Adverse Health Consequences of Environmental Exposure to 'Endocrine Disruptors'

Abstract

During the last decade concern has grown on the possible adverse health effects of chemicals which are capable of interacting with the endocrine system. Concerns on the effects of 'endocrine disruptors' (EDs) are largely based on reports of adverse effects on wildlife reproduction and on the plausible hypothesis that exposure to these substances is responsible for an increased incidence of certain estrogen-sensitive types of cancer, reproductive tract disorders and poor sperm quality. Most environmental EDs have proved to possess rather weak hormone-like effects, much weaker than those of physiological hormones, in in vitro and in vivo assays. Since EDs are found at relatively low levels in the environment, health risks posed by them would critically depend on the possibility of non-monotonic dose-effect relationships, on the relevance of low dose effects and on the type of interaction between different EDs. Results suggesting a synergistic interaction with combinations of xenoestrogens were not further confirmed by other laboratories and by their own authors. A few studies have provided data suggesting that exposure to low doses of xenoestrogens during prenatal development induces alterations in estrogen-sensitive tissues which are apparent in adulthood. These findings, however, need to be confirmed by independent research groups. No consistent epidemiological evidence has been provided indicating that environmental xenoestrogens (e.g. DDT) increase breast cancer risk. The instigating hypothesis that environmental EDs could adversely affect human health therefore remains to be confirmed by further experimental and epidemiological studies.