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SPERM COUNT DISTRIBUTIONS IN FERTILE MEN
Strader, L F., S C. Jeffay, A. H. Herring, Olshan. AF, L. Bradley, J. Smith, AND S P. Darney. SPERM COUNT DISTRIBUTIONS IN FERTILE MEN. Presented at American Society of Andrology, Seattle, WA, April 2-5, 2005.
Sperm concentration and count are often used as indicators of environmental impacts on male reproductive health. Existing clinical databases may be biased towards subfertile men with low sperm counts and less is known about expected sperm count distributions in cohorts of fertile men. We are surveying semen quality in a selected cohort of presumed fertile men (n=228) who are resident partners of pregnant women. These couples live in the metropolitan area of 1 of 3 mid-sized US cities selected for availability of environmental monitoring data. Semen was collected at home and cold-shipped to a central lab for analysis the following morning. For sperm concentration (106/ml semen determined by hemacytometer), mean = 147 ? 115.6 (SD), median = 114 and % < 20 (the WHO reference value) = 3.9%. For volume (ml), mean = 3.3 ? 1.7 and median = 3.0. For total sperm count (106), mean = 463 ? 410, median = 325, and % < 40 = 2.2%. Compared with another cohort of 156 fertile US men reported by Zinamen et al. (J. Androl 21:145, 2000), these values are relatively high. Differences in mean concentrations and counts by city of residence were statistically significant overall, p<0.01 (log-transformed, PROC GLM, SAS, controlling for abstinence). The city with the highest mean sperm concentration (169 ? 136, n=90) was different from that with the lowest (126 ? 92, n=46), p<0.02. These data will be used, in combination with other semen outcomes, to examine associations with other factors including lifestyle and environmental/occupational exposures. This preliminary analysis suggests that recently fecund men may have higher than expected sperm concentrations and counts, and that geographic differences in these outcomes may be detectable in relatively small cohorts of fertile men.