Cited by 1,389Genetic Associations and EpidemiologyAdvanced Causal Inference TechniquesStatistical Methods in Epidemiology

Efficient design for Mendelian randomization studies: subsample and 2-sample instrumental variable estimators.

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Pierce, B. L., Burgess, S.·2013·American Journal of Epidemiology

Abstract

Mendelian randomization (MR) is a method for estimating the causal relationship between an exposure and an outcome using a genetic factor as an instrumental variable (IV) for the exposure. In the traditional MR setting, data on the IV, exposure, and outcome are available for all participants. However, obtaining complete exposure data may be difficult in some settings, due to high measurement costs or lack of appropriate biospecimens. We used simulated data sets to assess statistical power and bias for MR when exposure data are available for a subset (or an independent set) of participants. We show that obtaining exposure data for a subset of participants is a cost-efficient strategy, often having negligible effects on power in comparison with a traditional complete-data analysis. The size of the subset needed to achieve maximum power depends on IV strength, and maximum power is approximately equal to the power of traditional IV estimators. Weak IVs are shown to lead to bias towards the null when the subsample is small and towards the confounded association when the subset is relatively large. Various approaches for confidence interval calculation are considered. These results have important implications for reducing the costs and increasing the feasibility of MR studies.

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  • Several large consortia have made summarized genetic association estimates publicly available for millions of variants.

    “Several large consortia have made such estimates publicly available for millions of variants 30, 35, 36 .”

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  1. [12]Buonaccorsi J Armitage P Colton T Fieller's theorem Encyclopedia of Biostatistics 2005 Chichester, United Kingdom John Wiley & Sons Ltd 1951 1952

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Authors
Pierce, B. L., & Burgess, S.
Affiliations
University of Chicago (US)
Corresponding author
Pierce, B. L.
Venue
American Journal of Epidemiology
Published
2013-07-17
Volume
178
Issue
7
Pages
1177-1184
ISSN
  • 0002-9262 (ISSN-L)
  • 1476-6256
OpenAlex
W2151872224
Cited by
1,389
References
18
Citations by year
2026: 90 · 2025: 221 · 2024: 378 · 2023: 204 · 2022: 123 · 2021: 121 · 2020: 64 · 2019: 44 · 2018: 57 · 2017: 22 · 2016: 38 · 2015: 15 · 2014: 10 · 2013: 1
FWCI
14.14
Type
journal article
Language
en
Open access
Licence
cc-by-nc
Locations
  • American Journal of Epidemiology (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
Funders
  • U.S. Department of Defense (W81XWH)
  • Wellcome Trust (100114)
  • National Institute for Health and Care Research (NF-SI-0512-10165)
  • British Heart Foundation (SP/08/007/23628, RG/08/014/24067)
  • National Institutes of Health (W81XWH, CA014599)
  • Directorate for Biological Sciences
  • Medical Research Council (MR/L003120/1)
  • National Cancer Institute (P30CA014599)
  • National Institute of Environmental Health Sciences (R01 ES02050)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
Keywords
Mendelian randomization, instrumental variable estimation, subsampling, statistical power, estimation bias, weak instruments, confounding, confidence interval estimation
MeSH terms
Computer Simulation, Humans, Sample Size, Mendelian Randomization Analysis

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