Integrating epidemiology and genetic association: the challenge of gene–environment interaction

• Published in: Philosophical transactions of the Royal Society of London. Series B. Biological sciences Vol. 360; no. 1460; pp. 1609 - 1616
• Main Authors: Kraft, Peter, Hunter, David
• Format: Journal Article
• Language: English
• Published: London The Royal Society 29.08.2005
• Subjects: Biological markers; Case control studies; Disease risk; Environmental disorders; Environmental Exposure; Epidemiology; Gene-Environment Interaction; Genes - genetics; Genetic diseases; Genetic Epidemiology; Genetic Predisposition to Disease; Genetic Variation; Genetics, Medical - methods; Genetics, Medical - trends; Genotypes; Human genetics; Humans; Medical genetics; Mendelian Randomization; Molecular Epidemiology - methods; Molecular Epidemiology - trends; Phenotypic traits; Research Design; Risk Factors; Study Design
• ISSN: 0962-8436; 1471-2970
• DOI: 10.1098/rstb.2005.1692

Recent advances in human genomics have made it possible to better understand the genetic basis of disease. In addition, genetic association studies can also elucidate the mechanisms by which 'non-genetic' exogenous and endogenous exposures influence the risk of disease. This is true both of studies that assess the marginal effect of a single gene and studies that look at the joint effect of genes and environmental exposures. For example, gene variants that are known to alter enzyme function or level can serve as surrogates for long-term biomarker levels that are impractical or impossible to measure on many subjects. Evidence that genetic variants modify the effect of an established risk factor may help specify the risk factor's biologically active components. We illustrate these ideas with several examples and discuss design and analysis challenges, particularly for studies of gene-environment interaction. We argue that to increase the power to detect interaction effects and limit the number of false positive results, large sample sizes will be needed, which are currently only available through planned collaborative efforts. Such collaborations also ensure a common approach to measuring variation at a genetic locus, avoiding a problem that has led to difficulties when comparing results from genetic association studies.