1 / 11

June 07, 2012

Nonlinearity in the relationship between bone lead concentrations and CBLI for an occupationally exposed group of participants. Sepideh Behinaein , David R Chettle , Lesley M Egden , Fiona E McNeill, Geoff Norman, Norbert Richard, and Susan Stever. PhD candidate

bono
Download Presentation

June 07, 2012

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nonlinearity in the relationship between bone lead concentrations and CBLI for an occupationally exposed group of participants SepidehBehinaein, David R Chettle, Lesley M Egden, Fiona E McNeill, Geoff Norman, Norbert Richard, and Susan Stever PhD candidate Supervised by Dr. David R Chettle June 07, 2012

  2. Outline What is CBLI Materials and Methods Linearity in CBLI and bone lead concentration Nonlinearity in CBLI and bone lead concentration

  3. What is CBLI? Cumulative blood lead index (CBLI): Blood Lead Level Pbi+1 Pbi ti ti+1 2008 Test Dates

  4. Lead metabolism in humans’ body

  5. Materials and Methods • 495 of smelter employees in the province of New Brunswick of Canada were measured for lead concentration in two different bone sites, left tibia and right calcaneus, each for 30 min. • Blood lead levels are available since 1967, where, depending on the exposure history, each employee has been measured for blood lead level at intervals of between one per month to one per year.

  6. Mean blood lead level as a function of test date • In 1976 to 1977 major improvements were made in occupational hygiene practices and • these resulted in a significant fall in PbB • There was a 10 month strike at the smelter from July 1990 to May 1991. • occupational health • the interruption in occupational exposure

  7. G1:Hired date between 1966 and 1976 (n= 63 R) DOB: [ 1927-1954] • G2: Hired date between 1966 and 1976 (n=89) DOB: [1923 (1)- 1946-1957] • G3: hired date between 1977 and 1991 (n=157) DOB:[1942-1971] • G4: Hired date after 1992 (n=185) DOB:[1945-1985] G1: 1923-1939 n=18 R G2: 1940-1950 n=85 (45 R) G3: 1951-1960 n=167 G4: 1961-1971 n=152 G5: 1972-1987 n=73 Hired date Age

  8. Hired Date Date of Birth

  9. the slope of bone versus CBLI is steeper when blood Pb is higher F1, 492, 0.999 = 10.95 Cal= (2.07±0.24) ×10-5 CBLI2 post + (0.0135±0.0038) CBLI post + (9.86±1.06) [n=495; R² = 0.7778; p< 0.001)]. Cal= (0.0452±0.0012)CBLI +( 4.38±0.94)R² = 0.7354

  10. the slope of bone versus CBLI is steeper when blood Pb is higher Ti = (1.04±0.16) ×10-5 CBLI2 post + (0.0142±0.0026) CBLI post + (5.47±0.74) [n=495; R² = 0.7614; p< 0.001)]. Ti= (0.0302±0.0008)CBLI + (2.73±0.63) R² = 0.732

  11. The nonlinearity in relationship is more solid for higher levels of exposure. • For the active group of workers, G2 and G3, there is a wide range of CBLIs (roughly 100 - 2200 µg.yrs/dL); whereas, for G4, CBLI is roughly ranged from 1 to 500 µg.yrs/dL; therefore, in groups G2 and G3, bone lead concentration can be expressed as a polynomial function of CBLI due to the wider range of CBLIs.

More Related