We further examined sex differences in heritability in different subsets of the data: the PGC2 data without the UK Biobank (referred to as PGC1.5) and the UK Biobank (UKB) by itself, which comprises a large proportion of PGC2. Similar to the overall PGC2, heritability in PGC1.5 was high in women and not significant in men. In contrast, in the UKB, male heritability was significant (h2SNP = 0.15, P = 1.38 × 10−3) and not significantly different (z = 0.23, P = 0.41) from heritability in women (h2SNP = 0.19, P = 2 × 10−10). Sensitivity analyses in UKB using different case and control definitions further confirm these results (Supplementary Table 1 and Supplementary Note 1).
