There was a prominent article in the Sunday Star Times yesterday about eating too many eggs being linked to heart disease.
The article referred to this investigation published in Jama Network: ‘Associations of Dietary Cholesterol or Egg Consumption With Incident Cardiovascular Disease and Mortality‘.
We asked our Epidemiologist, Dr Simon Thornley, for his expert comment. He says:
“I think the most important issue with this study is that it is an observational study with nutrition as the main exposure. The two big issues here are that the magnitude of the association between eating eggs and outcomes (mortality and CVD) is low. The hazard ratio indicates a 10-15% increased risk at most. This is a very small increase. The problems of unmeasured confounding and measurement error in the exposure (diet) are also likely to distort this evidence.
In my opinion, the most reliable evidence to answer the question of ‘How safe are eggs and fatty foods?’ is given by trials. This is because trials do not rely on measurement of diet (which is error prone) and they tend to balance measured and unmeasured confounders. In this trial for example,
https://www.sciencedirect.com/science/article/pii/S0140673689908283, reducing fat intake did not improve survival (contrary to the prior beliefs of investigators) and in fact increasing intake of fatty fish improved survival by 29%. This trial is more likely to provide useful dietary advice than from observational epidemiology. I no longer look closely at these sort of studies when trial evidence is available.”