Table 2 provides details on those SNPs that were genome-wide significant/suggestive (q<0.1/q< 0.2). Figure 1A shows Q-Q plots for meta-analyses. The plots show that the p-values from the GWAS are generally on a straight line, indicating that the p-value distribution generally conforms to the expected null distribution assuming no effects of the markers. However, in both plots, there is also evidence that markers in the right upper corner have p-values smaller than would be expected under the null hypothesis, suggesting true association between these markers and the outcome. The plots also display λ values (i.e., ratio of median observed p-value to the median expected p-value under the null hypothesis) approximately equal to 1 (λ = 0.998 and 1.000), indicating no systematic test statistic inflation and adequate control of population stratification (Supplementary Material 2 for study-specific Q-Q plots). Manhattan plots are provided in Figure 1B, and provide a low-resolution visualization of spatial clustering among association signals. The full set of GWAS p-values considered in this study is available for download at: http://www.pharmacy.vcu.edu/biomarker/resources/supplementary/.
