OCCUPATIONAL HEAT EXPOSURE AND MALE-FERTILITY - A REVIEW

In humans, as in most mammals, spermatogenesis is temperature dependen t. This temperature dependence has been clearly demonstrated by severa l experimental studies showing that artificial increases in scrotum or testicle temperature in fertile men reduce both sperm output and qual ity. Our knowledge of the effects of occupational heat exposure on mal e fertility comes mostly from a small number of epidemiological studie s. We conducted an extensive review of these published reports, focusi ng on methodology and design (retrospective or prospective; reference group; number of subjects) and principal results (using several indica tors such as the time taken to obtain a pregnancy or sperm characteris tics). We concluded that occupational heat exposure is a significant r isk factor for male infertility, affecting sperm morphology and result ing in delayed conception, The limits and biases involved in this type of research are also discussed.