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All ages study of blood-lead and bone-lead in urban Toronto: lessons learned from a collaborative study. T Arbuckle, F McNeill, M Inskip , D Chettle, WI Manton, M Fisher, N Healey, R Bray, L. Marro

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slide1

All ages study of blood-lead and bone-lead in urban Toronto: lessons learned from a collaborative study

T Arbuckle, F McNeill, M Inskip, D Chettle, WI Manton, M Fisher, N Healey, R Bray, L. Marro

Main funding: Health Canada, [Chemicals Surveillance Bureau, Environmental and Radiation Health Sciences Directorate]

co investigators and groups

Co-investigators and groups

Health Canada

Tye Arbuckle (Co -PI)

Mandy Fisher

Mike Inskip (now with McMaster University)

Norm Healey (now with Azimuth Consulting Group)

Leonora Marro

Department of Health Physics, McMaster Univ

David Chettle

Fiona McNeill (Co-PI)

SepidehBehinaein (Ph.D student)

University of Texas at Dallas

William Manton

Hospital coordinating centre– St Joseph’s Hospital, Toronto

Jessica Tyrwhitt

Toronto Public Health

Riina Bray

talk outline
Talk outline
  • Goals, study design and context
  • Techniques used
  • Results so far …..
  • Lessons learned
  • Discussion / summary
study goals
Study goals

The first Canadian study that we are aware of which attempts to measure bone Pb in young children. The pilot study goals were to demonstrate:

  • the feasibility of including in vivo XRF measurements of Pb in bone for young children in future surveys [like the ‘Canadian Health Measures Survey’]
  • the feasibility of 1) remote bone Pb measurements;
  • 2) partnership with a local community health centre for recruitment and subject measurement;
  • 3) quantification of serum Pb concentrations in environmentally exposed subjects
  • 4) recruitment of childhood subjects for venous blood sampling;
  • 5) development and delivery of appropriate risk communication materials.
testing and recruitment success total 263 272 participants
Testing and recruitment successTOTAL: 263/272 Participants

Age ExpectedTested

Males FemalesMales Females

1 to 5 10 10 10 6

6 to 10 23 20 23 16

11 to 19 23 20 23 20

20 to 35 21 25 21 25

36 to 50 25 29 25 29

51 to 64 21 24 21 24

65 to 85 10 11 9 11

Total 133 139132 131

  • 1 participant cancelled; 2 participants did not assent to participate in the study;
  • 5 appointments were cancelled - equipment malfunction (participants rescheduled)
methods techniques for success plans and reality 1
Methods / techniques for success:plans and reality #1
  • Very effective (and persistent) hospital coordinator for reaching potential volunteers / scheduling visits
  • Patient-friendly & very skilled child phlebotomist and measuring staff and well-designed procedures for family groups being measured + questionnaire time allowed.
  • Financial ($50) incentive
  • YES
  • YES – but early-on suspected a brief contamination event; Used TV games and books & adult distractions to keep children engaged
  • YES – but poorer participation rate by younggirls vs the boys
methods techniques for success plans and reality 2
Methods / techniques for success:plans and reality # 2
  • Training for obtaining serum samples (Class-100 clean room, gloves etc., centrifuge on site) and pre-cleaned sample tubes, sample dispatch processes.
  • Choice of experienced analytical lab for Pb
  • Communications with volunteers about health risk by Toronto Public Health personnel very familiar with PbB exposure routes in homes.
  • YES – but Couriers lost one batch of samples
  • YES: …although challenges.
  • Low blood lead values did not necessitate many home visits.
1 st blood sample venipuncture for whole blood and hematocrit
1st blood sample - venipuncture for:whole blood and hematocrit

Bluetop Vacutainer

tube

Place a drop of blood sample onto slide and draw

into a capillary tube.  The capillary tube is then spun to

separate the red blood cells from the plasma at which

time a Hematocrit value can then be measured. 

2 nd sample venipuncture for blood serum sample
2nd sample : Venipuncture for:blood serum sample

to measure a person’s Hematocrit is by

  • Use butterfly +syringe to slowly collect
  • 5ml blood. Remove butterfly tip, leave sample stand 20 minutes.
  • NB The following are done in CLEAN BOX
  • Slowly transfer blood to centrifuge tube*
  • Spin down using bench centrifuge
  • Decant plasma (Special tip*) into Teflon jar*
  • Record patient I.D. against jar number
  • Tighten lid & freeze sample
  • * provided
why is use of a hepa clean box class 100 air important
Why is use of a HEPA Clean Box (Class-100 air) important?
  • Differences: at least 100 times (!) less Pb is present in Plasma vs. whole blood
    • E.g., If PbB = 1 ug/dL, plasma Pb = 0.01 ug/dL or 100 pg/ml
  • Where things can get contaminated
    • Pb on airborne particles
    • Pb on hands or any surfaces.
    • One speck of dust enough to contaminate sample
    • Pb can also leach-out from plastics
blood collection protocol
Blood collection protocol
  • Blood volume: the phlebotomist must do their best to obtain as much as possible - up to the desired amount of 5mL.
  • For the serum sample, the tube is left to stand for 20 minutes
  • After centrifuging, a dedicated pipeter is used to transfer plasma; when not in use, it is kept in the clean box as the photo shows (hanging).
  • The rack of pre-cleaned 15 mL teflon jars and the centrifuge tubes must never leave the clean box.
  • The transfer of the supernatant plasma to the tubes must be done in the box.
slide15

Systematic representation of vascular organisation

in the diaphysis of a long-bone (From Mayo Foundation

for Medical Education and Research)

summary
Summary
  • Blood lead levels were lower than expected …but in the range found for the CHMS survey; Lead levels in serum required special attention for analysis
  • Serum lead levels were so low that the Texas laboratory had to develop a new technique to measure them.
  • Special attention to training of collection staff was a good investment (and critically important for obtaining reliable data).
  • Bone lead data were successfully obtained for young children by in vivo XRF; Themethod is being further evaluated as a tool for measuring children’s skeletal burden.
  • A multi-disciplinary team approach was considered essential for this study.
summary 2
Summary (2)
  • Analysis of data continues: e.g.:
    • Bone/PbB/serum data
    • Questionnaire results related to values
    • Additional information on isotope ratios in blood samples & possible source of environmental Pb
ad