Hierarchies of evidence applied to lifestyle Medicine (HEALM): introduction of a strength-of-evidence approach based on a methodological systematic review

Nature of the evidence base and approaches to guide nutrition interventions for individuals: a position paper from the Academy of Nutrition Sciences

This Position Paper from the Academy of Nutrition Sciences is the third in a series which describe the nature of the scientific evidence and frameworks that underpin nutrition recommendations for health. This paper focuses on evidence which guides the application of dietary recommendations for individuals. In some situations, modified nutrient intake becomes essential to prevent deficiency, optimise development and health, or manage symptoms and disease progression. Disease and its treatment can also affect taste, appetite and ability to access and prepare foods, with associated financial impacts. Therefore, the practice of nutrition and dietetics must integrate and apply the sciences of food, nutrition, biology, physiology, behaviour, management, communication and society to achieve and maintain human health. Thus, there is huge complexity in delivering evidence-based nutrition interventions to individuals. This paper examines available frameworks for appraising the quality and certainty of nutrition research evidence, the development nutrition practice guidelines to support evidence implementation in practice and the influence of other sources of nutrition information and misinformation. The paper also considers major challenges in applying research evidence to an individual and suggests consensus recommendations to begin to address these challenges in the future. Our recommendations target three groups; those who deliver nutrition interventions to individuals, those funding, commissioning or undertaking research aimed at delivering evidence-based nutrition practice, and those disseminating nutritional information to individuals.

Lifestyle Medicine Implementation in 8 Health Systems: Protocol for a Multiple Case Study Investigation

BACKGROUND

Lifestyle medicine (LM) is the use of therapeutic lifestyle changes (including a whole-food, plant-predominant eating pattern; regular physical activity; restorative sleep; stress management; avoidance of risky substances; and positive social connection) to prevent and treat chronic illness. Despite growing evidence, LM is still not widely implemented in health care settings. Potential challenges to LM implementation include lack of clinician training, staffing concerns, and misalignment of LM services with fee-for-service reimbursement, but the full range of factors facilitating or obstructing its implementation and long-term success are not yet understood. To learn important lessons for success and failure, it is crucial to understand the experiences of different LM programs.

OBJECTIVE

This study aims to describe in depth the protocol used to identify barriers and facilitators impacting the implementation of LM in health systems.

METHODS

The study team comprises team members at the American College of Lifestyle Medicine (ACLM), including staff and researchers with expertise in public health, LM, and qualitative research. We recruited health systems that were members of the ACLM Health Systems Council. From among 15 self-nominating health systems, we selected 7 to represent a diversity of geographic location, type, size, expertise, funding, patients, and LM services. Partway through the study, we recruited 1 additional contrasting health system to serve as a negative case. For each case, we conducted in-depth interviews, document reviews, site visits (limited due to the COVID-19 pandemic), and study team debriefs. Interviews lasted 45-90 minutes and followed a semistructured interview guide, loosely based on the Consolidated Framework for Implementation Research (CFIR) model. We are constructing detailed case narrative reports for each health system that are subsequently used in cross-case analyses to develop a contextually rich and detailed understanding of various predetermined and emergent topics. Cross-case analyses will draw on a variety of methodologies, including in-depth case familiarization, inductive or deductive coding, and thematic analysis, to identify cross-cutting themes.

RESULTS

The study team has completed data collection for all 8 participating health systems, including 68 interviews and 1 site visit. We are currently drafting descriptive case narratives, which will be disseminated to participating health systems for member checking and shared broadly as applied vignettes. We are also conducting cross-case analyses to identify critical facilitators and barriers, explore clinician training strategies to facilitate LM implementation, and develop an explanatory model connecting practitioner adoption of LM and experiences of burnout.

CONCLUSIONS

This protocol paper offers real-world insights into research methods and practices to identify barriers and facilitators to the implementation of LM in health systems. Findings can advise LM implementation across various health system contexts. Methodological limitations and lessons learned can guide the execution of other studies with similar methodologies.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51562.

Dietary fat quality, plasma atherogenic lipoproteins, and atherosclerotic cardiovascular disease: An overview of the rationale for dietary recommendations for fat intake

The scientific evidence supporting the current dietary recommendations for fat quality keeps accumulating; however, a paradoxical distrust has taken root among many researchers, clinicians, and in parts of the general public. One explanation for this distrust may relate to an incomplete overview of the totality of the evidence for the link between fat quality as a dietary exposure, and health outcomes such as atherosclerotic cardiovascular disease (ASCVD). Therefore, the main aim of the present narrative review was to provide a comprehensive overview of the rationale for dietary recommendations for fat intake, limiting our discussion to ASCVD as outcome. Herein, we provide a core framework - a causal model - that can help us understand the evidence that has accumulated to date, and that can help us understand new evidence that may become available in the future. The causal model for fat quality and ASCVD is comprised of three key research questions (RQs), each of which determine which scientific methods are most appropriate to use, and thereby which lines of evidence that should feed into the causal model. First, we discuss the link between low-density lipoprotein (LDL) particles and ASCVD (RQ1); we draw especially on evidence from genetic studies, randomized controlled trials (RCTs), epidemiology, and mechanistic studies. Second, we explain the link between dietary fat quality and LDL particles (RQ2); we draw especially on metabolic ward studies, controlled trials (randomized and non-randomized), and mechanistic studies. Third, we explain the link between dietary fat quality, LDL particles, and ASCVD (RQ3); we draw especially on RCTs in animals and humans, epidemiology, population-based changes, and experiments of nature. Additionally, the distrust over dietary recommendations for fat quality may partly relate to an unclear understanding of the scientific method, especially as applied in nutrition research, including the process of developing dietary guidelines. We therefore also aimed to clarify this process. We discuss how we assess causality in nutrition research, and how we progress from scientific evidence to providing dietary recommendations.

Introducing lifestyle medicine into family medicine: Theory and applications

"Lifestyle medicine (LM) is an evidence-based therapeutic intervention delivered by clinicians trained and certified in this specialty to prevent, treat, and often reverse chronic disease". Eighty percent of the conditions primary care physicians routinely encounter in their offices, e.g., diabetes mellitus, hypertension, COPD, cardiovascular disease, have root causes in poor lifestyle choices, e.g., smoking, insufficient sleep, being sedentary, eating highly processed foods. Lifestyle is the foundation of most chronic disease management guidelines aimed at reducing morbidity and mortality. Studies have shown that changes in lifestyle can be achieved and the changes link almost directly to reduction in risk for chronic illness. Primary care physicians are ideally positioned to incorporate LM into their practices. It is important to recognize and find solutions to the many barriers to implementing LM from the patient, physician, and system level. There is an urgent need to increase opportunities for practicing physicians to increase their knowledge and skills related to LM and include this in medical school and residency curricula. Many resources exist that can provide the necessary training to seasoned physicians and students/residents to become competent in practicing LM and address barriers to implementing LM. LM has the potential to revolutionize clinical practice by placing a greater emphasis on disease prevention and the role of healthy lifestyle behaviors in disease management and remission.

Nudging as a Support for Behavioral Change in Lifestyle Medicine

The practice of lifestyle medicine and its emphasis on behavioral change continues to grow around the world. Yet much of the burden of disease weighing on healthcare systems from chronic, modifiable conditions remains stubbornly present. From a behavior change perspective, efforts to date have primarily focused on public health messaging and public health campaigns (global approaches) to interventions such as health coaching (individual approaches). There exists an opportunity to consider contextual elements which support behavioral change. The practice of "nudging" behavior in primary care and allied health settings is proposed as a means of responding to these contextual opportunities. Nudging does not assure change; however, it can invite curiosity about change and small behavioral efforts in the direction of a desired change. Furthermore, its nature conserves autonomy and patient choice while inviting a health-creating behavior. As such, when considered and applied in the context of public health and individual treatment options, it creates a consistent milieu in which behavior change is facilitated.

Food Is Medicine: A Presidential Advisory From the American Heart Association

Unhealthy diets are a major impediment to achieving a healthier population in the United States. Although there is a relatively clear sense of what constitutes a healthy diet, most of the US population does not eat healthy food at rates consistent with the recommended clinical guidelines. An abundance of barriers, including food and nutrition insecurity, how food is marketed and advertised, access to and affordability of healthy foods, and behavioral challenges such as a focus on immediate versus delayed gratification, stand in the way of healthier dietary patterns for many Americans. Food Is Medicine may be defined as the provision of healthy food resources to prevent, manage, or treat specific clinical conditions in coordination with the health care sector. Although the field has promise, relatively few studies have been conducted with designs that provide strong evidence of associations between Food Is Medicine interventions and health outcomes or health costs. Much work needs to be done to create a stronger body of evidence that convincingly demonstrates the effectiveness and cost-effectiveness of different types of Food Is Medicine interventions. An estimated 90% of the $4.3 trillion annual cost of health care in the United States is spent on medical care for chronic disease. For many of these diseases, diet is a major risk factor, so even modest improvements in diet could have a significant impact. This presidential advisory offers an overview of the state of the field of Food Is Medicine and a road map for a new research initiative that strategically approaches the outstanding questions in the field while prioritizing a human-centered design approach to achieve high rates of patient engagement and sustained behavior change. This will ideally happen in the context of broader efforts to use a health equity-centered approach to enhance the ways in which our food system and related policies support improvements in health.

Using the Hierarchies of Evidence Applied to Lifestyle Medicine (HEALM) Approach to Assess the Strength of Evidence on Associations between Dietary Patterns and All-Cause Mortality

Dietary guidelines should be underpinned by high-quality evidence. Quality assessment methods that reflect traditional evidence hierarchies prioritise evidence from randomised controlled trials (RCTs). The Hierarchies of Evidence Applied to Lifestyle Medicine (HEALM) approach is an alternative quality assessment method for research questions that for practical and/or ethical reasons, cannot be answered using RCTs. The aim of this study was to investigate how the HEALM approach could be used to assess the strength of evidence on associations between dietary patterns and all-cause mortality (a research question that is difficult to answer using RCTs). Two data sources were used: an existing systematic review of dietary patterns and all-cause mortality that synthesised evidence from observational studies; and an overview of reviews that was conducted to summarise relevant evidence from mechanistic and intervention studies. A set of four criteria were developed and used in the application of HEALM. Using different datasets in combination, the strength of evidence was rated as ‘Grade B: moderate/suggestive’ or ‘Grade C: insufficient/inconclusive’. HEALM is a novel approach for integrating and assessing the strength of evidence from mechanistic, intervention, and observational studies. Further research is needed to address the practical challenges that were identified in the application of HEALM.

E-synthesis for carcinogenicity assessments: A case study of processed meat

RATIONALE, AIMS AND OBJECTIVES

Recent controversies about dietary advice concerning meat demonstrate that aggregating the available evidence to assess a putative causal link between food and cancer is a challenging enterprise.

METHODS

We show how a tool developed for assessing putative causal links between drugs and adverse drug reactions, E-Synthesis, can be applied for food carcinogenicity assessments. The application is demonstrated on the putative causal relationship between processed meat consumption and cancer.

RESULTS

The output of the assessment is a Bayesian probability that processed meat consumption causes cancer. This Bayesian probability is calculated from a Bayesian network model, which incorporates a representation of Bradford Hill's Guidelines as probabilistic indicators of causality. We show how to determine probabilities of indicators of causality for food carcinogenicity assessments based on assessments of the International Agency for Research on Cancer.

CONCLUSIONS

We find that E-Synthesis is a tool well-suited for food carcinogenicity assessments, as it enables a graphical representation of lines and weights of evidence, offers the possibility to make a great number of judgements explicit and transparent, outputs a probability of causality suitable for decision making and is flexible to aggregate different kinds of evidence.

Health effects associated with vegetable consumption: a Burden of Proof study

Previous research suggests a protective effect of vegetable consumption against chronic disease, but the quality of evidence underlying those findings remains uncertain. We applied a Bayesian meta-regression tool to estimate the mean risk function and quantify the quality of evidence for associations between vegetable consumption and ischemic heart disease (IHD), ischemic stroke, hemorrhagic stroke, type 2 diabetes and esophageal cancer. Increasing from no vegetable consumption to the theoretical minimum risk exposure level (306-372 g daily) was associated with a 23.2% decline (95% uncertainty interval, including between-study heterogeneity: 16.4-29.4) in ischemic stroke risk; a 22.9% (13.6-31.3) decline in IHD risk; a 15.9% (1.7-28.1) decline in hemorrhagic stroke risk; a 28.5% (-0.02-51.4) decline in esophageal cancer risk; and a 26.1% (-3.6-48.3) decline in type 2 diabetes risk. We found statistically significant protective effects of vegetable consumption for ischemic stroke (three stars), IHD (two stars), hemorrhagic stroke (two stars) and esophageal cancer (two stars). Including between-study heterogeneity, we did not detect a significant association with type 2 diabetes, corresponding to a one-star rating. Although current evidence supports increased efforts and policies to promote vegetable consumption, remaining uncertainties suggest the need for continued research.

The role of sugar-sweetened beverages in the global epidemics of obesity and chronic diseases

Sugar-sweetened beverages (SSBs) are a major source of added sugars in the diet. A robust body of evidence has linked habitual intake of SSBs with weight gain and a higher risk (compared with infrequent SSB consumption) of type 2 diabetes mellitus, cardiovascular diseases and some cancers, which makes these beverages a clear target for policy and regulatory actions. This Review provides an update on the evidence linking SSBs to obesity, cardiometabolic outcomes and related cancers, as well as methods to grade the strength of nutritional research. We discuss potential biological mechanisms by which constituent sugars can contribute to these outcomes. We also consider global trends in intake, alternative beverages (including artificially-sweetened beverages) and policy strategies targeting SSBs that have been implemented in different settings. Strong evidence from cohort studies on clinical outcomes and clinical trials assessing cardiometabolic risk factors supports an aetiological role of SSBs in relation to weight gain and cardiometabolic diseases. Many populations show high levels of SSB consumption and in low-income and middle-income countries, increased consumption patterns are associated with urbanization and economic growth. As such, more intensified policy efforts are needed to reduce intake of SSBs and the global burden of obesity and chronic diseases.

Public health interventions on prescription redemptions and secondary medication adherence among type 2 diabetes patients: systematic review and meta-analysis of randomized controlled trials

Background

Despite the inadequate filling of prescriptions among chronic care patients has been a problem, little is known about the intervention effect on it.

Objective

The aim of this systematic review and meta-analysis (SRMA) was to investigate the effectiveness of various public health interventions on primary and secondary medication adherence among T2DM patients.

Methods

Searching was done from the major databases; Cochrane Library, Medline/PubMed, EBSCOhost, and SCOPUS. A hand search was made to find grey works of literature. Articles focused on interventions to enhance primary and secondary medication among type 2 diabetes mellitus patients were included. After screening and checking eligibility, the methodological quality was assessed. Secondary medication adherence was synthesized descriptively due to measurement and definition variations across studies. Finally, a meta-analysis was made using the fixed effects model for primary medication adherence.

Results

3992 studies were screened for both primary and secondary medication adherences. Among these, 24 studies were included in the analysis for primary (5) and secondary (19) medication adherence. Pooled relative medication redemption difference was RD = 8% (95% CI: 6-11%) among the intervention groups. Age, intervention, provider setting, and IDF region were determinant factors of primary medication adherence. About two-thirds of the studies revealed that interventions were effective in improving secondary medication adherence.

Conclusion

Both primary and secondary medications were enhanced by a variety of public health interventions for patients worldwide. However, there is a scarcity of studies on primary medication adherence globally, and in resource-limited settings for the type of adherences.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00878-0.

Lifestyle Medicine and Economics: A Proposal for Research Priorities Informed by a Case Series of Disease Reversal

Chronic disease places an enormous economic burden on both individuals and the healthcare system, and existing fee-for-service models of healthcare prioritize symptom management, medications, and procedures over treating the root causes of disease through changing health behaviors. Value-based care is gaining traction, and there is a need for value-based care models that achieve the quadruple aim of (1) improved population health, (2) enhanced patient experience, (3) reduced healthcare costs, and (4) improved work life and decreased burnout of healthcare providers. Lifestyle medicine (LM) has the potential to achieve these four aims, including promoting health and wellness and reducing healthcare costs; however, the economic outcomes of LM approaches need to be better quantified in research. This paper demonstrates proof of concept by detailing four cases that utilized an intensive, therapeutic lifestyle intervention change (ITLC) to dramatically reverse disease and reduce healthcare costs. In addition, priorities for lifestyle medicine economic research related to the components of quadruple aim are proposed, including conducting rigorously designed research studies to adequately measure the effects of ITLC interventions, modeling the potential economic cost savings enabled by health improvements following lifestyle interventions as compared to usual disease progression and management, and examining the effects of lifestyle medicine implementation upon different payment models.

Evidence Use in the Development of the Australian Dietary Guidelines: A Qualitative Study

Dietary guidelines are important nutrition policy reference standards that should be informed by the best available evidence. The types of evidence that are reviewed and the evidence review methods that are used have implications for evidence translation. The aim of this study was to explore perceived advantages, disadvantages, and practicalities associated with the synthesis and translation of evidence from nutrient-based, food-based, and dietary patterns research in dietary guideline development. A qualitative descriptive study was conducted. Twenty-two semi-structured interviews were conducted with people involved in the development of the 2013 Australian Dietary Guidelines (ADGs). Transcripts were analysed thematically. To inform future ADGs, there was support for reviewing evidence on a range of dietary exposures (including dietary patterns, foods and food groups, nutrients and food components, and eating occasions) and health outcomes, as well as evidence on environmental sustainability and equity. At the evidence synthesis stage, practicalities associated with planning the evidence review and conducting original systematic reviews were discussed. At the evidence translation stage, practicalities associated with integrating the evidence and consulting stakeholders were described. To ensure that the best available evidence is translated into future ADGs, evidence review methods should be selected based on the exposures and outcomes of interest.

Toward more rigorous and informative nutritional epidemiology: The rational space between dismissal and defense of the status quo

To date, nutritional epidemiology has relied heavily on relatively weak methods including simple observational designs and substandard measurements. Despite low internal validity and other sources of bias, claims of causality are made commonly in this literature. Nutritional epidemiology investigations can be improved through greater scientific rigor and adherence to scientific reporting commensurate with research methods used. Some commentators advocate jettisoning nutritional epidemiology entirely, perhaps believing improvements are impossible. Still others support only normative refinements. But neither abolition nor minor tweaks are appropriate. Nutritional epidemiology, in its present state, offers utility, yet also needs marked, reformational renovation. Changing the status quo will require ongoing, unflinching scrutiny of research questions, practices, and reporting-and a willingness to admit that "good enough" is no longer good enough. As such, a workshop entitled "Toward more rigorous and informative nutritional epidemiology: the rational space between dismissal and defense of the status quo" was held from July 15 to August 14, 2020. This virtual symposium focused on: (1) Stronger Designs, (2) Stronger Measurement, (3) Stronger Analyses, and (4) Stronger Execution and Reporting. Participants from several leading academic institutions explored existing, evolving, and new better practices, tools, and techniques to collaboratively advance specific recommendations for strengthening nutritional epidemiology.

Nature of the evidence base and frameworks underpinning dietary recommendations for prevention of non-communicable diseases: a position paper from the Academy of Nutrition Sciences

This Position Paper from the Academy of Nutrition Sciences is the first in a series which describe the nature of the scientific evidence and frameworks that underpin nutrition recommendations for health. This first paper focuses on evidence which underpins dietary recommendations for prevention of non-communicable diseases. It considers methodological advances made in nutritional epidemiology and frameworks used by expert groups to support objective, rigorous and transparent translation of the evidence into dietary recommendations. The flexibility of these processes allows updating of recommendations as new evidence becomes available. For CVD and some cancers, the paper has highlighted the long-term consistency of a number of recommendations. The innate challenges in this complex area of science include those relating to dietary assessment, misreporting and the confounding of dietary associations due to changes in exposures over time. A large body of experimental data is available that has the potential to support epidemiological findings, but many of the studies have not been designed to allow their extrapolation to dietary recommendations for humans. Systematic criteria that would allow objective selection of these data based on rigour and relevance to human nutrition would significantly add to the translational value of this area of nutrition science. The Academy makes three recommendations: (i) the development of methodologies and criteria for selection of relevant experimental data, (ii) further development of innovative approaches for measuring human dietary intake and reducing confounding in long-term cohort studies and (iii) retention of national nutrition surveillance programmes needed for extrapolating global research findings to UK populations.

NUQUEST-NUtrition QUality Evaluation Strengthening Tools: development of tools for the evaluation of risk of bias in nutrition studies

BACKGROUND

Dietary exposure assessments are a critical issue in evaluating human nutrition studies; however, nutrition-specific criteria are not consistently included in existing bias assessment tools.

OBJECTIVES

Our objective was to develop a set of risk of bias (RoB) tools that integrated nutrition-specific criteria into validated generic assessment tools to address RoB issues, including those specific to dietary exposure assessment.

METHODS

The Nutrition QUality Evaluation Strengthening Tools (NUQUEST) development and validation process included 8 steps. The first steps identified 1) a development strategy; 2) generic assessment tools with demonstrated validity; and 3) nutrition-specific appraisal issues. This was followed by 4) generation of nutrition-specific items and 5) development of guidance to aid users of NUQUEST. The final steps used established ratings of selected studies and feedback from independent raters to 6) assess reliability and validity; 7) assess formatting and usability; and 8) finalize NUQUEST.

RESULTS

NUQUEST is based on the Scottish Intercollegiate Guidelines Network checklists for randomized controlled trials, cohort studies, and case-control studies. Using a purposive sample of 45 studies representing the 3 study designs, interrater reliability was high (Cohen's κ: 0.73; 95% CI: 0.52, 0.93) across all tools and at least moderate for individual tools (range: 0.57-1.00). The use of a worksheet improved usability and consistency of overall interrater agreement across all study designs (40% without worksheet, 80%-100% with worksheet). When compared to published ratings, NUQUEST ratings for evaluated studies demonstrated high concurrent validity (93% perfect or near-perfect agreement). Where there was disagreement, the nutrition-specific component was a contributing factor in discerning exposure methodological issues.

CONCLUSIONS

NUQUEST integrates nutrition-specific criteria with generic criteria from assessment tools with demonstrated reliability and validity. NUQUEST represents a consistent and transparent approach for evaluating RoB issues related to dietary exposure assessment commonly encountered in human nutrition studies.

Association between adiposity and cardiovascular outcomes: an umbrella review and meta-analysis of observational and Mendelian randomization studies

AIMS

The aim of this study was to investigate the causal relationship and evidence of an association between increased adiposity and the risk of incident cardiovascular disease (CVD) events or mortality.

METHODS AND RESULTS 

Observational (informing association) and Mendelian randomization (MR) (informing causality) studies were assessed to gather mutually complementary insights and elucidate perplexing epidemiological relationships. Systematic reviews and meta-analyses of observational and MR studies that were published until January 2021 and evaluated the association between obesity-related indices and CVD risk were searched. Twelve systematic reviews with 53 meta-analyses results (including over 501 cohort studies) and 12 MR studies were included in the analysis. A body mass index (BMI) increase was associated with higher risks of coronary heart disease, heart failure, atrial fibrillation, all-cause stroke, haemorrhagic stroke, ischaemic stroke, hypertension, aortic valve stenosis, pulmonary embolism, and venous thrombo-embolism. The MR study results demonstrated a causal effect of obesity on all indices but stroke. The CVD risk increase for every 5 kg/m2 increase in BMI varied from 10% [relative risk (RR) 1.10; 95% confidence interval (CI) 1.01-1.21; certainty of evidence, low] for haemorrhagic stroke to 49% (RR 1.49; 95% CI 1.40-1.60; certainty of evidence, high) for hypertension. The all-cause and CVD-specific mortality risks increased with adiposity in cohorts, but the MR studies demonstrated no causal effect of adiposity on all-cause mortality.

CONCLUSION 

High adiposity is associated with increased CVD risk despite divergent evidence gradients. Adiposity was a causal risk factor for CVD except all-cause mortality and stroke. Half (49%; 26/53) of the associations were supported by high-level evidence. The associations were consistent between sexes and across global regions. This study provides guidance on how to integrate evidence from observational (association) and genetics-driven (causation) studies accumulated to date, to enable a more reliable interpretation of epidemiological relationships.

Dietary recommendations for prevention of atherosclerosis

This review aims at summarizing updated evidence on cardiovascular disease (CVD) risk associated with consumption of specific food items to substantiate dietary strategies for atherosclerosis prevention. A systematic search on PubMed was performed to identify meta-analyses of cohort studies and RCTs with CVD outcomes. The evidence is highly concordant in showing that, for the healthy adult population, low consumption of salt and foods of animal origin, and increased intake of plant-based foods-whole grains, fruits, vegetables, legumes, and nuts-are linked with reduced atherosclerosis risk. The same applies for the replacement of butter and other animal/tropical fats with olive oil and other unsaturated-fat-rich oil. Although the literature reviewed overall endorses scientific society dietary recommendations, some relevant novelties emerge. With regard to meat, new evidence differentiates processed and red meat-both associated with increased CVD risk-from poultry, showing a neutral relationship with CVD for moderate intakes. Moreover, the preferential use of low-fat dairies in the healthy population is not supported by recent data, since both full-fat and low-fat dairies, in moderate amounts and in the context of a balanced diet, are not associated with increased CVD risk; furthermore, small quantities of cheese and regular yogurt consumption are even linked with a protective effect. Among other animal protein sources, moderate fish consumption is also supported by the latest evidence, although there might be sustainability concerns. New data endorse the replacement of most high glycemic index (GI) foods with both whole grain and low GI cereal foods. As for beverages, low consumption not only of alcohol, but also of coffee and tea is associated with a reduced atherosclerosis risk while soft drinks show a direct relationship with CVD risk. This review provides evidence-based support for promoting appropriate food choices for atherosclerosis prevention in the general population.

Introducing Plant-Based Mediterranean Diet as a Lifestyle Medicine Approach in Latin America: Opportunities Within the Chilean Context

Latin America is experiencing a significant epidemiological and nutritional transition, with a trend toward higher incidence of food-related chronic diseases. In this context, Lifestyle Medicine (LM) is a growing field focused on assisting individuals in adopting healthy behaviors for the prevention and treatment of these chronic diseases, including, among other pillars, a great emphasis on healthy eating. There is also a growing interest worldwide in environmental sustainability of dietary patterns, with increasing concern about their effects on planetary health. In this context, whole-food, plant-based diets -such as the Mediterranean diet (MD)- have emerged as a solution for both healthier eating and lowering environmental impact. Yet in order to be effective at these goals and achieve a high adherence to any nutritional prescription, the sociocultural reality of the community or population where we aim to practice must also be taken into account. In this review, we specifically highlight the plant-based MD as a LM-contextualized dietary pattern that is adaptable, applicable, and sustainable within the Chilean context and has the potential to address the current trend of chronic diseases in our country.

The Future of Meat: Health Impact Assessment with Randomized Evidence

Massive animal farming for meat production poses major problems in terms of resource use, environmental impact, and biodiversity. Furthermore, excessive meat consumption has been associated with multiple deleterious health consequences. However, more and better-designed randomized trials are needed to increase the level of evidence on the health impacts of meat. Novel meat alternatives, such as plant- and cell-based meat, are much less impactful to the environment and might replace traditional animal meat in the future, but, despite promising early data, the health consequences of these novel products need further study. This manuscript focuses on the health impacts of meat over 3 main sections: 1) overview of the evidence highlighting the association of meat consumption with health; 2) novel alternatives to meat, including plant-based and cell-based alternatives; and 3) examine the rationale for randomized studies to evaluate the effects of the novel meat alternatives compared with the standard animal meat.

Characteristics and quality of systematic reviews and meta-analyses of observational nutritional epidemiology: a cross-sectional study

BACKGROUND

Dietary recommendations and policies should be guided by rigorous systematic reviews. Reviews that are of poor methodological quality may be ineffective or misleading. Most of the evidence in nutrition comes from nonrandomized studies of nutritional exposures (usually referred to as nutritional epidemiology studies), but to date methodological evaluations of the quality of systematic reviews of such studies have been sparse and inconsistent.

OBJECTIVES

We aimed to investigate the quality of recently published systematic reviews and meta-analyses of nutritional epidemiology studies and to propose guidance addressing major limitations.

METHODS

We searched MEDLINE (January 2018-August 2019), EMBASE (January 2018-August 2019), and the Cochrane Database of Systematic Reviews (January 2018-February 2019) for systematic reviews of nutritional epidemiology studies. We included a random sample of 150 reviews.

RESULTS

Most reviews were published by authors from Asia (n = 49; 32.7%) or Europe (n = 43; 28.7%) and investigated foods or beverages (n = 60; 40.0%) and cancer morbidity and mortality (n = 54; 36%). Reviews often had important limitations: less than one-quarter (n = 30; 20.0%) reported preregistration of a protocol and almost one-third (n = 42; 28.0%) did not report a replicable search strategy. Suboptimal practices and errors in the synthesis of results were common: one-quarter of meta-analyses (n = 30; 26.1%) selected the meta-analytic model based on statistical indicators of heterogeneity and almost half of meta-analyses (n = 50; 43.5%) did not consider dose-response associations even when it was appropriate to do so. Only 16 (10.7%) reviews used an established system to evaluate the certainty of evidence.

CONCLUSIONS

Systematic reviews of nutritional epidemiology studies often have serious limitations. Authors can improve future reviews by involving statisticians, methodologists, and researchers with substantive knowledge in the specific area of nutrition being studied and using a rigorous and transparent system to evaluate the certainty of evidence.

Use of GRADE in evidence syntheses published in high-impact-factor nutrition journals: A methodological survey

OBJECTIVE

To identify and describe the use of the GRADE approach for rating the certainty of evidence in nutrition systematic reviews (SRs).

STUDY DESIGN AND SETTING

We systematically searched for SRs using GRADE that were published between 2015 and 2019 in the 10 "nutrition" journals with the highest impact factor according to the JCR 2018.

RESULTS

Out of 800 SRs, 55 SRs of randomized control trials (RCTs) and/or nonrandomized studies (NRSs) used GRADE. Forty-seven SRs (5.9%) rated the outcome specific certainty of evidence (n = 36 in 2018/2019). We identified a total of 465 certainty of evidence outcome ratings (n = 335 RCT ratings), ranging from very-low (28.8%) to low (41%), moderate (26.5%), and high (3.7%). Very-low and high certainty of evidence ratings accounted for 61.4% and 0.8% of ratings in SRs of NRSs, compared to 16.1% and 4.8% in SRs of RCTs. Certainty of evidence was downgraded mostly for risk of bias (37.8%) and imprecision (33%) in SRs of RCTs and for imprecision (32.7%), risk of bias (29.4%) and inconsistency (29%) in SRs of NRSs.

CONCLUSION

Our study suggests a need for directing more attention toward strengthening acceptance of GRADE as well as building knowledge of the GRADE methodology in nutrition evidence synthesis.

Randomized Trials Versus Common Sense and Clinical Observation: JACC Review Topic of the Week

Concerns about the external validity of traditional randomized clinical trials (RCTs), together with the widespread availability of real-world data and advanced data analytic tools, have led to claims that common sense and clinical observation, rather than RCTs, should be the preferred method to generate evidence to support clinical decision-making. However, over the past 4 decades, results from well-done RCTs have repeatedly contradicted practices supported by common sense and clinical observation. Common sense and clinical observation fail for several reasons: incomplete understanding of pathophysiology, biases and unmeasured confounding in observational research, and failure to understand risks and benefits of treatments within complex systems. Concerns about traditional RCT models are legitimate, but randomization remains a critical tool to understand the causal relationship between treatments and outcomes. Instead, development and promulgation of tools to apply randomization to real-world data are needed to build the best evidence base in cardiovascular medicine.

•

Well-conducted RCTs have repeatedly contradicted practices supported by common sense and clinical observation.

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Common sense and clinical observation fail because of the inability to fully understand complex biopsychosocial systems.

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RCTs must be integrated into clinical practice to improve the evidence base in cardiology.

[Reduction of red and processed meats in the Spanish population: What is its impact on total and cardiovascular mortality?]

Objetivo

Cuantificar el impacto de reducir el consumo de carnes rojas y procesadas sobre la mortalidad cardiovascular y la mortalidad total de la población adulta española, basado en 5 revisiones publicadas.

Participantes y mediciones principales

Se define la exposición como el consumo de ≥ 3 raciones/semana de carnes rojas o procesadas, y se consideran cuatro escenarios de población expuesta (30-60%). Con datos del Instituto Nacional de Estadística, se calcula la mortalidad ponderada en población española de 40-80 años y, utilizando los riesgos relativos (RR) y los intervalos de confianza (IC) al 95% publicados en 5 revisiones (RR = 0,88; IC 95%: 0,84-0,93 para mortalidad por todas las causas y RR = 0,92; IC 95%: 0,90-0,93 para la mortalidad cardiovascular), se calculó la tasa de mortalidad en expuestos y no expuestos. Multiplicando esas tasas por el número de expuestos, se obtuvo el número de muertes atribuibles.

Resultados

Asumiendo un 60% de población española de 40-80 años expuesta, el número de muertes anuales de causa cardiovascular que se podrían evitar consumiendo < 3 raciones/semana de carnes rojas o procesadas con un IC 95% está entre 2.112 y 3.055. Si la población expuesta fuese un 30% se podrían evitar entre 1.079 y 1.577 muertes.

Conclusiones

Incluso bajo el supuesto más conservador, el beneficio poblacional de reducir el consumo de carnes rojas o procesadas sobre la mortalidad cardiovascular y total sería muy importante. Las conclusiones de las revisiones mencionadas contradicen sus propios resultados y contribuyen a un estado de confusión que representa un daño a la salud pública.

Prioritized Research for the Prevention, Treatment, and Reversal of Chronic Disease: Recommendations From the Lifestyle Medicine Research Summit

Declining life expectancy and increasing all-cause mortality in the United States have been associated with unhealthy behaviors, socioecological factors, and preventable disease. A growing body of basic science, clinical research, and population health evidence points to the benefits of healthy behaviors, environments and policies to maintain health and prevent, treat, and reverse the root causes of common chronic diseases. Similarly, innovations in research methodologies, standards of evidence, emergence of unique study cohorts, and breakthroughs in data analytics and modeling create new possibilities for producing biomedical knowledge and clinical translation. To understand these advances and inform future directions research, The Lifestyle Medicine Research Summit was convened at the University of Pittsburgh on December 4–5, 2019. The Summit's goal was to review current status and define research priorities in the six core areas of lifestyle medicine: plant-predominant nutrition, physical activity, sleep, stress, addictive behaviors, and positive psychology/social connection. Forty invited subject matter experts (1) reviewed existing knowledge and gaps relating lifestyle behaviors to common chronic diseases, such as cardiovascular disease, diabetes, many cancers, inflammatory- and immune-related disorders and other conditions; and (2) discussed the potential for applying cutting-edge molecular, cellular, epigenetic and emerging science knowledge and computational methodologies, research designs, and study cohorts to accelerate clinical applications across all six domains of lifestyle medicine. Notably, federal health agencies, such as the Department of Defense and Veterans Administration have begun to adopt “whole-person health and performance” models that address these lifestyle and environmental root causes of chronic disease and associated morbidity, mortality, and cost. Recommendations strongly support leveraging emerging research methodologies, systems biology, and computational modeling in order to accelerate effective clinical and population solutions to improve health and reduce societal costs. New and alternative hierarchies of evidence are also be needed in order to assess the quality of evidence and develop evidence-based guidelines on lifestyle medicine. Children and underserved populations were identified as prioritized groups to study. The COVID-19 pandemic, which disproportionately impacts people with chronic diseases that are amenable to effective lifestyle medicine interventions, makes the Summit's findings and recommendations for future research particularly timely and relevant.

Dietary glycemic index, glycemic load, and chronic disease: an umbrella review of meta-analyses of prospective cohort studies

We aimed to present a comprehensive review of the association of dietary glycemic index (GI) and load (GL) with the risk of chronic disease. Published meta-analyses of prospective observational studies evaluating the association of dietary GI and GL with risk of chronic disease were identified by a search in PubMed and Scopus to November, 2020. Summary relative risks (SRRs) were recalculated using random-effects models. The certainty of evidence was rated by the GRADE approach. Eighteen meta-analyses of prospective cohort studies, reporting 19 SRRs for dietary GI and 17 SRRs for dietary GL were identified. There was a positive association between dietary GI and the risk of type 2 diabetes, coronary heart disease, and colorectal, breast, and bladder cancers, as well as between dietary GL and the risk of coronary heart disease, type 2 diabetes, and stroke. With regard to cancers at other sites, there was no significant association. The certainty of evidence ranged from very low to low. Although by GRADE classification no associations were rated stronger than low, they were classified as one grade higher when the NutriGrade system was used. Further research is needed to add evidence for the relation of dietary GI and GL with cancer risk.

Vegetable and Fruit Consumption and Prognosis Among Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies

The number of cancer survivors is growing rapidly worldwide, especially long-term survivors. Although a healthy diet with a high vegetable and fruit consumption is a key factor in primary cancer prevention, there is a lack of specific dietary recommendations for cancer survivors, except in the case of breast cancer [World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) report]. We have therefore carried out a systematic review and meta-analysis of cohort studies reporting on the associations between vegetable and fruit intake with cancer recurrence and mortality and all-cause mortality in cancer patients. After a comprehensive search of PubMed and Scopus databases, the results of 28 selected articles were analyzed. A high vegetable intake before diagnosis was inversely associated with overall mortality in survivors of head and neck (HR: 0.75; 95% CI: 0.65, 0.87) and ovarian cancer (HR: 0.78; 95% CI: 0.66, 0.91). In ovarian cancer patients, prediagnosis fruit intake was also inversely associated with all-cause mortality (HR: 0.82; 95% CI: 0.70, 0.96). The evidence was insufficient for survivors of other cancers, although these associations generally tended to be protective. Therefore, more studies are needed to clarify the association between vegetable and fruit consumption and the prognosis of these different types of cancer. To date, the general recommendation to consume ≥5 servings of vegetables and fruit per day (∼400 g/d) could underestimate the needs of cancer survivors, particularly those with ovarian tumors, in which the recommendation could increase to ∼600 g/d (i.e., 300 g/d of vegetables and 300 g/d of fruit).

Evidence-Based Policy Making for Public Health Interventions in Cardiovascular Diseases: Formally Assessing the Feasibility of Clinical Trials

Implementation of prevention policies has often been impeded or delayed due to the lack of randomized controlled trials (RCTs) with hard clinical outcomes (eg, incident disease, mortality). Despite the prominent role of RCTs in health care, it may not always be feasible to conduct RCTs of public health interventions with hard outcomes due to logistical and ethical considerations. RCTs may also lack external validity and have limited generalizability. Currently, there is insufficient guidance for policymakers charged with establishing evidence-based policy to determine whether an RCT with hard outcomes is needed before policy recommendations. In this context, the purpose of this article is to assess, in a case study, the feasibility of conducting an RCT of the oft-cited issue of sodium reduction on cardiovascular outcomes and then propose a framework for decision-making, which includes an assessment of the feasibility of conducting an RCT with hard clinical outcomes when such trials are unavailable. We designed and assessed the feasibility of potential individual- and cluster-randomized trials of sodium reduction on cardiovascular outcomes. Based on our assumptions, a trial using any of the designs considered would require tens of thousands of participants and cost hundreds of millions of dollars, which is prohibitively expensive. Our estimates may be conservative given several key challenges, such as the unknown costs of sustaining a long-term difference in sodium intake, the effect of differential cotreatment with antihypertensive medications, and long lag time to clinical outcomes. Thus, it would be extraordinarily difficult to conduct such a trial, and despite the high costs, would still be at substantial risk for a spuriously null result. A robust framework, such as the one we developed, should be used to guide policymakers when establishing evidence-based public health interventions in the absence of trials with hard clinical outcomes.

Impact of review method on the conclusions of clinical reviews: A systematic review on dietary interventions in depression as a case in point

Background

The recommendations of experts who write review articles are a critical determinant of the adaptation of new treatments by clinicians. Several types of reviews exist (narrative, systematic, meta-analytic), and some of these are more vulnerable to researcher bias than others. Recently, the interest in nutritional interventions in psychiatry has increased and many experts, who are often active researchers on this topic, have come to strong conclusions about the benefits of a healthy diet on depression. In a young and active field of study, we aimed to investigate whether the strength of an author’s conclusion is associated with the type of review article they wrote.

Methods

Systematic searches were performed in PubMed, Web of Science, Cochrane Database of Systematic Reviews, and Google Scholar for narrative reviews and systematic reviews with and without meta-analyses on the effects of diet on depression (final search date: May 30^th, 2020). Conclusions were extracted from the abstract and discussion section and rated as strong, moderate, or weak by independent raters who were blind to study type. A benchmark on legitimate conclusion strength was based on a GRADE assessment of the highest level of evidence. This systematic review was registered with PROSPERO, number CRD42020141372.

Findings

24 narrative reviews, 12 systematic reviews, and 14 meta-analyses were included. In the abstract, 33% of narrative reviews and 8% of systematic reviews came to strong conclusions, whereas no meta-analysis did. Narrative reviews were 8.94 (95% CI: 2.17, 36.84) times more likely to report stronger conclusions in the abstract than systematic reviews with and without meta-analyses. These findings were similar for conclusions in the discussion section. Narrative reviews used 45.6% fewer input studies and were more likely to be written by authors with potential conflicts of interest. A study limitation is the subjective nature of the conclusion classification system despite high inter-rater agreements and its confirmation outside of the review team.

Conclusions

We have shown that narrative reviews come to stronger conclusions about the benefits of a healthy diet on depression despite inconclusive evidence. This finding empirically underscores the importance of a systematic method for summarizing the evidence of a field of study. Journal editors may want to reconsider publishing narrative reviews before meta-analytic reviews are available.

Childhood Obesity Evidence Base Project: A Rationale for Taxonomic versus Conventional Meta-Analysis

Introduction: There is a great need for analytic techniques that allow for the synthesis of learning across seemingly idiosyncratic interventions. Objectives: The primary objective of this paper is to introduce taxonomic meta-analysis and explain how it is different from conventional meta-analysis. Results: Conventional meta-analysis has previously been used to examine the effectiveness of childhood obesity prevention interventions. However, these tend to examine narrowly defined sections of obesity prevention initiatives, and as such, do not allow the field to draw conclusions across settings, participants, or subjects. Compared with conventional meta-analysis, taxonomic meta-analysis widens the aperture of what can be examined to synthesize evidence across interventions with diverse topics, goals, research designs, and settings. A component approach is employed to examine interventions at the level of their essential features or activities to identify the concrete aspects of interventions that are used (intervention components), characteristics of the intended populations (target population or intended recipient characteristics), and facets of the environments in which they operate (contextual elements), and the relationship of these components to effect size. In addition, compared with conventional meta-analysis methods, taxonomic meta-analyses can include the results of natural experiments, policy initiatives, program implementation efforts and highly controlled experiments (as examples) regardless of the design of the report being analyzed as long as the intended outcome is the same. It also characterizes the domain of interventions that have been studied. Conclusion: Taxonomic meta-analysis can be a powerful tool for summarizing the evidence that exists and for generating hypotheses that are worthy of more rigorous testing.

Dietary patterns, foods and nutrients: a descriptive analysis of the systematic reviews conducted to inform the Australian Dietary Guidelines

Dietary guidelines should be underpinned by the best available evidence on relationships between diet and health, including evidence from nutrient-based, food-based and dietary patterns research. The primary aim of the present study was to analyse the systematic reviews conducted to inform the 2013 Australian Dietary Guidelines according to dietary exposure. The secondary aim was to analyse the reviews by health outcome, and design of included studies. To identify the systematic reviews, the dietary guidelines report was used as a starting point and relevant references were retrieved. The evidence report contained the data used in this analysis. Descriptive statistics were used to analyse reviews according to exposure, outcome, and design of included studies. A total of 143 systematic reviews were included in this analysis. Foods were the most common exposure (86·7 % of reviews), followed by nutrients (10·5 %) and dietary patterns (2·8 %). Chronic disease morbidity and/or mortality was the most common outcome (80·4 %), followed by chronic disease risk factors (19·6 %). Most reviews included evidence from cohort or nested case-control studies (92·3 %), many included evidence from case-control studies (61·5 %) and some included evidence from randomised controlled trials (28·7 %). These results reflect the research questions that were asked, the systematic review methods that were used, and the evidence that was available. In developing future iterations of the Australian Dietary Guidelines, there is an opportunity to review the latest evidence from dietary patterns research.

The Application of an Evidence Framework for Obesity Prevention at the Population-Level

PURPOSE OF REVIEW

To review existing frameworks for assessing the evidence of effectiveness of obesity prevention interventions, and discuss the application of a custom-developed evidence framework to inform an obesity prevention priority-setting study in Australia.

RECENT FINDINGS

There are a wide range of frameworks for grading evidence. However, most frameworks are not well suited to assess the effectiveness of obesity prevention interventions because they do not include processes to synthesise evidence from multiple study designs and outcome measures. The key features of the Obesity Prevention Evidence Assessment (OPEA) Framework are: [1] separately assessed weight-, diet- and physical activity-related outcomes; [2] consideration of the balance of evidence from multiple study types; and [3] a summary indication of the degree of certainty of intervention effectiveness. Evidence frameworks that recognise the complexities of obesity prevention research can support decision-makers in prioritising actions to address obesity alongside broader priority-setting considerations.

Red and Processed Meats and Health Risks: How Strong Is the Evidence?

Prevailing dietary guidelines have widely recommended diets relatively low in red and processed meats and high in minimally processed plant foods for the prevention of chronic diseases. However, an ad hoc research group called the Nutritional Recommendations (NutriRECS) consortium recently issued "new dietary guidelines" encouraging individuals to continue their current meat consumption habits due to "low certainty" of the evidence, difficulty of altering meat eaters' habits and preferences, and the lack of need to consider environmental impacts of red meat consumption. These recommendations are not justified, in large part because of the flawed methodologies used to review and grade nutritional evidence. The evidence evaluation was largely based on the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria, which are primarily designed to grade the strength of evidence for clinical interventions especially pharmacotherapy. However, the infeasibility for conducting large, long-term randomized clinical trials on most dietary, lifestyle, and environmental exposures makes the criteria inappropriate in these areas. A separate research group proposed a modified and validated system for rating the meta-evidence on nutritional studies (NutriGRADE) to address several limitations of the GRADE criteria. Applying NutriGRADE, the evidence on the positive association between red and processed meats and type 2 diabetes was rated to be of "high quality," while the evidence on the association between red and processed meats and mortality was rated to be of "moderate quality." Another important limitation is that inadequate attention was paid to what might be replacing red meat, be it plant-based proteins, refined carbohydrates, or other foods. In summary, the red/processed meat recommendations by NutriRECS suffer from important methodological limitations and involve misinterpretations of nutritional evidence. To improve human and planetary health, dietary guidelines should continue to emphasize dietary patterns low in red and processed meats and high in minimally processed plant foods such as fruits and vegetables, whole grains, nuts, and legumes.