The primary analysis approach for all three arms of our investigation was a meta-analysis of odds ratios using a consistently coded reference allele across the three studies in our largest ethnic sample, the subjects of European ancestry. This strategy maximized power to detect robust association while recognizing the potential impact of differences in ascertainment protocols and environmental differences among the studies. The analysis of the African American samples explored the consistency of signals in a distinct ancestral group. Finally, we conducted meta-analyses of the 6 ancestry-by-study strata to evaluate evidence for or against a consistent association across ancestral groups.
