Radionuclides in baby teeth: environmental exposure markers and association with childhood cancer

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1 Radionuclides in baby teeth: environmental exposure markers and association with childhood cancer Sumi Hoshiko, MPH Environmental Health Investigations Branch California Department of Public Health Western Regional Epidemiology Network Ashland, Oregon, May 15-16, 2008

2 Nuclear weapons testing overview Over 2000 nuclear weapons tests worldwide Nuclear weapons testing: above-ground tests by US US and Soviet Union moratorium Other countries continued to 1980 Additional 140 Peaceful Nuclear Explosions 800+ underground tests by US

3 Nuclear fallout and low-level environmental radiation NCI study; Gilbert et al 1998

4 St. Louis Baby Tooth Survey Large collaborative effort of Washington University, citizens, scientists, including Barry Commoner Committee volunteers mobilized, church, social organizations, Boy/Girl Scouts, YMCA/YWCA tooth collection (after nuclear testing started) US Public Health Service funded 300,000 baby teeth Strontium-90 analyzed Source: Washington University School of Dental Medicine:

5 US Public Health Service radionuclide monitoring 1954 US began in vivo monitoring Focus on Strontium-90 in human bone and teeth Sr-90 long half life (28.7 years) Autopsy studies - vertebrae of accident victims NYC, Chicago, San Francisco Dietary uptake in adults

6 US Government monitoring All in vivo monitoring programs discontinued by 1982 Monitoring of radionuclides in milk in 60 US cities Milk surveillance discontinued in 1990 after 33 years

7 St. Louis Baby Tooth Survey - Findings and Results Sr-90 levels rose 100-fold in children born Levels rose and fell in correlation with atomic bomb tests Tooth survey results contributed to decision to negotiate treaty with Soviet Union to end aboveground atomic testing in 1963

8 Radiation and Public Health Project In 2001, 85,000 unused baby teeth from the original study found in Washington Univ. basement Teeth donated to non-profit scientific/educational organization Radiation and Public Health Project

9 RPHP baby tooth study goals: Document current levels of Sr-90 since end of atmospheric testing Compare current Sr-90 patterns with those years ago Look at historic trends

10 Methods (2000 Study) Baby teeth solicited mainly from mass mailing of randomly selected households with children age 6 18 in 1999 Radio, print, television notices

11 Targeted Populations Near nuclear facilites: Western Suffolk County, NY Brookhaven nuclear research facility New Jersey Oyster Creek reactor Greater Miami area near 2 reactors Less exposed: Parts of Eastern Suffolk Parts of Queens, New York, northeastern NJ

12 Radiochemistry analysis (Waterloo, Ontario laboratory) Sr-90 activity per calcium Laboratory researchers blinded as to exposure status Sr-90 levels converted to levels at birth to standardize using half-life

13 Population 515 teeth analyzed by October 1999 for births ; final total in analysis = 476 Only 15 from , so omitted Few from less-exposed control areas of New York and New Jersey, so omitted Basic data collected: Mother & child name, address, phone birthdate birthweight residences - where mother carried child, birth place, and first year of life mother s age at birth of child age of child when tooth lost water source

14 Average and maximum concentrations of Sr-90 in baby teeth received by RPHP by October 1, 1999; births Sr-90, picocuries per gram calcium Area # teeth Average Maximum Western Suffolk (exposed) / Eastern Suffolk (less exposed) / Dade Co (Miami) (exposed) / Ocean County, NJ / (exposed) All other / All locations /

15 Results compared to St. Louis specimens Mean RPHP Sr-90 levels: 1.50 picocuries per gram calcium is roughly equivalent to that found in St. Louis children born in 1956, 5 years after start of nuclear testing in Nevada

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17 2003 study 2089 baby teeth tested Mainly from persons living near nuclear reactors: PA, NY, FL, NJ, CA, Other New counter, location, and method Reliability test: 10 teeth compared: REMS laboratory: 65 (95% CI=43-87) (mbq Sr-90 / gram calcium) University of Georgia: 79 (95% CI=56-102)

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19 Trend in gross beta in precipitation per liter of water; 60 US cities, average millibecquerels gross beta/ lite r o f p recip ita tio n

20 RPHP measurements of Sr-90 associations in baby teeth & childhood cancer Suffolk County children age teeth Mean annual concentrations in teeth 3-year moving average 3 year latency assumed; e.g. Sr-90 concentrations for are matched with cancer incidence for (best fit)

21 RPHP: Sr-90 in baby teeth and childhood cancer, Suffolk Co., NY

22 Gross alpha activity and childhood cancer, Suffolk County, New York

23 Commercial nuclear plants (source: Health Risks of Ionizing Radiation Russ, 2006; Clark University)

24 Sr-90 by state, baby teeth

25 Sr-90 in baby teeth, proximity to nuclear facilities

26 Risk of childhood leukemia near nuclear facilities Heasman 1984 Barton Barton Heasman 1986 Hole and Gillis Roman Roman Jablon Viel Viel Hoffman Guizard 0.1

27 Meta-analysis of childhood leukemia incidence in proximity to nuclear facilities SIR and 95% CI, random effects model , all areas 0-9, < 16 km 0-25, all areas 0-25, < 16 km Baker & Hoel, 2007

28 Meta-analysis of mortality rates for childhood leukemia in proximity to nuclear facilities SMR, 95% CI, random effects model , all areas 0-9, < 16 km 0-25, all areas 0-25, < 16 km Baker & Hoel, 2007

29 Some thoughts on risks and data Americans move frequently only 54% of Americans lived in the same house 5 years previously (2000 v. 1995) Environmental radiation relatively low but widespread Long latency for cancer - advantage of studying childhood cancer ages 0-4 Multi-generational risks ova of female fetus formed in utero

30 Goals: Exposure characterization: To gain additional knowledge on exposure patterns to better understand sources of exposure in the environment Are nuclear power plants adding to exposures in the US? How much? Health: Summarize current knowledge of risk of cancer from environmental radionuclide exposure Do we currently have enough information to adequately understand risk? Health: To quantify risk of cancer from environmental radionuclide exposure Should we be concerned?

31 Exposures How to study? Next steps? Environmental monitoring - additional Biomonitoring Health Surveillance baby teeth - California biomonitoring? Study of Sr-90 levels in teeth and risk factors (maybe children in occupationally exposed group?) Connecticut cancer data and radionuclide analysis independent re-analysis? Leukemia case-control study baby tooth testing Cohort analysis of St. Louis baby tooth data follow up for cancer outcomes