Therefore, the objective of this study is threefold: firstly, to examine the risk factors associated with CAVD; secondly, to investigate the correlation between lipids and their derived parameters (such as LDL and APOB/APOA1 ratio) and CAVD; and thirdly, to construct a multifactorial prediction model including APOB/APOA1 and evaluate its clinical application value. The gene discussed is APOA1; the disease is congenital bilateral aplasia of vas deferens from CFTR mutation.