Varicocele at High Altitude; Venous Outflow Restriction by Hypobaric Hypoxia

Testicular aches have been reported to occur on exposure to high altitude (HA). As a painful expression of venous congestion at the pampiniform plexus, varicocele (VC) might be a consequence of cardiovascular adjustments at HA. Chile's National Social Security Regulatory Body (SUSESO) emphasized evaluating this condition in the running follow-up study "Health effects of exposure to chronic intermittent hypoxia in Chilean mining workers."

This study aimed at investigating the prevalence of VC in a population usually shifting between sea level and HA, thereby intermittently being exposed to hypobaric hypoxia.

Miners (n=492) agreed to be examined at their working place by a physician, in the context of a general health survey, for the presence of palpable VC, either visible or not. Among them was a group exposed to low altitude (LA) <2,400 m; n=123; another one exposed to moderate high altitude (MHA) working 3,050 m; n=70, and a third one exposed to very high altitude (VHA) >3,900 m, n=165. The Chi² test and Kruskal-Wallis test were used for the descriptive analyses, and logistic regression was applied to evaluate the association of VC with exposure to HA. The Ethics Committee for Research in Human Beings, Faculty of Medicine, University of Chile, approved this project.

VC prevalence (grades 2 and 3) was found to be 10% at LA, 4.1% at MHA, and 16.7% at VHA (p≤0.05). Hemoglobin oxygen saturation (SaO₂) was lower, and hemoglobin concentrations were higher in workers with high-grade VC at VHA compared to LA and MHA (Wilcoxon tests, p<0.001). Odds ratios (OR) for the association of VC with HA were 3.7 (95%CI: 1.26 to 12.3) and 4.06 (95%CI: 1.73 to 11.2) for MHA and VHA, respectively.

Association of VC with HA, a clinically relevant finding, may be related to blood volume centralization mediated by hypobaric hypoxia.