Infertility, Blood Mercury Concentrations and Dietary Seafood Consumption: A Case-Control Study

Abstract

Both in vitro and animal studies suggest that mercury may adversely affect spermatogenesis. The human studies done to date have used small numbers and narrow ranges of both mercury concentrations and semen parameters. This case-control study compared blood mercury levels and patterns of seafood consumption in 157 infertile couples coming for in vitro fertilization and 26 fertile couples not known to have been exposed to mercury at the workplace. Whole-blood mercury concentrations were measured by atomic absorption spectrophotometry, and a dietitian administered a food-frequency questionnaire. Two consecutive semen samples were required for a designation of abnormal semen. The infertile group included 40 men with semen; the men had been infertile for nearly 6 years on average. Logistic regression analysis, controlling for age effects on blood mercury levels, showed the infertile group to have significantly higher mercury levels than the control subjects. Both infertile men with semen and women whose infertility was unexplained had significantly higher blood mercury levels than their fertile counterparts. A higher proportion of infertile women had abnormally elevated blood mercury levels compared with those who were fertile. Blood mercury correlated with the amount of seafood eaten. No other source of mercury exposure was identified. In this population elevated blood mercury was associated with male and female infertility and with eating more seafood.