A priori-defined Mediterranean-like dietary pattern predicts cardiovascular events better in north Europe than in Mediterranean countries

Diet quality and cardiovascular outcomes: A systematic review and meta-analysis of cohort studies

AIMS

To evaluate relationships between diet quality and cardiovascular outcomes.

METHODS

Six databases were searched for studies published between January 2007 and October 2021. Eligible studies included cohort studies that assessed the relationship between a priori diet quality and cardiovascular disease mortality and morbidity in adults. The Academy of Nutrition and Dietetics Checklist was used to assess the risk of bias. Study characteristics and outcomes were extracted from eligible studies using standardised processes. Data were summarised using risk ratios for cardiovascular disease incidence and mortality with difference compared for highest versus lowest diet quality synthesised in meta-analyses using a random effects model.

RESULTS

Of the 4780 studies identified, 159 studies (n = 6 272 676 adults) were included. Meta-analyses identified a significantly lower cardiovascular disease incidence (n = 42 studies, relative risk 0.83, 95% CI 0.82-0.84, p < 0.001) and mortality risk (n = 49 studies, relative risk 0.83, 95% CI 0.82-0.84, p < 0.001) among those with highest versus lowest diet quality. In sensitivity analyses of a high number of pooled studies (≥13 studies) the Mediterranean style diet patterns and adherence to the heart healthy diet guidelines were significantly associated with a risk reduction of 15% and 14% for cardiovascular disease incidence and 17% and 20% for cardiovascular disease mortality respectively (p < 0.05).

CONCLUSIONS

Higher diet quality is associated with lower incidence and risk of mortality for cardiovascular disease however, significant study heterogeneity was identified for these relationships.

Adherence to a Mediterranean type of diet in the world: a geographical analysis based on a systematic review of 57 studies with 1,125,560 participants

This systematic review aimed to assess the level and time-trends of adherence to Mediterranean-type diets (MTD) among the general population, globally. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a comprehensive literature search of the MEDLINE and Scopus databases was carried out, until 04/09/2023, based on specific criteria. Fifty-seven studies with 1,125,560 apparently healthy adults from Europe (n = 37), US (n = 8), Asia (n = 8), Australia (n = 4) and Africa (n = 1) were included. Adherence to an MTD was moderate with a significant decline observed in the last decade. European countries, mainly driven by Mediterranean countries, showed higher adherence than other regions. Geographical analysis revealed that adherence to an MTD is related to both geographic location and socioeconomic status throughout the world.

Cross-Sectional Gene-Smoking Interaction Analysis in Relation to Subclinical Atherosclerosis-Results From the IMPROVE Study

BACKGROUND

Smoking is associated with carotid intima-media thickness (C-IMT). However, knowledge about how genetics may influence this association is limited. We aimed to perform nonhypothesis driven gene-smoking interaction analyses to identify potential genetic variants, among those included in immune and metabolic platforms, that may modify the effect of smoking on carotid intima-media thickness.

METHODS

We used baseline data from 1551 men and 1700 women, aged 55 to 79, included in a European multi-center study. Carotid intima-media thickness maximum, the maximum of values measured at different locations of the carotid tree, was dichotomized with cut point values ≥75, respectively. Genetic data were retrieved through use of the Illumina Cardio-Metabo- and Immuno- Chips. Gene-smoking interactions were evaluated through calculations of Synergy index (S). After adjustments for multiple testing, P values of <2.4×10-7 for S were considered significant. The models were adjusted for age, sex, education, physical activity, type of diet, and population stratification.

RESULTS

Our screening of 207 586 SNPs available for analysis, resulted in the identification of 47 significant gene-smoking synergistic interactions in relation to carotid intima-media thickness maximum. Among the significant SNPs, 28 were in protein coding genes, 2 in noncoding RNA and the remaining 17 in intergenic regions.

CONCLUSIONS

Through nonhypothesis-driven analyses of gene-smoking interactions, several significant results were observed. These may stimulate further research on the role of specific genes in the process that determines the effect of smoking habits on the development of carotid atherosclerosis.

Increased Adherence to a Mediterranean Diet Is Associated with Reduced Low-Grade Inflammation after a 12.7-Year Period: Results from the Moli-sani Study

BACKGROUND

There is little knowledge on the association of changes over time in adherence to a Mediterranean diet (MD) with changes in modifiable cardiovascular disease (CVD) risk factors and of markers of low-grade inflammation.

OBJECTIVE

To evaluate the association between long-term changes in MD adherence and concurrent changes in established CVD risk factors and in markers of low-grade inflammation among adult Italians.

DESIGN

A prospective cohort study was conducted. Dietary and health data were obtained both at baseline (2005-2010) and at follow-up (2017-2020). Adherence to the MD was estimated by a Mediterranean Diet Score ranging from zero to nine points, and the exposure was change in this score measured after a median 12.7-year period.

PARTICIPANTS/SETTING

This study included a subgroup of 897 men and 1,126 women aged ≥35 years at enrolment in the Moli-sani Study (n = 24,325).

MAIN OUTCOME MEASURES

Changes in two composite z scores, including nine established CVD risk factors (eg, serum lipid levels and blood pressure) and four inflammatory markers (including C-reactive protein), respectively, were measured both at enrolment and after the same 12.7-year period.

STATISTICAL ANALYSES PERFORMED

Multivariable-adjusted linear regression models were used.

RESULTS

In a multivariable-adjusted analysis, an increased Mediterranean Diet Score over time was associated with decreased levels in the Inflammatory score (β = -0.372, 95% CI -0.720 to -0.025), but had little or no influence on the CVD risk score (β = -0.200, 95% CI -0.752 to 0.351), compared with individuals who had decreased their MD adherence. Among individual food groups/nutrients included in the Mediterranean Diet Score, an increased intake of monounsaturated over saturated fats over time was associated with lower CVD Risk Score, whereas increased consumption of cereals was inversely linked to the Inflammatory Score, compared with the reduced consumption group.

CONCLUSIONS

An increased adherence to a traditional MD over time was associated with reduced low-grade inflammation. These findings suggest the potential of a traditional Mediterranean eating pattern to help reduce the long-term risk of inflammation-related chronic diseases in an ageing population.

Impact of the level of adherence to the Mediterranean Diet on blood pressure: A systematic review and meta-analysis of observational studies

BACKGROUND

High blood pressure (BP) constitutes a common and serious medical condition which is rising globally, and is among preventable factors for cardiovascular, renal, brain and other diseases. Modifiable risk factors of high BP include unhealthy dietary patterns, presence of obesity, excess alcohol consumption and lack of physical activity. Data in regard to the different types of diets show that Mediterranean diet (MD) is associated with healthy levels of BP. In this study we aimed to investigate the impact of the level of adherence to MD in BP.

AIMS-METHODS

A systematic literature search (up to 08.2021) in PubMed, Scopus, Embase, Web of Science, Cochrane and Google Scholar databases was conducted, and 54 observational studies were included.

RESULTS

Systolic blood pressure (SBP) was found to be lower in the high adherence to MD group SMD: -0.08, (95%CI: -0.15, -0.02) whereas no differences regarding diastolic blood pressure (DBP) were observed between the high and low adherence to MD groups [SMD: -0.07, (95%CI: -0.13, 0.00)]. Mean DBP of all included studies for both high and low adherence groups were in healthy levels (<90 mmHg).

CONCLUSIONS

Higher adherence to MD could positively influence SBP, but further research is needed in this field due to the heterogeneous definitions of low/high adherence and the type of studies used (observational).

Impact of the Level of Adherence to Mediterranean Diet on the Parameters of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Observational Studies

High adherence to the Mediterranean diet (MD) has been associated with a lower prevalence of Metabolic Syndrome (MetS). The present study aimed to investigate the impact of MD adherence on parameters of MetS. A systematic literature search was performed in PubMed, Cochrane Central Registry of Clinical Trials (CENTRAL), Scopus, EMBASE, Web of Science and Google Scholar databases. Observational studies that recorded adherence to MD and components/measures of the MetS, such as waist circumference (WC), blood pressure (BP), fasting blood glucose (FBG), high-density lipoprotein (HDL) cholesterol and triglycerides (TG), were included in this study. A total of 58 studies were included in our study. WC and TG were significantly lower in the high adherence MD group (SMD: −0.20, (95%CI: −0.40, −0.01), SMD: −0.27 (95%CI: −0.27, −0.11), respectively), while HDL cholesterol was significantly higher in the same group (SMD: −0.28 (95%CI: 0.07, 0.50). There was no difference in FBG and SBP among the two groups (SMD: −0.21 (95%CI: −0.54, 0.12) & SMD: −0.15 (95%CI: −0.38, 0.07), respectively). MD may have a positive impact on all parameters of MetS. However, further research is needed in this field.

Intake of food rich in saturated fat in relation to subclinical atherosclerosis and potential modulating effects from single genetic variants

The relationship between intake of saturated fats and subclinical atherosclerosis, as well as the possible influence of genetic variants, is poorly understood and investigated. We aimed to investigate this relationship, with a hypothesis that it would be positive, and to explore whether genetics may modulate it, using data from a European cohort including 3,407 participants aged 54–79 at high risk of cardiovascular disease. Subclinical atherosclerosis was assessed by carotid intima-media thickness (C-IMT), measured at baseline and after 30 months. Logistic regression (OR; 95% CI) was employed to assess the association between high intake of food rich in saturated fat (vs. low) and: (1) the mean and the maximum values of C-IMT in the whole carotid artery (C-IMT_mean, C-IMT_max), in the bifurcation (Bif-), the common (CC-) and internal (ICA-) carotid arteries at baseline (binary, cut-point ≥ 75th), and (2) C-IMT progression (binary, cut-point > zero). For the genetic-diet interaction analyses, we considered 100,350 genetic variants. We defined interaction as departure from additivity of effects. After age- and sex-adjustment, high intake of saturated fat was associated with increased C-IMT_mean (OR:1.27;1.06–1.47), CC-IMT_mean (OR:1.22;1.04–1.44) and ICA-IMT_mean (OR:1.26;1.07–1.48). However, in multivariate analysis results were no longer significant. No clear associations were observed between high intake of saturated fat and risk of atherosclerotic progression. There was no evidence of interactions between high intake of saturated fat and any of the genetic variants considered, after multiple testing corrections. High intake of saturated fats was not independently associated with subclinical atherosclerosis. Moreover, we did not identify any significant genetic-dietary fat interactions in relation to risk of subclinical atherosclerosis.

Data on the association between a simplified Mediterranean diet score and the incidence of combined, cardio and cerebro vascular events

Data presented in this article are related to the research article entitled “A priori-defined Mediterranean-like dietary pattern predicts cardiovascular events better in north Europe than in Mediterranean countries” [Veglia et al., 2018]. Data contain information about the incidence of cardiovascular events in a high-risk European population (IMPROVE study) [Baldassarre et al., 2010, 2012, 2013]. Combined vascular events, as well as cardio- and cerebro-vascular events were stratified according to a priori-defined simple Mediterranean Diet (MD) score, based on just seven nutritional items (minimal adherence was 0 and maximal adherence was 7).

Adherence to the Mediterranean diet and risk of stroke and stroke subtypes

Several meta-analyses including a small number of cohorts showed inverse associations between the Mediterranean Diet (MedDiet) and risk of stroke. However, it remains unclear whether such a relation varies by region of the study population or by major subtypes of stroke. We searched PubMed and EMBASE databases for relevant studies and we further included unpublished results from the Singapore Chinese Health Study (N = 57,078) and the Seguimiento Universidad de Navarra (SUN) study (N = 12,670). We used a random-effects model to calculate summary relative risk (RR) with 95% confidence intervals (CI) of stroke for each 4-point increment of the MedDiet score, roughly corresponding to the difference between extreme quintiles of the MedDiet score among participants of the included studies. The final analyses included 20 prospective cohort studies involving 682,149 participants and 16,739 stroke cases. The summary RRs for each 4-point increment of the MedDiet score were 0.84 (95% CI 0.81-0.88; I² = 11.5%) for all combined, 0.76 (95% CI 0.65-0.89) for studies in Mediterranean populations and 0.86 (95% CI 0.83-0.89) for those in non-Mediterranean populations. Lower risk of stroke associated with higher MedDiet score also was observed in the analyses stratified by study population and methodological characteristics including study risk of bias, version of the MedDiet index, and definition of moderate alcohol consumption. The MedDiet was similarly associated with lower risk of ischemic stroke (RR 0.86, 95% CI 0.81-0.91; nine studies) and hemorrhagic stroke (RR 0.83, 95% CI 0.74-0.93; eight studies). Our meta-analysis suggests that adhering to the Mediterranean diet was associated with lower risk of stroke in both Mediterranean and non-Mediterranean populations, and for both ischemic stroke and hemorrhagic stroke risk.