The Effect of Age on Sperm Quality in City Policemen Exposed to Traffic-Related Air Pollution

The aim of this study was to detect the age-related changes in conventional semen parameters and sperm DNA damage in healthy nonsmoking men occupationally exposed to traffic pollutants. Semen samples from 150 Prague and 54 Ostrava City policemen aged 21 - 63 years were examined for standard semen parameters, sperm DNA fragmentation and high DNA stainability. A significant positive correlation was found between age and %DFI for both Prague (r = 0.359, p < 0.001) and Ostrava (r = 0.392, p = 0.003) policemen. In Prague, negative correlations were found between age and sperm vitality (r = -0.247, p < 0.001), % acrosome-intact sperm (r = -0.202, p = 0.013) and % normal sperm heads (r = -0.204, p = 0.012). A weak but significant negative correlation was found for high DNA stainability (% HDS) vs. age (r = -0.161, p = 0.050). At ages of 23-30, 31-40, 41-50, and 51-63 years, the mean %DFI values were 12.7±7.18, 14.7±7.42, 19.6±11.25, and 34.2±15.08, respectively. In Ostrava, only a negative correlation was found between age and percentage of morphologically normal sperm (r = -0.374, p = 0.005), % normal sperm heads (r = -0.310, p = 0.022) and % HDS (r = -0.332, p = 0.014). Sperm vitality was borderline (r = -0.256, p = 0.062). No significant correlation was detected between male age and the other investigated semen quality parameters in Ostrava. Our findings show a strong relationship between men's age and sperm DNA fragmentation in an occupational cohort at risk of exposure to heavy traffic-related air pollution in a large city centre.