Comparison of Postprandial Serum Triglyceride and Apolipoprotein B Concentrations between the Two Phases of Menstrual Cycle in Healthy Women

Abstract

Background: Sex hormones influence lipoprotein metabolism; whether the hormonal fluctuation during normal menstrual cycle has impact on non-fasting lipids remains unclear. Objective: To examine the differences in postprandial triglyceride, apolipoprotein B (ApoB) and nonhigh density lipoprotein cholesterol (non-HDL-C) concentrations using a standardized fat tolerance test during the 2 menstrual cycle phases. Methods: We enrolled 25 healthy, menstruating women. Each of them underwent a fat tolerance test during the 2 phases of the menstrual cycle. Blood samples were collected at baseline and up to 6 h postprandially. Differences in serum triglycerides, ApoB and non-HDL-C between the 2 phases were assessed. The incremental area under the curve (iAUC) was calculated. Reproducibility of the measurements was tested using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). Results: Serum triglyceride concentrations increased postprandially in both phases and the values were higher during the follicular compared with the luteal phase; however, the overall triglyceride response expressed as iAUC [median value (interquartile range)] did not differ between the follicular and the luteal phase [54.0 (-26.5, 107.0) and 48.0 (6.0, 114.5) mg x h/dl, respectively, p=0.64]. Serum ApoB concentrations did not increase postprandially and the overall ApoB response was not different between the 2 phases. Non-HDL-C concentrations changed postprandially, but the overall response was not different between the 2 phases of the menstrual cycle. Reproducibility of the measurements was moderate: ICC 0.689-0.848 for triglycerides, 0.721-0.771 for ApoB, 0.457-0.867 for non-HDL-C, and %CV >8 for all parameters. Conclusion: Serum triglyceride levels were higher during the follicular compared with the luteal phase after standardized meal consumption, but the overall postprandial triglyceride response did not differ between the 2 phases. Postprandial ApoB and non-HDL-C serum concentrations were not affected by the menstrual cycle.