Postprandial hyperlipidemia: another correlate of the "hypertriglyceridemic waist" phenotype in men

Fasting hypertriglyceridemia has been reported to be predictive of an exaggerated triglyceride (TG) response to an oral fat load. Abdominal obesity has also been associated with postprandial hyperlipidemia. The objective of the present study was to quantify the contribution of abdominal obesity and fasting hypertriglyceridemia to the magnitude of postprandial lipemia. For that purpose, potential differences in postprandial TG-rich lipoprotein (TRL) levels were examined among men characterized by the absence/presence of the "hypertriglyceridemic waist" phenotype following a standardized breakfast with a high fat content (64% calories as fat). Sixty-nine men (mean age +/- S.D.: 45.1 +/- 10.5 years) were classified according to waist girth (< 90 or >/ or = 90 cm) and fasting TG concentrations (< 2.0 or > or = 2.0 mmol/l). Subjects characterized by "hypertriglyceridemic waist" (waist > or = 90 cm and fasting TG > or = 2.0 mmol/l) showed the highest TRL-TG concentrations (P < 0.0001) throughout the entire postprandial period (8 h) as well as elevated concentrations of apolipoprotein (apo) B-48 and apo B-100 in all TRL fractions (large, medium and small) compared to subjects with low fasting TG levels who had waist girth values either above or below 90 cm. These higher postprandial TRL-TG levels among carriers of the "hypertriglyceridemic waist" phenotype also led to significantly greater postprandial TG-total area under the curve (AUC) in total TRLs resulting mainly from the increased concentrations of large- and medium-sized TRLs. Furthermore, subjects characterized by the "hypertriglyceridemic waist" phenotype displayed higher fasting insulin concentrations and postprandial insulin AUC compared to men with low fasting plasma TG levels and low waist girth values. In conclusion, results of the present study indicate that postprandial hyperlipidemia is associated with the simultaneous presence of abdominal obesity and elevated fasting TG concentrations: a condition that we have described as the "hypertriglyceridemic waist" phenotype.