Child Lead Exposure and Testing in Alaska

Transcription

1 Child Lead Exposure and Testing in Alaska Jonathan Bressler Environmental Public Health Program Section of Epidemiology Alaska Department of Health and Social Services

2 Lead: The Basics Soft metal that makes up a small percentage (0.002%) of the earth s crust. Exists naturally as a sulfur compound with zinc ore, or with other minerals. Has been mined and used for centuries for it s desirable properties Easy to mine and recycle Malleable/soft Doesn t biodegrade Resists corrosion High density with low melting point Abundant, low cost Byproduct of mining for other metals/minerals

3 Lead: The Basics Inorganic Lead TOXIC Organic Lead TOXIC + dermal & enhanced absorption Lead Acetate Lead Carbonate

4 Lead: The Basics Organic Lead Some grades of aviation fuel in US Piston-engine airplanes Leaded gasoline Still being phased out in some countries

5 Lead: The Basics Inorganic Lead Paints, construction materials, pipes, plumbing Ammunition, fishing weights Solder, batteries, copper alloys, ballasts, scuba diving weights, radiation shields Banned in house paint Still used for paint on bridges, ships, highway overpasses, railways Some imported products: spices, traditional remedies, ceramics, cosmetics, amulets/charms/jewelry, toys, candy

6 Lead in the human body Mimics/displaces calcium and other minerals Interferes with neurotransmitter release and cellular metabolism Has toxic effects on multiple organ systems Nervous, renal, cardiovascular, endocrine, hematological More toxic for fetuses and children Higher absorption from GI tract Disrupts normal development of brain and other organs No truly safe level of exposure Children are more likely to be exposed Higher consumption of air, water, soil, dust More time on floor and ground Hand to mouth and mouthing behaviors More risk for non-dietary ingestion WHO. Childhood Lead Poisoning

7 Lead in the human body 2 nd hand smoke Dust Inhalation Air Pollution Breastmilk Ingestion Dust Soil Food Water Swallowing non-food Items Dermal Transplacental

8 Lead in the human body Body Blood Soft Tissue/organs Up to 73-94% of total body burden of lead stored in bones and teeth Feces 36-day halflife Kidneys Urine Bones 27-yr halflife Released from bones back into bloodstream: Pregnancy Lactation Physiological stress Broken bones Hyperthyroidism, kidney disease, chronic illness Advanced age Calcium deficiency

9 IQ as a Function of Lifetime Average Blood Lead Lead: Toxicity Concentration. Canfield RL et al. N Engl J Med 2003;348:

10 Reuben et al., JAMA. 2017; 317(12):

11 Health Effects

12 National Policies and Testing

13 Policy History Lead poisoning prevention policies and BLLs in children aged 1 5 years, CDC, Brown MJ 2012

14 Elevated Blood Lead Level (EBLL) Prior to 2012: Blood lead level of concern 10 µg/dl Identified children who require case management After 2012: Blood lead reference level 5 µg/dl

15 Policy History CDC Advisory Committee on Childhood Lead Poisoning Prevention 2012 Summarized evidence that there is no threshold for lead toxicity Recommended reference value based on national 97.5 th percentile of BLL distribution for children 1-5 yrs old For , this was 5 µg/dl Reference value should be reconsidered every four years based on data

16 Blood Lead Levels United States, Distribution of BLLs in U.S. children under 72 months of age Reference level is progressive Stays at 97.5 th percentile Revised every four years 2012: 5 µg/dl 2016: 5 µg/dl 2018/2019: might change to 3.5 µg/dl

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18 Lead in Alaska

19 Lead policy history in Alaska

20 Lead policy history in Alaska

21 Policy History Lead poisoning prevention policies and BLLs in children aged 1 5 years, CDC, Brown MJ 2012

22 Blood Lead Testing Among Children <72 months of Age Alaska and U.S., Year Children tested Pop. Total United States % tested BLLs 5 µg/dl EBLL prev.* Children tested Pop. Total Alaska % tested BLLs 5 µg/dl EBLL prev.* ,070, , % % ,938, , % % ,418, , % % ,675, , % % ,415,604 79, % 1, % *Prevalence among tested

23 Blood Lead Testing Among Children <72 months of Age Alaska and U.S., Year Children tested Pop. Total United States % tested BLLs 5 µg/dl EBLL prev.* Children tested Pop. Total Alaska % tested BLLs 5 µg/dl EBLL prev.* ,070,635 24,452, % 224, % , % % ,938,161 24,324, % 154, % , % % ,418,668 24,209, % 101, % , % 6 1.0% ,675,145 24,205, % 100, % , % % ,415,604 24,219, % 79, % 1,641 63, % % *Prevalence among tested

24 Differences in Child Blood Lead Levels in AK and U.S. Among children tested , EBLL prevalence was lower for Alaska children than all U.S. children Less exposure Newer housing less lead-based paint National strategies that target BLL testing to areas with old housing identify more EBLLs Less practical in Alaska

25 Differences in Child Blood Lead Levels in AK and U.S. Among children tested , EBLL prevalence was lower for Alaska children than all U.S. children Less exposure Newer housing less lead-based paint National strategies that target BLL testing to areas with old housing identify more EBLLs Less practical in Alaska Occupied Housing Units Year Structure Built Alaska U.S or later 0.3% 0.4% 2010 to % 2.1% 2000 to % 14.7% 1980 to % 27.8% 1960 to % 26.5% 1940 to % 16.0% 1939 or earlier 1.5% 12.6% U.S. Census: ACS yr Estimates

26 Differences in Child Blood Lead Levels in AK and U.S. Still no safe level for lead toxicity For , 266 of 4962 tested (5.4%) had BLL 3.5 µg/dl 80 (1.6%) with BLL 5 µg/dl Low testing statewide implies many unidentified EBLLs As blood lead levels come down nationally, Alaska will cease to be an outlier for elevated BLLs. Reference level may decrease

27 Child Lead Exposure in Alaska

28 Identified through telephone follow-up. Section of Epi does not conduct on-site environmental investigations

29 Exposure Sources

30 Testing Children for Lead Exposure

31 Testing for Lead Capillary test: LeadCare II Minimally invasive, point-of-care, portable CLIA-waived; Proficiency Testing recommended Inappropriate for venous samples Detection limit: 3.3 µg/dl 50 µl of blood Other capillary tests Any lab AK State PH lab RAM Scientific Safe-T-Fill 200 µg All elevated capillary tests MUST be confirmed with a venous test Venous test Required for confirmatory testing CLIA certified high complexity tests

32 Screening & Testing Protocols as of 2017 Test all Medicaid-eligible children at ages 12 and 24 months, or before 72 months if not previously tested Assess all children aged <18 years, particularly those <72 months, for lead risk factors Test children with one or more risk factors Risk questionnaire available online:

33 Recent testing: both Medicaid and non-medicaid Lead Testing among Alaska Children 0-4 years of age, October 2017 June years of age Tests EBLLs %EBLL 2017 Pop. Est.* % Tested Anchorage % 21, % Gulf Coast Region % 5, % Interior Region % 8, % Mat-Su % 7, % Northern Region % 2, % Southeast Region % 4, % Southwest Region % 4, % Total % 54, % * Population estimates from U.S. Census / Alaska Department of Labor and Workforce Development Total includes Alaska children with missing city of residence in data.

34 Lead Risk Questionnaire for Non-MEC /LeadRiskAssessmentTool_Child.pdf

35 Lead Risk Questionnaire for Non-MEC 1. Does your child live in or visit homes, day care centers or other buildings built before 1978? Alaska Occupied Housing Units Year Structure Built Estimate 2014 or later 0.3% 2010 to % 2000 to % 1980 to % 1960 to % 1940 to % 1939 or earlier 1.5% 41.4% U.S. Census: ACS yr Estimates

36 Clinical Interventions BLL 5 µg/dl 5 44 µg/dl Obtain venous BLL, CBC with diff, retic. count, ZPPH*, Fe+; LFTs/iron studies if >15 µg/dl; AXR Consult specialist if > 20 µg/dl Confirm BLL isn t rising, then retest in 3 months >44 µg/dl Confirm venous BLL within 48 hr.; ensure cardiopulmonary and neurological stabilization, discuss indications for hospital admission and chelation As above + Renal function studies, UA, IV placement Consult with specialist In all children: Identify and eliminate potential sources of lead exposure Ensure appropriate developmental screenings Reduce risk of future exposure by Treating anemia, providing guidance on diet high in iron/vitc and Calcium (decreases GI absorption) Educating parents on ways to prevent/reduce lead exposure

37 Public Health Reporting Law Providers & labs required to report all BLLs to Section of Epidemiology 5 µg/dl for all ages: within 1 week All other levels: within 4 weeks Reporting form available:

38 Public Health Reporting Law 7 AAC Reporting of blood lead test results (a) Not later than one week after receiving the results of a blood lead test that exceeds 5 micrograms per deciliter, a health care provider shall report to the department (1) the name and address of the health care provider that requested the test; and (2) the person s (A) name; (B) date of birth; (C) sex; (D) race; (E) ethnicity; (F) community of residence; and (G) test results in micrograms per deciliter, including the date of the test, and the type of test (venous or capillary) (b) A public, private, military, hospital, other laboratory, or health care provider performing blood lead analyses in this state or on samples obtained in this state shall report, not later than four weeks after performing the test, (1) the name, date of birth, sex, race, ethnicity, and community of residence of the person tested; (2) the test result in micrograms per deciliter, including the date of the test, and type of test (venous or capillary); and (3) the name and address of the health care provider that ordered the test.

39 Thanks! Jonathan Bressler (907) leadfree.dhss.alaska.gov Environmental Public Health Program Section of Epidemiology Pages/lead/default.aspx

40 ZPPH ZPPH/ZPP: Zinc Protoporphyrin Indirect Measure of Lead exposure Lead interferes with heme production in red blood cells, heme intermediate, protoporphyrin IX incorporates a zinc ion to form ZPP instead of incorporating a ferrous ion to form heme. Measures biological effect (build up of protoporphyrin in red blood cells) Occurs at exposure levels around 25ug/dL or greater Not useful for screening Majority of exposures happen at level below 25ug/dL Not specific to lead, can also be elevated due to anemia or other underlying diseases May be useful in identifying timing of higher level chronic + ongoing exposure Elevated BLL and Normal FEP/ZPP = Recent exposure (2-6 weeks) Elevated BLL and Elevated FEP/ZPP = Chronic/ongoing exposure (3-4 months)