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A Small Dose of ™ Lead

Converging Issues: Lead, Ethics, and Our Children’s Potential or Should the CDC Lower the Blood lead action lever from 10 to 2 mcg/dl?. A Small Dose of ™ Lead. Wilson Memorial Hospital April 28, 2005 Steven G. Gilbert, PhD, DABT www.asmalldoseof.org. A Small Dose of Toxicology.

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A Small Dose of ™ Lead

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  1. Converging Issues: Lead, Ethics, and Our Children’s PotentialorShould the CDC Lower the Blood lead action lever from 10 to 2 mcg/dl? A Small Dose of ™ Lead Wilson Memorial Hospital April 28, 2005 Steven G. Gilbert, PhD, DABT www.asmalldoseof.org

  2. A Small Dose of Toxicology See: www.asmalldoseof.org -- smdose

  3. Child Health

  4. The First Bioethicist Aldo Leopold "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." - Aldo Leopold, 1949, A Sand County Almanac ---------- 1887 - 1948 ----------

  5. Limits on Freedom “An ethic, ecologically, is a limitation on freedom of action in the struggle for existence” Aldo Leopold

  6. “The Commons” The Tragedy of the Commons By Garrett Hardin, Science, 1968

  7. Technical Solutions “It is our considered professional judgment that this dilemma has no technical solution.” The Tragedy of the Commons By Garrett Hardin, Science, 1968

  8. Problems – Solutions? • Lead and kids • Fetal alcohol syndrome • Nuclear disarmament • Bioterrorism • Ocean Fisheries • Persistent chemicals • The Commons

  9. Toxicology Definitions The study of poisons or the adverse effects of chemical and physical agents on living organisms.

  10. Human & Environmental Health “Conditions that ensure that all living things have the best opportunity to reach and maintain their full genetic potential.” Steven G. Gilbert, 1999

  11. What do these have in common? • Hong Kong • Princess Diana • Ambassador to Mexico • Coeur d’Alene, Silver Valley, ID • Tacoma • Seattle Schools • $100 Billion, $65 Billion • Food, noise, dust • 11,000 to 689,000 Children

  12. Who are these white guys?

  13. What Is This? O CH3 CH3 N N 7 1 3 O N N CH3

  14. Hazard + Exposure = Risk Key Words of Toxicology Dose / Response Individual Susceptibility

  15. Effects of Amount on Response

  16. Effects of Size on Response

  17. Thalidomide • Introduced in 1956 as sedative (sleeping pill) and to reduce nausea and vomiting during pregnancy • Withdrawn in 1961 • Discovered to be a human teratogen causing absence of limbs or limb malformations in newborns • 5000 to 7000 infants effected • Resulted in new drug testing rules

  18. H H C C OH H H H What Is This? (CH3-CH2-OH)

  19. FAS Child

  20. The Mercury Cycle

  21. Canfield et al…, 2003 “Conclusions: Blood lead concentrations, even those below 10 mgc/dL, are inversely associated with children’s IQ scores at three and five years of age, and associated declines in IQ are greater at these concentrations than at higher concentrations. These findings suggest that more U.S. children may be adversely affected by environmental lead than previously estimated.” Canfield et al. 2003, NEJM, 384

  22. What Is Plumbun? Plumbing is derived from plumbun, Latin for lead

  23. Lead In Homes

  24. Lead in Families

  25. Ancient Awareness • 6500 BC. - Lead discovered in Turkey, first mine. • 500 BC-300 AD.- Roman lead smelting produces dangerous emissions. • 100 BC. - Greek physicians give clinical description of lead poisoning.

  26. Ancient Awareness "Lead makes the mind give way." Greek Dioscerides - 2nd BC

  27. Historical Awareness “If we were to judge of the interest excited by any medical subject by the number of writings to which it has given birth, we could not but regard the poisoning by lead as the most important to be known of all those that have been treated of, up to the present time.” Orfila, 1817

  28. L. Sullivan, 1991 “Lead Poisoning remains the most common and societal devastating environmental disease of young children.” Public Health Service - L. Sullivan, 1991

  29. Lead Based Paint Products

  30. Lead Based Paint 1887 - US medical authorities diagnose childhood lead poisoning 1904 - Child lead poisoning linked to lead-based paints 1909 - France, Belgium and Austria ban white-lead interior paint 1914- Pediatric lead-paint poisoning death from eating crib paint is described 1921 - National Lead Company admits lead is a poison 1922 - League of Nations bans white-lead interior paint; US declines to adopt 1943- Report concludes eating lead paint chips causes physical and neurological disorders, behavior, learning and intelligence problems in children 1971- Lead-Based Paint Poisoning Prevention Act passed

  31. Lead Industry Advertisements History of Lead Industry Advertisements (LINK) http://www.cincinnatichildrens.org/research/project/enviro/hazard/lead/lead-advertising/default.htm http://www.cincinnatichildrens.org/research/project/enviro/hazard/lead/lead-advertising/default.htm

  32. Lead In Gasoline 1854 - Tetraethyl lead discovered by German chemist 1921 - Midgley discovers that tetraethyl lead curbs engine knock 1922 - Public Health Service warns of dangers of lead production, leaded fuel 1923 - Leaded gasoline goes on sale in selected markets 1936 - 90 percent of gasoline sold in US contains Ethyl 1972 - EPA gives notice of proposed phase out of lead in gasoline. 1986 - Primary phase out of leaded gas in US completed 1994 - Study shows that US blood-lead levels declined by 78 percent from 1978 to 1991 2000 - European Union bans leaded gasoline

  33. Agency Blood Lead Levels

  34. Health Effects • Encephalopathy • Colic • Frank Anemia • Hemoglobin Synthesis • Peripheral Neuropathies • Infertility (MEN) • Systolic Blood Pressure (MEN) • Nerve Conduction Velocity • Erythrocyte Protoporphyrin • DEVELOPMENTAL TOXICITY • IQ, Memory, Learning • Growth

  35. Reproductive Effects Of Lead • WOMEN • lead crosses the placenta • low infant birth weight • retarded mental development • miscarriages • premature birth • stillbirth • MEN • decreased sex drive • impotence • sterility • altered sperm-birth defects

  36. CHILDRENADULTS Blood Lead (ug Pb/dl) 150 Death Encephalopathy 100 Encephalopathy Frank Anemia Nephropathy Frank Anemia Decreased Longevity Colic Hemoglobin Synthesis 50 Peripheral Neuropathies Infertility (MEN) Hemoglobin Synthesis 40 Nephropathy Systolic Blood Pressure (MEN) Vitamin D Metabolism 30 Hearing Acuity 20 Nerve Conduction Velocity Erythrocyte Protoporphyrin Erythrocyte Protoporphyrin (Women) Vitamin D Metabolism(?) DEVELOPMENTAL TOXICITY 10 Hypertension (?) IQ HEARING Transplacental Transfer GROWTH - Low birth weight - Miscarriages, Stillbirth - Premature birth

  37. Sources Of Lead • Lead Paint • Dust, Soil • Water • Industry • Hobbies • Traditional Ethnic Remedies

  38. Lead Contaminated Town Herculaneum, Missouri Doe Run – Lead smelter 160,000 tons of lead per year One of the largest lead smelters in US Past over 800 tons of lead released into the environment as part of the smelting process. Reduced to 81 tons in 2001 Target is 34 tons in 2002. NY Times, Jan 19, 2002

  39. Lead Out of Gasoline 1990 – lead removed from Gasoline Between 1976 and 1994, the mean blood lead concentration in children dropped from 13.7 mcg/dL to 3.2 mcg/dL One of the major public health triumphs of the 20th century

  40. Take Home Lead Exposure California, 1998 Lead poisoning in furniture workers and their families Father 46 µg/dL 18-month-old child BLL 26 µg/dL 4-month-old daughter BLL 24 µg/dL two refinishers BLLs of 29 and 54 µg/dL, the four carpenters BLLs of 46, 46, 47, and 56 µg/dL. MMWR - April 06, 2001 / 50(13);246-8

  41. Children Vulnerability CHILDREN are more vulnerable exposure than ADULTS Size Consume More Food Inhale More Air Developing Nervous System Increased need for Calcium

  42. Lead - Absorption Orally Consumed Lead Absorbed In Place of Calcium CHILDREN – 30-50% OF LEAD ADULTS – 5-10% OF LEAD Increased During Pregnancy

  43. Lead - Nutrition NUTRITIONAL DEFICIENCIES INCREASE ABSORPTION (high fat diets, iron, calcium) VITAMIN D (from sun) INCREASES

  44. Half-life Of Lead • 25 DAYS -- BLOOD • 40 DAYS -- SOFT TISSUE • 20 YEARS -- BONE

  45. Needleman, NEJM, 1979

  46. Lead-associated Reading Deficits in U.S. Children Reading Score Blood lead levels (g/dl) Lanphear BP, et al. Public Health Reports 2000;115:521-529. (BL’s slide)

  47. IQ and Blood Lead • Life time overall • Increase in 1 mcg/dl = 0.87 IQ drop • Covariates - 1 mcg/dl = 0.46 IQ drop • 1 to 10 mcg/dl (bigger drop) • Increase in 1 mcg/dl = 1.37 IQ drop • Non-linear - 1 mcg/dl = 0.74 IQ drop Canfield R, et al. NEJM 2003;348:1517-1526

  48. IQ and Blood Lead Canfield R, et al. NEJM 2003;348:1517-1526. (slide from BL)

  49. Consequences

  50. Childhood Lead Exposure -- LONG TERM PROBLEMS -- • LOW GRADES • • ABSENTEEISM • • READING DISABILITY • • HIGH SCHOOL DROP OUT •

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