We confirmed previously reported heritability estimates of MD (h2-SNP = 8.5%, s.e. = 0.003, K = 0.15) and AD (h2-SNP = 9.0%, s.e. = 0.019, K = 0.16), with K defined as the disease prevalence in the population (Walters et al., 2018; Wray et al., 2018). The h2-SNP of AC-frequency, which has not been previously reported, was estimated at 8.0% (s.e. = 0.003). The h2-SNP of AC-quantity using LD-score regression was estimated at 6.9% (s.e. = 0.004), which is lower than the GCTA-estimate reported by Clarke et al. (13%) who analyzed a smaller subset (n = 112 117) (Clarke et al., 2017) from the current data (n = 307 098). The lower estimate may be explained by differential methodology (i.e. LD-score regression v. GCTA) and by the fact that the first release of UK Biobank included a subset of individuals that was selected based on smoking and may be less representative of the general population than the current sample (Wain et al., 2015). These h2-SNP estimates are capturing 17–23% of heritabilities reported by twin studies (Sullivan et al., 2000; Verhulst et al., 2015).
