Assessment of temperature, pressure, humidity and daylight impact upon semen quality

Abstract

Testicular function is a temperature-dependent process, and high summer temperatures have been linked to lower sperm concentration and count. This study aims to assess the impact of temperature, pressure, humidity and daylight on semen quality. Semen samples were obtained from men subjected to semen evaluation as part of routine andrology workup (n= 11,657; January 2010- November 2016) and computer-assisted sperm analysis (CASA; n= 4,705) at the Laboratorio de Andrología y Reproducción (LAR), following WHO 2010 criteria. Temperature, pressure, humidity and daylight (average, minimum and maximum) readings were obtained from the Servicio Meteorológico Nacional for Córdoba region. Statistical analyses were performed with R (significant differences <0.05). Multiple regression analysis revealed that sperm concentration, count, total-motile spermatozoa and normal-motile spermatozoa were significantly correlated to average humidity, daylight, and minimum temperature and humidity. On the other hand, sperm motility was significantly correlated to average humidity, whereas sperm velocity (VSL, VCL and VAP) was significantly correlated to temperature (daily average, minimum and maximum) and maximum humidity. Moreover, sperm progression (LIN, STR, WOB) was correlated to temperature (average, minimum and maximum) and daylight. Among said climatic variables, temperature explained most kinematic variations, depicting a negative correlation with CASA variables. On the other hand, humidity explained variations in most routine semen parameters variations with a positive correlation. Thus, a deleterious effect of low humidity and high temperatures was found for routine semen parameters and sperm kinematics, respectively, in a large cohort of samples assessed under same laboratory standards subjected to strict quality assurance.