Hum. Reprod. Advance Access originally published online on May 3, 2007
Human Reproduction 2007 22(7):2072; doi:10.1093/humrep/dem093
Letters to the Editor |
Sperm forward motion and aging
1 Department of Urology, Institute of Biotechnology, University of Caxias do Sul, RS, Brazil 2 Department of Gynecology, Center for Biological and Health Sciences, University of Caxias do Sul, RS, Brazil
3 Correspondence address. E-mail: fabio.conception{at}terra.com.br
We read with great interest the recent article by Sloter et al. (2006)
who suggested that the average man may become progressively less fertile as he ages due to reduced proportions of motile sperm and decreased abilities of motile sperm to maintain forward motion along a linear path. Also, unlike fertility in women, there appears to be no evidence of an age threshold for these sperm parameters for men, but rather a gradual decline with advancing age throughout normal reproductive years and into senescence. Recently, we evaluated 889 men who were requested to provide a semen sample before undergoing a vasectomy and concluded that there is a tendency for a decrease in sperm concentration and normal motility, and a tendency for FSH levels to increase over time were detected (Pasqualotto et al., 2005). Sperm morphology tends to decrease as from 45 y of age. It is suggested that the aging effect be taken into consideration when standard values for semen parameters in routine semen analysis and normal values for hormone levels are proposed.
Sloter et al. (2006) stated that their study is the first to use computer-assisted sperm analysis (CASA) to assess the effects of age on sperm kinematics. However, this is a mistake, since we published last year a study evaluating sperm kinematics with CASA. However, our CASA results differ from the authors, since we did not find any difference in linearity, velocity straight line and velocity average path, among the groups evaluated. Also, the authors stated that, compared to a review published by Kidd et al. (2001), they have the larger number of older men included. However, in our study (Pasqualotto et al., 2005), we evaluated 889 normal fertile men who came for sterilization purposes. Of these men, 69 were more than 45 y old and we evaluated men up to 67 y old.
Anyway, we congratulate the authors and agree with them that these findings may have important implications for men who choose to delay fatherhood.
References
Pasqualotto FF, Sobreiro BP, Hallak J, Pasqualotto EB, Lucon AM. Sperm concentration and normal sperm morphology decrease and follicle-stimulating hormone level increases with age. BJU Int (2005) 96:1087–1091.[CrossRef][Web of Science][Medline]
Sloter E, Schmid TE, Marchetti F, Eskenazi B, Nath J, Wyrobek AJ. Quantitative effects of male age on sperm motion. Hum Reprod (2006) 21:2868–2875.
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