Higher consumption of dietary cholesterol or eggs linked to increased risk of incident CVD and mortality
Associations of Dietary Cholesterol or Egg Consumption With Incident Cardiovascular Disease and Mortality
Introduction and methods
The ongoing debate on dietary cholesterol consumption and risk of CVD has been intensified since the 2015-2020 Dietary Guidelines for Americans included 2 seemingly contradictory statements: (1) “Cholesterol is not a nutrient of concern for overconsumption”; and (2) “Individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern.” [1,2].
Cholesterol, saturated fat and animal protein often co-exist in diets . It remains uncertain how the interaction and independence between dietary cholesterol and these nutrients are related to CVD and mortality. Also, it is unclear whether the risk of CVD and mortality associated with dietary cholesterol consumption can be attenuated by consuming an overall high-quality diet, or if the food source of cholesterol (e.g. eggs, red meat, poultry, fish, and dairy products) is important. Reported associations of egg consumption with CVD and mortality have been inconsistent overall and by subtypes of CVD [3-8].
To address these gaps, this study (n=29.615) determined the associations of dietary cholesterol or egg consumption with incident CVD and all-cause mortality by pooling individual participants data from 6 cohorts from the Lifetime Risk Pooling Project (ARIC, CARDIA, FHS, FOS, JHS, and MESA) (collected between March 1985-Aug 2016). The Lifetime Risk Pooling Project included 20 community-based prospective cohorts of US participants primarily to examine long-term risks and development patterns of CVD over the life course in adults. Subjects were excluded if they had CVD at baseline or energy intake <500 kcal/day or >6000 kcal/day. Data on diet were self-reported at baseline and harmonized by cohort using a standardized protocol and data dictionary. To apply these study results to the general US population, effects of each additional 300 mg of dietary cholesterol or half an egg per day (equivalent to intake of 1 egg 3-4 times per week or 3-4 eggs per week in total) was examined. The primary outcomes were incident CVD (composite of fatal and non-fatal coronary heart disease (CHD), stroke, HF, and CVD mortality from other causes) and all-cause mortality. Median follow-up was 17.5 years (IQR: 13.0-21.7).
Consumption of dietary cholesterol or eggs and risk of incident CVD and all-cause mortality
- The associations between dietary cholesterol intake and incident CVD and all-cause mortality were monotonic (P=0.19 and P=0.83, respectively, for quadratic cholesterol consumption term), with higher risk with increasing cholesterol consumption.
- After multivariable adjustment, each additional 300 mg of dietary cholesterol consumed per day was significantly linked to increased risk of incident CVD (HR adj: 1.17, 95%CI: 1.09-1.26; adjusted absolute risk difference [ARD adj]: 3.24%, 95%CI: 1.39%-5.08%) and all-cause mortality (HR adj: 1.18, 95%CI: 1.10-1.16; ARD adj: 4.43%, 95%CI: 2.51%-6.36%), which both remained significant after further adjustment for saturated and unsaturated fat, animal protein, fiber, sodium, several cholesterol-containing foods (poultry, fish, dairy products, meat), or dietary patterns. However, the association of dietary cholesterol with incident CVD lost significance after adjustment for total consumption of eggs, total red meat, and the association of dietary cholesterol with all-cause mortality was no longer significant after adjustment for egg consumption or total consumption of egg and total red meat.
- The associations between egg consumption and incident CVD and all-cause mortality were monotonic (P=0.34 and P=0.48, respectively, for quadratic egg consumption term), with higher risk with increasing egg consumption.
- After multivariable adjustment, there was a significant association of each additional half egg consumed per day with increased risk of incident CVD (HR adj: 1.06, 95%CI: 1.03-1.10; ARD adj: 1.11%, 95%CI: 0.32%-1.89%) and all-cause mortality (HR adj: 1.08, 95%CI: 1.04-1.11; ARD adj: 1.93%, 95%CI: 1.10%-2.76%), which both remained significant after further adjustment for dietary fats, animal protein, fiber, sodium, or dietary patterns. However, both associations lost significance after adjustment for dietary cholesterol consumption.
Among US adults, higher intake of dietary cholesterol or eggs was significantly linked to increased risk of incident CVD and all-cause mortality in a dose-response manner, which was independent of nutrients or diets (for all-cause mortality: exception for total intake of eggs and red meat), and dietary patterns. These results should be considered in the development of dietary guidelines and updates.