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Sperm Quality and Pollution
 Traffic pollution damages sperm and may reduce male fertility in young and middle-aged men, reveals an Italian study of motorway tollgate attendants.
The attendants, who spend six hours a day sitting in a roadside booth, showed poorer sperm quality than men of the same age living in the same area but not exposed to the same level of exhaust fumes.
Researchers blamed nitrogen oxides and lead for the adverse effects. Although the sperm counts of tollgate workers were normal, their sperm performed less well in tests measuring the ability to reach and penetrate an egg.
"The sperm of the study group was more feeble and less active, so it has lower fertility potential," says Michele De Rosa, study lead at the University of Naples. "Our study demonstrates that continuous exposure to traffic pollutants impairs sperm quality in young and middle-aged men." Furthermore, the time taken for the tollgate attendants' wives to become pregnant - 15 months on average - was nearly double that of those whose husbands did not work next to the motorway.
However, Gerald Lincoln, an expert on male reproduction at the MRC's Human Reproductive Sciences Unit in Edinburgh, UK, urges caution in interpreting the results. Sitting for prolonged periods of time can also affect sperm because of heat in the pelvic area.
"Posture is absolutely crucial, it could have a much bigger effect on sperm characteristics than atmospheric effects."
This problem is acknowledged by the Italian group, who argue that the men in the control group also had sedentary jobs, as it was comprised of clerks, drivers, students and doctors.
 De Rosa and his colleagues examined semen quality in 85 tollgate attendants and compared this with 85 men who did not work near a motorway. Sperm function tests, measuring for example overall motility, forward progression and the lateral movement of the sperm head, reveal tollgate attendants as having less vigorous sperm.
However, they did not have a lower sperm volume or sperm count compared to the control group and hormone levels - including testosterone - did not differ significantly between the groups.
Environmental levels of nitrogen oxide, sulphur oxide and lead exceeded maximum legal limits at the tollgates and attendants showed significantly higher blood concentrations of these pollutants compared to the other men.
In attendants who showed damaged sperm, sperm motility and viability went down with increasing lead levels. Sperm function become poorer with increasing blood levels of methaemoglobin - a marker for nitrogen oxide.
"Health authorities should be alert to the insidious health effects of environmental pollution," they conclude.
Paul Ellis - Men's Health
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