Assessing the reproductive health of men with occupational exposures

Abstract

The earliest report linking environmental (occupational) exposure to adverse human male reproductive effects dates back to1775 when an English physician, Percival Pott, reported a high incidence of scrotal cancer in chimney sweeps. This observation led to safety regulations in the form of bathing requirements for these workers. The fact that male-mediated reproductive harm in humans may be a result of toxicant exposures did not become firmly established until relatively recently, when Lancranjan studied lead-exposed workers in Romania in 1975, and later in 1977, when Whorton examined the effects of dibromochloropropane (DBCP) on male workers in California. Since these discoveries, several additional human reproductive toxicants have been identified through the convergence of laboratory and observational findings. Many research gaps remain, as the pool of potential human exposures with undetermined effects on male reproduction is vast. This review provides an overview of methods used to study the effects of exposures on male reproduction and their reproductive health, with a primary emphasis on the implementation and interpretation of human studies. Emphasis will be on occupational exposures, although much of the information is also useful in assessing environmental studies, occupational exposures are usually much higher and better defined.

Aneuploidy: a common and early evidence-based biomarker for carcinogens and reproductive toxicants

“…Hence, sperm aneuploidy is of particular interest because this condition is associated with both increased risk of cancer and reproductive toxicity. Assessment of sperm aneuploidy induced by exposure to chemicals in both experimental models and epidemiological studies has proven effective and predictive of the risk to humans: of seven substances known to affect sperm genetic integrity [ 116 ], six are known or suspected carcinogens [ 125 ]. In light of these findings and considering that with the advent of automated chromosome counters and Laser Scanning Microscopy, sperm aneuploidy assessment has become much faster and reliable, it should be included to extend the evaluation of sperm aneuploidy in chemical hazard and risk assessment.…”

“…A complete answer is elusive to date, mainly because of the lack of sperm aneuploidy testing in experimental models and epidemiological cancer cohorts, but some initial evidence has emerged. A recent review of the reproductive health of men with occupational exposures [ 116 ] listed seven substances known to affect sperm genetic integrity: phthalates [ 117 ], styrene [ 118 ], organophosphates [ 119 ], carbaryl [ 120 ], fenvalerate [ 121 ], lead [ 122 , 123 ], and benzene [ 124 ]. Six of these seven are known or suspected carcinogens according to the Report on Carcinogens of the US National Toxicology Program [ 125 ] or are listed by the State of California ( http://oehha.ca.gov/prop65.html ) as chemicals known to cause cancer.…”

Routine assessment of occupational exposure and its relation to semen quality in infertile men: a cross-sectional study

“…Moreover, semen quality was used as a direct and objective measurement of male reproductive capacity (40), and all semen samples were analyzed by the same technicians with respect to standardized procedures. In order to minimize differential misclassification, the questionnaire Table 3.…”

Protection without Discrimination: Pregnancy and Occupational Health Regulations

“…41 Furthermore, small sample sizes and poor or lacking exposure estimates in most available epidemiological studies hinder the quantitative assessment of dose-response relationships. 42 Animal models may offer some guidance on causality and toxic doses. https://doi.org/10.1017/S1867299X00005808…”