Person:

Sands, Amanda Lee Prouty

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.

Due to their cholesterol content, limiting egg intake has been widely recommended for prevention of cardiovascular disease (CVD). However, recent reports by the 2015 Dietary Guidelines Committee and AHA/ACC suggest that there is insufficient evidence that dietary cholesterol is appreciably associated with blood cholesterol. In addition, the literature on the association with type 2 diabetes (T2D) is inconsistent.

These analyses aim to determine the association between egg intake and the risk of CVD and T2D in the Nurses’ Health Study (NHS), the Nurses’ Health II Study (NHSII), Health Professionals Follow-up Study (HPFS) and the NIH-AARP Diet and Health Study (AARP), and conduct a meta-analyses.

Egg intake was assessed via validated semi-quantitative food frequency questionnaires. Cox proportional hazard models, adjusted for age, lifestyle and dietary factors, were used to estimate relative risks (HR) and 95% Confidence Intervals (CI). We observed 12,832 and 16,570 cases of incident CVD and T2D in NHS, NHSII and HPFS, and 11,268 CVD mortality cases in AARP. An increase of one egg per day was not associated with risk of CVD in NHS, NHSII and HPFS (HR: 1.04, 95% CI: (0.96, 1.13)). In the AARP study an increase of one egg per day was associated with an increased risk of CVD mortality (HR: 1.13, 95% CI: (1.05, 1.20)) and, an increased risk of CVD mortality among diabetics (HR: 1.25, 95%CI: (1.11, 1.41)). One egg per day was associated with an increased risk of CVD (HR: 1.05, 95% CI: (1.01, 1.09)) in a meta-analysis of the current results and previously published studies. We also saw an increased risk of CVD among diabetics (HR: 1.24, 95% CI: (1.12, 1.37)). We observed an increased risk of T2D with an increase of one egg per day (HR: 1.09, 95% CI: (1.01, 1.18)) in NHS, NHSII and HPFS, and in the meta-analysis (HR: 1.13, 95% CI: (1.07, 1.19)).

Although there does not seem to be a significant association between egg intake and risk of CVD or T2D in healthy individuals, people at risk for CVD or T2D and those who currently have T2D may want to limit egg intake.