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  3. Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies
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Research

Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies

BMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i2716 (Published 14 June 2016) Cite this as: BMJ 2016;353:i2716
  1. Dagfinn Aune, PhD student1 2,
  2. NaNa Keum, postdoctoral fellow3,
  3. Edward Giovannucci, professor3 4 5,
  4. Lars T Fadnes, postdoctoral researcher6,
  5. Paolo Boffetta, professor7,
  6. Darren C Greenwood, senior lecturer8,
  7. Serena Tonstad, head physician9,
  8. Lars J Vatten, professor1,
  9. Elio Riboli, professor2,
  10. Teresa Norat, senior research fellow2
  1. 1Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
  2. 2Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
  3. 3Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA, USA
  4. 4Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA
  5. 5Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
  6. 6Centre for International Health, Department of Global Public Health and Primary Care and Department of Clinical Dentistry, University of Bergen, Bergen, Norway
  7. 7The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
  8. 8Biostatistics Unit, Centre for Epidemiology and Biostatistics, University of Leeds, Leeds, UK
  9. 9Section of Preventive Cardiology, Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital Ullevål, Oslo, Norway
  1. Correspondence to: D Aune, Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London W2 1PG, UK d.aune{at}imperial.ac.uk
  • Accepted 6 May 2016

Abstract

Objective To quantify the dose-response relation between consumption of whole grain and specific types of grains and the risk of cardiovascular disease, total cancer, and all cause and cause specific mortality.

Data sources PubMed and Embase searched up to 3 April 2016.

Study selection Prospective studies reporting adjusted relative risk estimates for the association between intake of whole grains or specific types of grains and cardiovascular disease, total cancer, all cause or cause specific mortality.

Data synthesis Summary relative risks and 95% confidence intervals calculated with a random effects model.

Results 45 studies (64 publications) were included. The summary relative risks per 90 g/day increase in whole grain intake (90 g is equivalent to three servings—for example, two slices of bread and one bowl of cereal or one and a half pieces of pita bread made from whole grains) was 0.81 (95% confidence interval 0.75 to 0.87; I2=9%, n=7 studies) for coronary heart disease, 0.88 (0.75 to 1.03; I2=56%, n=6) for stroke, and 0.78 (0.73 to 0.85; I2=40%, n=10) for cardiovascular disease, with similar results when studies were stratified by whether the outcome was incidence or mortality. The relative risks for morality were 0.85 (0.80 to 0.91; I2=37%, n=6) for total cancer, 0.83 (0.77 to 0.90; I2=83%, n=11) for all causes, 0.78 (0.70 to 0.87; I2=0%, n=4) for respiratory disease, 0.49 (0.23 to 1.05; I2=85%, n=4) for diabetes, 0.74 (0.56 to 0.96; I2=0%, n=3) for infectious diseases, 1.15 (0.66 to 2.02; I2=79%, n=2) for diseases of the nervous system disease, and 0.78 (0.75 to 0.82; I2=0%, n=5) for all non-cardiovascular, non-cancer causes. Reductions in risk were observed up to an intake of 210-225 g/day (seven to seven and a half servings per day) for most of the outcomes. Intakes of specific types of whole grains including whole grain bread, whole grain breakfast cereals, and added bran, as well as total bread and total breakfast cereals were also associated with reduced risks of cardiovascular disease and/or all cause mortality, but there was little evidence of an association with refined grains, white rice, total rice, or total grains.

Conclusions This meta-analysis provides further evidence that whole grain intake is associated with a reduced risk of coronary heart disease, cardiovascular disease, and total cancer, and mortality from all causes, respiratory diseases, infectious diseases, diabetes, and all non-cardiovascular, non-cancer causes. These findings support dietary guidelines that recommend increased intake of whole grain to reduce the risk of chronic diseases and premature mortality.

Footnotes

  • We thank Tao Huang and Lu Qi (Department of Nutrition, Harvard T Chan School of Public Health) for clarification of the data from the NIH-AARP Diet and Health Study, and Diewertje Sluik (Division of Human Nutrition, Wageningen University) for clarification of the data from the European Prospective Investigation into Cancer and Nutrition study.

  • Contributors: DA and TN conceived and designed the study. DA, NK, EG, LTF, PB, TN, DCG, ER, and ST acquired, analysed, and interpreted the data. DCG checked data extractions. DA drafted the manuscript, which was critically revised for important intellectual content by all authors. DA and DCG carried out the statistical analysis. DA, LJV, ST, and ER obtained funding. TN supervised the study. All authors have read and approved the final manuscript. DA is guarantor and had full access to all the data and takes responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding: This project was funded by Olav og Gerd Meidel Raagholt’s Stiftelse for Medisinsk Forskning, the liaison committee between the Central Norway Regional Health Authority (RHA) and the Norwegian University of Science and Technology (NTNU), and the Imperial College National Institute of Health Research (NIHR) Biomedical Research Centre (BRC). The funders had no role in the study design, data collection, data analysis and interpretation, writing of the report, or the decision to submit the article for publication.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at http://www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisation that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required.

  • Transparency: The lead author affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been disclosed.

  • Data sharing: No additional data available.

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 3.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/3.0/.

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