Purpose: To determine the effect of a self-selected meal on concentrations of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in a screening setting and to determine the effect of using nonfasting values to classify individuals according to National Cholesterol Education Program guidelines.
Subjects and methods: Study subjects were 115 employees who had previously participated in worksite total cholesterol screening, selected by stratified random sampling for sex and total cholesterol levels. Total cholesterol, triglycerides, HDL-C, and estimated LDL-C were determined before subjects ate a self-selected breakfast and 3 and 5 hours after eating it.
Results: LDL-C values determined 3 and 5 hours following breakfast were approximately 7% and 2.5% lower, respectively, than fasting values. Use of 3-hour and 5-hour LDL-C determinations to classify individuals with elevated fasting levels (> or = 3.36 mmol/L) resulted in false-negative rates of 20% and 14%, respectively. Three- and 5-hour HDL-C values were approximately 4% and 1.5% lower, respectively, than fasting levels. Use of 3-hour HDL-C values to classify individuals with low fasting levels (< 0.91 mmol/L) resulted in no false-negatives, whereas 1 of 7 individuals with low fasting HDL-C was misclassified when 5-hour values were used.
Conclusions: These results support the 1993 National Cholesterol Education Program guidelines that LDL-C levels should be determined only in fasting persons, and that nonfasting HDL-C values may be acceptable for screening purposes.