Development and validation of a Brief Diet Quality Assessment Tool in the French-speaking adults from Quebec.

BACKGROUND: The objective of this study was to develop and validate a short, self-administered questionnaire to assess diet quality in clinical settings, using the Alternative Healthy Eating Index (AHEI) as reference. METHODS: A total of 1040 men and women (aged 44.6 ± 14.4 y) completed a validated web-based food frequency questionnaire (webFFQ) and had their height and weight measured (development sample). Participants were categorized arbitrarily according to diet quality (high: AHEI score ≥ 65/110, low: AHEI score < 65/110) based on dietary intake data from the webFFQ. The Brief Diet Quality Assessment Tool was developed using a classification and regression tree (CART) approach and individual answers to the webFFQ among participants considered to have a plausible energy intake (ratio of reported energy intake to basal metabolic rate ≥ 1.2 and < 2.4; n = 1040). A second sample of 3344 older adults (aged 66.5 ± 6.4 y) was used to test the external validity of the Brief Diet Quality Assessment Tool (external validation sample). RESULTS: The decision tree included sequences of 3 to 6 binary questions, yielding 21 different pathways classifying diet quality as being high or low. In the development sample, the area under the receiver operating characteristic (ROC) curve of the predictive model was 0.92, with sensitivity, specificity and agreement values of 89.5, 83.9 and 87.2%. Compared with individuals having a low-quality diet according to the Brief Diet Quality Assessment Tool (mean AHEI 56.7 ± 11.4), individuals classified as having a high-quality diet (mean AHEI 71.3 ± 11.0) were significantly older, and had lower BMI, percent body fat and waist circumference, and had lower blood pressure, triglycerides, cholesterol/HDL ratio and fasting insulin as well as higher HDL-cholesterol concentrations (all P < 0.05). Similar results were observed in the external validation sample, although overall performance of the Brief Diet Quality Assessment Tool was slightly lower than in the development sample, with an area under the ROC curve of 0.79 and sensitivity, specificity and agreement values of 73.0, 69.0 and 71.3%, respectively. CONCLUSION: The CART approach yielded a simple and rapid Brief Diet Quality Assessment Tool that identifies individuals at risk of having a low-quality diet. Further studies are needed to test the performance of this tool in primary care settings.

Assessment of the American Heart Association's "Life's simple 7" score in French-speaking adults from Québec.

BACKGROUND AND AIMS: The "Life's Simple 7" (LS7) metrics were developed by the American Heart Association (AHA) to assess and promote cardiovascular health in the American population. The purpose of this study was to assess the overall cardiovascular health of French-speaking adults from the Province of Quebec using the LS7 score. METHODS AND RESULTS: A total of 777 age and sex-representative participants of five different administrative regions in the Province of Quebec (387 men and 390 women; mean age ± SEM: 41.9 ± 0.1 years) were included in these analyses. Metrics of the LS7 score (smoking, physical activity, diet, body mass index, blood pressure, fasting total cholesterol and blood glucose) were analysed to generate a final score ranging from 0 to 7. Only 0.5% of participants met all criteria for ideal cardiovascular health. The diet metric showed the lowest prevalence of "ideal" scores (4.8%) whereas not smoking was the metric with the highest prevalence (88.1%). Women had a higher LS7 score than men, while age and education level (negative and positive association, respectively; p < 0.0001) were also associated with the LS7 score. CONCLUSION: Consistent with studies conducted among other populations, very few French-speaking adults from the Province of Quebec achieve an ideal cardiovascular health. These data indicate that further public health efforts aimed at promoting the LS7 metrics, focusing primarily on diet, are urgently needed. Specific groups, including older adults and those with lower levels of education, should be targeted when developing cardiovascular health promotion interventions.

Docosahexaenoic acid-enriched canola oil increases adiponectin concentrations: a randomized crossover controlled intervention trial.

BACKGROUND AND AIMS: Little is known about the effect of various dietary fatty acids on pro- and anti-inflammatory processes. We investigated the effect of 5 oils containing various amounts of alpha-linolenic acid (ALA), linoleic acid (LA), oleic acid (OA) and docosahexaenoic acid (DHA) on plasma inflammatory biomarkers and expression levels of key inflammatory genes and transcription factors in whole blood cells. METHODS AND RESULTS: In a randomized, crossover controlled nutrition intervention, 114 adult men and women with abdominal obesity and at least one other criterion for the metabolic syndrome consumed 5 experimental isoenergetic diets for 4 weeks each, separated by 4-week washout periods. Each diet provided 60 g/3000 kcal of different oils: 1) control corn/safflower oil blend (CornSaff; LA-rich), 2) flax/safflower oil blend (FlaxSaff; ALA-rich), 3) conventional canola oil (Canola; OA-rich), 4) high oleic canola oil (CanolaOleic; highest OA content), 5) DHA-enriched high oleic canola oil (CanolaDHA; OA- and DHA-rich). Gene expression in whole blood cells was assessed in a subset of 62 subjects. CanolaDHA increased plasma adiponectin concentrations compared with the control CornSaff oil treatment (+4.5%, P = 0.04) and FlaxSaff (+6.9%, P = 0.0008). CanolaDHA also reduced relative expression levels of interleukin (IL)1B compared with CornSaff and Canola (-11% and -13%, respectively, both P = 0.03). High-sensitivity C-reactive protein concentrations were lower after Canola than after FlaxSaff (-17.8%, P = 0.047). CONCLUSION: DHA-enriched canola oil exerts anti-inflammatory effects compared with polyunsaturated fatty acids from plant sources.

The effect of a dietary portfolio compared to a DASH-type diet on blood pressure.

BACKGROUND AND AIM: Compared to a DASH-type diet, an intensively applied dietary portfolio reduced diastolic blood pressure at 24 weeks as a secondary outcome in a previous study. Due to the importance of strategies to reduce blood pressure, we performed an exploratory analysis pooling data from intensively and routinely applied portfolio treatments from the same study to assess the effect over time on systolic, diastolic and mean arterial pressure (MAP), and the relation to sodium (Na(+)), potassium (K(+)), and portfolio components. METHODS AND RESULTS: 241 participants with hyperlipidemia, from four academic centers across Canada were randomized and completed either a DASH-type diet (control n = 82) or a dietary portfolio that included, soy protein, viscous fibers and nuts (n = 159) for 24 weeks. Fasting measures and 7-day food records were obtained at weeks 0, 12 and 24, with 24-h urines at weeks 0 and 24. The dietary portfolio reduced systolic, diastolic and mean arterial blood pressure compared to the control by 2.1 mm Hg (95% CI, 4.2 to -0.1 mm Hg) (p = 0.056), 1.8 mm Hg (CI, 3.2 to 0.4 mm Hg) (p = 0.013) and 1.9 mm Hg (CI, 3.4 to 0.4 mm Hg) (p = 0.015), respectively. Blood pressure reductions were small at 12 weeks and only reached significance at 24 weeks. Nuts, soy and viscous fiber all related negatively to change in mean arterial pressure (ρ = -0.15 to -0.17, p ≤ 0.016) as did urinary potassium (ρ = -0.25, p = 0.001), while the Na(+)/K(+) ratio was positively associated (ρ = 0.20, p = 0.010). CONCLUSIONS: Consumption of a cholesterol-lowering dietary portfolio also decreased blood pressure by comparison with a healthy DASH-type diet. CLINICAL TRIAL REG. NO.: NCT00438425, clinicaltrials.gov.

Effect of sitagliptin therapy on triglyceride-rich lipoprotein kinetics in patients with type 2 diabetes.

AIM: To investigate the effects of sitagliptin therapy on the kinetics of triglyceride-rich lipoprotein (TRL) apolipoprotein (apo)B-48, VLDL apoB-100, apoE and apoC-III in patients with type 2 diabetes. METHODS: Twenty-two subjects with type 2 diabetes were recruited in this double-blind crossover study, during which the subjects received sitagliptin (100 mg/day) or placebo for a 6-week period each. At the end of each phase of treatment, the in vivo kinetics of the different apolipoproteins were assessed using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h, with the participants in a constantly fed state. RESULTS: Sitagliptin therapy significantly reduced fasting plasma triglyceride (-15.4%, p = 0.03), apoB-48 (-16.3%, p = 0.03) and free fatty acid concentrations (-9.5%, p = 0.04), as well as plasma HbA1c (placebo: 7.0% ± 0.8 vs. sitagliptin: 6.6% ± 0.7, p < 0.0001) and plasma glucose levels (-13.5%, p = 0.001), without any significant effect on insulin levels. Kinetic results showed that treatment with sitagliptin significantly reduced the pool size of TRL apoB-48 by -20.8% (p = 0.03), paralleled by a reduction in the production rate of these particles (-16.0%, p = 0.03). The VLDL apoB-100 pool size was also significantly decreased by sitagliptin therapy (-9.3%, p = 0.03), mainly because of a reduction in the hepatic secretion of these lipoproteins, although this difference did not reach statistical significance (-9.2%, p = 0.06). CONCLUSIONS: Treatment with sitagliptin for 6 weeks reduced triglyceride-rich apoB-containing lipoprotein levels by reducing the synthesis of these particles.

Impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol homeostasis in men and women.

BACKGROUND AND AIMS: Sphingolipids (SL) are important components of the milk fat globule membrane (MFGM) found in buttermilk. While studies in animal models suggest that dietary SL may have cholesterol-lowering properties, data in human are lacking. The aim of this study was to investigate the impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol (C) homeostasis in humans. METHODS AND RESULTS: Men and women (n = 34) with serum LDL-C <5.0 mmol/L at screening (mean LDL-C = 3.8 mmol/L) were recruited in this double-blinded randomized crossover placebo controlled study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro/micronutrient matched placebo (4 weeks each in random order). Serum lipid concentrations and surrogate markers of cholesterol homeostasis were measured post diet and compared using mixed models for repeated measures. Consumption of buttermilk led to reduction in serum cholesterol (-3.1%, P = 0.019), LDL-C (-3.1%, P = 0.057) and triacylglycerol (-10.7%, P = 0.007). Buttermilk consumption increased plasma lathosterol concentrations (+12.1%, P = 0.001), but multiple regression analysis indicated that variations in ß-sitosterol concentrations (P = 0.002) were the only significant predictor of the LDL-C response to buttermilk consumption. CONCLUSION: Buttermilk consumption may be associated with reduced cholesterol concentrations in men and women, primarily through inhibition of intestinal absorption of cholesterol. REGISTRATION NUMBER: This trial is registered at clinicaltrials.gov as NCT01248026.

Behavioural and metabolic characterisation of the low satiety phenotype.

Some individuals report weak appetite sensations and thus, have higher susceptibility to overeating. The aim of this study was (1) to evaluate the reliability of the satiety quotient (SQ), a marker of satiety efficiency; (2) to characterize the biopsychobehavioural profiles of individual presenting low satiety efficiency, i.e. the low satiety phenotype and (3) to document the impact of a weight loss program on these profiles. Sixty-nine obese men (BMI 33.6±3.0 kg/m², age 41.5±5.7 years) participated in a 16-week, non-restrictive weight loss intervention. Visual analog scales for appetite sensations in response to a test-meal were completed twice at baseline. Blood samples were collected before and during one test-meal. Questionnaires were administered before and after the intervention. The mean SQ showed good reliability (ICC=0.67). Baseline SQ scores tended to be negatively correlated with external hunger, anxiety and night eating symptoms (p<0.10). Moreover, the low satiety phenotype showed a lower cortisol response to the test-meal (p<0.05). The SQ seems to be a reliable marker of weaker appetite sensation responses. Stress/anxiety could be involved in the low satiety phenotype but did not influence the biopsychobehavioural changes in response to the intervention.

Investigation of LRP8 gene in 1p31 QTL linked to LDL peak particle diameter in the Quebec family study.

The small, dense LDL phenotype is associated with an increased cardiovascular disease risk. A genome-wide scan performed on 236 nuclear families of the Quebec Family Study (QFS) revealed a quantitative trait locus affecting LDL peak particle diameter (LDL-PPD) and density on the 1p31 region. This region contains the low-density lipoprotein receptor-related protein 8 (LRP8) gene. LRP8, a receptor for apolipoprotein (apo) E, modulates apoE levels, thus contributing to plasma cholesterol and triglyceride (TG) concentrations. We investigate the effects of LRP8 polymorphisms on LDL-PPD, on the relative proportion of small LDL (<255Å) and the absolute concentration of cholesterol among the small LDL particles. LRP8 rs5174 was associated with LDL-PPD and estimated cholesterol concentrations in the small LDL particles adjusted for the effects of age and sex (p=0.008, p=0.04, respectively). LRP8 rs3820198 was associated with total and LDL-cholesterol levels as well as with apoB concentrations adjusted for the effects of age and sex (p=0.005, p=0.004 and p=0.01, respectively) but not with LDL size-related variables. These results suggest that LRP8 gene polymorphisms influence plasma cholesterol levels as well as size and composition of LDL particles.

Effect of sitagliptin therapy on postprandial lipoprotein levels in patients with type 2 diabetes.

AIM: Recent studies indicate that type 2 diabetes is associated with an increased secretion of both hepatic and intestinal lipoproteins, leading to the accumulation of atherogenic triglyceride (TG)-rich lipoproteins. Sitagliptin is a selective inhibitor of dipeptidyl peptidase-4 that has been shown to reduce fasting and postprandial glucose levels in patients with type 2 diabetes presumably through incretin hormone-mediated improvements in islet function. The objective of the present study is to examine the effects of treatment with sitagliptin on postprandial lipid and incretin hormone levels as well as glucose homeostasis in patients with type 2 diabetes. METHODS: Thirty-six subjects with type 2 diabetes (30 men/6 postmenopausal women with a mean age of 58.1 ± 6.4 years and a body mass index of 30.7 ± 4.9 kg/m(2) ) were recruited in this double-blind cross-over study using sitagliptin 100 mg/day or placebo for a 6-week period each, with a 4-week washout period between the two phases. At the end of each phase of treatment, patients underwent an oral lipid tolerance test providing 35 g of fat per m(2) of body surface area and blood samples were taken over an 8-h period. RESULTS: Sitagliptin therapy significantly decreased the postprandial area under the curves (AUCs) for plasma apolipoprotein (apo)B (-5.1%, p = 0.002), apoB-48 (-7.8%, p = 0.03), TG (-9.4%, p = 0.006), very low-density lipoprotein (VLDL)-cholesterol (-9.3%, p = 0.001), free fatty acids (FFAs) (-7.6%, p = 0.005) and glucose (-9.7%, p < 0.0001). Furthermore, the postprandial AUCs for plasma intact glucagon-like peptide-1 (+67.8%, p < 0.0001) and glucose-dependent insulinotropic polypeptide (+67.3%, p < 0.0001) were significantly increased following treatment with sitagliptin, whereas the AUC for plasma glucagon was reduced by -9.7% (p = 0.001) with no significant changes in the AUCs for plasma insulin and C-peptide. Sitagliptin therapy also improved homeostasis model assessment (HOMA) index for insulin resistance (-14.6%, p = 0.01) and ß-cell function (+32.3%, p = 0.007). CONCLUSIONS: Treatment with sitagliptin for 6 weeks reduced postprandial plasma levels of TG-rich lipoproteins of both intestinal and hepatic origin, most likely by increasing incretin hormone levels, reducing circulating plasma FFA concentrations and improving insulin sensitivity and ß-cell function.

Effect of the Mediterranean diet with and without weight loss on cardiovascular risk factors in men with the metabolic syndrome.

BACKGROUND AND AIMS: No study has yet examined how weight loss modifies the impact of the Mediterranean diet (MedDiet) on cardiovascular risk factors in men with the metabolic syndrome (MetS). The objective of the study was to assess the efficacy of MedDiet, with and without weight loss, to modify the cardiometabolic risk profile of male patients with MetS. METHODS AND RESULTS: Twenty-six men aged between 24 and 62 years with the MetS consumed a North American control diet for 5 weeks followed by a 5-week MedDiet, both under weight-maintaining conditions. Participants then underwent a 20-week weight loss period, after which they consumed the MedDiet for five weeks under weight stable conditions. Body weight was reduced by 10.2% ± 2.9% after the weight loss period (p < 0.001). All foods were provided to participants during the weight stable phases of the study. The MedDiet in the absence of weight loss decreased total plasma cholesterol (C) (-7.1%), LDL-C (-9.3%) and the total/HDL-C ratio (-6.5%) compared to the control diet (all p < 0.04). The MedDiet combined with weight loss led to reductions in systolic blood pressure (-4.7%), diastolic blood pressure (-7.7%), triglycerides (-18.2%), ApoB (-10.7%), fasting glucose (-4.2%) and insulin (-29.9%) compared to the control diet (all p < 0.001). CONCLUSION: The MedDiet in the absence of weight loss leads to significant changes in plasma cholesterol concentrations but has little effects on other cardiometabolic risk factors associated with the MetS in men.

Plasma adiponectin concentration is strongly associated with VLDL-TG catabolism in postmenopausal women.

BACKGROUND AND AIMS: To investigate associations between plasma adiponectin concentration and very-low density lipoprotein-triglyceride (VLDL-TG) secretion and catabolism in postmenopausal women. METHODS AND RESULTS: This cross-sectional study included 30 postmenopausal women. Plasma adiponectin concentration was measured by ELISA. Insulin sensitivity was assessed by a 2-h euglycemic-hyperinsulinemic clamp. Fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG) were measured during an oral glucose tolerance test. The calculation of VLDL-TG fractional catabolic rate (FCR) and VLDL-TG total secretion rate (TSR) were based on the monoexponential decrease of TG-[²H5] glycerol values obtained following the administration of a ²H5-glycerol bolus. Plasma adiponectin concentration was negatively associated with VLDL-TG TSR (r=-0.50; p=0.005) and positively associated with VLDL-TG FCR (r=0.54; p<0.002). This latter association remained significant after further adjustments for insulin sensitivity, visceral adipose tissue, HDL-C, FPG and 2hPG concentrations. In a multivariate model including adiponectin, insulin sensitivity and 2hPG, plasma adiponectin level was the strongest correlate of VLDL-TG FCR. CONCLUSIONS: Elevated plasma adiponectin concentration is associated with a favourable VLDL-TG metabolism.

Associations between self-reported vegetable and fruit intake assessed with a new web-based 24-h dietary recall and serum carotenoids in free-living adults: a relative validation study.

The aim of the present study was to assess the relative validity of a new web-based 24-h dietary recall (R24W) in terms of vegetable and fruit (VF) intake assessment using serum carotenoid concentrations as reference biomarkers. A total of seventy-four women and seventy-three men (mean age 47·5 (sd 13·3) years; mean BMI 25·5 (sd 4·4) kg/m2) completed the R24W four times to assess their VF intake. Serum carotenoids were obtained from 12-h fasted blood samples and measured by HPLC. Raw and de-attenuated partial Spearman's correlations were performed to determine how usual vegetable and/or fruit intake was associated with serum carotenoids. Relevant confounders were selected using a stepwise regression analysis. Finally, cross-classification was used to determine agreement between intake of VF and serum carotenoids. Intake of total dietary carotenoids was significantly associated (r 0·40; P < 0·01) with total serum carotenoids (without lycopene). Total VF intake was also associated with total serum carotenoid concentrations without lycopene (r 0·44; P < 0·01). HDL-cholesterol, waist circumference and age were identified as confounders in the association between total VF intake and total serum carotenoids (without lycopene). De-attenuated partial correlation adjusted for these confounders increased the associations between dietary carotenoids and total serum carotenoids without lycopene (r 0·49; P < 0·01) and between total VF intake and total serum carotenoids without lycopene (r 0·48; P < 0·01). Almost 80 % of respondents were classified in the same or the adjacent quartile for total VF intake and total serum carotenoids without lycopene, while less than 6 % were classified in the opposite quartile. Overall, these observations support the appropriateness of the R24W to assess the dietary intake of VF.

Kinetics of plasma apolipoprotein C-III as a determinant of diet-induced changes in plasma triglyceride levels.

OBJECTIVE: To compare the effect of a high monounsaturated fatty acid (MUFA) diet and of a control low-fat diet consumed under ad libitum conditions on plasma apolipoprotein (apo) C-III metabolism. DESIGN: Randomized, two-arm parallel dietary trial. SETTING: Diets were prepared and consumed at the metabolic kitchen of the Department of Food Sciences and Nutrition, and laboratory analyses were performed at the Institute of Nutraceuticals and Functional Foods at Laval University. SUBJECTS AND INTERVENTIONS: Eighteen men were randomly assigned to either the high MUFA diet or the low-fat control diet, which they consumed for 6-7 weeks. Before and after the dietary intervention, subjects received a primed-constant infusion of [5,5,5-D(3)]-L-leucine for 12 h under constant feeding conditions for the determination of plasma apoC-III kinetics. RESULTS: The high-MUFA diet and the low-fat control diet had no significant impact on plasma apoC-III production rate (PR) or fractional catabolic rate. However, diet-induced variations in plasma apoCIII PR predicted the reduction in plasma triglycerides and apoC-III levels (r=0.85, P<0.01 and r=0.73, P<0.05, respectively) in the high MUFA group only. CONCLUSIONS: These results suggest that the hypotriglyceridemic effect of a high-MUFA diet may be attributable in part to a reduced hepatic production of apoC-III. SPONSORSHIP: This study was supported in part by an operating grant from the Canadian Institutes of Health Research (CIHR), and the Canada Research Chair in Nutrition and Cardiovascular Health (B Lamarche).

Triglyceride enrichment of HDL enhances in vivo metabolic clearance of HDL apo A-I in healthy men.

Triglyceride (TG) enrichment of HDL resulting from cholesteryl ester transfer protein-mediated exchange with TG-rich lipoproteins may enhance the lipolytic transformation and subsequent metabolic clearance of HDL particles in hypertriglyceridemic states. The present study investigates the effect of TG enrichment of HDL on the clearance of HDL-associated apo A-I in humans. HDL was isolated from plasma of six normolipidemic men (mean age: 29.7 +/- 2.7 years) in the fasting state and after a five-hour intravenous infusion with a synthetic TG emulsion, Intralipid. Intralipid infusion resulted in a 2.1-fold increase in the TG content of HDL. Each tracer was then whole-labeled with 125I or 131I and injected intravenously into the subject. Apo A-I in TG-enriched HDL was cleared 26% more rapidly than apo A-I in fasting HDL. A strong correlation between the Intralipid-induced increase in the TG content of HDL and the increase in HDL apo A-I fractional catabolic rate reinforced the importance of TG enrichment of HDL in enhancing its metabolic clearance. HDL was separated further into lipoproteins containing apo A-II (LpAI:AII) and those without apo A-II (LpAI). Results revealed that the enhanced clearance of apo A-I from TG-enriched HDL could be largely attributed to differences in the clearance of LpAI but not LpAI:AII. This is, to our knowledge, the first direct demonstration in humans that TG enrichment of HDL enhances the clearance of HDL apo A-I from the circulation. This phenomenon could provide an important mechanism explaining how HDL apo A-I and HDL cholesterol are lowered in hypertriglyceridemic states.

Effect of a nutritional intervention promoting the Mediterranean food pattern on anthropometric profile in healthy women from the Québec city metropolitan area.

OBJECTIVE: To evaluate the impact of a nutritional intervention promoting a Mediterranean food pattern on anthropometric profile in healthy women. DESIGN: Nutritional intervention study. SETTING: Laval University, Canada. SUBJECTS: Seventy-seven healthy women started the study and four did not complete the study. METHODS: A 12-week nutritional intervention in free-living conditions consisted of two group courses on nutrition and seven individual sessions with a dietitian. A follow-up visit was performed 12 weeks after the end of the intervention (week 24). A Mediterranean dietary score (MedScore), based on the 11 components of the Mediterranean pyramid, was established to evaluate the adherence to the Mediterranean food pattern. RESULTS: Small but significant decreases in body weight and waist circumference were observed after 12 weeks of intervention (0.5 kg and 1.2 cm, respectively (P<0.01)). Increase in partial MedScore for legumes, nuts and seeds (increase in consumption) as well as increase in partial MedScore for sweets (decrease in consumption) were significantly associated with changes in waist circumference (r=-0.36, P=0.001; r=0.24, P=0.05, respectively). No association was observed between changes in anthropometric profile and changes in the consumption of olive oil. CONCLUSION: Changes in dietary food pattern, more specifically an increase in the consumption of legumes, nuts and seeds, and a decrease in the consumption of sweets, were associated with some beneficial changes in anthropometric profile.

Comparison of various electrophoretic characteristics of LDL particles and their relationship to the risk of ischemic heart disease.

BACKGROUND: Several cross-sectional studies and 3 prospective, nested, case-control studies have indicated that individuals with small, dense low density lipoprotein (LDL) particles are at increased risk for ischemic heart disease (IHD). However, whether LDL particle size is an independent risk factor for future IHD events remains controversial. The objective of the present study was to further analyze the cardiovascular risk associated with various electrophoretic characteristics of LDL particles in men. METHODS AND RESULTS: LDL particles were characterized by polyacrylamide gradient gel electrophoresis (PAGGE) in a cohort of 2034 men of the Quebec Cardiovascular Study. All men were initially free of IHD and were followed up for a period of 5 years, during which 108 first IHD events were recorded. Among all LDL characteristics investigated by PAGGE, including LDL peak particle size, the cholesterol concentration in LDL particles with a diameter smaller than 255 A showed the strongest association with the risk of IHD (relative risk=4.6 in men in the third vs first tertile of the distribution, P<0.001). Multivariate logistic and survival models indicated that the relationship between LDL cholesterol levels in particles with a diameter <255 A and IHD risk was independent of all nonlipid risk factors and of LDL cholesterol, high density lipoprotein cholesterol, triglyceride, and lipoprotein(a) levels. CONCLUSIONS: Results from this large, population-based, prospective study suggest that further characterization of LDL particles by PAGGE, in addition to the traditional lipid profile, may improve our ability to predict IHD events in men.

Hypertriglyceridemic waist: A marker of the atherogenic metabolic triad (hyperinsulinemia; hyperapolipoprotein B; small, dense LDL) in men?

BACKGROUND: The present study tested the hypothesis that simple variables, such as waist circumference and fasting plasma triglyceride (TG) concentrations, could be used as screening tools for the identification of men characterized by a metabolic triad of nontraditional risk factors (elevated insulin and apolipoprotein [apo] B and small, dense LDL particles). METHODS AND RESULTS: Results of the metabolic study (study 1) conducted on 185 healthy men indicate that a large proportion (>80%) of men with waist circumference values >/=90 cm and with elevated TG levels (>/=2.0 mmol/L) were characterized by the atherogenic metabolic triad. Validation of the model in an angiographic study (study 2) on a sample of 287 men with and without coronary artery disease (CAD) revealed that only men with both elevated waist and TG levels were at increased risk of CAD (odds ratio of 3.6, P<0.03) compared with men with low waist and TG levels. CONCLUSIONS: It is suggested that the simultaneous measurement and interpretation of waist circumference and fasting TG could be used as inexpensive screening tools to identify men characterized by the atherogenic metabolic triad (hyperinsulinemia, elevated apo B, small, dense LDL) and at high risk for CAD.

Is lipoprotein(a) an independent risk factor for ischemic heart disease in men? The Quebec Cardiovascular Study.

OBJECTIVES: This study was undertaken to determine whether lipoprotein(a) [Lp(a)] is an independent risk factor for ischemic heart disease (IHD) and to establish the relation of Lp(a) to the other lipid fractions. BACKGROUND: Several, but not all, studies have shown that elevated Lp(a) concentrations may be associated with IHD; very few have been prospective. METHODS: A 5-year prospective follow-up study was conducted in 2,156 French Canadian men 47 to 76 years old, without clinical evidence of IHD. Lipid measurements obtained at baseline included total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, apoprotein B and Lp(a). During the follow-up period, there were 116 first IHD events (myocardial infarction, angina, death). Adjusted proportional hazards models were used to estimate the relative risk for the different variables. The cohort was also classified according to Lp(a) levels and other lipid risk factor tertiles to evaluate the relation of elevated Lp(a) levels to these risk factors. A cutoff value of 30 mg/dl was used for Lp(a). Risk ratios were calculated using the group with low Lp(a) levels and the first tertile of lipid measures as a reference. RESULTS: Lp(a) was not an independent risk factor for IHD but seemed to increase the deleterious effects of mildly elevated LDL cholesterol and elevated total cholesterol and apoprotein B levels and seemed to counteract the beneficial effects associated with elevated HDL cholesterol levels. CONCLUSIONS: In this cohort, Lp(a) was not an independent risk factor for IHD but appeared to increase the risk associated with other lipid risk factors.

Effects of endurance exercise training on plasma HDL cholesterol levels depend on levels of triglycerides: evidence from men of the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study.

High density lipoprotein (HDL) cholesterol concentrations have been shown to increase with regular endurance exercise and, therefore, can contribute to a lower risk of coronary heart disease in physically active individuals compared with sedentary subjects. Although low HDL cholesterol levels are frequently observed in combination with hypertriglyceridemia, some individuals may be characterized by isolated hypoalphalipoproteinemia, ie, low HDL cholesterol levels in the absence of elevated triglyceride (TG) concentrations. The present study compared the responses of numerous lipoprotein-lipid variables to a 20-week endurance exercise training program in men categorized on the basis of baseline TG and HDL cholesterol concentrations: (1) low TG and high HDL cholesterol (normolipidemia), (2) low TG and low HDL cholesterol (isolated low HDL cholesterol), (3) high TG and high HDL cholesterol (isolated high TGs), and (4) high TGs and low HDL cholesterol (high TG/low HDL cholesterol). A series of physical and metabolic variables was measured before and after the training program in a sample of 200 men enrolled in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study. At baseline, men with high TG/low HDL cholesterol had more visceral adipose tissue than did men with isolated low HDL cholesterol and men with normolipidemia. The 0.4% (not significant) exercise-induced increase in HDL cholesterol levels in men with isolated low HDL cholesterol suggests that they did not benefit from the "HDL-raising" effect of exercise. In contrast, men with high TG/low HDL cholesterol showed a significant increase in HDL cholesterol levels (4.9%, P<0.005). Whereas both subgroups of men with elevated TG levels showed reductions in plasma TGs ( approximately -15.0%, P<0.005), only those with high TG/low HDL cholesterol showed significantly reduced apolipoprotein B levels at the end of the study (-6.0%, P<0.005). Multiple regression analyses revealed that the exercise-induced change in abdominal subcutaneous adipose tissue (10.6%, P<0.01) was the only significant correlate of the increase in plasma HDL cholesterol with training in men with high TG/low HDL cholesterol. Results of the present study suggest that regular endurance exercise training may be particularly helpful in men with low HDL cholesterol, elevated TGs, and abdominal obesity.

Phytosterols in nonfat and low-fat beverages have no impact on the LDL size phenotype.

OBJECTIVE: To examine the impact of nonfat and low-fat phytosterol-enriched beverages on low-density lipoprotein (LDL) electrophoretic characteristics. DESIGN: Double-blind, randomized, crossover, placebo-controlled dietary trial. SETTING: Diets were prepared and consumed at the Mary Emily Clinical Nutrition Research Unit of McGill University. Analyses were performed at the Institute on Nutraceuticals and Functional Foods of Laval University. SUBJECTS AND INTERVENTION: In total, 15 moderately hypercholesterolemic persons consumed each of three experimental diets that each comprised a different beverage: nonfat placebo (NF control), nonfat with phytosterols (NFPS) or low-fat with phytosterols (LFPS). Participants consumed three beverages daily at meal time for a total of 1.8 g of phytosterols per day. Nondenaturing 2-16% polyacrylamide gradient gel electrophoreses were used to characterize LDL size characteristics. RESULTS: The NFPS and LFPS beverage induced no significant changes in several features of the LDL size phenotype compared to the control diet. CONCLUSION: The consumption of phytosterol-supplemented nonfat and low-fat beverages is not associated with clinically meaningful changes in the LDL particle size phenotype.