I would like to invite you to the following seminar. Please pass the message on to your colleagues and friends. Research Seminar Div. of Biostatistics & Epidemiology Dept. of Public Health Weill Cornell Medical College, New York, NY Title: Identifying SNPs for the Secondary Phenotypes in GWA studies: Application to Smoking Behavior Speaker: Sanjay Shete, PhD Affiliation: Professor Dept of Biostatistics, Dept. of Epidemiology. The University of Texas MD Anderson Cancer Center, Houston When: Friday, May 18, 2012 12:00 - 1:00 PM Where: Department of Public Health's Conference Center A 402 East 67th Street, Level C1 Abstract: Genetic association studies for binary diseases are designed as case-control studies: the cases are those affected with the primary disease and the controls are free of the disease. At the time of case-control collection, information about secondary phenotypes is also collected (e.g. smoking intensity on lung cancer case-control study). Association studies of secondary phenotype and genetic variants have received a great deal of interest recently. To study the secondary phenotypes, investigators are using standard regression approaches, such as logistic regression, where individuals with secondary phenotypes are coded as cases and those without secondary phenotypes are coded as controls. However, using the secondary phenotype as an outcome variable in a case-control study might lead to a biased estimate of odds ratios (ORs) for genetic variants. This is because the secondary phenotype is associated with the primary disease of interest; therefore, individuals with (case subject) and without (control subject) the secondary phenotype are not sampled following the principle of a case-control study design. We demonstrate that such analyses will lead to a biased estimate of OR, and the magnitude of the bias depends on the prevalence values of both the primary disease and the secondary phenotype. We propose new approaches to provide a more accurate OR estimate of genetic variants associated with the secondary phenotype for both un-matched and frequency-matched (with respect to the secondary phenotype of interest) case-control association studies. The proposed methods account for the prevalence values of the primary disease and secondary phenotype. The performance of our approach was demonstrated via simulation studies as well as a real data analysis. Applying our new method to smoking intensity as a secondary phenotype reduced the bias in odds ratio estimation for a single-nucleotide polymorphism in CHRNA5-A3 locus. Need more info? Contact: Gaza @ (646) 962-8024 or [log in to unmask]<http:[log in to unmask]> Samprit Banerjee, PhD Assistant Professor, Div. of Biostatistics & Epidemiology, Dept. of Public Health Weill Medical College, Cornell University 402 E 67th Street, LA233 New York, NY-10065 Phone: (646) 962-8014 (1-8014, Internal) Fax: (646) 962-0281 http://www.weill.cornell.edu/public.health <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> If you wish to unsubscribe from the NFS-L List, please send an E-mail to: "[log in to unmask]". Within the body of the text, only write the following:"SIGNOFF NFS-L".