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Within-person variation in serum lipids: implications for clinical trials
Mark A Pereira1, Rianne M Weggemans, David R Jacobs
1University of Minnesota, School of Public Health, Division of Epidemiology, Minneapolis, MN 55454, USA. pereira@epiumn.umn.edu
International Journal of Epidemiology
|March 17, 2004
Summary
Study reveals that factors like diet, blood draw timing, and genetics significantly impact cholesterol level variability. Understanding these factors is crucial for accurate intervention studies and sample size calculations.
Area of Science:
- Lipid Metabolism and Cardiovascular Health
- Human Genetics and Personalized Medicine
- Nutritional Epidemiology
Background:
- Limited understanding of factors influencing within-person variability in serum cholesterol levels.
- Behavioral, biological, and genetic traits are suspected contributors to cholesterol fluctuations.
- Investigating these variations is key for accurate health assessments.
Purpose of the Study:
- To quantify within-person variation in serum total and high-density lipoprotein (HDL) cholesterol.
- To identify study design and participant characteristics associated with increased lipid variability.
- To inform the design and interpretation of dietary intervention studies.
Main Methods:
- Analysis of serum total and HDL cholesterol from 458 participants across 27 dietary intervention studies.
- Utilized mixed-model linear regressions to assess within-person variance.
- Examined effects of time between blood draws, diet control, phlebotomy standardization, sex, and genetic polymorphisms (APOA4, MTP).
Main Results:
- Median within-person coefficient of variation was 3.0% for both total and HDL cholesterol.
- Increased lipid variance correlated with longer intervals between blood draws and self-selected diets.
- Female sex, non-standardized phlebotomy, and specific APOA4/MTP genotypes were associated with higher total cholesterol variance.
Conclusions:
- Study design choices (e.g., diet control, phlebotomy standardization) and participant characteristics (sex, genetics) significantly influence within-person lipid variability.
- Increased variability necessitates larger sample sizes and impacts the time and cost efficiency of intervention studies.
- Findings highlight the importance of considering individual variability in cholesterol levels for research and clinical practice.