Skip Navigation



IJE Advance Access published online on March 11, 2004
International Journal of Epidemiology, doi:10.1093/ije/dyh057
© 2004 by International Epidemiological Association
This Article
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
33/3/534    most recent
dyh057v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Pereira, M. A.
Right arrow Articles by Katan, M. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pereira, M. A.
Right arrow Articles by Katan, M. B.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Accepted October 22, 2003

Original paper

Within-person variation in serum lipids: implications for clinical trials

Mark A. Pereira 1*, Rianne M. Weggemans 2, David R. Jacobs Jr3, Peter J. Hanan 1, Peter L. Zock 4, Jose M. Ordovas 5, Martijn B. Katan 4

1 University of Minnesota, School of Public Health, Division of Epidemiology, Minneapolis, MN, USA
2 Unilever Health Institute, Unilever Research & Development, Vlaardingen, The Netherlands
3 University of Minnesota, School of Public Health, Division of Epidemiology, Minneapolis, MN, USA; Institute for Nutrition Research, University of Oslo, Oslo, Norway
4 Wageningen University, Division of Human Nutrition and Epidemiology, Wageningen, The Netherlands; Wageningen Centre for Food Sciences, Wageningen, The Netherlands
5 USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA

* To whom correspondence should be addressed. E-mail: pereira{at}epi.umn.edu.


  Abstract

Background Little is known about the degree to which behavioural, biological, and genetic traits contribute to within-person variation in serum cholesterol.

Materials and Methods The authors studied within-person variation in serum total and high density lipoprotein (HDL) cholesterol in 458 participants of 27 dietary intervention studies in Wageningen, The Netherlands, from 1976 to 1995.

Results For a median of 4 days between blood draws, the geometric mean of the within-person standard deviation was 0.13 mmol/l (~5 mg/dl, coefficient of variation = 3.0%) for total cholesterol and 0.04 mmol/l (~1.5 mg/dl, coefficient of variation = 3.0%) for HDL cholesterol. In mixed-model linear regressions using within-person variance as the dependent variable and including lipid concentration and covariaties listed below, within-person variance of both total cholesterol and HDL cholesterol was higher for greater number of days between blood draws and for self-selected diet rather than investigator-controlled diet. Within-person variance of total cholesterol only was higher for non-standardized versus standardized phlebotomy protocol and for female sex. The authors found evidence that the APOA4 -347 (12/22 genotype) and MTP -493 (11 genotype) polymorphisms may increase the within-person variation in total cholesterol.

Conclusion Under certain study design (self-selected diet, use of non-standardized phlebotomy protocol) or participant characteristics (female, certain polymorphisms) within-person lipid variance is increased and required sample size will be greater. These findings may have important implications for the time and cost of such interventions.

Keywords Cholesterol, data interpretation, diet, lipoproteins, periodicity, randomized controlled trials


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 ANN INTERN MEDHome page
P. P. Glasziou, L. Irwig, S. Heritier, R. J. Simes, A. Tonkin, and for the LIPID Study Investigators
Monitoring Cholesterol Levels: Measurement Error or True Change?
Ann Intern Med, May 6, 2008; 148(9): 656 - 661.
[Abstract] [Full Text] [PDF]

Home page
 Int J EpidemiolHome page
G. D. Smith
Classics in epidemiology: should they get it right?
Int. J. Epidemiol., June 1, 2004; 33(3): 441 - 442.
[Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.