GWAS of BioBank Japan (BBJ) project

To increase the sample sizes, we obtained the GWAS summary statistics of the BBJ from the data repository of NBDC Human Database (https://humandbs.biosciencedbc.jp/hum0014-v26#58qt).¹² The BBJ project is a large hospital-based case-control study launched in 2003 and collected DNA and clinical information from about 20,000 participants who visited about 130 hospitals throughout Japan,¹³ of whom 142,097 subjects had data for SCr and 143,658 subjects had data for eGFR after subjects with severe CKD (eGFR <15 mL/min/1.73 m²) were excluded from the analyses. The GWAS genotyping and imputation procedures are as described elsewhere.¹⁴