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

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 post-prandially. 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.

Automated summary

The study showed that serum triglyceride levels were higher during the follicular compared with the luteal phase in women after a standardized fat tolerance test, but the overall postprandial triglyceride response did not differ significantly between the two phases. Postprandial ApoB and non-HDL-C serum concentrations were not affected by the menstrual cycle.