The Nordic Nutrition Recommendations 2022 - handbook for qualified systematic reviews

Abstract

Background: Systematic reviews (SRs) constitute a major part of the Nordic Nutrition Recommendations (NNRs). The step-by-step procedure used to develop SRs has evolved considerably over time and is often tailored to fit the exposure and outcomes in focus.

Objective: To describe a detailed procedure for developing qualified SRs commissioned by the NNR2022 project.

Design: Scrutinizing procedures of recent SRs commissioned by leading national food and health authorities or international food and health organizations.

Results: The following eight steps must be included when developing qualified SRs for the NNR2022 project: 1) define research question, 2) protocol development, 3) literature search, 4) screening and selection of studies, 5) data extraction, 6) assessing risk of bias, 7) synthesis and grading of total strength of evidence, and 8) reporting according to certain standards.

Discussion: This guide is based on the guidelines developed for the fifth edition of NNR but includes some important new domains in order to adhere to more recent, authoritative standards.

Conclusion: All qualified SRs in the NNR2022 project will follow the protocol described here.

Keywords: Nordic and Baltic countries; dietary reference values; evidence-based nutrition; food-based dietary guidelines; national food and health authorities; nutrient recommendations; systematic reviews.

Fig. 1

The individual steps involved when conducting SRs in NNR2022 project.

Fig. 2

Example of a risk of bias graph figure, showing the proportion of studies with low, unclear, or high risk of bias. Reprinted from the Cochrane Handbook (20).