Effects of occupational exposure - is there a link between exposure based on an occupational questionnaire and semen quality?

Several studies have suggested that human semen quality has declined over past decades and some have associated decline with occupational exposures. Many studies have been conducted in occupational settings, where exposure to occupational pollutants is intense. Our objective was to examine the association between exposure to occupational factors based on an occupational exposure questionnaire, and semen quality parameters (sperm concentration, motility, sperm morphology) and sperm chromatin structure. The study population consisted of 336 men who were attending an infertility clinic for diagnostic purposes and who had a normal semen concentration of >= 15 mln/ml according to WHO criteria. All participants were interviewed and provided a semen sample. Additionally, a detailed questionnaire about the exposure to occupational factors was performed among the study participants. The results of the study suggest that occupational factors may affect semen quality. The exposure to noise during work was associated with decreased motility and increased DNA damage (p = 0.005 and p = 0.02, respectively). Exposure to polyvinyl chloride (PVC) decreased sperm concentration and motility (p = 0.02 and p = 0.03, respectively). Whereas exposure to high temperatures and sitting for more than 6 hours during work was positively associated with DNA fragmentation index (DFI) (p = 0.03 and p = 0.001, respectively). After applying the correction for multiple comparisons only the exposure to noise and sitting >= 6 hours during work was associated with poorer semen quality (decreased motility and increased DFI, respectively). This study showed associations between self-reported occupational exposures and impaired semen parameters. The occupational exposure questionnaire may be useful in clinical practice for patients and physicians to identify the work factors associated with poorer semen quality.