Effects of prolonged autovehicle driving on male reproduction function: a study among taxi drivers

This study had the purpose of exploring the possible association between the work exposures of professional drivers and their reproductive health, by studying a group of 201 taxi drivers in the city of Rome. Data on work and reproductive history were collected by interviews. Biological markers examined in 72 subjects included salivary testosterone levels, sperm quality (i.e., sperm concentration, sperm morphology, and motility), and fertility experience, including time to pregnancy. Their spermatologic profile was compared with that of a control group of 50 healthy subjects of similar age and smoking habits. The results showed that taxi drivers, compared to the controls, had a significantly lower prevalence of normal sperm forms (45.8% vs. 64.0%); this was particularly true for those with a longer time on this job. This result was confirmed by a multivariate analysis in which confounders such as age, smoking, and alcohol consumption were controlled. The other sperm parameters did not differ in the study and the control groups. Among the life-style factors, we found smoking to be associated with poorer sperm morphology. Moderate alcohol consumption was associated with a better seminologic profile, while the pattern in respect to coffee intake was inconclusive. Subjects with poor semen quality also more frequently exhibited longer time to pregnancy of their partner. The results suggest that prolonged urban automobile driving might be a risk factors for sperm quality, and particularly for sperm morphology, but the finding needs further confirmation.