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

Abstract

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.

Keywords:

• Carbohydrates
• cardiovascular disease
• cohort studies
• coronary heart disease
• glycemic index
• glycemic load
• meta-analysis
• mortality
• neoplasms

Acknowledgements

Financial Support: This research received no specific grant from any funding agency, commercial or not-for-profit sectors.

Conflict of interest: None.

Authorship: AJ conceived and designed the study, conducted systematic search, screened articles, selected eligible articles, extracted the information from eligible studies, performed analyses and interpreted the results, and wrote the first draft of the manuscript; SS conducted systematic search, screened articles, selected eligible articles, extracted the information from eligible studies, and wrote the first draft of the manuscript; DJ and JS critically revised the manuscript and contributed to the interpretation of the results; SSb conceived and designed the study, critically revised the manuscript and contributed to the interpretation of the results. SSb is the guarantor. All authors have read and approved the final manuscript. All authors had full access to all the data and take responsibility for the integrity of the data and the accuracy of the data analysis.