Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 54 2 2025 02 08 361 369 Qian Zhang 1. Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China 2. Department of Child Health, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Yao Ge Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Yuan Chen Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Yun Zhang Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Xiaoyan Xie Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Jian Yu Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Yunlei Bao Department of Neonatology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China Feng Jiang Department of Neonatology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China Chuyan Wu Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China 2024 03 26 2024 10 06 Background: Childhood asthma ranks among the prevailing chronic respiratory conditions affecting a significant number of individuals. The long-term hypoxic state and chronic inflammatory state caused by asthma could be linked with spermatozoa apoptosis. However, the correlation between childhood asthma and abnormal spermatozoa is currently unknown. Methods: In our study, the method of two-sample Mendelian randomization (2SMR) was used by searching an appropriate European population genome-wide association studies (GWAS) database of childhood asthma and abnormal spermatozoa from the Ieu Open GWAS Project database. Sixteen related single-nucleotide polymorphisms (SNPs) were screened as instrumental variables (IV). Subsequently, we employ various statistical methods including inverse variance weighting (IVW), weighted median method (WME), MR-Egger regression, Simple mode, and Weighted mode to investigate the causal link between childhood asthma and the development of abnormal spermatozoa. Results: Based on IVW results, childhood asthma is not an independent risk factor for abnormal sperm formation (P=0.14). Other statistical models such as WME, MR-Egger regression, Simple mode, and weighted mode also showed the same results. Leave-one-out sensitivity analysis and heterogeneity test were conducted and no horizontal pleiotropy was found. Conclusion: There was no causal relationship between childhood asthma and abnormal spermatozoa formation at the genetic level. https://ijph.tums.ac.ir/index.php/ijph/article/view/34991 https://ijph.tums.ac.ir/index.php/ijph/article/download/34991/8471