1 Department of Molecular and Clinical Endocrinology and Oncology and 2 Department of Preventive Medical Sciences, University "Federico II", Via S. Pansini 5, 80131 Naples, Italy
3 To whom correspondence should be addressed e-mail: miderosa{at}unina.it
Dear Sir,
We have appreciated the letter by Drs Mehta and Anand Kumar as it gives us the opportunity to emphasize some of our recent findings.
In our previous report we have demonstrated that an inverse correlation exists between traffic pollutants and semen parameters. Particularly, environmental SO, NO, CO and Pb decrease sperm motility, kinetics and function in exposed subjects (De Rosa et al., 2003).
Multicentric research performed in Austria, France and Switzerland (Kunzli et al., 2000) has demonstrated that exposure to particulate matter (<10 µm, PM10) constituted by CO, SO, NO, deriving from vehicle exhaust and diesel emissions, increases mortality in adults >30 years, respiratory and cardiovascular hospital admissions at all ages, incidence of chronic bronchitis in adults >25years, bronchitis episode in children <15 years, restricted activity days in adults >20 years and asthma attacks in adults and children. Particularly, air pollution caused 6% of total mortality or more than 40 000 attributable cases per year. About half of all mortality caused by air pollution was attributed to motorized traffic, accounting also for: more than 25 000 new cases of chronic bronchitis in adults and more than 290 000 episodes of bronchitis in children; more than 0.5x106 asthma attacks and more than 16x106 person-days of restricted activities. In the same period, Samet et al. (2000
) demonstrated that an increase of PM10 levels in 20 American cities was associated with the risk of death from all causes and, particularly, from cardiovascular and respiratory illnesses. Besides the negative effects on the cardiovascular and respiratory system, pollutants affect sperm quality. In fact, Mehta and Kumar (1997
) reported an inverse correlation between environmental levels of PM and sperm count and semen quality. Previously, the prolonged exposure to this particulate extract was shown to reduce sperm motility in vitro (Fredricsson et al., 1993
). Finally, it has been demonstrated that these exhausts stimulate hormonal secretion of the adrenal cortex, depresses gonadotrophin release and inhibits spermatogenesis in rats (Watanabe and Oonuki, 1999
). In our study we have not reported on particulate matter as further studies are ongoing to evaluate the role of PM in the exposed subjects.
In addition to the detrimental effects of pollutants on semen quality, the prolonged sitting position might have an independent role as it has been implicated in poor semen quality (Figà-Talamanca et al., 1996; Bhattacharya, 2003
) by increasing temperature in the pelvic region (Bujan et al., 2000
). It should be noted that the exposure to environmental pollutants in our study group compared with an age-matched group of controls equally working in a sitting position confirms the harmful role of chemical pollutants on the spermatogenesis (De Rosa et al., 2003
).
Finally, it is a long time since a number of papers have demonstrated that chronic exposure to pollutants induces a modification of human chromosomes. Particularly it has been demonstrated that lead exposure induce a dissociation of the acrocentric chromosomes (Verschaeve et al., 1979) and severe chrosomomal aberrations (rings and dicentric) (Deknudt et al., 1977
). All these effects should be kept in mind when studying the spermatogenesis in exposed subjects, because they could worsen negative male fertility potential.
References
Bhattacharya, S. (2003) Traffic pollution damages mens sperms. New Scientist, April 30, 2003
Bujan, L., Daudin, M., Charlet, J.P., Thonneau, P. and Mieusset, R. (2000) Increase in scrotal temperature in car drivers. Hum. Reprod., 15, 13551357.
De Rosa, M., Zarrilli, S., Paesano, L., Carbone, U., Boggia, B., Petretta, M., Maisto, A., Cimmino, F., Puca, G., Colao, A and Lombardi, G. (2003) Traffic pollutants affect fertility in men. Hum. Reprod., 18, 10551061.
Deknudt, G., Manuel, Y. and Gerber, G.B. (1977) Chromosomal aberrations in workers professionally exposed to lead. J. Toxicol. Environ. Health, 3, 885891.[ISI][Medline]
Figà-Talamanca, I., Cini, C., Varricchio, G.C., Dondero, F., Gandini, L., Lenzi, A., Lombardo, F., Angelucci, L., Di Grezia, R. and Patacchioli, F.R. (1996) Effects of prolonged autovehicle driving on male reproduction function: a study among taxi drivers. Am. J. Ind. Med., 6, 750758.[CrossRef]
Fredricsson, B., Muller, L., Pousette, Å. and Westerholm, R. (1993) Human sperm motility is affected by plasticizers and diesel particle extracts. Pharmacol. Toxicol., 72, 128135.[ISI][Medline]
Kunzli, N., Kaiser, R., Medina, S., Studnicka, M., Chanel, O., Filliger, P., Herry, M., Horak, F. Jr, Puybonnieux-Texier, V., Quenel, P. et al. (2000) Public-health impact of outdoor and traffic-related air pollution: a European assessment. Lancet. 2, 795801.[CrossRef]
Mehta, R.H. and Anand Kumar, T.C. (1997) Declining semen quality in Bangloreans: A preliminary report. Curr. Sci., 72, 621622.[ISI]
Samet, J.M., Dominici, F., Curriero, F.C. Coursac, I., Zeger, S.L., Samet, J.M., Dominici, F., Curriero, F.C., Coursac, I. and Zeger, S.L. (2000) Fine particulate air pollution and mortality in 20 U.S. cities, 19871994. N. Engl. J. Med., 14, 17421749.
Verschaeve, L., Driesen, M., Kirsch-Volders, M., Hens, L. and Susanne, C. (1979) Chromosome distribution studies after inorganic lead exposure. Hum. Genet., 19, 147158[CrossRef]
Watanabe, N. and Oonuki, Y. (1999) Inhalation of diesel engine exhaust affects spermatogenesis in growing male rats. Environ. Health Perspect., 107, 539544.[ISI][Medline]