Kidney function and obstructive lung disease: a bidirectional Mendelian randomisation study.
Additional study is warranted to investigate the causal effects between kidney function and obstructive lung disease.This study was a bidirectional two-sample Mendelian randomisation (MR) analysis. The CKDGen genome-wide association study (GWAS) meta-analysis for estimated glomerular filtration rate (eGFR) including individuals of European ancestry (N=567 460) provided the genetic instrument for kidney function and outcome summary statistics. A GWAS for FEV1/FVC including individuals of European ancestry from the UK Biobank (N=321 047) provided the genetic instrument for FEV1/FVC and outcome data. A polygenic score (PGS) analysis was performed to test the causal estimates from kidney function to binary obstructive lung disease outcomes, including chronic obstructive pulmonary disease (COPD), asthma, and FEV1/FVC<70%, and to perform non-linear MR with individual-level UK Biobank data.The causal estimates by summary-level MR indicated that genetically predicted increased kidney function was significantly associated with increased FEV1/FVC Z scores [10% increase in eGFR, beta 0.055 (0.024, 0.086)]. The PGS for increased eGFR showed a significant association with a reduced risk of FEV1/FVC<70% [OR 0.93 (0.87, 0.99)], COPD [OR 0.93 (0.87, 0.99)] and late-onset (≥50 years old) asthma [OR 0.93 (0.88, 0.99)]. The non-linear MR demonstrated that the causal effect from eGFR to FEV1/FVC was apparent in eGFR ranges lower than 60 mL/min/1.73 m2. On the other hand, genetically predicted FEV1/FVC showed nonsignificant causal estimates of eGFR change [beta 0.568% (-0.458, 1.605%)].This study supports kidney function impairment would be a causative factor for obstructive lung disease.
Authors: Sehoon Park, Soojin Lee, Yaerim Kim, Semin Cho, Kwangsoo Kim, Yong Chul Kim, Seung Seok Han, Hajeong Lee, Jung Pyo Lee, Kwon Wook Joo, Chun Soo Lim, Yon Su Kim, Dong Ki Kim