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Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up: results from the prospective EPIC-Oxford study

BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l4897 (Published 04 September 2019) Cite this as: BMJ 2019;366:l4897

Linked editorial

Vegetarian diets and health

  1. Tammy Y N Tong, nutritional epidemiologist1,
  2. Paul N Appleby, senior statistician1,
  3. Kathryn E Bradbury, nutritional epidemiologist1,
  4. Aurora Perez-Cornago, nutritional epidemiologist1,
  5. Ruth C Travis, associate professor1,
  6. Robert Clarke, professor of epidemiology and public health medicine2,
  7. Timothy J Key, deputy director1
  1. 1Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Oxford OX3 7LF, UK
  2. 2Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford, UK
  1. Correspondence to: T Y N Tong tammy.tong{at}ndph.ox.ac.uk (or @tammy_tong on Twitter)
  • Accepted 10 July 2019

Abstract

Objective To examine the associations of vegetarianism with risks of ischaemic heart disease and stroke.

Design Prospective cohort study.

Setting The EPIC-Oxford study, a cohort in the United Kingdom with a large proportion of non-meat eaters, recruited across the country between 1993 and 2001.

Participants 48 188 participants with no history of ischaemic heart disease, stroke, or angina (or cardiovascular disease) were classified into three distinct diet groups: meat eaters (participants who consumed meat, regardless of whether they consumed fish, dairy, or eggs; n=24 428), fish eaters (consumed fish but no meat; n=7506), and vegetarians including vegans (n=16 254), based on dietary information collected at baseline, and subsequently around 2010 (n=28 364).

Main outcome measures Incident cases of ischaemic heart disease and stroke (including ischaemic and haemorrhagic types) identified through record linkage until 2016.

Results Over 18.1 years of follow-up, 2820 cases of ischaemic heart disease and 1072 cases of total stroke (519 ischaemic stroke and 300 haemorrhagic stroke) were recorded. After adjusting for sociodemographic and lifestyle confounders, fish eaters and vegetarians had 13% (hazard ratio 0.87, 95% confidence interval 0.77 to 0.99) and 22% (0.78, 0.70 to 0.87) lower rates of ischaemic heart disease than meat eaters, respectively (P<0.001 for heterogeneity). This difference was equivalent to 10 fewer cases of ischaemic heart disease (95% confidence interval 6.7 to 13.1 fewer) in vegetarians than in meat eaters per 1000 population over 10 years. The associations for ischaemic heart disease were partly attenuated after adjustment for self reported high blood cholesterol, high blood pressure, diabetes, and body mass index (hazard ratio 0.90, 95% confidence interval 0.81 to 1.00 in vegetarians with all adjustments). By contrast, vegetarians had 20% higher rates of total stroke (hazard ratio 1.20, 95% confidence interval 1.02 to 1.40) than meat eaters, equivalent to three more cases of total stroke (95% confidence interval 0.8 to 5.4 more) per 1000 population over 10 years, mostly due to a higher rate of haemorrhagic stroke. The associations for stroke did not attenuate after further adjustment of disease risk factors.

Conclusions In this prospective cohort in the UK, fish eaters and vegetarians had lower rates of ischaemic heart disease than meat eaters, although vegetarians had higher rates of haemorrhagic and total stroke.

Footnotes

  • Contributors: TYNT and TJK conceived and designed the research question. TYNT analysed the data and wrote the first draft of the manuscript; PNA created the figure and prepared the data for analysis; and PNA, KEB, AP-C, RCT, RC, and TJK provided input on data analysis and interpretation of results. All authors revised the manuscript critically for important intellectual content, and read and approved the final manuscript. TYNT is the guarantor. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding: The work is supported by the UK Medical Research Council MR/M012190/1 and Wellcome Trust Our Planet Our Health (Livestock, Environment, and People, LEAP 205212/Z/16/Z). KEB is supported by the Girdlers’ New Zealand Health Research Council Fellowship.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: support from the UK Medical Research Council and Wellcome Trust for the submitted work; no financial relationships with any organisations 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: The study protocol was approved by a multicentre research ethics committee (Scotland A research ethics committee), and all participants provided written informed consent.

  • Data sharing: The data access policy for the EPIC-Oxford study is available via the study website (www.epic-oxford.org/data-access-sharing-and-collaboration/).

  • The lead author (the manuscript’s guarantor) affirms that this 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 (and, if relevant, registered) have been explained.

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