Testing for the indirect effect under the null for genome-wide mediation analyses.

TitleTesting for the indirect effect under the null for genome-wide mediation analyses.
Publication TypeJournal Article
Year of Publication2017
AuthorsBarfield, R, Shen, J, Just, AC, Vokonas, PS, Schwartz, J, Baccarelli, AA, VanderWeele, TJ, Lin, X
JournalGenet Epidemiol
Volume41
Issue8
Pagination824-833
Date Published2017 12
ISSN1098-2272
KeywordsBasic Helix-Loop-Helix Transcription Factors, DNA Methylation, Epigenomics, Genome-Wide Association Study, Humans, Lung Neoplasms, Models, Genetic, Repressor Proteins
Abstract

Mediation analysis helps researchers assess whether part or all of an exposure's effect on an outcome is due to an intermediate variable. The indirect effect can help in designing interventions on the mediator as opposed to the exposure and better understanding the outcome's mechanisms. Mediation analysis has seen increased use in genome-wide epidemiological studies to test for an exposure of interest being mediated through a genomic measure such as gene expression or DNA methylation (DNAm). Testing for the indirect effect is challenged by the fact that the null hypothesis is composite. We examined the performance of commonly used mediation testing methods for the indirect effect in genome-wide mediation studies. When there is no association between the exposure and the mediator and no association between the mediator and the outcome, we show that these common tests are overly conservative. This is a case that will arise frequently in genome-wide mediation studies. Caution is hence needed when applying the commonly used mediation tests in genome-wide mediation studies. We evaluated the performance of these methods using simulation studies, and performed an epigenome-wide mediation association study in the Normative Aging Study, analyzing DNAm as a mediator of the effect of pack-years on FEV .

DOI10.1002/gepi.22084
Alternate JournalGenet Epidemiol
PubMed ID29082545
PubMed Central IDPMC5696067
Grant ListR01 ES015172 / ES / NIEHS NIH HHS / United States
R35 CA197449 / CA / NCI NIH HHS / United States
R01 ES025225 / ES / NIEHS NIH HHS / United States
U19 CA203654 / CA / NCI NIH HHS / United States
T32 ES007142 / ES / NIEHS NIH HHS / United States
R01 ES021733 / ES / NIEHS NIH HHS / United States
R01 HL113338 / HL / NHLBI NIH HHS / United States
T32 GM074897 / GM / NIGMS NIH HHS / United States
P01 CA134294 / CA / NCI NIH HHS / United States
U01 HG009088 / HG / NHGRI NIH HHS / United States
R01 ES017876 / ES / NIEHS NIH HHS / United States