To determine whether postprandial lipoproteins were associated with atherosclerosis, and if
so, whether the association was statistically independent of that between fasting
lipoproteins and atherosclerosis.
Fatty diets are a likely cause of atherosclerosis, and lipoproteins appearing in blood after
a fatty meal may be particularly atherogenic. Yet nearly all published research up to 1990
on the relationship of blood lipids to atherosclerosis in humans measured lipids only in
fasting or casual samples.
The atherogenicity of postprandial lipoproteins, particularly remnants of triglyceride-rich
particles, was suggested by in vitro studies of foam cell induction, feeding experiments in
animals, and observations of Type III hyperlipoproteinemia in humans. Indirect evidence for
the hypothesis arose from research on conditions characterized by high fasting triglycerides
and low HDL-cholesterol, denser LDL particles, and elevations of apolipoprotein B or
intermediate-density lipoproteins. The hypothesis received direct support from two small
studies by Krauss in 1987 and Simons in 1987 which showed higher postprandial chylomicron
remnant concentrations in coronary patients than controls. However, neither study had the
statistical power to evaluate the relative associations of fasting and postprandial
measurements with disease. Such an evaluation, because of close correlations between fasting
and postprandial lipoproteins, required studies with large sample sizes.
The initiative originated in the Division of Epidemiology and Clinical Applications with
input from the Division of Heart and Vascular Diseases and the two Divisions' Advisory
Groups and was approved in May 1989 by the National Heart, Lung, and Blood Advisory Council.
The Request for Applications was released in September 1989. Awards were made in July 1990.
Columbia University: Cases and controls were recruited from individuals undergoing
electrocardiographic examination or thallium stress testing. Blood was taken before and
during an eight hour period after ingestion of a fat-formula meal. Plasma levels of lipids,
lipoproteins, apoproteins, lipolytic enzyme activities, glucose, and insulin were measured.
Apo E phenotype and LDL size were also determined. These factors, along with sex, age, blood
pressure, smoking status, and waist-hip ratio were used as covariates in the analysis.
Postprandial remnant lipoproteins were also characterized.
University of North Carolina: Participants were administered an established and standardized
fat challenge test containing vitamin A. Food frequency history was also taken. Blood
specimens were drawn after fasting and at 3.5 and 9 hours after the test meal. Various
parameters of fasting and postprandial lipemia, as well as markers for intestinal and
hepatic triglyceride-rich lipoproteins were measured. There were five consortia associated
with the study: the University of Minnesota, Johns Hopkins University, the University of
Mississippi, Bowman Gray School of Medicine, and Baylor College of Medicine.
- Men and Women 18 years and older
- Undergoing diagnostic exercise electrocardiographic or thallium stress tests at our
- Prior diagnosis of coronary artery disease (CAD)
- Unable to fast due to health reasons