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Gene-Environment Correlation: Difficulties and a Natural Experiment-Based Strategy


Wagner, Brandon; Li, Jiang; Liu, Hexuan; & Guo, Guang (2013). Gene-Environment Correlation: Difficulties and a Natural Experiment-Based Strategy. American Journal of Public Health, 103(S1), S167-173. PMCID: PMC3778033


Objectives: We explored how gene-environment correlations can result in endogenous models, how natural experiments can protect against this threat, and if unbiased estimates from natural experiments are generalizable to other contexts.
Methods: We compared a natural experiment, the College Roommate Study, which measured genes and behaviors of college students and their randomly assigned roommates in a southern public university, with observational data from the National Longitudinal Study of Adolescent Health in 2008. We predicted exposure to exercising peers using genetic markers and estimated environmental effects on alcohol consumption. A mixed-linear model estimated an alcohol consumption variance that was attributable to genetic markers and across peer environments.
Results: Peer exercise environment was associated with respondent genotype in observational data, but not in the natural experiment. The effects of peer drinking and presence of a general gene-environment interaction were similar between data sets.
Conclusions: Natural experiments, like random roommate assignment, could protect against potential bias introduced by gene-environment correlations. When combined with representative observational data, unbiased and generalizable causal effects could be estimated.


Reference Type

Journal Article

Year Published


Journal Title

American Journal of Public Health


Wagner, Brandon
Li, Jiang
Liu, Hexuan
Guo, Guang