An updated systematic review and meta-analysis on adherence to mediterranean diet and risk of cancer

Jakub Morze; Anna Danielewicz; Katarzyna Przybyłowicz; Hongmei Zeng; Georg Hoffmann; Lukas Schwingshackl

doi:10.1007/s00394-020-02346-6

An updated systematic review and meta-analysis on adherence to mediterranean diet and risk of cancer

Eur J Nutr. 2021 Apr;60(3):1561-1586. doi: 10.1007/s00394-020-02346-6. Epub 2020 Aug 8.

Authors

Jakub Morze^{1

2}, Anna Danielewicz³, Katarzyna Przybyłowicz³, Hongmei Zeng^{4

5}, Georg Hoffmann⁶, Lukas Schwingshackl⁷

Affiliations

¹ Department of Cardiology and Internal Diseases, University of Warmia and Mazury, al. Warszawska 30, 10-082, Olsztyn, Poland. jakub.morze@uwm.edu.pl.
² Department of Human Nutrition, University of Warmia and Mazury, ul. Sloneczna 45f, 10-718, Olsztyn, Poland. jakub.morze@uwm.edu.pl.
³ Department of Human Nutrition, University of Warmia and Mazury, ul. Sloneczna 45f, 10-718, Olsztyn, Poland.
⁴ National Cancer Registry Office, National Cancer Center, 17 South Lane, Beijing, 100021, China.
⁵ Department of Nutrition, Harvard T.H. Chan School of Public Health, 655 Huntington Ave, Building 2, Boston, MA, 02551, USA.
⁶ Department of Nutritional Sciences, University of Vienna, Althanstraße 14, UZA II, 1090, Vienna, Austria.
⁷ Institute for Evidence in Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Straße 153, 79110, Freiburg, Germany.

Abstract

Purpose: The aim of current systematic review was to update the body of evidence on associations between adherence to the Mediterranean diet (MedDiet) and risk of cancer mortality, site-specific cancer in the general population; all-cause, and cancer mortality as well as cancer reoccurrence among cancer survivors.

Methods: A literature search for randomized controlled trials (RCTs), case-control and cohort studies published up to April 2020 was performed using PubMed and Scopus. Study-specific risk estimates for the highest versus lowest adherence to the MedDiet category were pooled using random-effects meta-analyses. Certainty of evidence from cohort studies and RCTs was evaluated using the NutriGrade scoring system.

Results: The updated search revealed 44 studies not identified in the previous review. Altogether, 117 studies including 3,202,496 participants were enclosed for meta-analysis. The highest adherence to MedDiet was inversely associated with cancer mortality (RR_cohort: 0.87, 95% CI 0.82, 0.92; N = 18 studies), all-cause mortality among cancer survivors (RR_cohort: 0.75, 95% CI 0.66, 0.86; N = 8), breast (RR_{observational}: 0.94, 95% CI 0.90, 0.97; N = 23), colorectal (RR_{observational}: 0.83, 95% CI 0.76, 0.90; N = 17), head and neck (RR_{observational}: 0.56, 95% CI 0.44, 0.72; N = 9), respiratory (RR_cohort: 0.84, 95% CI 0.76, 0.94; N = 5), gastric (RR_{observational}: 0.70, 95% CI 0.61, 0.80; N = 7), bladder (RR_{observational}: 0.87, 95% CI 0.76, 0.98; N = 4), and liver cancer (RR_{observational}: 0.64, 95% CI 0.54, 0.75; N = 4). Adhering to MedDiet did not modify risk of blood, esophageal, pancreatic and prostate cancer risk.

Conclusion: In conclusion, our results suggest that highest adherence to the MedDiet was related to lower risk of cancer mortality in the general population, and all-cause mortality among cancer survivors as well as colorectal, head and neck, respiratory, gastric, liver and bladder cancer risks. Moderate certainty of evidence from cohort studies suggest an inverse association for cancer mortality and colorectal cancer, but most of the comparisons were rated as low or very low certainty of evidence.

Keywords: Cancer; Certainty of evidence; Mediterranean diet; Meta-analysis.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Case-Control Studies
Cohort Studies
Diet, Mediterranean*
Humans
Male
Neoplasms* / prevention & control
Risk

Grants and funding

010/RID/2018/19/Ministerstwo Nauki i Szkolnictwa Wyższego