Cited by 188Genetic Associations and EpidemiologyAdvanced Causal Inference TechniquesStatistical Methods in Epidemiology

Powerful three-sample genome-wide design and robust statistical inference in summary-data Mendelian randomization.

Zhao, Qingyuan, Chen, Yang, Wang, Jingshu, Small, Dylan S·2019·International Journal of Epidemiology

Abstract

BACKGROUND: Summary-data Mendelian randomization (MR) has become a popular research design to estimate the causal effect of risk exposures. With the sample size of GWAS continuing to increase, it is now possible to use genetic instruments that are only weakly associated with the exposure. DEVELOPMENT: We propose a three-sample genome-wide design where typically 1000 independent genetic instruments across the whole genome are used. We develop an empirical partially Bayes statistical analysis approach where instruments are weighted according to their strength; thus weak instruments bring less variation to the estimator. The estimator is highly efficient with many weak genetic instruments and is robust to balanced and/or sparse pleiotropy. APPLICATION: We apply our method to estimate the causal effect of body mass index (BMI) and major blood lipids on cardiovascular disease outcomes, and obtain substantially shorter confidence intervals (CIs). In particular, the estimated causal odds ratio of BMI on ischaemic stroke is 1.19 (95% CI: 1.07-1.32, P-value <0.001); the estimated causal odds ratio of high-density lipoprotein cholesterol (HDL-C) on coronary artery disease (CAD) is 0.78 (95% CI: 0.73-0.84, P-value <0.001). However, the estimated effect of HDL-C attenuates and become statistically non-significant when we only use strong instruments. CONCLUSIONS: A genome-wide design can greatly improve the statistical power of MR studies. Robust statistical methods may alleviate but not solve the problem of horizontal pleiotropy. Our empirical results suggest that the relationship between HDL-C and CAD is heterogeneous, and it may be too soon to completely dismiss the HDL hypothesis.

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Crossref · 10.1093/ije/dyz142

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  • Various statistical methods have been proposed to reduce weak instrument bias due to sample overlap and bias due to winner's curse.

    “Various statistical methods have been proposed to reduce weak instrument bias due to sample overlap and bias due to winner’s curse (see Section 3) 43– 45 .”

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Authors
Zhao, Q., Chen, Y., Wang, J., & Small, D. S.
Affiliations
  • University of Pennsylvania (US)
  • University of Michigan (US)
Corresponding author
Zhao, Qingyuan
Venue
International Journal of Epidemiology
Published
2019-07-11
Volume
48
Issue
5
Pages
1478-1492
ISSN
  • 0300-5771 (ISSN-L)
  • 1464-3685
OpenAlex
W2956730167
Cited by
188
References
67
Citations by year
2026: 10 · 2025: 26 · 2024: 35 · 2023: 51 · 2022: 33 · 2021: 20 · 2020: 9 · 2019: 4
FWCI
9.91
Type
journal article
Language
en
Open access
closed
Locations
  • International Journal of Epidemiology (publishedVersion)
  • PubMed (publishedVersion)
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
pleiotropy, statistical power, body mass index, cardiovascular disease, ischemic stroke, HDL cholesterol, coronary artery disease, serum lipids, causal inference
MeSH terms
Bayes Theorem, Coronary Artery Disease, Humans, Lipids, Cholesterol, HDL, Cholesterol, LDL, Myocardial Infarction, Models, Statistical, Body Mass Index, Odds Ratio, Stroke, Genome-Wide Association Study, Mendelian Randomization Analysis

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