Blood Lead Levels in Kansas Children

1. Henri Ménager, MPH Epidemiologist Kansas Environmental Public Health Tracking Program Kansas Department of Health and Environment 68th Annual Kansas Public Health Association Fall Conference Wichita, KS - September 21-22, 2011 Blood Lead Levels in Kansas Children

2. Background: Lead (Pb) • Highly toxic soft metal • It’s heavy (atomic number 82) • Widely available in the crust of the earth • Cheap • Stable • Has been used in a variety of products including • Paint Gasoline • Ceramics Batteries • Pipes (drinking water) Cosmetics • Solders Pencils and bullets

3. Background: Signs and Symptoms • The effects of lead poisoning are often not apparent until high levels of lead have accumulated in the body. • In children • Irritability Learning difficulties • Loss of appetite Anemia • Weight loss Constipation • Fatigue or hyper activity Sleep disorders • Abdominal pain • Vomiting

4. Background: Signs and Symptoms • Even at low levels, the long-term effects can be devastating. That includes: • Nervous system and kidney damage • Learning disabilities • Speech, language, and behavior problems • Poor muscle coordination • Growth retardation • Hearing loss

5. How Does Lead Enter the Body? • Lead enters the body through the mouth or nose. • Lead is not absorbed through the skin.

6. Who is at risk? • Children • All children are at risk; especially younger children. The effects of lead poisoning are more severe in children less than 6 years old. • Children can be exposed to lead during fetal development. • Adults in some occupations • Welders • Battery plant workers • Others • Adults with some leisure activities • Minority populations • The poor

7. Sources of Contamination • Sources include • Soil • Water • Lead paint • Household dust • Imported canned food • Traditional remedies • Cosmetics • Amulets

8. How Does Lead Enter the Body? • Lead enters the body through the mouth or nose. • Lead is not absorbed through the skin.

9. Background: Efforts to Decrease Exposure to Lead • Since 1980, federal and state regulations have contributed to the reduction of lead in the environment and in consumer products. • In 1978, the US EPA reduced the amount of lead allowed in gasoline. • In 1986, Congress restricted the use of lead in pipes, solder, and other household items (Safe Drinking Water Act). • In 1995, the US banned the use of lead in food cans.

10. Background: Legal • Kansas Statutes Annotated (KSA) 65-1,200 through 65,1,214 authorize KDHE to maintain a database of blood lead tests administered to children and adults • The Healthy Homes and Lead Hazard Prevention Program (HHLHPP) database contains records dating from 1993. • Laboratories must report to KDHE the results of all blood test results (KAR 28-1-18).

11. Background: Study Purpose • This study focuses on blood tests of children 0 to 17 years old. • This study uses geometric mean as a more appropriate measure to compare entities.

12. Methods: Data Processing • Data from the STELLAR v. 4.0 database was used to conduct the analysis • all tests results with a sample drawn on or between January 1, 2000 and December 31, 2010 were included in the study • Each record represents a blood test, not an individual • Geometric mean rather than arithmetic mean was calculated using SAS® software version 9.2 • Tests with missing or invalid addresses were kept in the analysis as they may constitute a source of bias.

13. Methods: Geometric mean (gm) • Each test value (except for 0) was log-transformed • Mean and confidence intervals around the mean of the log-transformed values were calculated • All values were then exponentiated to obtain the gm and its confidence interval • SAS® Proc Survey means was used to compute standard errors and confidence intervals • The gm will be always less than or equal to the arithmetic mean (am) • Generally used to evaluate data sets bound by zero, data covering several orders of magnitude, and to evaluate ratios and percentage of changes (Costa J, nd)

14. Distribution of the Test Values

15. Results • There were 314,092 tests where the blood sample was drawn on or between 1/1/2000 and 12/31/2010 • Number of unique children tested: 230,566 including 115,955 males, 109,264 females, and 5,347 with unknown sex. • There were 75024 records (23.8%) with no address and of the remaining about 18% were invalid addresses.

16. Results • Mean blood lead levels varied with age

17. Mean Value of Blood Lead Levels by Age Group, 2000-2010

18. Mean Value of Blood Lead Levels by Age Group, 2000-2010

19. Results • Mean blood lead levels varied with age • Boys were more likely than girls to have a high mean blood lead level

20. Mean Value of Blood Lead Levels by Sex, 2000-2010

21. Mean Value of Blood Lead Levels by Sex, 2000-2010

22. Results • Mean blood lead levels varied with age • Boys were more likely than girls to have a high mean blood lead level • There was a steady decline in mean blood lead levels over time

23. Mean (GM) Blood Lead Levels (µg/dL) AmongChildren 0 to 17 Years Old by Year of Sample, 2000-2010

24. Mean Value of Blood Lead Levels by Year of Blood Sample, 2000-2010

26. Mean (GM) Blood Lead Levels (µg/dL) AmongChildren 0 to 17 Years Old by District and by Year of Sample, 2000-2010

28. Results • Mean blood lead levels varied with age • Boys were more likely than girls to have a high mean blood lead level • There was a steady decline in mean blood lead levels over time • Children living in rural counties were more likely than others to have a high mean blood lead level

29. Classification of Counties by Population Density* • *Census 2000 • Kansas: Densely-Settled Rural – 105 counties

31. Mean Value of Blood Lead Levels by Population Density, 2000-2010

32. Mean Value of Blood Lead Levels by Population Density, 2000-2010

33. Limitations • 24% of the addresses were missing and another 18% had invalid addresses. This could constitute a significant source of bias if one region was more affected than others. However, preliminary analysis let to believe that the problem is evenly distributed throughout the state. • Lack of precision of tests, especially below 5 µg /dL • Several test with different sensitivity and specificity provided the results analyzed

34. Discussion • Due to efforts at the federal, state, and local levels, elevated blood lead levels are decreasing in Kansas as found in this study • Based on this study, children are more likely to have elevated blood lead levels if they live in rural counties rather than other counties in Kansas. Boys are more likely than girls to have elevated blood lead levels. These findings may have programmatic value • Further studies are warranted to clarify these findings • Programmatic interventions to properly collect addresses, race, and ethnicity information would significantly enhance the quality of the data.

35. Discussion: The KS-EPHTP • Kansas Environmental Public Health Tracking Program (EPHTP) • New program to improve our knowledge on how human health is affected by the environment • Tracks parallely health hazards, environmental exposure, and health outcomes • Part of the National EPHT Network • Currently poised to track: childhood blood lead poisoning, air emissions, drinking water, selected cancers, hospitalization for asthma and myocardial infarctions, birth defects, carbon monoxide poisoning.

36. References • Costa ,J. (nd). Calculating Geometric Means. Buzzards Bay National Estuary Program. Retrieved on September 18, 2011 from http://www.buzzardsbay.org/geomean.htm. • CDC (nd). Lead: Topic Home, retrieved on September 18, 2011 from http://www.cdc.gov/lead/ • ASTDR (March 2011). Lead. retrieved on September 18, 2011 from http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=22

37. Credit • Many thanks to the HHLHPP staff • Dr. Farah AhmedEnvironmental Health Officer (KDHE) • Thomas Langer, MPABureau of Environmental Health Director (KDHE)

38. Questions