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Environmental Impact on Congenital Anomalies CONCLUSIONS

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  1. Environmental Impact on Congenital AnomaliesCONCLUSIONS Luc Hens Human Ecology Department Vrije Universiteit Brussel E-mail: human.ecology@vub.ac.be

  2. Issues • Problem formulation • Methodological approaches • Mechanisms • Communications Conclusions Kos, June 8-11th, 2005

  3. Congenital Anomalies commonly studied in relation to environmental exposure After Dolk and Vrijheid, 2003 Conclusions Kos, June 8-11th, 2005

  4. Chemicals associated with congenital anomalies in humans • Pharmaceuticals (DES, Thalidomide, Wafarin) • Hair dyes • Pesticides • Non-pesticide ED (bisphenol A, phtalates, TCDD, vinyl chloride) • Heavy metals (Pb, Hg, Cd, As, Cr and Ni) • Organic solvents (styrene) Conclusions Kos, June 8-11th, 2005

  5. Exposure conditions associated with congenital anomalies • Drinking water (heavy metals, nitrates, chlorinated substances) • Residence near (hazardous) waste deposit sites • Pesticides in agricultural areas • Air pollution • Food contamination (dioxins, PCBs) • Industrial point sources (smelters, incinerators) • Disasters (Hiroshima, Minamata) • (Working conditions : hair dressers) Examples in Kos 2005 workshop After Dolk and Vrijheid, 2003 Conclusions Kos, June 8-11th, 2005

  6. Problem situation • Embryonic and fetal life are sensitive periods to environmental exposures • Increasing number of chemicals and exposure conditions are associated with congenital anomalies • Increasing prevalence of selected congenital anomalies (hypospadias, cryptorchidism, gastroschisis) in industrialized countries • Convergence between pollutants in environmental health outcomes • Links between congenital anomalies, fertility and pregnancy loss (mechanisms?, risk factors?) Conclusions Kos, June 8-11th, 2005

  7. Epidemiological evidence • “Limited” • RR is significant for environmental exposure • Limitations3.1 statistical power, sensitivity, dilution3.2 consistency of diagnosis (e.g. hypospadias)3.3 “missing what is real” – “finding what is not real” Conclusions Kos, June 8-11th, 2005

  8. Risk figures Vrijheid and Dolk, 2005 Kristensen et al., 1997 Conclusions Kos, June 8-11th, 2005

  9. Risk figures Longnecker et al., 2002 Olea et al., 2005 Conclusions Kos, June 8-11th, 2005

  10. Developmental toxicological evidence • Standard tests exist (two generation essay) • Interesting developments (e.g. stem cells) • No single test Conclusions Kos, June 8-11th, 2005

  11. Clinical evidence • Historical examples of the alert physician1.1 Thalidomide1.2 Anticonvulsants1.3 PCBs • Systematic survelance of public health (Eurocat)2.1 “Limited” information2.2 Important methodological challenges2.3 More coordination necessary Conclusions Kos, June 8-11th, 2005

  12. Wildlife evidence • Selected cases1.1 EDs cause abortion in sea lions1.2 DDT/DDE cause cryptorchidism in rodents • Congenital defects in relation to pollution are found in:2.1 fish: intersex2.2 amphibians: intersex, gonidal dysgenesis, hermaphroditism2.3 Mammals: impaired reproduction, hermaphroditism, abnormal testes, impaired spermatogenesis • Fast accumulating evidence Conclusions Kos, June 8-11th, 2005

  13. Examples of mechanisms • Thalidomide : I and F growth factor mediated mechanism • Steroidogenesis in testes • Testicular dysgenesis syndrome (TDS) Conclusions Kos, June 8-11th, 2005

  14. Changing concepts • Not only dose matters (“practical threshold”) • Exposure window – sensitivity period – timing is crucial • Individual susceptibility • Long latency • Consider mixture (of chemicals, of chemicals with body molecules) Conclusions Kos, June 8-11th, 2005

  15. Information • Parents prior to conception • Prenatal service providers and counsellors (e.g. OTIS) • Decision makers3.1 principles3.2 messages Conclusions Kos, June 8-11th, 2005

  16. Core messages for couples • Be aware of pollutants in your lifestyle (cosmetics, medical drugs, food, pesticide use in gardening) • Care about your internal environment (long term) • Health practices: iodine intake, folic acid, antioxidants and breastfeeding Conclusions Kos, June 8-11th, 2005

  17. Core messages for counselors • Evaluate environmental aspects (not only genetics) • Defining and communicate risk • Bring down avoidable medication during pregnancy3.1 prescription behavior3.2 alternatives Conclusions Kos, June 8-11th, 2005

  18. Principles for decision making • “How much evidence is enough?”1.1 Bradford Hill criteria1.2 Related models (e.g. IPCC criteria) • Preventable conditions • Precautionary principles Conclusions Kos, June 8-11th, 2005

  19. Core messages for policy making • Even if the proportion of congenital anomalies attributable to environmental pollution might not be high, any excess cases represent a failure of our environmental health protection system • Precautionary new generation of standards • Growing evidence mainly from wildlife to bring EDCs under prior authorization under REACH Conclusions Kos, June 8-11th, 2005

  20. At last • Submit manuscripts not later than August 20th 2005 • THANK YOU Conclusions Kos, June 8-11th, 2005