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This article has been corrected. The original version (PDF) is appended to this article as a Supplement.Background: Studying dietary patterns may provide insights into the potential effects of red and processed meat on health outcomes.Purpose: To evaluate the effect of dietary patterns, including different amounts of red or processed meat, on all-cause mortality, cardiometabolic outcomes, and cancer incidence and mortality.Data Sources: Systematic search of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, CINAHL, Web of Science, and ProQuest Dissertations & Theses Global from inception to April 2019 with no restrictions on year or language.Study Selection: Teams of 2 reviewers independently screened search results and included prospective cohort studies with 1000 or more participants that reported on the association between dietary patterns and health outcomes.Data Extraction: Two reviewers independently extracted data, assessed risk of bias, and evaluated the certainty of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria.Data Synthesis: Eligible studies that followed patients for 2 to 34 years revealed low- to very-low-certainty evidence that dietary patterns lower in red and processed meat intake result in very small or possibly small decreases in all-cause mortality, cancer mortality and incidence, cardiovascular mortality, nonfatal coronary heart disease, fatal and nonfatal myocardial infarction, and type 2 diabetes. For all-cause, cancer, and cardiovascular mortality and incidence of some types of cancer, the total sample included more than 400 000 patients; for other outcomes, total samples included 4000 to more than 300 000 patients.Limitation: Observational studies are prone to residual confounding, and these studies provide low- or very-low-certainty evidence according to the GRADE criteria.Conclusion: Low- or very-low-certainty evidence suggests that dietary patterns with less red and processed meat intake may result in very small reductions in adverse cardiometabolic and cancer outcomes.Primary Funding Source: None. (PROSPERO: CRD42017074074). [ABSTRACT FROM AUTHOR]

This article has been corrected. The original version (PDF) is appended to this article as a Supplement.Background: Few randomized trials have evaluated the effect of reducing red meat intake on clinically important outcomes.Purpose: To summarize the effect of lower versus higher red meat intake on the incidence of cardiometabolic and cancer outcomes in adults.Data Sources: EMBASE, CENTRAL, CINAHL, Web of Science, and ProQuest from inception to July 2018 and MEDLINE from inception to April 2019, without language restrictions.Study Selection: Randomized trials (published in any language) comparing diets lower in red meat with diets higher in red meat that differed by a gradient of at least 1 serving per week for 6 months or more.Data Extraction: Teams of 2 reviewers independently extracted data and assessed the risk of bias and the certainty of the evidence.Data Synthesis: Of 12 eligible trials, a single trial enrolling 48 835 women provided the most credible, though still low-certainty, evidence that diets lower in red meat may have little or no effect on all-cause mortality (hazard ratio [HR], 0.99 [95% CI, 0.95 to 1.03]), cardiovascular mortality (HR, 0.98 [CI, 0.91 to 1.06]), and cardiovascular disease (HR, 0.99 [CI, 0.94 to 1.05]). That trial also provided low- to very-low-certainty evidence that diets lower in red meat may have little or no effect on total cancer mortality (HR, 0.95 [CI, 0.89 to 1.01]) and the incidence of cancer, including colorectal cancer (HR, 1.04 [CI, 0.90 to 1.20]) and breast cancer (HR, 0.97 [0.90 to 1.04]).Limitations: There were few trials, most addressing only surrogate outcomes, with heterogeneous comparators and small gradients in red meat consumption between lower versus higher intake groups.Conclusion: Low- to very-low-certainty evidence suggests that diets restricted in red meat may have little or no effect on major cardiometabolic outcomes and cancer mortality and incidence.Primary Funding Source: None (PROSPERO: CRD42017074074). [ABSTRACT FROM AUTHOR]

This article has been corrected. The original version (PDF) is appended to this article as a Supplement.Background: Cancer incidence has continuously increased over the past few centuries and represents a major health burden worldwide.Purpose: To evaluate the possible causal relationship between intake of red and processed meat and cancer mortality and incidence.Data Sources: Embase, Cochrane Central Register of Controlled Trials, Web of Science, CINAHL, and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019 without language restrictions.Study Selection: Cohort studies that included more than 1000 adults and reported the association between consumption of unprocessed red and processed meat and cancer mortality and incidence.Data Extraction: Teams of 2 reviewers independently extracted data and assessed risk of bias; 1 reviewer evaluated the certainty of evidence, which was confirmed or revised by the senior reviewer.Data Synthesis: Of 118 articles (56 cohorts) with more than 6 million participants, 73 articles were eligible for the dose-response meta-analyses, 30 addressed cancer mortality, and 80 reported cancer incidence. Low-certainty evidence suggested that an intake reduction of 3 servings of unprocessed meat per week was associated with a very small reduction in overall cancer mortality over a lifetime. Evidence of low to very low certainty suggested that each intake reduction of 3 servings of processed meat per week was associated with very small decreases in overall cancer mortality over a lifetime; prostate cancer mortality; and incidence of esophageal, colorectal, and breast cancer.Limitation: Limited causal inferences due to residual confounding in observational studies, risk of bias due to limitations in diet assessment and adjustment for confounders, recall bias in dietary assessment, and insufficient data for planned subgroup analyses.Conclusion: The possible absolute effects of red and processed meat consumption on cancer mortality and incidence are very small, and the certainty of evidence is low to very low.Primary Funding Source: None. (PROSPERO: CRD42017074074). [ABSTRACT FROM AUTHOR]

Background: Adaptation of existing guidelines can be an efficient way to develop contextualized recommendations. Transparent reporting of the adaptation approach can support the transparency and usability of the adapted guidelines., Objective: To develop an extension of the RIGHT (Reporting Items for practice Guidelines in HealThcare) statement for the reporting of adapted guidelines (including recommendations that have been adopted, adapted, or developed de novo), the RIGHT-Ad@pt checklist., Design: A multistep process was followed to develop the checklist: establishing a working group, generating an initial checklist, optimizing the checklist (through an initial assessment of adapted guidelines, semistructured interviews, a Delphi consensus survey, an external review, and a final assessment of adapted guidelines), and approval of the final checklist by the working group., Setting: International collaboration., Participants: A total of 119 professionals participated in the development process., Measurements: Participants' consensus on items in the checklist., Results: The RIGHT-Ad@pt checklist contains 34 items grouped in 7 sections: basic information (7 items); scope (6 items); rigor of development (10 items); recommendations (4 items); external review and quality assurance (2 items); funding, declaration, and management of interest (2 items); and other information (3 items). A user guide with explanations and real-world examples for each item was developed to provide a better user experience., Limitation: The RIGHT-Ad@pt checklist requires further validation in real-life use., Conclusion: The RIGHT-Ad@pt checklist has been developed to improve the reporting of adapted guidelines, focusing on the standardization, rigor, and transparency of the process and the clarity and explicitness of adapted recommendations., Primary Funding Source: None.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement., Description: Dietary guideline recommendations require consideration of the certainty in the evidence, the magnitude of potential benefits and harms, and explicit consideration of people's values and preferences. A set of recommendations on red meat and processed meat consumption was developed on the basis of 5 de novo systematic reviews that considered all of these issues., Methods: The recommendations were developed by using the Nutritional Recommendations (NutriRECS) guideline development process, which includes rigorous systematic review methodology, and GRADE methods to rate the certainty of evidence for each outcome and to move from evidence to recommendations. A panel of 14 members, including 3 community members, from 7 countries voted on the final recommendations. Strict criteria limited the conflicts of interest among panel members. Considerations of environmental impact or animal welfare did not bear on the recommendations. Four systematic reviews addressed the health effects associated with red meat and processed meat consumption, and 1 systematic review addressed people's health-related values and preferences regarding meat consumption., Recommendations: The panel suggests that adults continue current unprocessed red meat consumption (weak recommendation, low-certainty evidence). Similarly, the panel suggests adults continue current processed meat consumption (weak recommendation, low-certainty evidence)., Primary Funding Source: None. (PROSPERO 2017: CRD42017074074; PROSPERO 2018: CRD42018088854).

This article has been corrected. The original version (PDF) is appended to this article as a Supplement., Background: A person's meat consumption is often determined by their values and preferences., Purpose: To identify and evaluate evidence addressing health-related values and preferences regarding meat consumption., Data Sources: MEDLINE, EMBASE, Web of Science, Centre for Agriculture and Biosciences Abstracts, International System for Agricultural Science and Technology, and Food Science and Technology Abstracts were searched from inception to July 2018 without language restrictions., Study Selection: Pairs of reviewers independently screened search results and included quantitative and qualitative studies reporting adults' health-related values and preferences regarding meat consumption., Data Extraction: Pairs of reviewers independently extracted data and assessed risk of bias., Data Synthesis: Data were synthesized into narrative form, and summaries were tabulated and certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Of 19 172 initial citations, 41 quantitative studies (38 addressed reasons for meat consumption and 5 addressed willingness to reduce meat consumption) and 13 qualitative studies (10 addressed reasons for meat consumption and 4 addressed willingness to reduce meat consumption) were eligible for inclusion. Thirteen studies reported that omnivores enjoy eating meat, 18 reported that these persons consider meat an essential component of a healthy diet, and 7 reported that they believe they lack the skills needed to prepare satisfactory meals without meat. Omnivores are generally unwilling to change their meat consumption. The certainty of evidence was low for both "reasons for meat consumption" and "willingness to reduce meat consumption in the face of undesirable health effects.", Limitation: Limited generalizability of findings to lower-income countries, low-certainty evidence for willingness to reduce meat consumption, and limited applicability to specific types of meat (red and processed meat)., Conclusion: Low-certainty evidence suggests that omnivores are attached to meat and are unwilling to change this behavior when faced with potentially undesirable health effects., Primary Funding Source: None. (PROSPERO: CRD42018088854).

This article has been corrected. The original version (PDF) is appended to this article as a Supplement., Background: Dietary guidelines generally recommend limiting intake of red and processed meat. However, the quality of evidence implicating red and processed meat in adverse health outcomes remains unclear., Purpose: To evaluate the association between red and processed meat consumption and all-cause mortality, cardiometabolic outcomes, quality of life, and satisfaction with diet among adults., Data Sources: EMBASE (Elsevier), Cochrane Central Register of Controlled Trials (Wiley), Web of Science (Clarivate Analytics), CINAHL (EBSCO), and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019, without language restrictions, as well as bibliographies of relevant articles., Study Selection: Cohort studies with at least 1000 participants that reported an association between unprocessed red or processed meat intake and outcomes of interest., Data Extraction: Teams of 2 reviewers independently extracted data and assessed risk of bias. One investigator assessed certainty of evidence, and the senior investigator confirmed the assessments., Data Synthesis: Of 61 articles reporting on 55 cohorts with more than 4 million participants, none addressed quality of life or satisfaction with diet. Low-certainty evidence was found that a reduction in unprocessed red meat intake of 3 servings per week is associated with a very small reduction in risk for cardiovascular mortality, stroke, myocardial infarction (MI), and type 2 diabetes. Likewise, low-certainty evidence was found that a reduction in processed meat intake of 3 servings per week is associated with a very small decrease in risk for all-cause mortality, cardiovascular mortality, stroke, MI, and type 2 diabetes., Limitation: Inadequate adjustment for known confounders, residual confounding due to observational design, and recall bias associated with dietary measurement., Conclusion: The magnitude of association between red and processed meat consumption and all-cause mortality and adverse cardiometabolic outcomes is very small, and the evidence is of low certainty., Primary Funding Source: None. (PROSPERO: CRD42017074074).