Affiliations: Departments of Internal Medicine, Epidemiology, and Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA | [x] University of Michigan Medical Center, Ann Arbor, MI 48109-0930, USA | [y] CHS National Cancer Control Center, Department of Community Medicine and Epidemiology, Carmel Medical Center and B. Rappaport Faculty of Medicine, Technion Haifa, Israel
Correspondence:
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Corresponding author: Stephen B. Gruber, MD, PhD, MPH, Division of Molecular Medicine and Genetics, University of Michigan, 4301 MSRB III, Ann Arbor, MI 48109-0638, USA. Tel.: +1 734 615 9712; Fax: +1 734 763 7672; E-mail: [email protected].
Abstract: Population stratification represents the principle that genetic variation differs across populations, and these differences may lead to problematic interpretations of epidemiologic studies when the composition of the study population could lead to unmeasured confounding. Advances in genotyping technology greatly facilitate genetic association studies, yet it is critical to understand the relationship between genotype, haplotype, and functional risk alleles. Insights from extended studies of a chromosomal region can provide perspective into the ancestral heritage of founder populations and risk alleles. Examples from studies of colorectal cancer in Ashkenazi Jewish populations, and studies of smoking behavior in Caucasians of European origin, Mexican-Americans, Japanese and Han Chinese illustrate these principles.
