On Combining Family and Case-Control Studies

• Activity Number: 12
• Type: Topic Contributed
• Date/Time: Sunday, August 1, 2010 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Ruth Pfeiffer*+
• Companies: National Cancer Institute
• Keywords: Ascertainment ; Nested random effects model ; Stratified sampling

Abstract

I propose two approaches to combine a case-control study and a family study that collected families with multiple cases to detect disease associations. First, I view a family as the sampling unit and specify the joint likelihood for the family members using a two-level mixed effects model to account for correlations among family members. The family likelihood is conditioned on the ascertainment event. The individuals in the case-control study are viewed as families of size one; their unconditional likelihood is combined with the conditional likelihood for the families. Subject specific maximum likelihood estimates of covariate effects are obtained. In the second approach an individual is the sampling unit. The sampling scheme is accommodated using two-phase sampling techniques, marginal covariate effects are estimated; correlations among family members are accounted for in the variance.