Which dietary and lifestyle behaviours may be important in the aetiology (and prevention) of stroke?

Impact of adherence to the Mediterranean diet on stroke risk

Stroke is a leading cause of morbidity and mortality worldwide, and dietary patterns have emerged as a significant modifiable factor in stroke prevention. The Mediterranean diet, characterized by high intake of fruits, vegetables, whole grains, nuts, olive oil, and fish, has been widely recognized for its cardiovascular benefits. However, its specific impact on stroke risk requires further elucidation. We conducted a comprehensive meta-analysis of 30 studies, including both cohort and case-control designs, to evaluate the relationship between adherence to the Mediterranean diet and the risk of stroke. A systematic search was performed across multiple databases, and a random-effects model was used to estimate pooled hazard ratios (HRs) with 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic, and publication bias was examined through funnel plots and Egger's regression test. Additionally, trial sequential analysis was conducted to determine the adequacy of the sample size. The meta-analysis revealed a significant reduction in stroke risk among individuals adhering to the Mediterranean diet, with a pooled HR of 0.88 (95% CI: 0.84-0.91). Notably, a significant heterogeneity was detected (I2 = 34%). The Z-score plot from trial sequential analysis confirmed that the sample sizes were sufficient to draw definitive conclusions. However, a potential publication bias was identified. The case-control studies confirmed a highly significant effect (HR = 0.54, 95% CI: 0.4-0.73). The funnel plots in both settings hinted at the presence of a potential publication bias, supported by a significant Egger's test. Our findings provide robust evidence supporting the protective effect of the Mediterranean diet against stroke. Despite the presence of some heterogeneity and potential publication bias, the cumulative evidence suggests that promoting the Mediterranean diet could serve as an effective public health strategy for stroke prevention. Further research is recommended to explore the underlying mechanisms and to assess the diet's impact across diverse populations.

Territorial and Sustainable Healthy Diets

The rapid changes that societies have gone through in the last few decades have led to the increase in the prevalence of malnutrition in all its forms and to the degradation of natural resources and the environment. The change in the dietary habits and production systems are responsible for much of this change. Some territorial diets have been shown as potentially capable of reversing these trends by positively contributing to the health of people and the environment such as the Mediterranean Diet and the New Nordic Diet. In this paper, we review the contribution of these 2 diets to health and nutrition and to environmental, sociocultural, and economic sustainability proposing pertinent indicators. Learning from a culturally established diet and a constructed one, tradeoff could be reached to ensure better health and sustainability outcomes. Strong factors for achieving this goal lie in building on the sociocultural appropriation of diets, having the proper tools and indicators, investing in cross-sector collaboration and policy coherence, and having the necessary political support to push the agenda of sustainability forward.

The Mediterranean Diet and Cardiovascular Health

The Mediterranean diet (MedDiet), abundant in minimally processed plant-based foods, rich in monounsaturated fat from olive oil, but lower in saturated fat, meats, and dairy products, seems an ideal nutritional model for cardiovascular health. Methodological aspects of Mediterranean intervention trials, limitations in the quality of some meta-analyses, and other issues may have raised recent controversies. It remains unclear whether such limitations are important enough as to attenuate the postulated cardiovascular benefits of the MedDiet. We aimed to critically review current evidence on the role of the MedDiet in cardiovascular health. We systematically searched observational prospective cohorts and randomized controlled trials which explicitly reported to assess the effect of the MedDiet on hard cardiovascular end points. We critically assessed all the original cohorts and randomized controlled trials included in the 5 most comprehensive meta-analyses published between 2014 and 2018 and additional prospective studies not included in these meta-analyses, totaling 45 reports of prospective studies (including 4 randomized controlled trials and 32 independent observational cohorts). We addressed the existing controversies on methodology and other issues. Some departures from individual randomization in a subsample of the landmark Spanish trial (PREDIMED [Prevención con Dieta Mediterránea]) did not represent any clinically meaningful attenuation in the strength of its findings and the results of PREDIMED were robust in a wide range of sensitivity analyses. The criteria for causality were met and potential sources of controversies did not represent any reason to compromise the main findings of the available observational studies and randomized controlled trials. The available evidence is large, strong, and consistent. Better conformity with the traditional MedDiet is associated with better cardiovascular health outcomes, including clinically meaningful reductions in rates of coronary heart disease, ischemic stroke, and total cardiovascular disease.

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.

Evaluating Mediterranean diet and risk of chronic disease in cohort studies: an umbrella review of meta-analyses

Several meta-analyses have been published summarizing the associations of the Mediterranean diet (MedDiet) with chronic diseases. We evaluated the quality and credibility of evidence from these meta-analyses as well as characterized the different indices used to define MedDiet and re-calculated the associations with the different indices identified. We conducted an umbrella review of meta-analyses on cohort studies evaluating the association of the MedDiet with type 2 diabetes, cardiovascular disease, cancer and cognitive-related diseases. We used the AMSTAR (A MeaSurement Tool to Assess systematic Reviews) checklist to evaluate the methodological quality of the meta-analyses, and the NutriGrade scoring system to evaluate the credibility of evidence. We also identified different indices used to define MedDiet; tests for subgroup differences were performed to compare the associations with the different indices when at least 2 studies were available for different definitions. Fourteen publications were identified and within them 27 meta-analyses which were based on 70 primary studies. Almost all meta-analyses reported inverse associations between MedDiet and risk of chronic disease, but the credibility of evidence was rated low to moderate. Moreover, substantial heterogeneity was observed on the use of the indices assessing adherence to the MedDiet, but two indices were the most used ones [Trichopoulou MedDiet (tMedDiet) and alternative MedDiet (aMedDiet)]. Overall, we observed little difference in risk associations comparing different MedDiet indices in the subgroup meta-analyses. Future prospective cohort studies are advised to use more homogenous definitions of the MedDiet to improve the comparability across meta-analyses.

Mediterranean diet and cardiovascular disease: a systematic review and meta-analysis of observational studies

PURPOSE

To provide evidence of the relationship of Mediterranean diet (MD) on incidence/mortality for cardiovascular disease (CVD), coronary/ischemic heart disease (CHD)/acute myocardial infarction (AMI) and stroke (ischemic/hemorrhagic) by sex, geographic region, study design and type of MD score (MDS).

METHODS

We performed a systematic review and meta-analysis of observational studies. Pooled relative risks (RRs) were calculated using random-effects models.

RESULTS

We identified 29 articles. The RR for the highest versus the lowest category of the MDS was 0.81 (95% CI 0.74-0.88) for the 11 studies that considered unspecified CVD, consistent across all strata. The corresponding pooled RR for CHD/AMI risk was 0.70 (95% CI 0.62-0.80), based on 11 studies. The inverse relationship was consistent across strata of study design, end point (incidence and mortality), sex, geographic area, and the MDS used. The overall RR for the six studies that considered unspecified stroke was 0.73 (95% CI 0.59-0.91) for the highest versus the lowest category of the MDS. The corresponding values were 0.82 (95% CI 0.73-0.92) for ischemic (five studies) and 1.01 (95% CI 0.74-1.37) for hemorrhagic stroke (four studies).

CONCLUSIONS

Our findings indicate and further quantify that MD exerts a protective effect on the risk of CVD. This inverse association includes CHD and ischemic stroke, but apparently not hemorrhagic stroke.

Dietary patterns and the risk of obesity, type 2 diabetes mellitus, cardiovascular diseases, asthma, and neurodegenerative diseases

Diet and lifestyle play a significant role in the development chronic diseases; however the full complexity of this relationship is not yet understood. Dietary pattern investigation, which reflects the complexity of dietary intake, has emerged as an alternative and complementary approach for examining the association between diet and chronic diseases. Literature on this association has largely focused on individual nutrients, with conflicting outcomes, but individuals consume a combination of foods from many groups that form dietary patterns. Our objective was to systematically review the current findings on the effects of dietary patterns on chronic diseases. In this review, we describe and discuss the relationships between dietary patterns, such as the Mediterranean, the Dietary Approach to Stop Hypertension, Prudent, Seventh-day Adventists, and Western, with risk of obesity, type-2 diabetes mellitus, cardiovascular diseases, asthma, and neurodegenearive diseases. Evidence is increasing from both observational and clinical studies that plant-based dietary patterns, which are rich in fruits, vegetables, and whole grains, are valuable in preventing various chronic diseases, whereas a diet high in red and processed meat, refined grains and added sugar seems to increase said risk. Dietary pattern analysis might be especially valuable to the development and evaluation of food-based dietary guidelines.

Dietary patterns are associated with general and central obesity in elderly living in a Brazilian city

Objective: dietary pattern evaluation is often used in order to determine wheter a diet is healthy, as well as to predict the onset of diseases. This study aimed to identify dietary patterns, and to examine their associations with general (body mass index) and central (waist circumference and waist-to-hip ratio) obesity in community-living elderly in a Brazilian city. Methods: this cross-sectional study included 126 elderly subjects aged 60 or older (57.1% females and mean age 74.2 ± 6.46 years). Anthropometric variables, weight, height, waist (WC) and hip (HC) circumferences, were measured. Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated. Answers to a Food Frequency Questionnaire were interpreted by Principal Component Analysis in order to identify dietary patterns. Results: five dietary patterns were identified and named as prudent (fruit, vegetables and meat), sweets and fats (pastries, sugary foods, fatty foods, whole milk), typical Brazilian (fried eggs, cooked beans, beef, candy, string beans, fried cassava), Mediterranean (fruit, vegetables, olive oil and nuts) and traditional meal (rice and beans). Moderate and high adherences to the Mediterranean pattern were protective factors to general and central obesity (WHR). High adherence to prudent was also protective to central obesity (WC). Conclusion: adherences to the dietary patterns prudent and Mediterranean were protective factors to general and central obesity in elderly.

Mediterranean diet, stroke, cognitive impairment, and depression: A meta-analysis

OBJECTIVE

This meta-analysis aims to quantitatively synthesize all studies that examine the association between adherence to a Mediterranean diet and risk of stroke, depression, cognitive impairment, and Parkinson disease.

METHODS

Potentially eligible publications were those providing effect estimates of relative risk (RR) for the association between Mediterranean diet and the aforementioned outcomes. Studies were sought in PubMed up to October 31, 2012. Maximally adjusted effect estimates were extracted; separate analyses were performed for high and moderate adherence.

RESULTS

Twenty-two eligible studies were included (11 covered stroke, 9 covered depression, and 8 covered cognitive impairment; only 1 pertained to Parkinson's disease). High adherence to Mediterranean diet was consistently associated with reduced risk for stroke (RR = 0.71, 95% confidence interval [CI] = 0.57-0.89), depression (RR = 0.68, 95% CI = 0.54-0.86), and cognitive impairment (RR = 0.60, 95% CI = 0.43-0.83). Moderate adherence was similarly associated with reduced risk for depression and cognitive impairment, whereas the protective trend concerning stroke was only marginal. Subgroup analyses highlighted the protective actions of high adherence in terms of reduced risk for ischemic stroke, mild cognitive impairment, dementia, and particularly Alzheimer disease. Meta-regression analysis indicated that the protective effects of Mediterranean diet in stroke prevention seemed more sizeable among males. Concerning depression, the protective effects of high adherence seemed independent of age, whereas the favorable actions of moderate adherence seemed to fade away with more advanced age.

INTERPRETATION

Adherence to a Mediterranean diet may contribute to the prevention of a series of brain diseases; this may be of special value given the aging of Western societies.

Impact of nutritional status and dietary quality on stroke: do we need specific recommendations?

Stroke, one of the most prevalent geriatric diseases, is a leading cause of death worldwide that often results in permanent physical disability and decreased quality of life, and can have a negative impact on families both financially and emotionally. Although many previous studies have shown relationships between the risk of stroke and nutritional factors, clear dietary recommendations for the prevention and reduction of stroke recurrence have not been established. Several factors should be considered to control and manage stroke. For example, a considerable number of patients with stroke are poorly nourished, have several comorbidities and undesirable health-related behaviors may be present. Stroke patients are less likely to consume beneficial foods, have poorer eating habits and have impoverished dietary quality. In addition, psychological factors such as depression must also be considered in stroke management. Given these factors, dietary recommendations for stroke patients should be established. In this article, we summarized the nutritional status and dietary quality of stroke patients. We also suggested some nutritional guidelines for stroke patients and for those who are at risk for stroke.

The association of a priori and a posterior dietary patterns with the risk of incident stroke in Chinese older people in Hong Kong

BACKGROUND

Dietary patterns can be identified by a priori and a posterior approaches. Limited data have related dietary patterns with stroke risk in Chinese population. This study examined stroke risk associated with patterns identified by both approaches.

METHODS

Data on 1,338 Chinese men and 1,397 Chinese women aged >= 65 years participating in a cohort study examining the risk factors for osteoporosis in Hong Kong were analyzed. Baseline dietary data were collected between 2001 and 2003 using a validated food frequency questionnaire. Adherence to a priori dietary patterns including the Mediterranean Diet Score (MDS) and the Dietary Approaches to Stop Hypertension (DASH) was assessed. Factor analysis (FA) identified three a posterior dietary patterns: "vegetables-fruits", "snacks-drinks-milk products", and "meat-fish". Data on incidence of stroke were retrieved from an official database in 2008. Cox regression was used to estimate hazard ratios (HRs) for stroke risk adjusted for potential confounders.

RESULTS

There were 156 incident stroke events during a median follow up of 5.7 years. A posterior dietary patterns derived by FA were not associated with risk of incident stroke in either men or women. MDS was inversely associated with risk of incident stroke [Adjusted HR=0.55 (95% CI: 0.31-0.99) of the highest level of MDS compared with the lowest level, ptrend=0.008] in men but not in women. Similar non-significant inverse association was observed between DASH accordance and stroke risk in men [Multivariate HR (95% CI) of the DASH score of >=4.5 = 0.62 (0.38-1.04) compared with the DASH score of <=4, ptrend = 0.068] but not in women.

CONCLUSION

Our findings suggest that higher MDS and possibly higher DASH scores were associated with lower stroke risk in Chinese older people in Hong Kong.

Adherence to the mediterranean diet in relation to ischemic stroke nonfatal events in nonhypercholesterolemic and hypercholesterolemic participants: results of a case/case-control study

The aim of the present work was to evaluate the association between adherence to the Mediterranean diet and the development of ischemic stroke according to cholesterol levels. During 2009-2010, 500 participants were enrolled; 250 were consecutive patients (77 ± 9 years, 55.6% men) with a first ischemic stroke and 250 population-based, control participants, matched to the patients by age and sex. Sociodemographic, clinical, dietary, and other lifestyle characteristics were measured. Adherence to the Mediterranean diet was assessed by the validated MedDietScore (theoretical range: 0-55). After various adjustments, each 1/55 unit increase in the MedDietScore was associated with 17% lower likelihood of having an ischemic stroke in nonhypercholesterolemic participants (95%CI: 0.72-0.96) and 10% lower likelihood in participants with hypercholesterolemia (95%CI: 0.81-0.99). The present work highlights the cardioprotective benefits from the adoption of the Mediterranean diet, by showing its beneficial effect regarding ischemic stroke development, regardless of the presence of hypercholesterolemia.

Adherence to the Mediterranean diet in relation to acute coronary syndrome or stroke nonfatal events: a comparative analysis of a case/case-control study

BACKGROUND

Although the role of Mediterranean diet on cardiovascular disease prevention has long been evaluated and understood, its association with the development of stroke has been rarely examined. The aim of the present work was to comparatively evaluate the association between adherence to the Mediterranean diet and the development of an acute coronary syndrome (ACS) or ischemic stroke.

METHODS

During the period from 2009 to 2010, 1,000 participants were enrolled; 250 were consecutive patients with a first ACS, 250 were consecutive patients with a first ischemic stroke, and 500 population-based, control subjects, 1-for-1 matched to the patients by age and sex. Sociodemographic, clinical, psychological, dietary, and other lifestyle characteristics were measured. Adherence to the Mediterranean diet was assessed by the validated MedDietScore (theoretical range 0-55).

RESULTS

After various adjustments were made, it was observed that for each 1-of-55-unit increase of the MedDietScore, the corresponding odds ratio for having an ACS was 0.91 (95% CI 0.87-0.96), whereas regarding stroke, it was 0.88 (95% CI 0.82-0.94).

CONCLUSIONS

The present work extended the current knowledge about the cardioprotective benefits from the adoption of the Mediterranean diet by showing an additional protective effect on ischemic stroke development.