L. Valeri, S. Reese, Shanshan Zhao, C. Page, W. Nystad, B. Coull, S. London
Epigenomics, 2017
AIMS Assessing whether epigenetic alterations mediate associations between environmental exposures and health outcomes is increasingly popular. We investigate the impact of exposure misclassification in such investigations. MATERIALS & METHODS We quantify bias and false-positive rates due to exposure misclassification in mediation analysis and assess the performance of the simulation extrapolation method (SIMEX). We evaluate whether DNA-methylation mediates smoking-birth weight relationship in the Norwegian Mother and Child Study birth cohort. RESULTS Ignoring exposure misclassification increases type I error in mediation analysis. The direct effect is underestimated and, when the mediator is a biomarker of the exposure, as is true for smoking, the indirect effect is overestimated. CONCLUSION Misclassification correction plus cautious interpretation are recommended for mediation analyses in the presence of exposure misclassification.
Cited by 19 publications.
Field of study: Biology