Egg consumption in relation to risk of cardiovascular disease and diabetes: a systematic review and meta-analysis

Abstract

Background: The associations of egg consumption with cardiovascular disease (CVD) and diabetes are still unclear.

Objective: We aimed to quantitatively summarize the literature on egg consumption and risk of CVD, cardiac mortality, and type 2 diabetes by conducting a meta-analysis of prospective cohort studies.

Design: A systematic literature review was conducted for published studies in PubMed and EMBASE through March 2012. Additional information was retrieved through Google or a hand review of the reference from relevant articles. Studies were included if they had a prospective study design, were published in English-language journals, and provided HRs and 95% CIs for the associations of interest. Data were independently extracted by 2 investigators, and the weighted HRs and 95% CIs for the associations of interest were estimated by using a random-effects model.

Results: A total of 22 independent cohorts from 16 studies were identified, including participants ranging in number from 1600 to 90,735 and in follow-up time from 5.8 to 20.0 y. Comparison of the highest category (≥1 egg/d) of egg consumption with the lowest (<1 egg/wk or never) resulted in a pooled HR (95% CI) of 0.96 (0.88, 1.05) for overall CVD, 0.97 (0.86, 1.09) for ischemic heart disease, 0.93 (0.81, 1.07) for stroke, 0.98 (0.77, 1.24) for ischemic heart disease mortality, 0.92 (0.56, 1.50) for stroke mortality, and 1.42 (1.09, 1.86) for type 2 diabetes. Of the studies conducted in diabetic patients, the pooled HR (95% CI) was 1.69 (1.09, 2.62) for overall CVD.

Conclusions: This meta-analysis suggests that egg consumption is not associated with the risk of CVD and cardiac mortality in the general population. However, egg consumption may be associated with an increased incidence of type 2 diabetes among the general population and CVD comorbidity among diabetic patients.

FIGURE 1.

Process of study selection.

FIGURE 2.

Pooled HRs and 95% CIs for incident IHD, stroke, and overall CVD. The pooled estimates were obtained by using a random-effects model. The dots indicate the adjusted HRs from a comparison of the highest category of egg consumption (≥1 egg/d) with the lowest (<1 egg/wk or never). The size of the shaded square is proportional to the weight of the individual study. The horizontal lines represent 95% CIs. The diamond data markers indicate the pooled HRs. CVD, cardiovascular disease; IHD, ischemic heart disease.

FIGURE 3.

Pooled HRs and 95% CIs of incident overall CVD in diabetic patients. The pooled estimates were obtained by using a random-effects model. The dots indicate the adjusted HRs from a comparison of the highest category of egg consumption (≥1 egg/d) with the lowest (<1 egg/wk or never). The size of the shaded square is proportional to the weight of the individual study. The horizontal lines represent 95% CIs. The diamond data markers indicate the pooled HR.