Presentation Authors: Philip Cheng*, Sorena Keihani, Angela Presson, Chong Zhang, Heidi Hanson, Ken Smith, Douglas Carrell, Kenneth Aston, Alexander Pastuszak, James Hotaling, Salt Lake City, UT
Introduction: Studies have shown that there is seasonal variation in semen parameters and birth rates. However, birth outcomes from subjects with semen analysis (SA) data have not been reported. Here we evaluate seasonal variation in semen parameters and resulting birth outcomes among a large cohort of subfertile men.
Methods: We analyzed a cohort of 11,929 subfertile men seen in a single andrology clinic over an 18-year period (1996-2013) that were linked to the Utah Population Database, a large comprehensive database of medical and demographic data. We obtained age, birth records following the first SA, and first SA results, including total motile count (TMC), total sperm count (TSC), sperm concentration, and progressive motility. Linear regression models assessed the effect of seasons on semen parameters controlling for patient age and year of SA. Average seasonal birth numbers were estimated across the 18-year time span, and the summer season was compared with fall, winter, and spring using Wilcoxon signed rank tests.
Results: The meanÂ±SD age at the time of the first SA was 32Â±6.5 years. Linear regression demonstrated a consistent U-shaped relationship between TMC, TSC, and sperm concentration and season, with winter yielding the highest values with a decline in the summer and fall. Comparing summer to spring, significantly higher TMC (132Â±153 vs. 137Â±149 million, p=0.03) and concentration (79Â±74 vs. 82Â±74 million/mL, p=0.03) was observed in the spring. Mean TSC (238Â±248 vs. 249Â±247 million, p=0.04) and concentration (79Â±74 vs. 83Â±76 million/mL, p=0.01) were also observed to be higher in the winter than in the summer. During a mean follow-up of 7.7Â±4.7 years following their SA, 61% of men had one or more offspring. Over the 18-year period, summer had the highest births per year (188Â±111 births), followed by spring (178Â±112, p=0.06), fall (174Â±102, p=0.02), and winter (170Â±99, p=0.01).
Conclusions: In a single-center study of subfertile men, semen parameters were highest in the spring and winter and lowest in the summer and fall. However, the timing of peak births did not correspond with the distribution of semen parameters.
Source of Funding: This investigation was supported by the University of Utah Study Design and Biostatistics Center, with funding in part from the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Hea