Group Identification and Variable Selection in Multivariable Mendelian Randomization with Highly-Correlated Exposures

Fuente: arXiv
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Autores principales: Wu, Yinxiang, Davies, Neil M., Ye, Ting
Formato: Preprint
Publicado: 2025
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author Wu, Yinxiang
Davies, Neil M.
Ye, Ting
author_facet Wu, Yinxiang
Davies, Neil M.
Ye, Ting
contents Multivariable Mendelian Randomization (MVMR) estimates the direct causal effects of multiple risk factors on an outcome using genetic variants as instruments. The growing availability of summary-level genetic data has created opportunities to apply MVMR in high-dimensional settings with many strongly correlated candidate risk factors. However, existing methods face three major limitations: weak instrument bias, limited interpretability, and the absence of valid post-selection inference. Here we introduce MVMR-PACS, a method that identifies signal-groups -- sets of causal risk factors with high genetic correlation or indistinguishable causal effects -- and estimates the direct effect of each group. MVMR-PACS minimizes a debiased objective function that reduces weak instrument bias while yielding interpretable estimates with theoretical guarantees for variable selection. We adapt a data-thinning strategy to summary-data MVMR to enable valid post-selection inference. In simulations, MVMR-PACS outperforms existing approaches in both estimation accuracy and variable selection. When applied to 27 lipoprotein subfraction traits and coronary artery disease risk, MVMR-PACS identifies biologically meaningful and robust signal-groups with interpretable direct causal effects.
format Preprint
id arxiv_https___arxiv_org_abs_2511_12375
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Group Identification and Variable Selection in Multivariable Mendelian Randomization with Highly-Correlated Exposures
Wu, Yinxiang
Davies, Neil M.
Ye, Ting
Methodology
Applications
Multivariable Mendelian Randomization (MVMR) estimates the direct causal effects of multiple risk factors on an outcome using genetic variants as instruments. The growing availability of summary-level genetic data has created opportunities to apply MVMR in high-dimensional settings with many strongly correlated candidate risk factors. However, existing methods face three major limitations: weak instrument bias, limited interpretability, and the absence of valid post-selection inference. Here we introduce MVMR-PACS, a method that identifies signal-groups -- sets of causal risk factors with high genetic correlation or indistinguishable causal effects -- and estimates the direct effect of each group. MVMR-PACS minimizes a debiased objective function that reduces weak instrument bias while yielding interpretable estimates with theoretical guarantees for variable selection. We adapt a data-thinning strategy to summary-data MVMR to enable valid post-selection inference. In simulations, MVMR-PACS outperforms existing approaches in both estimation accuracy and variable selection. When applied to 27 lipoprotein subfraction traits and coronary artery disease risk, MVMR-PACS identifies biologically meaningful and robust signal-groups with interpretable direct causal effects.
title Group Identification and Variable Selection in Multivariable Mendelian Randomization with Highly-Correlated Exposures
topic Methodology
Applications
url https://arxiv.org/abs/2511.12375