Background: We are not aware of other longitudinal cohort studies of boys with annual assessments of pubertal development and long term follow-up to adulthood to evaluate semen quality.
Objective: To describe semen quality and investigate its predictors in a longitudinal cohort study of Russian boys followed from prepuberty until adulthood.
Design and methods: From 2003 to 2005, 516 prepubertal 89-year-old boys were enrolled (86% of all eligible Chapaevsk boys, Russia) and underwent annual growth and sexual development assessments for ten years, including Tanner staging and measurement of testicular volume. At age 18, the young men collected two semen samples one week apart. 150 men provided two samples and nine men one sample (total 309) for 54% participation among those eligible. Semen samples were analyzed for volume, sperm concentration and motility by one technician (LS) according to the NAFA-ESHRE manual. A total of 67 samples were excluded due to severe chronic illness (six), lost semen (nine), age>20 years (two) and long/short abstinence time (50). 98 matched pair samples were analysed by Wilcoxon signed-rank test to compare repeat semen parameters.
Results: No differences were found between first and second samples. Based on second samples (n=129), men had a median (interquartile range, IQR) volume, sperm concentration, progressive and total motility of 2.6 (23.7) ml, 48 (25.778.5)×106/ml, 56% (4961%) and 64% (5769%), respectively. Median (IQR) total sperm count and total motile sperm count were 126.0 (68.2221.8) and 78.5 (38.4144.4)×106/ejaculate respectively. 24, 16, 31 and 33% of men had semen parameters below normal reference limits for volume (2 ml), sperm concentration (20×106/ml), total sperm count (80×106/ejaculate) and motility (60%) respectively. Data are being analysed for predictors of semen quality.
Conclusion: This is one of the first prospectively designed studies to follow a large cohort of boys annually from prepuberty until adulthood and collect semen samples.
Funding: This work was supported by the NIH (grants ## R01ES0014370, P30ES000002), the Russian Science Foundation (grant # 14-45-0065).
01 Oct 2015 - 03 Oct 2015