Plain language summary
Eggs have a high cholesterol content and have therefore been associated with a risk for heart disease. However, studies to substantiate this have been conflicting, with some studies showing associations and others not. This systematic review and meta-analysis of over five million people and 763 studies aimed to evaluate the association between egg intake and the risk of heart disease. The results showed that higher egg intake was associated with a poor diet. Egg intake was not associated with heart disease and this was evident even in people who ate at least one egg per day. Even in people with other associated diseases, such as type 2 diabetes and high blood pressure, egg intake was not associated with heart disease. It was concluded that egg consumption does not increase an individual’s risk for heart disease. This study could be used by healthcare professionals to justify the recommendation that patients at risk of heart disease or those who have heart disease, can still eat up to one egg per day, without risk of exacerbating their condition.
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 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, I =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, I =38.2%), and stroke (22 risk estimates, 1 059 315 participants, 53 617 stroke events; 0.99, 0.91 to 1.07, I =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, I =30.8%) or European cohorts (1.05, 0.92 to 1.19, I =64.7%), but an inverse association was seen in Asian cohorts (0.92, 0.85 to 0.99, I =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. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42019129650.