Selecting controls is not selecting "normals": Design and analysis issues for studying the etiology of polycystic ovary syndrome

Michael S. Bloom, Enrique F. Schisterman, Mary L. Hediger

Research output: Contribution to journalArticle

Abstract

Introduction: Polycystic ovary syndrome (PCOS) is a highly prevalent disorder among postmenarcheal premenopausal women, accounting for much of anovulatory infertility, and it is associated with several comorbidities. The natural history of PCOS, as well as hypotheses regarding its etiology, facilitates employment of the case-control study design. However, a review of the literature suggested that inconsistency of research findings in relation to the etiology of PCOS might be, in part, due to the different choice of controls for case-control design and application. Design: Investigators have often employed "healthy" control groups and neglected to consider the tenability of the "rare disease" assumption in the analysis when instituting the case-control strategy. This might result in the introduction of a positive bias or overestimation of odds ratios, producing an effect estimate that is more extreme than that in the underlying population. Using several quantitative, though hypothetical, literature-driven examples, this bias is described and demonstrated. In addition, recommendations are provided with regard to case-sampling strategy when the rare disease assumption is untenable, as it may frequently be in studies of PCOS. Conclusion(s): It is hoped that more consistent case-control methodology, in concert with recent consensus on case definition, will more effectively facilitate the elucidation of the causes and consequences of PCOS.

Original languageEnglish (US)
Pages (from-to)1-12
Number of pages12
JournalFertility and Sterility
Volume86
Issue number1
DOIs
StatePublished - Jul 2006
Externally publishedYes

Fingerprint

Polycystic Ovary Syndrome
Rare Diseases
Infertility
Case-Control Studies
Comorbidity
Odds Ratio
Research Personnel
Control Groups
Research
Population

Keywords

  • Bias
  • case-control study
  • collider stratification
  • methods
  • odds ratio
  • PCOS
  • polycystic ovary syndrome
  • prevalence

ASJC Scopus subject areas

  • Obstetrics and Gynecology

Cite this

Selecting controls is not selecting "normals" : Design and analysis issues for studying the etiology of polycystic ovary syndrome. / Bloom, Michael S.; Schisterman, Enrique F.; Hediger, Mary L.

In: Fertility and Sterility, Vol. 86, No. 1, 07.2006, p. 1-12.

Research output: Contribution to journalArticle

Bloom, Michael S. ; Schisterman, Enrique F. ; Hediger, Mary L. / Selecting controls is not selecting "normals" : Design and analysis issues for studying the etiology of polycystic ovary syndrome. In: Fertility and Sterility. 2006 ; Vol. 86, No. 1. pp. 1-12.
@article{b4dd3225437346f49bda6e666aeeff1e,
title = "Selecting controls is not selecting {"}normals{"}: Design and analysis issues for studying the etiology of polycystic ovary syndrome",
abstract = "Introduction: Polycystic ovary syndrome (PCOS) is a highly prevalent disorder among postmenarcheal premenopausal women, accounting for much of anovulatory infertility, and it is associated with several comorbidities. The natural history of PCOS, as well as hypotheses regarding its etiology, facilitates employment of the case-control study design. However, a review of the literature suggested that inconsistency of research findings in relation to the etiology of PCOS might be, in part, due to the different choice of controls for case-control design and application. Design: Investigators have often employed {"}healthy{"} control groups and neglected to consider the tenability of the {"}rare disease{"} assumption in the analysis when instituting the case-control strategy. This might result in the introduction of a positive bias or overestimation of odds ratios, producing an effect estimate that is more extreme than that in the underlying population. Using several quantitative, though hypothetical, literature-driven examples, this bias is described and demonstrated. In addition, recommendations are provided with regard to case-sampling strategy when the rare disease assumption is untenable, as it may frequently be in studies of PCOS. Conclusion(s): It is hoped that more consistent case-control methodology, in concert with recent consensus on case definition, will more effectively facilitate the elucidation of the causes and consequences of PCOS.",
keywords = "Bias, case-control study, collider stratification, methods, odds ratio, PCOS, polycystic ovary syndrome, prevalence",
author = "Bloom, {Michael S.} and Schisterman, {Enrique F.} and Hediger, {Mary L.}",
year = "2006",
month = "7",
doi = "10.1016/j.fertnstert.2005.09.066",
language = "English (US)",
volume = "86",
pages = "1--12",
journal = "Fertility and Sterility",
issn = "0015-0282",
publisher = "Elsevier Inc.",
number = "1",

}

TY - JOUR

T1 - Selecting controls is not selecting "normals"

T2 - Design and analysis issues for studying the etiology of polycystic ovary syndrome

AU - Bloom, Michael S.

AU - Schisterman, Enrique F.

AU - Hediger, Mary L.

PY - 2006/7

Y1 - 2006/7

N2 - Introduction: Polycystic ovary syndrome (PCOS) is a highly prevalent disorder among postmenarcheal premenopausal women, accounting for much of anovulatory infertility, and it is associated with several comorbidities. The natural history of PCOS, as well as hypotheses regarding its etiology, facilitates employment of the case-control study design. However, a review of the literature suggested that inconsistency of research findings in relation to the etiology of PCOS might be, in part, due to the different choice of controls for case-control design and application. Design: Investigators have often employed "healthy" control groups and neglected to consider the tenability of the "rare disease" assumption in the analysis when instituting the case-control strategy. This might result in the introduction of a positive bias or overestimation of odds ratios, producing an effect estimate that is more extreme than that in the underlying population. Using several quantitative, though hypothetical, literature-driven examples, this bias is described and demonstrated. In addition, recommendations are provided with regard to case-sampling strategy when the rare disease assumption is untenable, as it may frequently be in studies of PCOS. Conclusion(s): It is hoped that more consistent case-control methodology, in concert with recent consensus on case definition, will more effectively facilitate the elucidation of the causes and consequences of PCOS.

AB - Introduction: Polycystic ovary syndrome (PCOS) is a highly prevalent disorder among postmenarcheal premenopausal women, accounting for much of anovulatory infertility, and it is associated with several comorbidities. The natural history of PCOS, as well as hypotheses regarding its etiology, facilitates employment of the case-control study design. However, a review of the literature suggested that inconsistency of research findings in relation to the etiology of PCOS might be, in part, due to the different choice of controls for case-control design and application. Design: Investigators have often employed "healthy" control groups and neglected to consider the tenability of the "rare disease" assumption in the analysis when instituting the case-control strategy. This might result in the introduction of a positive bias or overestimation of odds ratios, producing an effect estimate that is more extreme than that in the underlying population. Using several quantitative, though hypothetical, literature-driven examples, this bias is described and demonstrated. In addition, recommendations are provided with regard to case-sampling strategy when the rare disease assumption is untenable, as it may frequently be in studies of PCOS. Conclusion(s): It is hoped that more consistent case-control methodology, in concert with recent consensus on case definition, will more effectively facilitate the elucidation of the causes and consequences of PCOS.

KW - Bias

KW - case-control study

KW - collider stratification

KW - methods

KW - odds ratio

KW - PCOS

KW - polycystic ovary syndrome

KW - prevalence

UR - http://www.scopus.com/inward/record.url?scp=33745514680&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33745514680&partnerID=8YFLogxK

U2 - 10.1016/j.fertnstert.2005.09.066

DO - 10.1016/j.fertnstert.2005.09.066

M3 - Article

C2 - 16750830

AN - SCOPUS:33745514680

VL - 86

SP - 1

EP - 12

JO - Fertility and Sterility

JF - Fertility and Sterility

SN - 0015-0282

IS - 1

ER -