Mendelian randomization study of childhood asthma and chronic obstructive pulmonary disease in European and East Asian population.

Objective: The present study aimed to explore the potential causal relationship between childhood asthma and chronic obstructive pulmonary disease (COPD) in European and East Asian populations with Mendelian randomization (MR) analysis. Methods: Based on summary data from genome-wide association studies, single nucleotide polymorphisms (SNPs) associated with childhood asthma were used as instrumental variables. The MR analysis employed the inverse variance weighting, MR-Egger regression and weighted median method to estimate the causal effect between childhood asthma and COPD in European and East Asian populations. Cochran's Q test, MR-PRESSO method and MR-Egger intercept were used to detect heterogeneity, outliers and horizontal pleiotropy, respectively. Leave-one-out analysis applied to assess the effect of removing individual SNP on the estimate of causal association. Results: The MR analysis showed no genetic causal relationship between childhood asthma and COPD. The results of Cochran's Q test, MR-PRESSO and MR-Egger regression indicated the absence of heterogeneity, outliers and horizontal pleiotropy, respectively. Leave-one-out analysis showed no significant difference in the statistical results after exclusion of single SNPs. Conclusions: The MR analysis revealed that there is no causal relationship between childhood asthma and COPD at the genetic level in both European and East Asian populations. Additionally, due to the presence of shared confounding factors and pathogenic genes, further research is needed to comprehensively assess the relationship between childhood asthma and COPD.