After performing each meta-analysis, we again calculated a lambda factor based on the distribution of overall test statistics, i.e. from β-estimates and SE based on the fixed effect method or on the Z-score from the weighted Z-score method. The overall lambda factors in the mixed-gender analysis were λGC_WC = 1.09 and λGC_WHR = 1.07 for the waist phenotypes. GC correction based on these overall lambda factors was then also applied (overall GC correction). We also found it informative to calculate λGC_1000, which is an adjusted inflation factor for an equivalent study of 1,000 cases and 1,000 controls which can be calculated by rescaling λGC as previously described [19]. The results for the mixed-gender analysis for these adjusted inflation factors were λGC_WC_1000 = 1.003 and λGC_WHR_1000 = 1.002 for the two waist phenotypes.
