Egg consumption and risk of type 2 diabetes: a prospective study and dose-response meta-analysis

Aims/hypothesis In this study, we aimed to investigate the association between egg consumption and type 2 diabetes risk in the Cohort of Swedish Men and to conduct a meta-analysis to summarise available prospective evidence on this association. Methods We followed 39,610 men (aged 45-79 years) from 1998 up to 2012 for incident type 2 diabetes. Egg consumption was assessed at baseline using a food frequency questionnaire. HRs (95% CIs) were estimated using Cox proportional hazards regression models. We searched PubMed (up to 14 December 2015) and reference lists of retrieved articles to identify eligible studies for meta-analysis. Results During the 15 years of follow up, 4,173 men were diagnosed with type 2 diabetes. Compared with men who consumed eggs <1 time/week, the multivariable-adjusted HRs were 0.98 (95% CI 0.92, 1.05), 1.11 (95% CI 0.99, 1.24) and 1.11 (95% CI 0.95, 1.29) for egg consumption 1-2, 3-4 and >= 5 times/week, respectively (p(trend)=0.06). In a random-effects dose-response meta-analysis, heterogeneity in the overall estimate was partly explained by differences across regions. The overall HRs for type 2 diabetes for each 3 times/week increment in consumption were 1.18 (95% CI 1.13, 1.24) in five US studies (I-2 = 0%) and 0.97 (95% CI 0.90, 1.05) in seven non-US studies. Conclusions/interpretation Our findings in Swedish men do not support an association between egg consumption and risk of type 2 diabetes. In a meta-analysis, frequent egg consumption was associated with a higher risk of type 2 diabetes in US studies only. Egg consumption habits and associated overall dietary patterns may differ between populations and could potentially explain the discrepancies between reported results. Given the inconsistent results, this relationship warrants further study.