Dust control not effective in preventing children's exposure to residential lead hazards

Submitted by Norm Roulet on Mon, 05/22/2006 - 13:00.

 It is extremely important to control all dust in and around any home where there is a lead risk. Unfortunately, research shows that where there are lead risks dust control alone has little impact in reducing lead poisoning - the reduction in elevated blood lead levels is measurable and worthwhile but not sufficient to have an overall benefit to the child, or surface a solution for society.

 

ELECTRONIC ARTICLE:
Long-Term Effect of Dust Control on Blood Lead Concentrations

Bruce P. Lanphear, MD, MPH*, Shirley Eberly, MS§, and Cynthia R. Howard, MD, MPHDagger

From the * Children's Hospital Medical Center, Cincinnati Ohio, and the Departments of Dagger  Pediatrics and § Biostatistics, University of Rochester School of Medicine and Dentistry, Rochester, New York.

 

Background.  Dust control is recommended to prevent children's exposure to residential lead hazards, but the long-term effect of dust control on children's exposure to environmental lead is unknown.

Objective.  To determine the effect of dust control on children's exposure to lead, as measured by blood lead concentration at 48 months of age.

Design.  A randomized, controlled trial.

Setting.  Rochester, New York.

Participants.  A total of 275 urban children were randomized at 6 months of age; 189 (69%) were available for the 48-month follow-up blood test.

Intervention.  Children and their families were randomly assigned to an intervention group that received cleaning equipment and up to 8 visits by a trained lead hazard control advisor or to a control group. The intervention was terminated when the children were 24 months of age.

Outcome Measures.  Geometric mean blood lead concentration and prevalence of elevated blood lead concentration (ie, = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />10 µg/dL, = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />15 µg/dL, and = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />20 µg/dL), by group assignment.

Results.  For children with 48-month blood tests, baseline geometric mean blood lead concentrations were 2.8 µg/dL (95% confidence interval [CI]: 2.6,3.0); there were no significant differences in baseline characteristics or lead exposure by group assignment. At 48 months of age, the geometric mean blood lead was 5.9 µg/dL (95% CI: 5.3,6.7) for the intervention group and 6.1 µg/dL (95% CI: 5.5,6.9) for the control group. The percentage of children with a 48-month blood lead = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />10 µg/dL, = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />15 µg/dL, and = " src="http://pediatrics.aappublications.org/math/12pt/normal/ge.gif" />20 µg/dL was 19% versus 19%, 2% versus 9%, and 1% versus 2% in the intervention and control groups, respectively.

Conclusions.  We conclude that dust control, as performed by families and in the absence of lead hazard controls to reduce ongoing contamination from lead-based paint, was not effective in preventing children's exposure to residential lead hazards.  Key words:  blood lead, lead-contaminated house dust, randomized trial, children, environmental exposure, lead poisoning, prevention.

Despite the dramatic decline in the prevalence of children having blood lead of 10 µg/dL or higher,1 undue lead exposure remains endemic among children living in some cities, especially those in the Northeastern United States.2,3 Numerous recommendations exist to reduce a child's risk of exposure to residential lead hazards, such as dust control, close supervision, and hand-washing. But it is uncertain that any of these efforts, when performed by families, are effective at reducing children's lead exposure, because they fail to repair or remove lead-based paint hazards from the child's environment.4

The American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend educating families to conduct dust control to reduce children's exposure to lead-contaminated house dust---a major source of lead intake.5-10 Unfortunately, trials of dust control involving children who had blood lead levels <25 µg/dL have not consistently demonstrated a reduction in blood lead levels.11-14 Rhoads et al11 reported a 17% decline in blood lead concentration among children who received professional cleaning compared with a control group. In contrast, in an earlier analysis of the cohort described in this present study, we found no significant difference in children's blood lead concentration at 24 months of age in those assigned to a dust control intervention performed by a family member.12 There was, however, a trend toward lower blood lead concentrations in the experimental group. It was unknown, however, if the beneficial effect of dust control would become more evident with extended follow-up.

The purpose of this study was to assess the long-term effect of dust control in preventing children's exposure to lead, as measured by blood lead concentration at 48 months of age.