Population Stratification in a Case-Control Study of Brain Arteriovenous Malformation in Latinos
Year: 2008
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Genetic association studies conducted in admixed populations may be confounded by population stratification resulting in spurious associations. The purpose of this pilot study was to determine the presence and effect of population stratification in a case-control study of brain arteriovenous malformation (BAVM). METHODS: We tested 83 ancestry informative markers in BAVM cases and healthy controls of self-reported Latino race/ethnicity (n = 294). Individual ancestry estimates (IAE) were obtained using the Structure program, assuming 3 underlying subpopulations. Summary chi(2) tests comparing genotype frequency of ancestry informative markers were used to detect stratification and IAE were included as covariates in logistic regression analysis to account for differences in genetic background. RESULTS: Admixture estimates for Latinos (overall 47% native American, 45% European and 8% African ancestry) revealed heterogeneity between individuals within ancestral groups. The summary chi(2) test was significant (p = 0.005), suggesting ancestral differences between cases and controls. Furthermore, genetic ancestry was associated with frequency differences in a promoter variant in the IL-6 gene (IL-6 -174G>C). On average, subjects with the IL6 -174 GG genotype had 6% greater Native American ancestry (p = 0.023). Age- and sex-adjusted risk of BAVM associated with the IL-6 -174 GG genotype was 1.85 (95% CI 0.99-3.48, p = 0.055), and further adjustments for IAE yielded an OR of 1.96 (95% CI 1.03-3.72, p = 0.039). CONCLUSION: The IL-6 -174G>C polymorphism was associated with increased risk of BAVM among Latinos after accounting for differences in ancestral background. These results suggest subtle, negative confounding and illustrate the importance of addressing population stratification in case-control studies conducted in admixed populations.
Source: Neuroepidemiology
DOI: 10.1159/000160215
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: bronze
Funders: American Heart Association, National Institutes of Health, National Heart, Lung, and Blood Institute, National Institute of General Medical Sciences, National Institute of Neurological Disorders and Stroke, National Center on Minority Health and Health Disparities, National Institute on Minority Health and Health Disparities
Awards: G1208189138, Upstream Regulators of the prothrombotic state, Genetic influences on clinical outcome in brain arteriovenous malformations, G3950177779, Pharmacogenomics of Membrane Transporters, G738716470, Case-control Association Studies and Genetic Confounding, Pharmacogenetics of Membrane Transporters, Predictors of spontaneous cerebral AVM hemorrhage, G9000267065
OpenAlex ID: W2135431987