Cited by 19Advanced Causal Inference TechniquesGenetic Associations and EpidemiologyStatistical Methods in Epidemiology

Application of the Instrumental Inequalities to a Mendelian Randomization Study With Multiple Proposed Instruments

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Diemer, Elizabeth W., Labrecque, Jeremy, Tiemeier, Henning, Swanson, Sonja A.·2020·Epidemiology

Abstract

Background: Investigators often support the validity of Mendelian randomization (MR) studies, an instrumental variable approach proposing genetic variants as instruments, via. subject matter knowledge. However, the instrumental variable model implies certain inequalities, offering an empirical method of falsifying (but not verifying) the underlying assumptions. Although these inequalities are said to detect only extreme assumption violations in practice, to our knowledge they have not been used in settings with multiple proposed instruments. Methods: We applied the instrumental inequalities to an MR analysis of the effect of maternal pregnancy vitamin D on offspring psychiatric outcomes, proposing four independent maternal genetic variants as instruments. We assessed whether the proposed instruments satisfied the instrumental inequalities separately and jointly and explored the instrumental inequalities’ properties via simulations. Results: The instrumental inequalities were satisfied (i.e., we did not falsify the MR model) when considering each variant separately. However, the inequalities were violated when considering four variants jointly and for some combinations of two or three variants (two of 36 two-variant combinations and 18 of 24 three-variant combinations). In simulations, the inequalities detected structural biases more often when assessing proposed instruments jointly, although falsification in the absence of structural bias remained rare. Conclusions: The instrumental inequalities detected violations of the MR assumptions for genetic variants jointly proposed as instruments in our study, although the instrumental inequalities were satisfied when considering each proposed instrument separately. We discuss how investigators can assess instrumental inequalities to eliminate clearly invalid analyses in settings with many proposed instruments and provide appropriate code.

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  • One further method for identifying potential violations of the IV conditions when the exposure is binary or categorical is using IV inequality constraints.

    “One further method for identifying potential violations of the IV conditions when the exposure is binary or categorical is using IV inequality constraints.29,67,68”

    From Mendelian randomization (2022) · cites this paper as [67]

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Research works printed but not linked: 4

  1. [10]Tchetgen EJT Sun B Walter S The GENIUS approach to robust Mendelian randomization inference. 2017 arXiv preprint arXiv:1709.07779. · arXiv
  2. [14]Pearl J On the testability of causal models with latent and instrumental variables. In: Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence August 18–20, 1995 San Francisco, CA: Morgan Kaufmann Publishers Inc.
  3. [15]Bonet B Instrumentality tests revisited. In: Proceedings of the Seventeenth Conference on Uncertainty in Artificial Intelligence August 2–5, 2001 San Francisco, CA: Morgan Kaufmann Publishers Inc.
  4. [31]Ross AC Taylor CL Yaktine AL; Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. Dietary Reference Intakes for Calcium and Vitamin D. 2011 Washington, DC: The National Academies Press. 21796828

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Authors
Diemer, E. W., Labrecque, J., Tiemeier, H., & Swanson, S. A.
Affiliations
  • Erasmus MC (NL)
  • Harvard University (US)
Corresponding author
Diemer, Elizabeth W.
Venue
Epidemiology
Published
2020-01
Volume
31
Issue
1
Pages
65-74
ISSN
1044-3983 (ISSN-L)
OpenAlex
W2980988155
Cited by
19
References
40
Citations by year
2024: 3 · 2023: 7 · 2022: 5 · 2021: 3 · 2020: 1
FWCI
1.76
Type
journal article
Language
en
Open access
Locations
  • Epidemiology (publishedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • EUR Research Repository (Erasmus University Rotterdam) (publishedVersion)
  • EUR Research Repository (Erasmus University Rotterdam) (submittedVersion)
  • RePub (Erasmus University Rotterdam) (submittedVersion, other-oa)
Funders
ZonMw (91617066)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
Keywords
Mendelian randomization, multiple instruments, assessment validity, structural bias, maternal vitamin D, genetic variants, simulation study
MeSH terms
Humans, Bias, Mendelian Randomization Analysis

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