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HomeEditor's PickOne egg per day does not increase CVD risk — Harvard meta-analysis

One egg per day does not increase CVD risk — Harvard meta-analysis

Consuming up to one egg per day does not appear to be associated with cardiovascular disease (CVD) risk, according to a new study and meta-analysis led by researchers at Harvard TH Chan School of Public Health. “Recent studies reignited the debate on this controversial topic, but our study provides compelling evidence supporting the lack of an appreciable association between moderate egg consumption and cardiovascular disease,” said first author Jean-Philippe Drouin-Chartier, visiting scientist in the department of nutrition and assistant professor at Laval University in Québec, Canada. The relationship between egg consumption and CVD risk has been a topic of intense debate in the scientific community in recent decades. Just in the past 12 months, three published studies have reported conflicting results.

The new findings update a 1999 study – the first major analysis of eggs and cardiovascular disease – that found no association between eggs and CVD risk. That study was led by Frank Hu, Fredrick J Stare professor of nutrition and epidemiology, chair of the department of nutrition, and a co-author of the current study.

For this study, researchers analysed health data from 173,563 women and 90,214 men participating in the Nurses’ Health Study (NHS) I and II, and the Health Professionals Follow-Up Study (HPFS) who were free of CVD, type 2 diabetes, and cancer at baseline. They used repeated measures of diet during up to 32 years of follow-up to gain a detailed picture of potentially confounding lifestyle factors such as high body mass index and red meat consumption. The researchers also conducted the largest meta-analysis of this topic, including 28 prospective cohort studies with up to 1.7m participants.

The analysis of NHS and HPFS participants found no association between moderate egg consumption and risk of CVD. Results from the meta-analysis supported this finding in US and European populations; however, some evidence suggested that moderate egg consumption may be associated with lower CVD risk in Asian populations although this may be confounded by the overall dietary pattern.

Study co-author Shilpa Bhupathiraju, research scientist in the Harvard Chan School department of nutrition and associate epidemiologist at Brigham and Women’s Hospital, said that while moderate egg consumption can be part of a healthy eating pattern, it is not essential. “There is a range of other foods that can be included in a healthy breakfast, such as whole grain toasts, plain yogurt, and fruits.”

Abstract
Objective: To evaluate the association between egg intake and cardiovascular disease risk among women and men in the United States, and to conduct a meta-analysis of prospective cohort studies.
Design: Prospective cohort study, and a systematic review and meta-analysis of prospective cohort studies.
Setting: Nurses’ Health Study (NHS, 1980-2012), NHS II (1991-2013), Health Professionals’ Follow-Up Study (HPFS, 1986-2012).
Participants: Cohort analyses included 83 349 women from NHS, 90 214 women from NHS II, and 42 055 men from HPFS who were free of cardiovascular disease, type 2 diabetes, and cancer at baseline.
Main outcome measures: Incident cardiovascular disease, which included non-fatal myocardial infarction, fatal coronary heart disease, and stroke.
Results: Over up to 32 years of follow-up (>5.54 million person years), 14 806 participants with incident cardiovascular disease were identified in the three cohorts. Participants with a higher egg intake had a higher body mass index, were less likely to be treated with statins, and consumed more red meats. Most people consumed between one and less than five eggs per week. In the pooled multivariable analysis, consumption of at least one egg per day was not associated with incident cardiovascular disease risk after adjustment for updated lifestyle and dietary factors associated with egg intake (hazard ratio for at least one egg per day v less than one egg per month 0.93, 95% confidence interval 0.82 to 1.05). In the updated meta-analysis of prospective cohort studies (33 risk estimates, 1 720 108 participants, 139 195 cardiovascular disease events), an increase of one egg per day was not associated with cardiovascular disease risk (pooled relative risk 0.98, 95% confidence interval 0.93 to 1.03, I2=62.3%). Results were similar for coronary heart disease (21 risk estimates, 1 411 261 participants, 59 713 coronary heart disease events; 0.96, 0.91 to 1.03, I2=38.2%), and stroke (22 risk estimates, 1 059 315 participants, 53 617 stroke events; 0.99, 0.91 to 1.07, I2=71.5%). In analyses stratified by geographical location (P for interaction=0.07), no association was found between egg consumption and cardiovascular disease risk among US cohorts (1.01, 0.96 to 1.06, I2=30.8%) or European cohorts (1.05, 0.92 to 1.19, I2=64.7%), but an inverse association was seen in Asian cohorts (0.92, 0.85 to 0.99, I2=44.8%).

Conclusions: Results from the three cohorts and from the updated meta-analysis show that moderate egg consumption (up to one egg per day) is not associated with cardiovascular disease risk overall, and is associated with potentially lower cardiovascular disease risk in Asian populations.

Authors
Jean-Philippe Drouin-Chartier, Siyu Chen, Yanping Li, Amanda L Schwab, Meir J Stampfer, Frank M Sacks, Bernard Rosner, Walter C Willett, Frank B Hu, Shilpa N Bhupathiraju

[link url="https://www.hsph.harvard.edu/news/press-releases/moderate-egg-consumption-not-associated-with-higher-cardiovascular-disease-risk/"]Harvard TH Chan School of Public Health material[/link]

[link url="https://www.bmj.com/content/368/bmj.m513"]BMJ abstract[/link]

[link url="https://www.bmj.com/content/368/bmj.m744"]BMJ editorial[/link]

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