Your cohort consists exclusively of male partners of HPV-positive women attending IVF. This design introduces a critical confounder, as the sample is drawn from a pre-selected, infertile population with a high likelihood of recent partner HPV transmission. Without a control group of men from fertile couples, or at least men with HPV-negative partners, it is challenging to isolate the specific effect of male HPV infection from the overarching context of couple infertility and the confirmed HPV status of the female partner.
The current comparison, between HPV-positive and HPV-negative men within this already infertile population, makes it difficult to determine if the observed differences in seminal parameters, such as the counterintuitive increase in rapid progressive motility among HPV-positive men, represent a true biological effect of HPV or are an epiphenomenon related to the shared clinical context. The direction of causality and the potential influence of the female partner’s infection on the couple’s fertility status are not addressed.
Could you please clarify how this potential confounding was considered in the design? In particular, were any statistical adjustments made to account for the uniform “infertile couple/HPV-positive female” background of the entire cohort, and was the inclusion of a control group of fertile men considered to strengthen the causal inference?