Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies2013; 346 doi: http://dx.doi.org/10.1136/bmj.e8539 (Published 07 January 2013) Cite this as: 2013;346:e8539
- Ying Rong, doctoral student12,
- Li Chen, research fellow12,
- Tingting Zhu, research fellow12,
- Yadong Song, research fellow12,
- Miao Yu, research fellow12,
- Zhilei Shan, research fellow12,
- Amanda Sands, doctoral student3,
- Frank B Hu, professor3,
- Liegang Liu, professor12
- 1Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan, People’s Republic of China
- 2Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, People’s Republic of China
- 3Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA, USA
- Correspondence to: L Liu
- Accepted 10 December 2012
Objective To investigate and quantify the potential dose-response association between egg consumption and risk of coronary heart disease and stroke.
Design Dose-response meta-analysis of prospective cohort studies.
Data sources PubMed and Embase prior to June 2012 and references of relevant original papers and review articles.
Eligibility criteria for selecting studies Prospective cohort studies with relative risks and 95% confidence intervals of coronary heart disease or stroke for three or more categories of egg consumption.
Results Eight articles with 17 reports (nine for coronary heart disease, eight for stroke) were eligible for inclusion in the meta-analysis (3 081 269 person years and 5847 incident cases for coronary heart disease, and 4 148 095 person years and 7579 incident cases for stroke). No evidence of a curve linear association was seen between egg consumption and risk of coronary heart disease or stroke (P=0.67 and P=0.27 for non-linearity, respectively). The summary relative risk of coronary heart disease for an increase of one egg consumed per day was 0.99 (95% confidence interval 0.85 to 1.15; P=0.88 for linear trend) without heterogeneity among studies (P=0.97, I2=0%). For stroke, the combined relative risk for an increase of one egg consumed per day was 0.91 (0.81 to 1.02; P=0.10 for linear trend) without heterogeneity among studies (P=0.46, I2=0%). In a subgroup analysis of diabetic populations, the relative risk of coronary heart disease comparing the highest with the lowest egg consumption was 1.54 (1.14 to 2.09; P=0.01). In addition, people with higher egg consumption had a 25% (0.57 to 0.99; P=0.04) lower risk of developing hemorrhagic stroke.
Conclusions Higher consumption of eggs (up to one egg per day) is not associated with increased risk of coronary heart disease or stroke. The increased risk of coronary heart disease among diabetic patients and reduced risk of hemorrhagic stroke associated with higher egg consumption in subgroup analyses warrant further studies.
We thank Catherine Sauvaget, Eric J Grant, and Adam M Bernstein for providing data for the meta-analysis.
Contributors: YR and LL conceived the study. YR and LC searched the databases and checked them according to the eligible criteria and exclusion criteria. LL helped develop search strategies. TZ gave advice on meta-analysis methodology. YS helped extract quantitative data from some papers. YS, MY, and ZS analyzed the data. YR wrote the draft of the paper. LC, TZ, YS, MY, ZS, AS, FBH, and LL contributed to writing, reviewing, or revising the paper. LL is the guarantor.
Funding: This work was funded by the National Science and Technology Support Program (2012BAI02B02), National Natural Science Foundation (NSFC 81072291), and National Basic Research Program (2009CB118803) of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Ethical approval not needed.
Data sharing: No additional data available.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.