Objective-To evaluate the effects of recent and long term occupational lead exposure on indicators of male reproductive health.Methods-In a cross sectional study of male employees of a lead smelter (n = 2469), blood samples were obtained from 152 workers including 119 who also provided semen samples. Semen analysis and serum concentrations of testosterone, follicle stimulating hormone, and luteinising hormone were used as indicators of reproductive health. Semen and hormone variables were examined in relation to measures of current and long term body lead burden estimated from current blood lead concentrations and historical blood lead monitoring data. Results-For current blood lead concentration groups of < 15, 15-24, 25-39, > 40 ugldl, the geometric mean sperm concentrations were, respectively, 79-1, 56-5, 62-7, and 44-4 million cells/ml and geometric mean total sperm counts were 186, 153, 137, and 89 million cells (P for trend 0-04). Compared with workers with blood lead concentrations less than 15 ug/dl, workers with current blood lead concentrations of 40 ug/dl or more had an increased risk of below normal sperm concentration (odds ratio (OR) 8-2, 95% confidence interval (95% CI) 1-2-57.9) and total sperm count (OR 2-6, 95% CI 0-4-15-7), based on World Health Organisation standards. Independent of current lead exposure, sperm concentration, total sperm count, and total motile sperm count were inversely related to measures of long term lead exposure. No association was found between lead exposure and measures of sperm motility, sperm morphology, or serum concentrations of reproductive hormones. Conclusions-Blood lead concentrations below the currently accepted worker protection criteria seem to adversely affect spermatogenesis. (Occup Environ Med 1996;53:411-416)

While blood lead concentration has been inversely associated with indicators of reproductive health in occupationally exposed male workers, the utility of lead concentration in semen as an indicator of lead exposure to the male reproductive system has not been fully explored. Blood and semen lead concentrations from 81 lead smelter workers were examined in relation to semen quality and endocrine function parameters. Mean blood and semen lead concentrations were 22.8 μg/dl (range 5–58) and 1.9 μg/dl (range 0.1–17.6), respectively. Total sperm count and concentration decreased with increasing blood lead concentration; p for trend was 0.003 and 0.009, respectively. Semen lead concentration was inversely related to total sperm count (p = 0.05), ejaculate volume (p = 0.001), and serum testosterone (p = 0.004), but not to sperm concentration. The association between semen lead concentration and total sperm count was eliminated when volume was included in the model. Blood lead concentration was more consistently associated with indicators of sperm production than was semen lead. In contrast, semen lead concentration was negatively associated with circulating testosterone concentrations. Our findings indicate that measurement of semen lead may not be a valuable adjunct to conventional blood lead monitoring for investigations of male reproductive system toxicity. Am. J. Ind. Med. 34:464–469, 1998. © 1998 Wiley‐Liss, Inc.

While blood lead concentration has been inversely associated with indicators of reproductive health in occupationally exposed male workers, the utility of lead concentration in semen as an indicator of lead exposure to the male reproductive system has not been fully explored. Blood and semen lead concentrations from 81 lead smelter workers were examined in relation to semen quality and endocrine function parameters. Mean blood and semen lead concentrations were 22.8 µg/dl (range 5-58) and 1.9 µg/dl (range 0.1-17.6 INTRODUCTIONOccupational lead exposure has been associated with poor semen quality, including decreased sperm concentrations and total sperm counts, poor sperm motility, and abnormal sperm morphology [Lancranjan et al., 1975;Assennato et al., 1987;Lerda, 1992;Alexander et al., 1996]. However, the mechanism by which an elevated blood lead concentration interferes with spermatogenesis is poorly understood. The regulation of spermatogenesis by the hypothalamic-pituitary-testicular axis, as determined by circulating levels of reproductive hormones, is not consistently associated with blood lead concentration, particularly in the absence of clinical lead poisoning [Cullen et al., 1984;Assennato et al., 1987;Gustafson et al., 1989;Ng et al., 1991;Alexander et al., 1996]. Other possible mechanisms include a disturbance of testicular function at the cellular level, a direct effect on the developing spermatocytes or a postspermiation effect of lead on spermatozoa [Winder, 1993]. Blood lead concentration may influence all of these possible mechanisms; the latter possibility would likely relate to the presence of lead in the semen. Blood lead measurement is an indicator of lead body burden, but it pertains mainly to intake in the preceding several months and does not necessarily reflect the dose at a target organ or tissue. The use of lead in semen as an adjunct biological marker of exposure for reproductive toxicity studies has only been explored to a limited extent [Robins et al., 1997].In this article we present comparative findings of associations of blood and semen lead concentrations with semen quality parameters, based on data from a previously reported study of lead smelter workers [Alexander et al., 1996] that only considered blood lead concentration as the exposure variable. Our objective was to determine whether semen lead is a useful adjunct exposure biomarker for epidemiologic studies of occupational lead and semen quality. METHODSSemen quality parameters and blood and semen lead levels were examined in a cross-sectional study of men employed at a primary lead smelter in Trail, British Columbia. Participants in this analysis are a subset of a previous study that found inverse relations between both current and chronic measures of blood lead levels and sperm count and concentration. The details are published elsewhere [Alexander et al., 1996]. Briefly, 119 men employed at the smelter donated semen and blood samples in June and July of 1993. The study protocol was approved by the University of Washing...

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