The causal effect between psoriasis and male reproductive health, and the mediating effect of serum inflammatory factors and metabolites.

The relationship between psoriasis and male reproductive health has sparked extensive research. But the causal relationship and direction remain unknown. To examine the causal association between psoriasis and male reproductive health, and to investigate the role of serum inflammatory factor and metabolites as mediators. A 2-step Mendelian randomization analysis was utilized. Inverse variance weighted method to explore the causal effects. The Cochran Q test was employed to assess the heterogeneity. The Mendelian randomization-Egger and Mendelian randomization-PRESSO method was used to explore the genetic pleiotropy. The mediating effects can be verified using a stepwise testing approach. Psoriasis vulgaris (P = .005, odds ratios [OR] = 1.137), arthropathic psoriasis (P = .044, OR = 1.112), guttate psoriasis (P = .026, OR = 1.041), and other and unspecified psoriasis (P = .030, OR = 1.085) were found to be risk factors for abnormal spermatozoa. X-09026 (49.219%) and macrophage migration inhibitory factor (18.000%) serve as mediators in the regulation of the causal association between Psoriasis vulgaris and abnormal spermatozoa. Methylcysteine (35.849%) also acts as a mediator in the regulation of the causal relationship between arthropathic psoriasis and abnormal spermatozoa. Psoriasis may cause sperm abnormality through metabolites such as X-09026, macrophage migration inhibitory factor, and methylcysteine.