value = 0.0042 and 0.0045, respectively) in participants of the GOLDN study (n = 98). In turn, SREBF1 expression was directly associated with HDL cholesterol (P-value = 0.0429). Genetic variants in SREBF1, PHOSPHO1, ABCG1 and CPT1A were also associated with lipid profile. Further research is warranted to functionally validate these new loci and assess the causality of new and established associations between these differentially methylated loci and lipid metabolism.

Lower-normal TSH is associated with better metabolic risk factors: A cross-sectional study on Spanish men

BACKGROUND AND AIMS

Subclinical thyroid conditions, defined by normal thyroxin (T4) but abnormal thyroid-stimulating hormone (TSH) levels, may be associated with cardiovascular and metabolic risk. More recently, TSH levels within the normal range have been suggested to be associated with metabolic syndrome and cardiovascular risk. This work studies the linearity of the relationship between metabolic syndrome and TSH across the euthyroid range.

METHODS AND RESULTS

We studied 3533 male participants of the Aragon Workers' Health Study (AWHS) with normal TSH and free T4 levels, across quintiles of these variables, after adjusting for age, alcohol intake, and smoking. Compared with the lowest TSH quintile, the odds ratios for metabolic syndrome at the higher quintiles, which indicate lower thyroid function, were 1.34 (1.04, 1.73), 1.56 (1.21, 2.01), 1.57 (1.22, 2.03), and 1.71 (1.32, 2.21). The lowest free T4 quintile also showed an odds ratio of 1.49 (1.16, 1.90) with respect to the highest quintile. In addition, spline models showed departures from linearity: the risk of metabolic syndrome mostly increases at TSH values below the median (sample half-closest to subclinical hyperthyroidism). Interestingly, glucose also increases with TSH primarily below the median TSH, diastolic blood pressure shows similar changes across the entire TSH range, whereas body mass index, triglycerides, and high-density lipoprotein (HDL)-cholesterol change only at the highest normal TSH values, which are associated with lower free T4 concentration.

CONCLUSIONS

TSH and free T4 within the normal range are associated with the metabolic syndrome. The sample half-below the TSH median (with probably higher functional thyroid status) exhibited better metabolic and cardiovascular profiles.

The association between LRP-1 variants and chylomicron uptake after a high fat meal

BACKGROUND AND AIMS

In vitro studies suggest that low density lipoprotein receptor-related protein 1 (LRP1) plays a role in the secondary uptake of chylomicrons. In addition, in vivo studies using LRP-1 knockout mice show these animals exhibit delayed chylomicron clearance. Whether this is true in humans is unknown. We aimed to determine whether genetic variants in LRP-1 are associated with postprandial chylomicron uptake in humans given an oral fat challenge.

METHODS AND RESULTS

As many as 817 men and women (mean age +/- standard deviation = 48.4 +/- 16.4 years) forming the study population for the Genetics of Lipid Lowering Drugs Network (GOLDN) study ingested an oral fat load of 700 kilocalories per m² of body surface area at 83% fat, after an 8-h fast. Chylomicrons were measured by nuclear resonance spectroscopy (NMR) at fasting, and 3.5 and 6 h after the meal. 26 Single nucleotide polymorphisms (SNPs) in the LRP-1 gene were genotyped on the Affymetrix 6.0 array. Chylomicrons were, as expected, zero at fasting. Mixed linear models adjusted for age, sex, study site and pedigree tested for associations between LRP-1 SNPs and changes in chylomicron concentrations 3.5-6 h. A gene-based test across all 26 SNPs was conducted which corrected for the linkage disequilibrium (LD) between SNPs. 11 LRP-1 SNPs were significantly associated with the change in chylomicron concentration correction for multiple testing (Q < 0.05). The subsequent gene-based test, was also significant (P = 0.01).

CONCLUSION

These results require replication but strongly indicate the role of LRP1 in postprandial lipoprotein uptake and/or clearance.

Preliminary evidence of genetic determinants of adiponectin response to fenofibrate in the Genetics of Lipid Lowering Drugs and Diet Network

BACKGROUND AND AIMS

Adiponectin is an adipose-secreted protein that has been linked to changes in insulin sensitivity, high-density lipoprotein cholesterol levels, and inflammatory patterns. Although fenofibrate therapy can raise adiponectin levels, treatment response is heterogeneous and heritable, suggesting a role for genetic mediators. This is the first genome-wide association study of fenofibrate effects on circulating adiponectin.

METHODS AND RESULTS

Plasma adiponectin was measured in participants of the Genetics of Lipid Lowering Drugs and Diet Network (n = 793) before and after a 3-week daily treatment with 160 mg of fenofibrate. Associations between variants on the Affymetrix Genome-Wide Human SNP Array 6.0 and adiponectin were assessed using mixed linear models, adjusted for age, sex, site, and family. We observed a statistically significant (P = 5 × 10⁻⁸) association between rs2384207 in 12q24, a region previously linked to several metabolic traits, and the fenofibrate-induced change in circulating adiponectin. Additionally, our genome-wide analysis of baseline adiponectin levels replicated the previously reported association with CDH13 and suggested novel associations with markers near the PCK1, ZBP1, TMEM18, and SCUBE1 genes. The findings from the single marker tests were corroborated in gene-based analyses. Biological pathway analyses suggested a borderline significant association between the EGF receptor signaling pathway and baseline adiponectin levels.

CONCLUSIONS

We present preliminary evidence linking several biologically relevant genetic variants to adiponectin levels at baseline and in response to fenofibrate therapy. Our findings provide support for fine-mapping of the 12q24 region to investigate the shared biological mechanisms underlying levels of circulating adiponectin and susceptibility to metabolic disease.

Education modulates the association of the FTO rs9939609 polymorphism with body mass index and obesity risk in the Mediterranean population

OBJECTIVE

To define whether the rs9939609 FTO (fat mass and obesity associated) single nucleotide polymorphism (SNP) is associated with anthropometric measurements and its modulation by educational level in a Mediterranean population.

METHODS

We studied 3 independent adult samples: a random sample (n = 1580) from the general population (GP), obese hospital patients (OHP) (n = 203) and elderly subjects (n = 1027) with high cardiovascular risk (HCR). Weight and height were directly measured. Education and physical activity (PA) were measured using questionnaires.

RESULTS

The rs9939609 presented heterogeneous associations with BMI. In the GP, the minor A-allele was significantly associated with greater BMI, following a co-dominant pattern (P = 0.009), whereas in the OHP this association was recessive (P = 0.004). Conversely, we did not find a significant association with BMI in the HCR group (P < 0.596). In the GP we found a significant interaction between the FTO SNP and education (P = 0.048). In the stratified analysis, no association of the FTO SNP with greater BMI in university subjects was detected (P = 0.786), whereas the association was observed in non-university subjects (P = 0.001). The FTO × education interaction (P = 0.020) was also observed in determining obesity risk in the GP. A-allele carriers had a greater risk of being obese only if they had no university education (OR: 1.56; 95%CI: 1.09-2.23 for TA and OR: 2.01; 95%CI: 1.27-3.26 for AA subjects). The interaction of the FTO with education remained significant even after adjustment for PA.

CONCLUSIONS

The association of the FTO SNP with greater BMI and obesity risk in the GP was strongly modulated by education.

Fatty Acid desaturase gene variants, cardiovascular risk factors, and myocardial infarction in the costa rica study

Genetic variation in fatty acid desaturases (FADS) has previously been linked to long-chain polyunsaturated fatty acids (PUFAs) in adipose tissue and cardiovascular risk. The goal of our study was to test associations between six common FADS polymorphisms (rs174556, rs3834458, rs174570, rs2524299, rs174589, rs174627), intermediate cardiovascular risk factors, and non-fatal myocardial infarction (MI) in a matched population based case–control study of Costa Rican adults (n = 1756). Generalized linear models and multiple conditional logistic regression models were used to assess the associations of interest. Analyses involving intermediate cardiovascular risk factors and MI were also conducted in two replication cohorts, The Nurses’ Health Study (n = 1200) and The Health Professionals Follow-Up Study (n = 1295). In the Costa Rica Study, genetic variation in the FADS cluster was associated with a robust linear decrease in adipose gamma-linolenic, arachidonic, and eicosapentaenoic fatty acids, and significant or borderline significant increases in the eicosadienoic, eicosatrienoic, and dihomo-gamma-linolenic fatty acids. However, the associations with adipose tissue fatty acids did not translate into changes in inflammatory biomarkers, blood lipids, or the risk of MI in the discovery or the replication cohorts. In conclusion, fatty acid desaturase polymorphisms impact long-chain PUFA biosynthesis, but their overall effect on cardiovascular health likely involves multiple pathways and merits further investigation.

The PPAR alpha gene is associated with triglyceride, low-density cholesterol and inflammation marker response to fenofibrate intervention: the GOLDN study

As a peroxisome proliferator-activated receptor alpha (PPARα) agonist, fenofibrate favorably modulates dyslipidemia and inflammation markers, which are associated with cardiovascular risk. To determine whether variation in the PPARα receptor gene was associated with lipid and inflammatory marker response, we conducted a three week trial of fenofibrate in 861 men and women. Mixed linear models which controlled for age and sex, as well as family pedigree and study-center, were constructed using SNPs in the PPARα gene as predictors and changes in fasting triglycerides (TGs), cholesterol and inflammatory markers as outcomes. Significant associations with low-density cholesterol (LDL-C) and interleukin-2 (IL-2; P<.001) responses to fenofibrate were found. Although there were suggestive associations with tumour necrosis factor-alpha (TNF-α) and TG responses (P<.05), these did not survive the correction for multiple testing. We conclude that variants in the PPARα gene may contribute to future pharmacogenomic paradigms seeking to predict fenofibrate responders from both an anti-dyslipidemic and anti-inflammatory perspective.

Acculturation and sociocultural influences on dietary intake and health status among Puerto Rican adults in Massachusetts

BACKGROUND

Previous studies have shown negative consequences of acculturation on lifestyle factors, health status, and dietary intake of Hispanic immigrants in the US. Despite prevalent type 2 diabetes and low socioeconomic status (SES) among Puerto Rican adults living on the US mainland, little is known about acculturation in this group.

OBJECTIVE

We investigated associations among acculturation, lifestyle characteristics, health status, and carbohydrate nutrition in Puerto Rican adults. A secondary objective was to investigate possible confounding and/or effect modification on these associations by SES.

DESIGN

Cross-sectional data from the Boston Puerto Rican Health Study, which included 1219 Puerto Ricans in the Boston area, aged 45-75 years.

STATISTICAL ANALYSES

Characteristics were compared using ANCOVA, linear trend and Pearson's chi-square tests across quartiles of acculturation. Tests for interaction by poverty status were conducted. Proportional contributions of foods to intake of total carbohydrate and fiber were assessed using SAS RANK.

RESULTS

Levels of acculturation were low, despite young age at first arrival to the US mainland (25.4 ± 12.3 y) and long length of stay (34.2 ± 12.2 y). Greater English language use was associated with higher SES, alcohol consumption, physical activity, better perceived health, and less central obesity. Acculturation was associated with lower legume fiber and greater cereal fiber intake. Among those above the poverty threshold, acculturation was associated with lower dietary glycemic index and starch intake, and greater fruit and non-starchy vegetable intake.

CONCLUSIONS

In contrast to studies with Mexican Americans, the association of acculturation with dietary quality in these Puerto Rican adults was mixed, but tended toward better carbohydrate quality. Dietary recommendations should include maintenance of traditional, healthful dietary practices including consumption of legumes, but also reduction in refined grains, and greater inclusion of fruit, non-starchy vegetables, and whole grains. Interventions to improve access to better quality carbohydrate sources are necessary for this group disproportionately affected by diabetes.

Polymorphism at the TRIB1 gene modulates plasma lipid levels: insight from the Spanish familial hypercholesterolemia cohort study

BACKGROUND AND AIMS

rs17321515 SNP has been associated with variation in LDL-C, high density lipoprotein cholesterol and triglycerides concentrations. This effect has never been studied in patients with severe hypercholesterolemia. Therefore, our aims were to assess the association of the rs17321515 (TRIB1) SNP with plasma lipids concentrations and anthropometric variables and to explore the interaction between this SNP and some classic risk factors in patients with familial hypercholesterolemia (FH).

METHODS AND RESULTS

rs17321515 SNP was genotyped in 531 subjects with genetic diagnosis of FH. Homozygous A/A had significantly higher waist circumference compared with G/G subjects (P = 0.006) and carriers of the minor allele G (P = 0.039). Interestingly, smokers homozygous for the A allele displayed higher plasma triglycerides concentrations (P = 0.029), higher VLDL-C levels (P = 0.023) and higher TC/HDL-C ratio (P = 0.035) than carriers of the minor allele G. In addition, homozygous A/A with the presence of arcus cornealis displayed lower plasma ApoA-I levels (P = 0.024) and higher TC/HDL-C ratio (P = 0.046) than carriers of the minor allele G.

CONCLUSIONS

Smoking status and presence of arcus cornealis modulate the effect of rs17321515 (TRIB1) polymorphism on plasma lipids levels in patients with FH. These results could explain the differences in the susceptibility to coronary heart disease in these patients.

The APOA1/C3/A4/A5 cluster and markers of allostatic load in the Boston Puerto Rican Health Study

BACKGROUND AND AIMS

The APOA1/C3/A4/A5 cluster encodes key regulators of plasma lipids. Interactions between dietary factors and single nucleotide polymorphisms (SNPs) in the cluster have been reported. Allostatic load, or physiological dysregulation in response to stress, has been implicated in shaping health disparities in ethnic groups. We aimed to determine the association between polymorphisms in the APOA1/C3/A4/A5 cluster with allostatic load parameters, alone, and in interaction with dietary fat intake in Puerto Ricans adults.

METHODS AND RESULTS

Data on demographic and anthropometric measures, lifestyle behaviors, and medication use, as well as blood and urine samples for biomarker analysis, were obtained from participants of the Boston Puerto Rican Health Study (n=821, age 45-75 y). The 12 polymorphisms analyzed were not associated with allostatic load parameters. Significant interactions were observed between dietary fat intake and APOA1-75 in association with waist circumference (WC), (P=0.005), APOC3-640 with diastolic blood pressure (DBP), (P=0.003), and APOA4 N147S and APOA5 S19W with systolic blood pressure (SBP), (P=0.001 and P=0.002, respectively). Puerto Ricans homozygous for the common allele of APOA1-75, APOA4 N147S and APOA5 S19W had lower WC and SBP when consuming <31% of total fat from energy, than participants with the minor allele. Participants heterozygous for APOC3-640 had lower DBP at total fat intake ≥31% from energy.

CONCLUSION

SNPs in APOA1/C3/A4/A5, as modulated by dietary fat intake, appear to influence allostatic load parameters in Puerto Ricans.

Dietary Carbohydrate Modifies the Inverse Association Between Saturated Fat Intake and Cholesterol on Very Low-Density Lipoproteins

We aimed to investigate the relationship between dietary saturated fat on fasting triglyceride (TG) and cholesterol levels, and any mediation of this relationship by dietary carbohydrate intake. Men and women in the NHLBI Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) study (n = 1036, mean age ± SD = 49 ± 16 y) were included. Mixed linear models were run with saturated fat as a predictor variable and fasting TG, very low density lipoprotein cholesterol (VLDL-C), low density cholesterol (LDL-C) and high density cholesterol (HDL-C) as separate outcome variables. Subsequent models were run which included dietary carbohydrate as a predictor variable, and an interaction term between saturated fat and carbohydrate. All models controlled for age, sex, BMI, blood pressure and dietary covariates. In models that included only saturated fat as a predictor, saturated fat did not show significant associations with fasting lipids. When carbohydrate intake and an interaction term between carbohydrates and saturated fat intake was included, carbohydrate intake did not associate with lipids, but there was an inverse relationship between saturated fat intake and VLDL-C (P = 0.01) with a significant interaction (P = 0.01) between saturated fat and carbohydrate with regard to fasting VLDL-C concentrations. Similar results were observed for fasting TG levels. We conclude that, when controlling for carbohydrate intake, higher saturated fat was associated with lower VLDL-C and TGs. This was not the case at higher intakes of carbohydrate. This has important implications for dietary advice aimed at reducing TG and VLDL-C levels.

Circulating uncarboxylated matrix gla protein is associated with vitamin K nutritional status, but not coronary artery calcium, in older adults

Matrix Gla protein (MGP) is a calcification inhibitor in vascular tissue that must be carboxylated by vitamin K to function. Evidence suggests circulating uncarboxylated MGP (ucMGP) is elevated in persons with disease characterized by vascular calcification. The primary purpose of this study was to determine cross-sectional and longitudinal associations between plasma ucMGP, vitamin K status, and coronary artery calcium (CAC) in older adults without coronary heart disease. Genetic determinants of ucMGP were also explored. Cross-sectional associations among baseline plasma ucMGP, vitamin K status biomarkers [plasma phylloquinone, uncarboxylated prothrombin (PIVKA-II), serum uncarboxylated osteocalcin (%ucOC)], CAC, and plausible genetic polymorphisms were examined in 438 community-dwelling adults (60-80 y, 59% women). The effect of phylloquinone supplementation (500 μg/d) for 3 y on plasma ucMGP was determined among 374 participants. At baseline, plasma phylloquinone was lower and %ucOC and PIVKA-II were greater across higher plasma ucMGP quartiles (all P < 0.001, age-adjusted). Major allele homozygotes for MGP rs1800801 and rs4236 had higher plasma ucMGP than heterozygotes or minor allele homozygotes. (P ≤ 0.004). The decrease in plasma ucMGP was greater in the 190 participants who received phylloquinone (mean ± SD) (-345 ± 251 pmol/L) than in the 184 who did not (-40 ± 196 pmol/L) (P < 0.0001). CAC did not differ according to ucMGP quartile (P = 0.35, age-adjusted). In the phylloquinone-supplemented group, the 3-y change in ucMGP was not associated with the 3-y change in CAC [unstandard β (SE) = -0.02 (0.02); P = 0.44]. Plasma ucMGP was associated with vitamin K status biomarkers and was reduced following phylloquinone supplementation, suggesting it may be a useful marker of vitamin K status in vascular tissue. Plasma ucMGP did not reflect CAC in healthy older adults.

Clinical characteristics and evaluation of LDL-cholesterol treatment of the Spanish Familial Hypercholesterolemia Longitudinal Cohort Study (SAFEHEART)

Aim

Familial hypercholesterolemia (FH) patients are at high risk for premature coronary heart disease (CHD). Despite the use of statins, most patients do not achieve an optimal LDL-cholesterol goal. The aims of this study are to describe baseline characteristics and to evaluate Lipid Lowering Therapy (LLT) in FH patients recruited in SAFEHEART.

Methods and Results

A cross-sectional analysis of cases recruited in the Spanish FH cohort at inclusion was performed. Demographic, lifestyle, medical and therapeutic data were collected by specific surveys. Blood samples for lipid profile and DNA were obtained. Genetic test for FH was performed through DNA-microarray. Data from 1852 subjects (47.5% males) over 19 years old were analyzed: 1262 (68.1%, mean age 45.6 years) had genetic diagnosis of FH and 590 (31.9%, mean age 41.3 years) were non-FH. Cardiovascular disease was present in 14% of FH and in 3.2% of non-FH subjects (P < 0.001), and was significantly higher in patients carrying a null mutation compared with those carrying a defective mutation (14.87% vs. 10.6%, respectively, P < 0.05). Prevalence of current smokers was 28.4% in FH subjects. Most FH cases were receiving LLT (84%). Although 51.5% were receiving treatment expected to reduce LDL-c levels at least 50%, only 13.6% were on maximum statin dose combined with ezetimibe. Mean LDL-c level in treated FH cases was 186.5 mg/dl (SD: 65.6) and only 3.4% of patients reached and LDL-c under 100 mg/dl. The best predictor for LDL-c goal attainment was the use of combined therapy with statin and ezetimibe.

Conclusion

Although most of this high risk population is receiving LLT, prevalence of cardiovascular disease and LDL-c levels are still high and far from the optimum LDL-c therapeutic goal. However, LDL-c levels could be reduced by using more intensive LLT such as combined therapy with maximum statin dose and ezetimibe.

Associations of APOE gene polymorphisms with bone mineral density and fracture risk: a meta-analysis

To determine the association of the Apolipoprotein E (APOE) E4 gene polymorphism with bone mineral density (BMD) and fractures we conducted a meta-analysis of 17 reports. Despite lower trochanteric and lumbar BMD in APOE4 carriers, there is insufficient evidence to support a consistent association of APOE with bone health.

INTRODUCTION

APOE has been studied for its potential role in osteoporosis risk. It is hypothesized that genetic variation at APOE locus, known as E2, E3, and E4, may modulate BMD through its effects on lipoproteins and vitamin K transport. The purpose of this study was to determine the association of the APOE-E4 gene polymorphism with bone-related phenotypes.

METHODS

We conducted a meta-analysis that combined newly analyzed individual data from two community-based cohorts, the Framingham Offspring Study (N = 1,495) and the vitamin K clinical trial (N = 377), with 15 other eligible published reports. Bone phenotypes included BMD measurements of the hip (total hip and trochanteric and femoral neck sites) and lumbar spine (from the L2 to L4 vertebrae) and prevalence or incidence of vertebral, hip, and other fractures.

RESULTS

In sex-pooled analyses, APOE4 carriers had a 0.018 g/cm(2) lower weighted mean trochanteric BMD than non carriers (p = 0.0002) with no evidence for between-study heterogeneity. A significant association was also detected with lumbar spine BMD (p = 0.006); however, inter-study heterogeneity was observed. Associations with lumbar spine and trochanteric BMD were observed predominantly in women and became less significant in meta-regression (p = 0.055 and 0.01, respectively). There were no consistent associations of APOE4 genotype with BMD at other skeletal sites or with fracture risk.

CONCLUSIONS

Based on these findings, there is insufficient evidence to support a strong and consistent association of the APOE genotype with BMD and fracture incidence.

Consumption of diets with different type of fat influences triacylglycerols-rich lipoproteins particle number and size during the postprandial state

BACKGROUND AND AIMS

Previous evidence suggests that dietary fat could influence the composition and size of triacylglycerols-rich lipoproteins (TRL). In a controlled intervention study on healthy subjects, we evaluated the influence of 3 dietary interventions, with different types of fat on postprandial TRL particle size and number.

METHODS AND RESULTS

Volunteers followed three different diets for four weeks each, according to a randomized crossover design. Western diet: 15% protein, 47% carbohydrates (CHO), 38% fat (22% saturated fatty acid (SFA)); Mediterranean diet: 15% protein, 47% CHO, 38% fat (24% monounsaturated fatty acid (MUFA)); high CHO enriched with ALNA diet: 15% protein, 55% CHO, <30% fat (8% polyunsaturated fatty acid (PUFA)). After a 12-h fast, volunteers consumed a breakfast with 1g fat and 7 mg cholesterol per kg body weight and a fat composition similar to that consumed in each of the diets: Butter meal: 35% SFA; Olive oil meal: 36% MUFA; Walnut meal: 16% PUFA, 4% α-linolenic acid. Tryglicerides (TG) in TRL (large and small TRL) were determined by ultracentrifugation and size and number of lipoprotein particles were measured with Nuclear Magnetic Resonance Spectroscopy at different time points. The olive oil meal reduced the number of total TRL postprandial particles compared with the other meals (P=0.002). Moreover, the olive oil meal also increased the TRL particle size compared with the walnut meal (P=0.001).

CONCLUSION

Our data showed that short-term intake of the Mediterranean diet and the acute intake of an olive oil meal lead to the formation of a reduced number and higher-size TRL particle compared with other fat sources. These novel findings have implications for understanding the postprandial lipoprotein mechanisms, and could favour the lower cardiovascular risk in Mediterranean countries.

Association between the APOA2 promoter polymorphism and body weight in Mediterranean and Asian populations: replication of a gene-saturated fat interaction

OBJECTIVE

The APOA2 gene has been associated with obesity and insulin resistance (IR) in animal and human studies with controversial results. We have reported an APOA2-saturated fat interaction determining body mass index (BMI) and obesity in American populations. This work aims to extend our findings to European and Asian populations.

METHODS

Cross-sectional study in 4602 subjects from two independent populations: a high-cardiovascular risk Mediterranean population (n = 907 men and women; aged 67 ± 6 years) and a multiethnic Asian population (n = 2506 Chinese, n = 605 Malays and n = 494 Asian Indians; aged 39 ± 12 years) participating in a Singapore National Health Survey. Anthropometric, clinical, biochemical, lifestyle and dietary variables were determined. Homeostasis model assessment of insulin resistance was used in Asians. We analyzed gene-diet interactions between the APOA2 -265T>C polymorphism and saturated fat intake (<or ≥ 22 g per day) on anthropometric measures and IR.

RESULTS

Frequency of CC (homozygous for the minor allele) subjects differed among populations (1-15%). We confirmed a recessive effect of the APOA2 polymorphism and replicated the APOA2-saturated fat interaction on body weight. In Mediterranean individuals, the CC genotype was associated with a 6.8% greater BMI in those consuming a high (P = 0.018), but not a low (P = 0.316) saturated fat diet. Likewise, the CC genotype was significantly associated with higher obesity prevalence in Chinese and Asian Indians only, with a high-saturated fat intake (P = 0.036). We also found a significant APOA2-saturated fat interaction in determining IR in Chinese and Asian Indians (P = 0.026).

CONCLUSION

The influence of the APOA2 -265T>C polymorphism on body-weight-related measures was modulated by saturated fat in Mediterranean and Asian populations.

The effects of ABCG5/G8 polymorphisms on HDL-cholesterol concentrations depend on ABCA1 genetic variants in the Boston Puerto Rican Health Study

BACKGROUND AND AIMS

ATP-binding cassette transporters G5/G8 (ABCG5/G8) are associated with HDL-C concentrations. To assess whether the effect of ABCG5/G8 genetic variants on HDL-C concentrations is dependent on ATP-binding cassette transporters A1 (ABCA1), we studied potential interactions between single nucleotide polymorphisms (SNPs) at ABCG5/G8 (i7892T > C, 5U145A > C, T54CA > G, T400KC > A) and ABCA1 (i27943G > A, i48168G > A, K219RG > A, i125970G > C, 3U8995A > G) genes with HDL-C concentrations.

METHODS AND RESULTS

ABCG5/G8 and ABCA1 SNPs were genotyped in 788 subjects (228 men and 560 women) who participated in the Boston Puerto Rican Health Study. Biochemical measurements were determined by standard procedures. Genotyping was performed using TaqMan assays according to routine laboratory protocols. Significant gene-gene interactions for HDL-C were found between ABCG8 (5U145A > C, T54CA > G, T400KC > A) SNPs and ABCA1_i48168G > A genetic variant (P = 0.009, P = 0.042 and P = 0.036, respectively), in which carriers of the 5U145C and 54C alleles, and homozygotes for the T400 allele at ABCG8 genetic variants displayed lower HDL-C concentrations than homozygotes for the 5U145A and T54 alleles, and heterozygotes for the 400K allele at ABCG8 SNPs, only if they were also homozygous for the minor allele (A) at the aforementioned ABCA1 SNP.

CONCLUSIONS

The gene-gene interactions reported in the present study support the hypothesis that the effect of ABCG5/G8 genetic variants on HDL-C concentrations is dependent on ABCA1 expression. Replication of these analyses to further populations, particularly with low HDL-C, is clearly warranted.

A composite scoring of genotypes discriminates coronary heart disease risk beyond conventional risk factors in the Boston Puerto Rican Health Study

BACKGROUND AND AIMS

Using a genetic predisposition score (GPS), integrating the additive associations of a set of single nucleotide polymorphisms (SNPs) with CHD, we examined the consequences of the joint presence of a high GPS and conventional risk factors (CRFs).

METHODS AND RESULTS

We studied 11 SNPs at eight loci in 197 participants with prior CHD and 524 CHD-free subjects from the Boston Puerto Rican Health Study. Each polymorphism contributed 1 unit (high-risk allele homozygous), 0.5 units (heterozygous) and 0 units (low-risk allele homozygous) to the GPS. Odds ratio (OR) of CHD for those at high risk because of GPS (>5) and simultaneous presence of CRFs were estimated, compared with subjects at low risk, for both measurements. The mean score was higher in participants with prior CHD than those CHD-free (P=0.015), and the OR for CHD with a GPS>5 was 2.90 (P<0.001).The joint presence of a high GPS and each CRF was associated with higher risk of CHD. Compared to participants with high GPS, those with low GPS (<or=5) were protected against CHD even if they were smokers (OR=0.44), heavy drinkers (OR=0.43), displayed low physical activity (OR=0.35), had hypertension (OR=0.52) or hyperlipidemia (OR=0.34) (P values ranging from 0.004 to 0.023).

CONCLUSION

A simple genetic score of 11 polymorphisms may identify those subjects at increased risk of CHD beyond conventional risk factors.

The effect of a novel intergenic polymorphism (rs11774572) on HDL-cholesterol concentrations depends on TaqIB polymorphism in the cholesterol ester transfer protein gene

BACKGROUND AND AIMS

Several genes have been shown to individually affect plasma lipoprotein metabolism in humans. Studies on gene-gene interactions could offer more insight into how genes affect lipid metabolism and may be useful in predicting lipid concentrations. We tested for gene-gene interactions between TaqIB SNP in the cholesterol ester transfer protein (CETP) and three novel single nucleotide polymorphisms (SNPs), namely rs11774572, rs7819412 and rs6995374 for their effect on metabolic syndrome (MetS) components and related traits.

METHODS AND RESULTS

The aforementioned SNPs were genotyped in 1002 subjects who participated in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study. Lipids were measured by standard procedures and lipoprotein subfractions, by proton nuclear magnetic resonance spectroscopy. Polymorphism rs11774572 was significantly associated with MetS (P=0.020), mainly driven by the association of the C allele with lower HDL-C (P=0.043) and higher triglycerides (P=0.049) and insulin (P=0.040) concentrations than TT subjects. A significant interaction between SNPs rs11774572 and CETP-TaqIB SNPs was found for HDL-C concentrations (P=0.006) and for HDL (P=0.008) and LDL particle sizes (P=0.009), small LDL (P=0.004), and VLDL concentrations (P=0.021), in which TT homozygotes displayed higher HDL-C concentrations and for HDL and LDL particle sizes, and lower small LDL and VLDL concentrations than C carriers, if they were CETP B2 allele carriers (P values ranging from <0.001 to 0.001).

CONCLUSIONS

The rs11774572 polymorphism may play a role in the dyslipidemia that characterizes MetS. The interaction between rs11774572 and CETP-TaqIB SNPs on HDL-C concentrations provides some insights into the underlying mechanisms.

Forty-three loci associated with plasma lipoprotein size, concentration, and cholesterol content in genome-wide analysis

While conventional LDL-C, HDL-C, and triglyceride measurements reflect aggregate properties of plasma lipoprotein fractions, NMR-based measurements more accurately reflect lipoprotein particle concentrations according to class (LDL, HDL, and VLDL) and particle size (small, medium, and large). The concentrations of these lipoprotein sub-fractions may be related to risk of cardiovascular disease and related metabolic disorders. We performed a genome-wide association study of 17 lipoprotein measures determined by NMR together with LDL-C, HDL-C, triglycerides, ApoA1, and ApoB in 17,296 women from the Women's Genome Health Study (WGHS). Among 36 loci with genome-wide significance (P<5×10⁻⁸) in primary and secondary analysis, ten (PCCB/STAG1 (3q22.3), GMPR/MYLIP (6p22.3), BTNL2 (6p21.32), KLF14 (7q32.2), 8p23.1, JMJD1C (10q21.3), SBF2 (11p15.4), 12q23.2, CCDC92/DNAH10/ZNF664 (12q24.31.B), and WIPI1 (17q24.2)) have not been reported in prior genome-wide association studies for plasma lipid concentration. Associations with mean lipoprotein particle size but not cholesterol content were found for LDL at four loci (7q11.23, LPL (8p21.3), 12q24.31.B, and LIPG (18q21.1)) and for HDL at one locus (GCKR (2p23.3)). In addition, genetic determinants of total IDL and total VLDL concentration were found at many loci, most strongly at LIPC (15q22.1) and APOC-APOE complex (19q13.32), respectively. Associations at seven more loci previously known for effects on conventional plasma lipid measures reveal additional genetic influences on lipoprotein profiles and bring the total number of loci to 43. Thus, genome-wide associations identified novel loci involved with lipoprotein metabolism—including loci that affect the NMR-based measures of concentration or size of LDL, HDL, and VLDL particles—all characteristics of lipoprotein profiles that may impact disease risk but are not available by conventional assay.

Genome-wide association studies (GWAS) of plasma lipoprotein fractions hold great promise for understanding lipid metabolism and its central role in cardiovascular disease and related disorders. Conventional assays for lipoprotein status determine total cholesterol content of low- or high-density lipoprotein particles (LDL-C or HDL-C, respectively) or total plasma triglyceride content (as an estimate of very-low density lipoprotein particle concentration [VLDL]). All three measures have been targets for recent GWAS. However, a more precise target for GWAS of lipoprotein metabolism would be the concentration of the individual lipoprotein particles according to class (LDL, HDL, VLDL) and size (small, medium, and large), all of which can be measured by NMR-based methods. In a population of 17,296 women of European ancestry from the Women's Genome Health Study, we have performed a GWAS for 22 lipoprotein measures derived from NMR-based and conventional assays. We find 43 genetic loci involved in lipoprotein metabolism, including 10 novel loci. The results offer a clearer picture of common genetic influences on lipoprotein metabolism than available previously, including genetic effects on the distribution of LDL, HDL, and VLDL particle size, as well as on IDL and VLDL particle concentration, neither of which can be assessed by conventional measures.

Circadian rhythm of clock genes in human adipose explants

To analyze in severely obese women the circadian expression of the clock genes hPer2, hBmal1, and hCry1 in explants from subcutaneous (SAT) and visceral (VAT) adipose tissue (AT), in order to elucidate whether this circadian clockwork can oscillate accurately and independently of the suprachiasmatic nucleus (SCN) and if glucocorticoid metabolism-related genes such as glucocorticoid receptor (hGr) and 11beta-hydroxysteroid dehydrogenase 1 (h11 beta Hsd1) and the transcription factor peroxisome proliferator activated receptor gamma (hPPAR gamma) are part of the clock controlled genes. AT biopsies were obtained from morbid obese patients (BMI > or =40 kg/m(2)) (n = 7). Anthropometric variables were measured and fasting plasma lipids and lipoprotein concentrations were analyzed. In order to carry out rhythmic expression analysis, AT explants were cultured during 24 h and gene expression was performed at the following times (T): 0, 6, 12, and 18 h, with quantitative real-time PCR. Clock genes oscillated accurately and independently of the SCN in AT explants. Their intrinsic oscillatory mechanism regulated the timing of other genes such as hPPAR gamma and glucocorticoid-related genes. Circadian patterns differed between VAT and SAT. Correlation analyses between the genetic circadian oscillation and components of the metabolic syndrome (MetS) revealed that subjects with a higher sagittal diameter showed an increased circadian variability in hPer2 expression (r = 0.91; P = 0.031) and hBmal1 (r = 0.90; P = 0.040). Data demonstrate the presence of peripheral circadian oscillators in human AT independently of the central circadian control mechanism. This knowledge paves the way for a better understanding of the circadian contribution to medical conditions such as obesity and MetS.

Vitamin K supplementation and progression of coronary artery calcium in older men and women

BACKGROUND

Coronary artery calcification (CAC) is an independent predictor of cardiovascular disease. A preventive role for vitamin K in CAC progression has been proposed on the basis of the properties of matrix Gla protein (MGP) as a vitamin K-dependent calcification inhibitor.

OBJECTIVE

The objective was to determine the effect of phylloquinone (vitamin K1) supplementation on CAC progression in older men and women.

DESIGN

CAC was measured at baseline and after 3 y of follow-up in 388 healthy men and postmenopausal women; 200 received a multivitamin with 500 microg phylloquinone/d (treatment), and 188 received a multivitamin alone (control).

RESULTS

In an intention-to-treat analysis, there was no difference in CAC progression between the phylloquinone group and the control group; the mean (+/-SEM) changes in Agatston scores were 27 +/- 6 and 37 +/- 7, respectively. In a subgroup analysis of participants who were > or =85% adherent to supplementation (n = 367), there was less CAC progression in the phylloquinone group than in the control group (P = 0.03). Of those with preexisting CAC (Agatston score > 10), those who received phylloquinone supplements had 6% less progression than did those who received the multivitamin alone (P = 0.04). Phylloquinone-associated decreases in CAC progression were independent of changes in serum MGP. MGP carboxylation status was not determined.

CONCLUSIONS

Phylloquinone supplementation slows the progression of CAC in healthy older adults with preexisting CAC, independent of its effect on total MGP concentrations. Because our data are hypothesis-generating, further studies are warranted to clarify this mechanism. This trial was registered at clinicaltrials.gov as NCT00183001.

Genetic influences on blood lipids and cardiovascular disease risk: tools for primary prevention

Genetic polymorphism in human populations is part of the evolutionary process that results from the interaction between the environment and the human genome. Recent changes in diet have upset this equilibrium, potentially influencing the risk of most common morbidities such as cardiovascular diseases, obesity, diabetes, and cancer. Reduction of these conditions is a major public health concern, and such a reduction could be achieved by improving our ability to detect disease predisposition early in life and by providing more personalized behavioral recommendations for successful primary prevention. In terms of cardiovascular diseases, polymorphisms at multiple genes have been associated with differential effects in terms of lipid metabolism; however, the connection with cardiovascular disease has been more elusive, and considerable heterogeneity exists among studies regarding the predictive value of genetic markers. This may be because of experimental limitations, the intrinsic complexity of the phenotypes, and the aforementioned interactions with environmental factors. The integration of genetic and environmental complexity into current and future research will drive the field toward the implementation of clinical tools aimed at providing dietary advice optimized for the individual's genome. This may imply that dietary changes are implemented early in life to gain maximum benefit. However, it is important to highlight that most reported studies have focused on adult populations and to extrapolate these findings to children and adolescents may not be justified until proper studies have been carried out in these populations and until the ethical and legal issues associated with this new field are adequately addressed.

Vitamin K, circulating cytokines, and bone mineral density in older men and women

BACKGROUND

Vitamin K modulates cytokines involved in bone turnover, including interleukin-6 (IL-6) and osteoprotegerin in vitro.

OBJECTIVE

The objective of this study was to assess 1) associations between measures of vitamin K status [plasma phylloquinone and serum percentage of undercarboxylated osteocalcin (%ucOC)] and IL-6, osteoprotegerin, and C-reactive protein (CRP) concentrations and 2) the effect of daily 500 mug phylloquinone supplementation for 3 y on cytokine concentrations.

DESIGN

Concentrations of IL-6, osteoprotegerin, and CRP and bone mineral density (BMD) were measured at baseline and after 3 y of follow-up in 379 healthy men and women (60-81 y; 58.5% women) participating in a randomized trial that studied the effect of vitamin K supplementation on bone loss.

RESULTS

Cross-sectionally, plasma phylloquinone was inversely associated with IL-6 and CRP, whereas serum %ucOC was inversely associated with IL-6. Osteoprotegerin was associated positively with plasma phylloquinone and inversely with %ucOC. No differences were observed in the 3-y change in IL-6, osteoprotegerin, and CRP concentrations between participants who received phylloquinone supplementation and those who did not. Overall, no association was observed between the 3-y changes in circulating cytokines and BMD.

CONCLUSIONS

Poor vitamin K status was associated with high concentrations of cytokines involved in bone turnover, but vitamin K supplementation did not confer a decrease in cytokine concentrations. The healthy status of this cohort may explain a lack of effect of vitamin K supplementation on cytokine concentrations. This trial was registered with www.clinicaltrials.gov as NCT00183001.

Vitamin K and vitamin D status: associations with inflammatory markers in the Framingham Offspring Study

In vitro data suggest protective roles for vitamins K and D in inflammation. To examine associations between vitamins K and D and inflammation in vivo, the authors used multiple linear regression analyses, adjusted for age, sex, body mass index, triglyceride concentrations, use of aspirin, use of lipid-lowering medication, season, menopausal status, and hormone replacement therapy. Participants were from the Framingham Offspring Study (1997-2001; n = 1,381; mean age = 59 years; 52% women). Vitamin K status, measured by plasma phylloquinone concentration and phylloquinone intake, was inversely associated with circulating inflammatory markers as a group and with several individual inflammatory biomarkers (p < 0.01). Percentage of undercarboxylated osteocalcin, a functional measure of vitamin K status, was not associated with overall inflammation but was associated with C-reactive protein (p < 0.01). Although plasma 25-hydroxyvitamin D was inversely associated with urinary isoprostane concentration, an indicator of oxidative stress (p < 0.01), overall associations between vitamin D status and inflammation were inconsistent. The observation that high vitamin K status was associated with lower concentrations of inflammatory markers suggests that a possible protective role for vitamin K in inflammation merits further investigation.

Genetic and non-genetic correlates of vitamins K and D

OBJECTIVE

To assess the genetic and nongenetic correlates of circulating measures of vitamins K and D status in a community-based sample of men and women.

SUBJECTS/METHODS

A cross-sectional study of 1762 participants of the Framingham Offspring Study (919 women; mean age 59 years). Vitamin K status was measured as plasma phylloquinone and serum percent undercarboxylated osteocalcin (ucOC), and vitamin D was measured using plasma 25-hydroxyvitamin D (25(OH)D). Associations between vitamin K status and vitamin D status with biologically plausible nongenetic factors were assessed using stepwise regression. Heritability and linkage were determined using Sequential Oligogenic Linkage Analysis Routines (SOLAR).

RESULTS

Nongenetic factors accounted for 20.1 and 12.3% of the variability in plasma phylloquinone in men and women respectively, with triglycerides and phylloquinone intake being the primary correlates. In men 12.2% and in women 14.6% of the variability in %ucOC was explained by nongenetic factors in our models. Heritability estimates for these vitamin K status biomarkers were nonsignificant. Season, vitamin D intake, high-density lipoprotein (HDL) cholesterol and waist circumference explained 24.7% (men) and 24.2% (women) of the variability in plasma 25(OH)D. Of the three vitamins examined, only 25(OH)D was significantly heritable (heritability estimate=28.8%, P<0.01), but linkage analysis of 25(OH)D did not achieve genome-wide significance.

CONCLUSIONS

Variability in biomarkers of vitamin K status was attributed to nongenetic factors, whereas plasma 25(OH)D was found to be significantly heritable. Further studies are warranted to investigate genetic loci influencing vitamin D status.

Identification of a functional polymorphism at the adipose fatty acid binding protein gene (FABP4) and demonstration of its association with cardiovascular disease: a path to follow

Fatty acid binding proteins (FABPs) are proteins that reversibly bind fatty acids and other lipids. So far, nine tissue-specific cytoplasmic FABPs have been identified. Adipose tissue FABP (FABP4) has been suggested to be a bridge between inflammation and other pathways related to the metabolic syndrome. In this regard, genetic variability at the FABP4 locus has been shown to be associated with plasma lipid levels, type 2 diabetes, and coronary heart disease risk.

Metabolic syndrome pathophysiology: the role of adipose tissue

Several pathophysiological explanations for the metabolic syndrome have been proposed involving insulin resistance, chronic inflammation and ectopic fat accumulation following adipose tissue saturation. However, current concepts create several paradoxes, including limited cardiovascular risk reduction with intensive glucose control in diabetics, therapies that result in weight gain (PPAR agonists), and presence of some of the metabolic traits among some lipodystrophies. We propose the functional failure of an organ, in this case, the adipose tissue as a model to interpret its manifestations and to reconcile some of the apparent paradox. A cornerstone of this model is the failure of the adipose tissue to buffer postprandial lipids. In addition, homeostatic feedback loops guide physiological and pathological adipose tissue activities. Fat turnover is determined by a complex equilibrium in which insulin is a main factor but not the only one. Chronically inadequate energy balance may be a key factor, stressing the system. In this situation, an adipose tissue functional failure occurs resulting in changes in systemic energy delivery, impaired glucose consumption and activation of self-regulatory mechanisms that extend their influence to whole body homeostasis system. These include changes in adipokines secretion and vascular effects. The functional capacity of the adipose tissue varies among subjects explaining the incomplete overlapping among the metabolic syndrome and obesity. Variations at multiple gene loci will be partially responsible for these interindividual differences. Two of those candidate genes, the adiponectin (APM1) and the perilipin (PLIN) genes, are discussed in more detail.

The association of SNP276G>T at adiponectin gene with circulating adiponectin and insulin resistance in response to mild weight loss

OBJECTIVE

The purpose of this study was to determine whether common single nucleotide polymorphisms (SNPs) at the adiponectin (ADIPOQ) locus influence changes in circulating adiponectin and the features of insulin resistance in response to a weight loss intervention.

SUBJECTS

In total, 294 nondiabetic/overweight-obese Koreans participated in a clinical intervention study lasting 12 weeks involving a caloric reduction of -300kcal/day.

METHODS

Plasma adiponectin, blood lipids, glucose and insulin concentrations were measured at baseline and after weight loss. Insulin resistance was estimated by homeostasis model assessment insulin resistance (HOMA-IR) derived from fasting glucose and insulin concentrations. We genotyped for three SNPs, 45T>G, 276G>T and -11377C>G.

RESULTS

At baseline, HOMA-IR was significantly higher in GG homozygotes than in carriers of the T allele at SNP276G>T of the adiponectin gene (P<0.05). With regard to SNP45T>G and SNP -11377C>G, we did not find any genotype related differences in baseline levels of HOMA-IR and adiponectin. In the 45/276 haplotype test, homozygous for the TG haplotype had significantly lower concentrations of plasma adiponectin (P<0.05). After the 12-week weight loss intervention, the significant decreases in HOMA-IR (P<0.001) and increases in adiponectin (P<0.01) were observed in GG homozygotes at SNP276, which were not shown in carriers of the T allele. Furthermore, there was a significant difference in the decreases in HOMA-IR between the GG homozygotes and carriers of the T allele at SNP276 (P<0.05). Regarding SNP45T>G and SNP -11377C>G, there was no association between SNP45T>G and SNP -11377C>G and decreases in HOMA-IR. In the 45/276 haplotype test, there was a significant difference in changes of adiponectin levels among those with different haplotype combinations (P<0.05).

CONCLUSION

The SNP276G>T of the ADIPOQ gene is associated with different responses of circulating adiponectin and insulin resistance to mild weight loss in overweight-obese subjects.

Genetic variation at the perilipin locus is associated with changes in serum free fatty acids and abdominal fat following mild weight loss

OBJECTIVE

Perilipin (PLIN) is a class of protein-coating lipid droplets in adipocytes. We aimed to examine the association between common single-nucleotide polymorphisms (SNPs) at PLIN locus with circulating free fatty acid (FFA) and abdominal fat distribution in response to weight loss.

METHODS

Non-diabetic/overweight-obese Koreans (n=177) participated in a 12-week calorie restriction (-300kcal/day) program. Seven SNPs (6209T>C, 10076C>G, 10171A>T, 11482G>A, 13042A>G, 13048C>T and 14995A>T), abdominal fat areas (visceral/subcutaneous fat areas at 1st lumbar and 4th lumbar levels), serum lipids, glucose, insulin, FFA, oxidized low-density lipoprotein (LDL) and urinary 8-epi-prostaglandin F(2alpha) (PGF(2alpha)) were examined.

RESULTS

Single-nucleotide polymorphisms 10076C>G/10171A>T showed the strongest positive linkage disequilibrium (LD) (D'=0.923, R (2)=0.839, P<0.001) and SNPs11482G>A/14995A>T showed moderate positive LD (D'=0.824, R (2)=0.578, P<0.001). Calorie restriction induced 4.6% weight loss with significant abdominal fat reduction. In response to weight loss, subjects with nCA/nCA haplotypes at SNPs 10076C>G/10171A>T showed greater reduction in FFA levels than those with CA/CA haplotype (CA/CA: C/C at SNP 10076 and A/A at SNP 10171, nCA: non-CA haplotype carrier). On the other hand, subjects with nGA/nGA haplotype at SNPs 11482G>A/14995A>T had increased FFA levels with a rapid loss in abdominal fat, whereas GA/GA haplotype carriers had reduction in FFA levels. These results still remained significant after adjusting for age, gender and BMI. Prostaglandin F(2alpha) and oxidized LDL were also more reduced in GA/GA haplotype carriers than in nGA haplotype carriers. This effect remained significant after adjusting for baseline level, age, gender and BMI. Paradoxically, nGA haplotype carriers had increased levels of urinary PGF(2alpha) after weight reduction.

CONCLUSION

Fasting plasma FFA changes following a modest weight loss in overweight-obese subjects are influenced by the genetic variability at the PLIN locus. Furthermore, circulating FFA changes rather than body fat itself may determine changes in lipid peroxides such as urinary PGF(2alpha) and oxidized LDL.