Screening for Elevated Lead Levels in Childhood and Pregnancy: Updated Summary of Evidence, Table 1

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Table 1. Chelation Interventions

Author, Year	Type of Intervention	N	Population/Risk Factors	Lead Levels	Duration of followup	Results	Adverse Effects
Besunder, 1995⁶⁶	Chelation with DMSA and abatement of domestic lead hazards	46 treated, 18 excluded, N=28	Referral population, 35% African American, 10% Hispanic	25-49 µg/dL	80 days	BLL: post-treatment (day 18) -43% (±20.8%), 80 Days -31% (±20.2%). ZPP post-treatment (day 18) -12% (±21.7%), 80 days -32% (±21.9%).	Neutropenia (N=1)
Chisolm, 2000⁶⁸	Chelation with DMSA, relocation to lead-safe housing	59	Children age 12-65 months	25-70 µg/dL	21 days	Mean BLL decreased to below 35% of pretreatment value after 4 weeks of DMSA treatment; rebounded to 58% of pretreatment level 2-3 weeks after termination of treatment	Elevated alkaline phosphate levels (n=2), eosinophilia (N=1)
Dietrich, 2004⁶³ TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized	Children age 12‑33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	6 years (until 7 years of age)	No statistically significant difference in neurobehavioral outcomes except DMSA-treated children did worse on attention/executive functions	No statistically significant difference compared to placebo. Excess noted: trauma, scalp rashes, neutropenia/ thrombocytopenia, elevated ALT.
Liu, 2002⁶² TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized, results from 741 reanalyzed for this study	Children age 12-33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	36 months	6 months after treatment, BLL had fallen a similar amount in both DMSA and placebo groups. There was no association between change in BLL and change in cognitive test score. BLL continued to fall, but at 36 months after treatment, cognitive test scores improved 4.0 points for every 10 µg/dL drop in BLL in the placebo group only.	No statistically significant difference compared to placebo. Excess noted: trauma, scalp rashes, neutropenia/ thrombocytopenia, elevated ALT.
O'Connor, 1999⁶⁷	Chelation with DMSA, domestic cleaning and repair	39	Low-income African-American inner-city children 2.5-5 years old	30-45 µg/dL	6 months	DMSA: baseline 34.9 ±4.7 µg/dL, 1 month 27.4 ±7.5 µg/dL, 6 months 28.8 ±6.4 µg/dL. Placebo: baseline 33.0 ±6.2 µg/dL, 1 month 33.2 ±10.3 µg/dL, 6 months 25.1 ±6.8 µg/dL (p=0.06). Differences in BLL between groups were not statistically significant (p=0.16 at 1 month, p=0.06 at 6 months)	ND
Peterson, 2004⁶⁴ TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized	Children age 12-33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	34 months	Difference in mean change in height, DMSA vs. Placebo: 0-9 months: -0.27 cm (CI -.42, -.11) 0-34 months: -0.43 cm (CI -0.77, -0-.01)	Small, marginally significant decrease in height among treatment group compared to placebo. Excess noted: trauma, scalp rashes, neutropenia/ thrombocytopenia, elevated ALT.
Rogan, 1998⁶⁰ TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized	Children age 12-33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	36 months	Description of baseline measurements, group characteristics, study methodology.	ND
Rogan, 2000⁶⁵ TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized	Children age 12-33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	12 months	DMSA group: BLL 11 µg/dL lower at one week. Rebound began at 1 week, and at 7 weeks DMSA group mean BLL was 72% of baseline (placebo group mean BLL was 88% of baseline). During the 6 months after initiation of treatment, the DMSA group had a mean BLL 4.5 µg/dL lower than the control group. At 12 months mean DMSA group BLL was 2.7 µg/dL lower than the control group, but confidence intervals overlap. At 12 months groups are similar.	No statistically significant difference compared to placebo. Excess noted: trauma, scalp rashes, neutropenia/ thrombocytopenia, elevated ALT.
Rogan, 2001⁶¹ TLC	Chelation with DMSA after domestic cleaning with HEPA vacuum and damp cloth wiping	1,854 evaluated, 780 randomized	Children ages 12-33 months, 77% African-American. Most had poor, single mothers and lived in older, poorly maintained residences.	20-44 µg/dL	36 months	First 6 months: DMSA mean BLL 4.5 µg/dL lower than placebo. At 36 months, DMSA group scored on average 1 IQ point lower than the control group, and had slightly worse behavior by parental rating compared to the placebo group. The placebo group fared slightly better on a developmental neuropsychological battery of tests. Overall, there was no statistically significant difference.	No statistically significant difference compared to placebo. Excess noted: trauma, scalp rashes, neutropenia/ thrombocytopenia, elevated ALT.

Abbreviations: ALT=Alanine transferase; BLL= Blood lead level; CBC=Complete blood count; DMSA=Dimercaptosuccinic acid; HEPA=High efficiency particulate air; ND= Adverse events not described; TLC=Treatment of Lead-exposed Children study; WBC=White blood cell count; ZPP=Zinc protoporphyrin.

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