DASH Dietary Pattern and Cardiometabolic Risk: An Umbrella Review of Systematic Reviews and Meta-analyses of Prospective Cohort Studies and Randomized and Non-randomized Controlled Trials

Background: The DASH Dietary Pattern, which emphasizes intake of fruits and vegetables, low-fat or non-fat dairy, nuts, and legumes and limits saturated fat and red meat intake, is associated with reduced cardiovascular disease and diabetes risk in prospective cohort studies and has been shown to lower blood pressure and other intermediate cardiometabolic risk factors in randomized controlled trials. Despite the endorsement of the DASH Dietary Pattern by major international diabetes and cardiovascular guidelines, the European Association for the Study of Diabetes (EASD) guidelines for nutrition therapy have not made any specific recommendations for the DASH dietary pattern. The present umbrella review using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was commissioned by the Diabetes and Nutrition Study Group (DNSG) of the EASD to summarize the available evidence from recent systematic reviews and meta-analyses of prospective cohort studies and randomized and non-randomized controlled trials of the relationship between the DASH dietary pattern and cardiometabolic risk.

Need for proposed research: Public health policy and clinical practice guidelines are established with the use of systematic reviews and meta-analyses of randomized and non-randomized controlled trials and prospective cohort studies, which are regarded as the highest levels of evidence. As dietary guidelines and public health policy have shifted toward food and dietary-pattern based recommendations, there is a need to summarize the evidence from systematic reviews and meta-analyses assessing the effect of the DASH dietary pattern trials on cardiometabolic risk factors.

Objective: The investigators will conduct an umbrella review of systematic reviews and meta-analyses using GRADE to summarize the relation of the DASH dietary pattern with incident cardiometabolic disease outcomes in prospective cohort studies and the effect the DASH dietary pattern on intermediate cardiometabolic risk factors in randomzied and non-randomized controlled trials.

Design: The umbrella review will be conducted according to the principals of the Cochrane Handbook for Systematic Reviews of Interventions for the controlled clinical trials and the GRADE handbook with reporting according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines for prospective cohort studies and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for controlled trials.

Data sources: MEDLINE and EMBASE will be searched using appropriate search terms. Authors will be contacted for applicable missing data.