African Americans with diagnosed type 2 diabetes mellitus (T2DM) may be eating more eggs; but eggs were not associated with the development of T2DM.
The Jackson Heart Study is the largest single-site, prospective, epidemiologic investigation of cardiovascular disease among African Americans. Diabetes is among the important risk factors for cardiovascular disease being studied among this cohort.
In this study, the researchers evaluated whether there was an association between egg consumption and risk of T2DM. The results pose a chicken and egg type question about which came first, diabetes or higher egg consumption?
- At the start of the study (looking at a cross-section in time in those with existing T2DM), prevalence of diabetes was higher among African Americans with higher egg consumption. In other words, subjects who were already diagnosed with T2DM were more likely to eat eggs 1 or more times per week.
Then came surprising results suggesting that diabetes might have preceded higher egg consumption.
- There was no relationship between egg consumption and T2DM risk factors or indicators, including glycosylated hemoglobin (an indicator of blood sugar control), HOMA-IR or HOMA-B (indicators of insulin resistance) among subjects without T2DM at baseline.
- Furthermore, during 7.3 years of follow-up in subjects who were free of T2DM at the start of the study, there was no relationship between egg consumption and risk of developing T2DM. This evidence does not support a cause-effect relationship between eggs and T2DM.
The researchers concluded that. . .
“[E]gg consumption was not associated with the risk of developing T2DM.”
In discussing findings, they noted the lack of association with incident T2DM was consistent with other research studies, while contrary to others, and conjectured one possible reason for the association observed cross-sectionally at baseline in those with existing T2DM:
“It is possible that subjects diagnosed with T2DM altered their diet voluntarily or per clinicians’ advice to obtain their proteins from eggs…”
This was an important study both for being a large study examining diet and key health risk factors among African Americans and for identifying the incongruence of associations between eggs and T2DM depending on which came first… higher egg consumption or diabetes.
Djousse, L et al. “Egg consumption and risk of type 2 diabetes among African Americans: The Jackson Heart Study.” Clinical Nutrition 2015; published online as DOI: http://dx.doi.org/10.1016/j.clnu.2015.04.016