Looking Hard at Early Exposures
Tart, Kimberly Thigpen, Environmental Health Perspectives
Children's health was the focus of almost 30 different sessions at the International Conference on Environmental Epidemiology and Exposure, held 2-6 September 2006 in Paris. Exposure to environmental toxicants early in life, and even parental exposure prior to conception, may lead to metabolic effects, cardiovascular disease, and reproductive problems later in life, said researchers speaking at the meeting.
According to Germaine Buck Louis, an epidemiologist from the National Institute of Child Health and Human Development, there is scientific evidence to support a relationship between maternal and paternal exposures prior to conception and testicular dysgenesis syndrome, a collection of adverse effects in testes, as well as the less well-studied ovarian dysgenesis. Said Buck Louis, "Periconception is a vital stage for research on exposures."
George Davey-Smith, a researcher in the University of Bristol Department of Social Medicine, told plenary attendees that prenatal and early-life exposures to environmental factors such as infectious agents and tobacco smoke have been associated with effects on blood pressure, insulin resistance (possibly leading to obesity), and cardiovascular disease in adults. Smith says that so-called predictive adaptive responses--developmental "programming" in response to adverse environmental cues--may underlie some of these associations. Evolutionarily, these responses are intended prepare the developing organism for a life of hardship. For example, a mother's poor nutrition during pregnancy may "predict" a life of nutritional hardship for her fetus. The resulting changes in fetal metabolic and cardiovascular development can prove maladaptive if the child is not, in fact, nutritionally deprived; the result can be metabolic syndrome.
In a particularly packed session on children's health and environmental chemicals, Brenda Eskenazi, a professor of epidemiology at the University of California, Berkeley, presented the as yet unpublished, compiled results of studies from three NIEHS/EPA Children's Environmental Health Centers (UC-Berkeley, Columbia University, and Mount Sinai Medical Center) that showed similar associations between exposure to organophosphate pesticides and neurodevelopmental effects. …