Скачать презентацию Association between children s blood lead levels lead service Скачать презентацию Association between children s blood lead levels lead service

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Association between children’s blood lead levels, lead service lines, and use of chloramines for Association between children’s blood lead levels, lead service lines, and use of chloramines for water disinfection in Washington DC, 1998 -2006 Jaime Raymond, MPH Lead Poisoning Prevention Branch National Center for Environmental Health Centers for Disease Control and Prevention

Introduction l DC Water and Sewer Authority (WASA) modified its drinking water disinfectant process Introduction l DC Water and Sewer Authority (WASA) modified its drinking water disinfectant process in preparation of the Disinfection Byproducts Rule (EPA 2006 a) l In late 2000, DC WASA began using chloramine as a disinfectant for drinking water to reduce the byproducts in the drinking water l New disinfectant process raised concerns of possible leaching of lead into the drinking water

Background l Chloramine strips the mineral scale from water services lines entering residences l Background l Chloramine strips the mineral scale from water services lines entering residences l Lead Service Lines – These lines connect the water main to the house l EPA standard for lead in drinking water is 15 ppb

Objective Examine the association between childhood blood lead levels (BLL), exposure to lead service Objective Examine the association between childhood blood lead levels (BLL), exposure to lead service lines (LSL), and chloramine as a water disinfectant in Washington DC from 1998 - 2006

Hypotheses l Association between LSL and BLL among children < 6 years of age Hypotheses l Association between LSL and BLL among children < 6 years of age living in Washington DC. l Association between chloramine use and BLL among children < 6 years of age living in Washington DC. l Synergistic concomitant association between chloramine use and LSL and increasing BLL within this population.

Methods Study Design Cross-sectional study conducted to examine association between LSL, chloramine use, and Methods Study Design Cross-sectional study conducted to examine association between LSL, chloramine use, and BLL between 1998 and 2006 in Washington DC

Methods (2) Study Population l 49, 084 unique children received a blood lead test Methods (2) Study Population l 49, 084 unique children received a blood lead test between 1998 and 2006 l 26, 141 dwellings had LSL during the same time period (Data from DC WASA) l 6, 670 children tested lived in a dwelling with a LSL (16, 311 children tested lived in a dwelling without a LSL) l 22, 981 – Final sample size

Methods (3) Variables Examined Primary Exposure variables l LSL l Chloramine use (pre, during, Methods (3) Variables Examined Primary Exposure variables l LSL l Chloramine use (pre, during, post) Primary Outcome variable l BLL (≥ 5 µg/d. L, ≥ 10 µg/d. L) Covariates l Gender l Age at time of test l Sample type l Age of housing unit l Year of BL test

Methods (4) Analysis Plan l Univariate analyses conducted to examine first order associations l Methods (4) Analysis Plan l Univariate analyses conducted to examine first order associations l Generalized Linear Models developed to examine trends in BLL over time: pre, during, and post chloramine use l Multiple logistic regression models developed to describe interaction and control for confounding

Univariate Analysis Characteristic Gender Male Female Unknown Age 0 -11 months 12 -23 months Univariate Analysis Characteristic Gender Male Female Unknown Age 0 -11 months 12 -23 months 24 -35 months 36 -47 months 48 -72 months Sample Type Capillary Venous Unknown < 5 µg/d. L n % Blood Lead Levels 5 - 9 µg/d. L n % ≥ 10 µg/d. L n % Chi-Square p-Value 18, 205 17, 574 738 49. 9 48. 1 2. 0 5, 247 4, 772 228 51. 2 46. 6 2. 2 1, 217 1, 080 23 52. 5 46. 5 1. 0 < 0. 0001 6, 216 7, 003 6, 631 5, 498 11, 169 17. 0 19. 2 18. 2 15. 1 30. 5 1, 685 1, 928 2, 223 1, 720 2, 691 16. 4 18. 8 21. 7 16. 8 26. 3 385 476 546 364 549 16. 6 20. 5 23. 5 15. 7 23. 7 <0. 0001 1, 492 29, 535 5, 490 4. 1 80. 9 15. 0 515 7, 986 1, 746 5. 0 77. 9 17. 1 55 2, 134 131 2. 4 91. 9 5. 7 <0. 0001

Univariate Analysis (2) Characteristic Chloramine Use Pre-Chloramine During Chloramine Post Chloramine Age of Housing Univariate Analysis (2) Characteristic Chloramine Use Pre-Chloramine During Chloramine Post Chloramine Age of Housing Pre- 1950 1951 -1978 Post 1978 Unknown < 5 µg/d. L n % Blood Lead Levels 5 - 9 µg/d. L n % ≥ 10 µg/d. L n % Chi-Square p-Value 9, 719 17, 147 9, 651 26. 6 47. 0 26. 4 4, 042 4, 916 1, 289 39. 4 48. 0 12. 6 976 1, 086 258 42. 1 46. 8 11. 1 <0. 0001 12, 484 1, 469 642 21, 922 34. 2 4. 0 1. 8 60. 0 4, 588 258 108 5, 293 44. 8 2. 5 1. 1 51. 7 1, 300 43 11 966 56. 1 1. 9 0. 4 41. 6 <0. 0001

Univariate Analysis (3) Characteristic Lead Service Line Yes No Unknown Sample Year 1998 1999 Univariate Analysis (3) Characteristic Lead Service Line Yes No Unknown Sample Year 1998 1999 2000 2001 2002 2003 2004 2005 2006 < 5 µg/d. L n % Blood Lead Levels 5 - 9 µg/d. L n % ≥ 10 µg/d. L n % Chi-Square p-Value 4, 329 13, 732 18, 456 11. 9 37. 6 50. 5 1, 863 2, 069 6, 315 18. 2 20. 2 61. 6 568 420 1, 332 24. 5 18. 1 57. 4 <0. 0001 1, 984 3, 776 3, 959 3, 780 4, 019 3, 039 6, 309 5, 430 4, 221 5. 4 10. 3 10. 8 10. 4 11. 0 8. 3 17. 3 14. 9 11. 6 998 1, 714 1, 330 1, 450 1, 418 846 1, 202 641 648 9. 7 16. 7 13. 0 14. 2 13. 8 8. 3 11. 7 6. 3 386 328 262 338 294 200 254 124 134 16. 6 14. 1 11. 3 14. 6 12. 7 8. 6 10. 9 5. 3 5. 8 <0. 0001

Percentage of children with EBLL, by year and water-line type Percentage of children with EBLL, by year and water-line type

Associations of BLL between LSL and chloramine use During use of Chloramine (2001 -2004) Associations of BLL between LSL and chloramine use During use of Chloramine (2001 -2004) Post Chloramine use (2005 - 2006) LSL No LSL POR 95% CI ≥ 5 µg/d. L 1, 343 1, 250 3. 0 (2. 7, 3. 3) 244 1, 216 1. 4 (1. 2, 1. 7) < 5 µg/d. L 2, 062 5, 698 1, 122 8, 003 ≥ 10 µg/d. L 292 229 2. 8 (2. 3, 3. 3) 50 184 1. 9 (1. 4, 2. 6) < 10 µg/d. L 3, 113 6, 719 1, 316 9, 035 POR = Prevalence Odds Ratio

Adjusted multivariate model for BLLs ≥ 5 µg/d. L among children < 6 years Adjusted multivariate model for BLLs ≥ 5 µg/d. L among children < 6 years of age living in Washington DC Variable Adjusted Model Parameter Estimates Age of Housing (referent = post 1978) OR 95% CI P-value Pre-1978 1. 5 (1. 3, 1. 8) <0. 0001 Pre-1950 2. 3 (1. 9, 2. 8) <0. 0001 Lead Service Line (LSL) 4. 4^ <0. 0001 Chloramine Use 0. 2225 <0. 0001 LSL*Chloramine Use 0. 2178 <0. 0001 ^ Represents the OR for a child living in a house with a LSL, when chloramine was used

Adjusted multivariate model for BLLs ≥ 10 µg/d. L among children < 6 years Adjusted multivariate model for BLLs ≥ 10 µg/d. L among children < 6 years of age living in Washington DC Variable Adjusted Model OR 95% CI P-value Sample Type (referent=capillary) 3. 6 (1. 9, 6. 5) <0. 0001 Pre-1978 2. 1 (1. 4, 3. 1) 0. 0004 Pre-1950 4. 2 (3. 7, 4. 9) 0. 0004 Lead Service Line (LSL) 2. 7 (2. 2, 3. 2) <0. 0001 Chloramine Use 1. 4 (1. 3, 1. 5) <0. 0001 Age of Housing (referent = post 1978)

Graphic interpretation of interaction between LSL and chloramine use for BLLs ≥ 5 µg/d. Graphic interpretation of interaction between LSL and chloramine use for BLLs ≥ 5 µg/d. L

Discussion l Age of Housing continued to be significantly associated with BLLs ≥ 5 Discussion l Age of Housing continued to be significantly associated with BLLs ≥ 5 µg/d. L and ≥ 10 µg/d. L even after controlling for confounders. l Lead paint in older housing continues to be the main source of lead exposure in children < 6 years of age u u Chipping and peeling paint Lead paint dust

Discussion (2) l LSL – Children who were tested and had BLL ≥ 5 Discussion (2) l LSL – Children who were tested and had BLL ≥ 5 µg/d. L or ≥ 10 µg/d. L were significantly more likely to have lived in a HU with a LSL compared to children with lower BLLs even after adjusting for confounders. l LSL are found across Washington DC l Possible that children with BLLs <5 µg/d. L or <10 µg/d. L u u Lived in a HU that had a non-lead service line Tended to drink bottled water

Discussion (3) l Chloramine use – The proportion of children tested with BLL ≥ Discussion (3) l Chloramine use – The proportion of children tested with BLL ≥ 5 µg/d. L or ≥ 10 µg/d. L was significantly higher during the time that chloramine use was in effect compared to after use was discontinued. l Chloramine may have stripped the lead from LSL resulting in subsequent leaching into the drinking water.

Discussion (4) l There is a significant interaction between LSL exposure and chloramine use Discussion (4) l There is a significant interaction between LSL exposure and chloramine use among children with BLLs ≥ 5 µg/d. L l Concomitant use of chloramine and LSL resulted in a significant increase in the proportion of children with BLLs ≥ 5 µg/d. L because of the leaching of lead from the LSL during the use of chloramine as the water disinfectant.

Conclusion l The use of chloramine in the water system as a water disinfectant Conclusion l The use of chloramine in the water system as a water disinfectant may have caused LSL to leach lead into the water, contributing to the raise of BLLs in young children. l Eliminating chloramine as a drinking water disinfectant dramatically reduced BLLs in children < 6 years old in Washington DC.

Conclusion (2) l Lead paint in older housing (pre-1950, pre 1978) continues to be Conclusion (2) l Lead paint in older housing (pre-1950, pre 1978) continues to be a significant source of lead exposure in children < 6 years of age living in Washington DC. l There is no safe level of lead and all exposure to this environmental hazard should be avoided.

Thank you! Co-Investigators Chinaro Kennedy, Dr. PH, MPH (Team Leader, Epi and Surveillance Section, Thank you! Co-Investigators Chinaro Kennedy, Dr. PH, MPH (Team Leader, Epi and Surveillance Section, Lead Poisoning Prevention Branch, CDC) Mary Jean Brown, Sc. D, RN (Chief, Lead Poisoning Prevention Branch, CDC)