83 research outputs found
Chern-Simons black holes: scalar perturbations, mass and area spectrum and greybody factors
We study the Chern-Simons black holes in d-dimensions and we calculate
analytically the quasi-normal modes of the scalar perturbations and we show
that they depend on the highest power of curvature present in the Chern-Simons
theory. We obtain the mass and area spectrum of these black holes and we show
that they have a strong dependence on the topology of the transverse space and
they are not evenly spaced. We also calculate analytically the reflection and
transmission coefficients and the absorption cross section and we show that at
low frequency limit there is a range of modes which contributes to the
absorption cross section.Comment: 19 pages, 18 figures, the title has been changed to reflect the
addition of an another section on the reflection, transmission coefficients
and absorption cross sections of the Chern-Simons black holes. Version to be
published in JHE
Mediterranean Diet and atherothrombosis biomarkers: a randomized controlled trial
Scope. To assess whether following a Mediterranean diet (MedDiet) improved
atherothrombosis biomarkers in high cardiovascular risk individuals.
Methods and results. In 358 random volunteers from the PREvención con DIeta MEDiterránea trial, we assessed the 1-year effects on atherothrombosis markers of an
intervention with MedDiet, enriched with virgin olive oil (MedDiet-VOO; n=120) or nuts
(MedDiet-Nuts; n=119) versus a low-fat control diet (n=119). We also studied whether large increments in MedDiet adherence (≥3 score points, relative to compliance
decreases) and intake changes in key food items were associated with 1-year differences
in biomarkers. We observed differences between 1-year changes in the MedDiet-VOO intervention and control diet on the activity of platelet activating factor acetylhydrolase in
HDLs (+7.5% [95% confidence interval: 0.17; 14.8]) and HDL-bound α1-antitrypsin levels (-
6.1% [-11.8; -0.29]), and between the MedDiet-Nuts intervention and the control arm on non-esterified fatty acid concentrations (-9.3% [-18.1; -0.53]). Large MedDiet adherence
increments were associated with less fibrinogen (-9.5% [-18.3; -0.60]) and non-esterified fatty acid concentrations (-16.7% [-31.7; -1.74]). Increases in nut, fruit, vegetable, and fatty
fish consumption, and decreases in processed meat intake were linked to beneficial changes in atherothrombosis biomarkers.
Conclusion. Following a MedDiet improved atherothrombosis biomarkers in high cardiovascular risk individual
Predictors of adherence to a Mediterranean-type diet in the PREDIMED trial.
BACKGROUND:
Determinants of dietary changes obtained with a nutritional intervention promoting the Mediterranean diet have been rarely evaluated.
AIM:
To identify predictors of higher success of an intervention aimed to increase adherence to a Mediterranean diet (MeDiet) in individuals at high cardiovascular risk participating in a trial for primary prevention of cardiovascular disease: the PREDIMED (PREvención con DIeta MEDiterránea) trial. Candidate predictors included demographic and socioeconomic characteristics, cardiovascular risk factors, and baseline dietary habits.
METHODS:
A total of 1,048 asymptomatic subjects aged 55-80 years allocated to the active intervention groups (subjects in the control group were excluded). Participants' characteristics were assessed at baseline among subjects. Dietary changes were evaluated after 12 months. Main outcome measures were: attained changes in five dietary goals: increases in (1) fruit consumption, (2) vegetable consumption, (3) monounsaturated fatty acid (MUFA)/saturated fatty acid (SFA) ratio, and decreases in (4) sweets and pastries consumption, (5) and meat consumption. Univariate and multivariate logistic regression analyses were used to examine associations between the candidate predictors and likelihood of attaining optimum dietary change (improved adherence to a MeDiet).
RESULTS:
Among men, positive changes toward better compliance with the MeDiet were more frequent among non-diabetics, and among those with worse dietary habits at baseline (higher consumption of meat, higher SFA intake, lower consumption of fruit and vegetables). Among women, marital status (married) and worse baseline dietary habits (high in meats, low in fruits and vegetables) were the strongest predictors of success in improving adherence to the MeDiet.
CONCLUSIONS:
Some participant characteristics (marital status and baseline dietary habits) could contribute to predicting the likelihood of achieving dietary goals in interventions aimed to improve adherence to a MeDiet, and may be useful for promoting individualized long-term dietary changes and improving the effectiveness of dietary counseling
Primary prevention of cardiovascular disease with a Mediterranean diet
BACKGROUND:
Observational cohort studies and a secondary prevention trial have shown an inverse association between adherence to the Mediterranean diet and cardiovascular risk. We conducted a randomized trial of this diet pattern for the primary prevention of cardiovascular events.
METHODS:
In a multicenter trial in Spain, we randomly assigned participants who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). On the basis of the results of an interim analysis, the trial was stopped after a median follow-up of 4.8 years.
RESULTS:
A total of 7447 persons were enrolled (age range, 55 to 80 years); 57% were women. The two Mediterranean-diet groups had good adherence to the intervention, according to self-reported intake and biomarker analyses. A primary end-point event occurred in 288 participants. The multivariable-adjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.54 to 0.92) and 0.72 (95% CI, 0.54 to 0.96) for the group assigned to a Mediterranean diet with extra-virgin olive oil (96 events) and the group assigned to a Mediterranean diet with nuts (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported.
CONCLUSIONS:
Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events
Longitudinal association of changes in diet with changes in body weight and waist circumference in subjects at high cardiovascular risk: the PREDIMED trial
Background: Consumption of certain foods is associated with long-term weight gains and abdominal fat accumulation in healthy, middle-aged and young, non-obese participants. Whether the same foods might be associated with changes in adiposity in elderly population at high cardiovascular risk is less known.
Objective: Using yearly repeated measurements of both food habits and adiposity parameters, we aimed to investigate how changes in the consumption of specific foods were associated with concurrent changes in weight or waist circumference (WC) in the PREDIMED trial.
Design: We followed-up 7009 participants aged 55-70 years at high cardiovascular risk for a median time of 4.8 years. A validated 137-item semi-quantitative Food Frequency Questionnaire was used for dietary assessment with yearly repeated measurements. We longitudinally assessed associations between yearly changes in food consumption (serving/d) and concurrent changes in weight (kg) or WC (cm).
Results: Yearly increments in weight were observed with increased consumption (kg per each additional increase in 1 serving/d) for refined grains (0.32 kg/serving/d), red meat (0.24), potatoes (0.23), alcoholic beverages (0.18), processed meat (0.15), white bread (0.07) and sweets (0.04); whereas inverse associations were detected for increased consumption of low-fat yogurt (- 0.18), and low-fat milk (- 0.06). Annual WC gain (cm per each additional increase in 1 serving/d) occurred with increased consumption of snacks, fast-foods and pre-prepared dishes (0.28), processed meat (0.18), alcoholic beverages (0.13), and sweets (0.08); whereas increased consumption of vegetables (- 0.23), and nuts (- 0.17), were associated with reductions in WC.
Conclusions: In this assessment conducted in high-risk subjects using yearly repeated measurements of food habits and adiposity, some ultra-processed foods, refined carbohydrates (including white bread), potatoes, red meats and alcohol were associated with higher weight and WC gain, whereas increases in consumption of low-fat dairy products and plant foods were associated with less gain in weight and WC
American heart association's life simple 7 and the risk of atrial fibrillation in the PREDIMED study cohort
Background and aims
The American Heart Association proposed 7 ideal cardiovascular health metrics (Life's Simple 7 [LS7]) namely, not smoking, body mass index <25 kg/m2, healthy diet, moderate physical activity ≥150 min/week, total blood cholesterol <200 mg/dL, blood pressure <120/80 mmHg and fasting blood glucose <100 mg/dL. Our objective was to assess the association between these LS7 metrics and the incidence of atrial fibrillation (AF).
Methods and results
A total of 6,479 participants of the PREDIMED study were included. We calculated the participants’ baseline LS7 index ranging 0–7 points to categorize them according to their adherence to these LS7 health metrics. Multivariable Cox regression models were used to estimate Hazard Ratios (HR) and their 95% Confidence Intervals (95% CI). After a median follow-up of 4.8 years, we identified 250 incident cases of AF. After adjusting for potential confounders, adherence to LS7 index was not associated with the incidence of AF (adjusted HR 0.90 [95% CI: 0.56–1.45] for highest vs. lowest LS7 categories). Body mass index <25 kg/m2 was the only health metric individually associated with a lower risk of AF (HR 0.36 [95% CI: 0.16–0.78]).
Conclusions
In a high cardiovascular risk Spanish population, adherence to American Heart Association's LS7 metrics was not associated with the risk of incident AF
Circulating Amino Acids and Risk of Peripheral Artery Disease in the PREDIMED Trial
Effective prevention and risk prediction are important for peripheral artery disease (PAD) due to its poor prognosis and the huge disease burden it produces. Circulating amino acids (AA) and their metabolites may serve as biomarkers of PAD risk, but they have been scarcely investigated. The objective was to prospectively analyze the associations of baseline levels of plasma AA (and their pathways) with subsequent risk of PAD and the potential effect modification by a nutritional intervention with the Mediterranean diet (MedDiet). A matched case-control study was nested in the PREDIMED trial, in which participants were randomized to three arms: MedDiet with tree nut supplementation group, MedDiet with extra-virgin olive oil (EVOO) supplementation group or control group (low-fat diet). One hundred and sixty-seven PAD cases were matched with 250 controls. Plasma AA was measured with liquid chromatography/mass spectrometry at the Broad Institute. Baseline tryptophan, serine and threonine were inversely associated with PAD (ORfor 1 SD increase = 0.78 (0.61–0.99); 0.67 (0.51–0.86) and 0.75 (0.59–0.95), respectively) in a multivariable-adjusted conditional logistic regression model. The kynurenine/tryptophan ratio was directly associated with PAD (ORfor 1 SD increase = 1.50 (1.14–1.98)). The nutritional intervention with the MedDiet+nuts modified the association between threonine and PAD (p-value interaction = 0.018) compared with the control group. However, subjects allocated to the MedDiet+EVOO group were protected against PAD independently of baseline threonine. Plasma tryptophan, kynurenine/tryptophan ratio, serine and threonine might serve as early biomarkers of future PAD in subjects at a high risk of cardiovascular disease. The MedDiet supplemented with EVOO exerted a protective effect, regardless of baseline levels of threonine
Metabolites related to purine catabolism and risk of type 2 diabetes incidence; modifying efects of the TCF7L2-rs7903146 polymorphism
Studies examining associations between purine metabolites and type 2 diabetes (T2D) are limited. We prospectively examined associations between plasma levels of purine metabolites with T2D risk and the modifying effects of transcription factor-7-like-2 (TCF7L2) rs7903146 polymorphism on these associations. This is a case-cohort design study within the PREDIMED study, with 251 incident T2D cases and a random sample of 694 participants (641 non-cases and 53 overlapping cases) without T2D at baseline (median follow-up: 3.8 years). Metabolites were semi-quantitatively profiled with LC-MS/MS. Cox regression analysis revealed that high plasma allantoin levels, including allantoin-to-uric acid ratio and high xanthine-to-hypoxanthine ratio were inversely and positively associated with T2D risk, respectively, independently of classical risk factors. Elevated plasma xanthine and inosine levels were associated with a higher T2D risk in homozygous carriers of the TCF7L2-rs7903146 T-allele. The potential mechanisms linking the aforementioned purine metabolites and T2D risk must be also further investigated
Circulating citric acid cycle metabolites and risk of cardiovascular disease in the PREDIMED study
Background and aim
Plasma citric acid cycle (CAC) metabolites might be likely related to cardiovascular disease (CVD). However, studies assessing the longitudinal associations between circulating CAC-related metabolites and CVD risk are lacking. The aim of this study was to evaluate the association of baseline and 1-year levels of plasma CAC-related metabolites with CVD incidence (a composite of myocardial infarction, stroke or cardiovascular death), and their interaction with Mediterranean diet interventions.
Methods and results
Case-cohort study from the PREDIMED trial involving participants aged 55–80 years at high cardiovascular risk, allocated to MedDiets or control diet. A subcohort of 791 participants was selected at baseline, and a total of 231 cases were identified after a median follow-up of 4.8 years. Nine plasma CAC-related metabolites (pyruvate, lactate, citrate, aconitate, isocitrate, 2-hydroxyglutarate, fumarate, malate and succinate) were measured using liquid chromatography-tandem mass spectrometry. Weighted Cox multiple regression was used to calculate hazard ratios (HRs). Baseline fasting plasma levels of 3 metabolites were associated with higher CVD risk, with HRs (for each standard deviation, 1-SD) of 1.46 (95%CI:1.20–1.78) for 2-hydroxyglutarate, 1.33 (95%CI:1.12–1.58) for fumarate and 1.47 (95%CI:1.21–1.78) for malate (p of linear trend <0.001 for all). A higher risk of CVD was also found for a 1-SD increment of a combined score of these 3 metabolites (HR = 1.60; 95%CI: 1.32–1.94, p trend <0.001). This result was replicated using plasma measurements after one-year. No interactions were detected with the nutritional intervention.
Conclusion
Plasma 2-hydroxyglutarate, fumarate and malate levels were prospectively associated with increased cardiovascular risk
The Effect of a Mediterranean Diet on the Incidence of Cataract Surgery
Background: Cataract is a leading cause of vision impairment worldwide, and surgery
is the only available treatment. The process that initiates lens opacification is dependent on the
oxidative stress experienced by the lens components. A healthy overall dietary pattern, with the
potential to reduce oxidative stress, has been suggested as a means to decrease the risk of developing
cataract. We aimed to investigate the hypothesis that an intervention with a Mediterranean diet
(MedDiet) rather than a low-fat diet could decrease the incidence of cataract surgery in elderly subjects.
Methods: We included 5802 men and women (age range: 55–80 years) from the Prevención con
Dieta Mediterránea study (multicenter, parallel-group, randomized controlled clinical trial) who had not undergone cataract surgery. They were randomly assigned to one of three intervention groups:
(1) a MedDiet enriched with extra-virgin olive oil (EVOO) (n = 1998); (2) a MedDiet enriched with
nuts (n = 1914), and a control group recommended to follow a low-fat diet (n = 1890). The incidence
of cataract surgery was recorded yearly during follow-up clinical evaluations. Primary analyses
were performed on an intention-to-treat basis. Cox regression analyses were used to assess the
relationship between the nutritional intervention and the incidence of cataract surgery. Results:
During a follow-up period of 7.0 years (mean follow-up period: 5.7 years; median: 5.9 years),
559 subjects underwent cataract surgery. Two hundred and six participants from the MedDiet + EVOO
group, 174 from the MedDiet + Nuts group, and 179 from the control group underwent cataract
surgery. We did not observe a reduction in the incidence of cataract surgery in the MedDiet groups
compared to the control group. The multivariable adjusted hazard ratios were 1.03 (95% confidence
interval [CI]: 0.84–1.26, p = 0.79) for the control group versus the MedDiet + EVOO group and
1.06 (95% CI: 0.86–1.31, p = 0.58) for the control group versus the MedDiet + Nuts group. Conclusions:
To our knowledge, this is the first large randomized trial assessing the role of a MedDiet on the
incidence of cataract surgery. Our results showed that the incidence of cataract surgery was similar in
the MedDiet with EVOO, MedDiet with nuts, and low-fat diet groups. Further studies are necessary
to investigate whether a MedDiet could have a preventive role in cataract surgery
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