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Childhood lead poisoning prevention through prenatal housing inspection and remediation in St. Louis, MO

      Objective

      We assessed the screening and remediation of home lead hazards prenatally in a high-risk population, hypothesizing that average blood-lead level and the number of poisonings would drop by 25%.

      Study Design

      One hundred fifty-two women underwent prenatal home inspections by certified lead inspectors. The hazards that were identified were remediated. The blood-lead levels of children of participating women were compared with matched control subjects.

      Reuslts

      Blood-lead levels were obtained from 60 children and compared with matched control subjects. The average blood-lead level of children in the treatment group was 2.70 μg/dL vs 3.73 μg/dL in control subjects (P = .019). The percentage of children with levels >10 μg/dL in the treatment group was 0% vs 4.2% in control subjects (P = .128).

      Conclusion

      Screening and remediation of houses of pregnant women is effective to reduce the average blood-lead level and number of children that exceed the federal level of concern for lead poisoning in a high-risk population.

      Key words

      Childhood lead poisoning is associated with decreased intelligence, antisocial behavior, attention deficit hyperactivity disorder–related behaviors, and other neurobehavioral deficits.
      • Pocock S.J.
      • Smith M.
      • Baghurst P.
      Environmental lead and children's intelligence: a systematic review of the epidemiological evidence.
      Children in the City of St. Louis experience an above-average risk as predicted by established lead poisoning risk factors that include quality and age of housing stock, African American race, and poverty.
      • Kaufmann R.B.
      • Clouse T.L.
      • Olson D.R.
      • Matte T.D.
      Elevated blood lead levels and blood lead screening among US children aged one to five years: 1988-1994.
      Historically, the City of St. Louis has used secondary prevention systems that rely on the testing of children and then addressing home lead hazards to prevent further harm. A flaw in this approach is that children are already poisoned before any intervention occurs. A primary prevention approach addresses hazards before children are poisoned. The Heavy Metal Project aimed to target the homes of pregnant women in the City of St. Louis who were recruited from a clinic that primarily served African American women receiving Medicaid to receive prenatal inspection and remediation of lead hazards.
      For Editors' Commentary, see Table of Contents

      Methods

      Pregnant women who lived in the City of St. Louis and who provided informed consent were eligible to participate. Recruitment occurred between August 2007 and December 2009. Because prenatal home inspection and remediation had become standard practice of the City of St. Louis Health Department and because the project was considered an evaluation of an existing city program, institutional review board approval was deemed exempt (Washington University X-07-079). Because we believed that this program would lower children's blood-lead levels, we did not include a prospective control population.
      Health Department workers, building inspectors, and lead contractors were funded through the City of St. Louis federal Housing and Urban Development (HUD) grant and city tax revenue. Recruitment primarily occurred in the outpatient clinics of the Barnes-Jewish Hospital, with a few patients coming from other urban clinics that also served populations at high risk by virtue of geography, race, and income. Basic information was recorded that included patient name, address, expected delivery date, names of other children, and 3 contact phone numbers.
      Home inspections were conducted by certified inspectors from the City of St. Louis Building Division in accordance with HUD regulations, which included visual paint inspection, x-ray fluoroscopy, and dust swipes. Hazards were defined in one of the following ways: visibly deteriorated paint that registered >1.0 mg/cm2 on x-ray fluoroscopy; dust wipe >40 μg/sq ft on the floor or 250 μg/sq ft on window sills; and soil >400 μg/g for play areas or >1200 μg/g for other residential yards. These levels were also used to define clearance levels.
      Remediation efforts included paint stabilization, window replacement, and cleaning as needed. The work was performed either by the city's certified lead workers or by a contractor who was paid through the city's HUD grant. Information on inspections was maintained by the Building Division in the Lead Housing Tracking database. All homes that underwent remediation passed clearance dust wipes.
      Contact with each family was done at 3- to 6-month intervals through phone calls with the use of a standardized script. At these times health workers updated information regarding the names of the children and demographics and encouraged the mothers to have their children tested for lead. Most of the children were tested by their pediatricians, although a few parents used free testing programs that are offered by the Health Department. Lead levels were checked by capillary or venous blood samples. Children with multiple blood-lead levels had the highest number of samples that were used for analysis. All data were kept on a password-protected database at the Health Department or the Lead Housing Tracking database. Missouri mandates the reporting of blood-lead level data, and these data are maintained in Missouri Health Strategic Architecture and Information Cooperative Database.
      To identify control subjects, the Missouri Health Strategic Architecture and Information Cooperative Database was searched for all children who lived in the same census tracts as the program participants, who were born ±0.2 years of the date of the birth of the participants, and who had blood-lead levels drawn within the same calendar year as the participants. We chose census tract as the geographic unit of comparison because this has been found to be a good correlate for blood-lead levels, as compared with zip code data.
      • Kaplowitz S.
      • Perlstadt H.
      • Post L.
      Comparing lead poisoning risk assessment methods: census block group characteristics vs zip codes as predictors.
      The list was parsed for data duplication, and children whose homes had received an intervention were removed from the control subjects. Each study participant was matched with 2 control subjects who were selected randomly from the pool of control subjects within the matching census tract with the correct age and date of blood draw.
      Mean blood-lead levels were compared with the use of a t test. The number of children with levels of ≥5 μg/dL was analyzed by χ2 test and levels ≥10 μg/dL by 1-tailed Fisher's exact test.

      Results

      Between August 2007 and December 2009, 492 pregnant women signed consent forms; of those, 152 women underwent prenatal home inspections. Lead hazards were identified and remediated in 62.5% of the inspected homes. Of the 152 participating pregnant women, blood-lead levels were obtained for 60 children. Sixty children were lost to follow-up evaluation; 29 children were identified but did not have a blood-lead level checked; 2 mothers withdrew consent after inspection, and 1 child was eliminated from analysis (see explanation later in article). There were no significant differences between participants and control subjects in terms of race, sex, or age at time of lead testing (Table 1).
      TABLE 1Demographic information
      Demographic descriptorParticipantsControl subjects
      Children, n60120
      African American race, %8781
      Age at time of lead test, y
      Data given as mean ± SD.
      1.5 ± 0.51.5 ± 0.5
      Female, %51.748.3
      Berg. Lead poisoning prevention through prenatal home remediation. Am J Obstet Gynecol 2012.
      a Data given as mean ± SD.
      The average blood-lead level was 2.70 μg/dL among participants and 3.63 μg/dL among control subjects (P = .019); 13.3% of participants (8/60) and 22.5% of control subjects (27/120) had blood-lead levels of ≥5 μg/dL (P = .143). No study child had a blood-lead level of ≥10 μg/dL (0/60); 5 of the 120 control subjects (4.2%) did (P = .128) (Table 2).
      TABLE 2Results
      Blood-lead categoriesParticipants (n = 60)Control subjects (n = 120)P value
      Mean blood-lead level, μg/dL2.703.63.019
      t test;
      ≥5 μg/dL, %13.322.5.143
      χ2 test;
      ≥10 μg/dL, %04.2.128
      1-sided Fisher's exact test.
      Berg. Lead poisoning prevention through prenatal home remediation. Am J Obstet Gynecol 2012.
      a t test;
      b χ2 test;
      c 1-sided Fisher's exact test.
      One child was eliminated from the analysis. The child's home had undergone inspection, but no remediation was performed because the homeowner lacked homeowner's insurance. This legally precluded the use of the HUD grant to remediate the home. Although the family was present during the inspection and received a Letter of Violation that detailed the hazards in the home, minimal work was done at the property, and the child was later found to have a blood-lead level of 14.3 μg/dL at 12 months of age. We ran a second analysis that included this outlier with 2 additional control subjects. Intent-to-treat analysis included this child. The average blood-lead level was 2.89 μg/dL among participants and 3.61 μg/dL among control subjects (P = .059); 1 of 61 participating children (1.6%) had a blood-lead level of >10 μg/dL; 5 of 122 control subjects (4.1%) had blood-lead levels of >10 μg/dL (P = .347).

      Comment

      We evaluated a city government program to screen and remediate lead paint hazards in the housing of high-risk pregnant women. We found this strategy to be effective to prevent childhood lead poisoning and to reduce the overall burden of lead toxicity in children.
      The major strength of our study was that we demonstrated an ability to decrease children's lead burden using existing resources in a novel manner. A weakness of the study was the difficulty that was encountered with efforts to follow patients who originally signed consents for participation. Initial problems included patients denying access to city inspectors, changing their address and contact information before inspection, or changing their minds about having an inspection. Of the patients who originally were recruited, 31% underwent home inspection.
      A second area of difficulty occurred between home inspection and a child's 1-year blood-lead level check. Mothers frequently changed their contact information, which made child identification challenging. Of the children whose names and birthdays were identified, most had a blood-lead level recorded in the Missouri Health Strategic Architecture and Information Cooperative Database (60/89 children).
      Lack of funding also limited our capacity to case-manage participants. Outside of funding that was designated for the city's childhood lead-poisoning prevention program, there was no other source of financial support. Most of the project management was provided by practicum students who contributed 3-6 months of time while earning their MPH or MSW degrees.
      Previous studies have shown that correcting lead-paint hazards to HUD standards results in lower blood-lead levels of children.
      • Strauss W.
      • Pivetz T.
      • Ashley P.
      • Menedick J.
      • Slone E.
      • Cameron S.
      Evaluation of lead hazard control treatments in four Massachusetts communities through analysis of blood-lead surveillance data.
      • Wilson J.
      • Pivetz T.
      • Ashley P.
      • et al.
      Evaluation of HUD-funded lead hazard control treatments at 6 years post-intervention.
      A recent primary prevention trial, however, did not show similar results.
      • Campbell C.
      • Tran M.
      • Gracely E.
      • et al.
      Primary prevention of lead exposure: the Philadelphia lead safe homes study.
      The Philadelphia Lead Safe Homes Study screened and remediated the homes of newborn infants and included a component of parental education. Possible explanations for improvement in our study, compared with the Philadelphia study, are that 62.5% of the homes underwent remediation in the City of St. Louis; only 28.2% of homes were remediated in Philadelphia. Second, our control population had a higher mean blood-lead level (3.63 vs 2.7 μg/dL, respectively), which likely is related to the older age of our children at time of blood testing (18 vs 10 months, respectively) and possibly a higher risk housing environment. Finally, by screening homes in the prenatal period, we minimized exposure that was caused by the delay between enrollment and remediation of the property.
      To our knowledge, no one previously has documented the effectiveness of a prenatal home screening and remediation strategy. Our program directly addressed lead-paint hazards without specifically providing education or postremediation dust control. This design was in response to multiple studies that have failed to show a decrease in children's blood-lead levels with educational and dust control interventions.
      • Woofenden Y.
      • Wheeler D.M.
      • Alperstein G.
      • Lanphear B.
      Household interventions for prevention of domestic lead exposure in children (review).
      • Dugbatey K.
      • Croskey V.
      • Evans R.G.
      • Narayan G.
      • Osamudiamen O.E.
      Lessons from a primary-prevention program for lead poisoning among inner-city children.
      Correctly targeting high-risk populations is essential for cost-effectiveness. Multiple studies have characterized risk factors for childhood lead poisoning that allow for successful targeting of high-risk homes.
      • Lanphear B.P.
      • Matte T.
      • Rogers J.
      • et al.
      The contribution of lead-contaminated house dust and residential soil to children's blood lead levels: a pooled analysis of 12 epidemiologic studies.
      • Lanphear B.P.
      • Hornung R.
      • Ho M.
      Screening housing to prevent lead toxicity in children.
      An effective strategy must screen the homes of low-income women who are living in high-risk neighborhoods with poor housing conditions.
      Our data provide evidence that prenatal home screening and lead hazard remediation is effective. Not only did children of participating mothers have a lower rate of poisoning, but they also had a lower average blood-lead level. This is significant because IQ decrements in children are observed with blood-lead levels below the government definition of lead poisoning (10 μg/dL), and no safe threshold of lead exposure in children has been found.
      • Canfield R.
      • Henderson C.
      • Cory-Slechta D.
      • Cox C.
      • Jusko T.
      • Lanphear B.
      Intellectual impairment in children with blood lead concentrations below 10 micrograms per deciliter.
      Ideally, cities would be able to correct lead hazards in all available housing, but this is not financially possible. In the City of St. Louis alone, there are 71,557 homes that were built before 1946.
      US Department of Housing and Urban Development
      Healthy homes and lead hazard programs OMB approval no. 2539-0015.
      Long-term solutions will be possible with only well-designed public policies that make use of both private and public monies for building repair, demolition, creation of new affordable housing developments, and targeted home screenings such as we described in this study.
      Screening homes of pregnant women for lead hazards is philosophically similar to screening pregnancies for potential complications and newborn infants for congenital metabolic diseases. Lead poisoning, however, is more prevalent than phenylketonuria, congenital hypothyroidism, and other complications. Neonatal screening can detect a treatable disease in 1 of 800 newborn infants, but screening the homes of pregnant women for lead hazards can prevent lead poisoning in 1 of 27 children in the City of St. Louis.
      Future studies on a larger, broader scale will serve to prove the reproducibility of prenatal home lead hazard screening and remediation. Further, cost-effectiveness analyses that compare the benefits of this approach with other prevention strategies and other perinatal screening programs could build on the work of previous analyses to help incorporate this strategy into routine prenatal care in high-risk populations.
      • Gould E.
      Childhood lead poisoning: conservative estimates of the social and economic benefits of lead hazard control.
      • Nevin R.
      • Jacobs D.E.
      • Berg M.
      • Cohen J.
      Monetary benefits of preventing childhood lead poisoning with lead-safe window replacement.

      Acknowledgments

      From the City of St. Louis Health Department: Jeanine Arrighi, Director of Children's Environmental Health; Judy Wider-Jones, Public Health Nurse; Joyce Driver, Public Health Program Representative; Mary Shands, Citizen Advocate; Pat Curtis, Public Health Nurse Supervisor.
      From the City of St. Louis Building Division: Jerry Wessels, Building Inspection Supervisor; Kerry Humphries, Building Inspection Manager; Jeanette Thomas, Inspector; Mark Ritter, Inspector.
      Student interns: Kenyetta Daniels, St. Louis University School of Public Health; Alfred Frager, St. Louis University School of Industrial and Organizational Psychology; Rebecca Hendrickson, Washington University Medical School; Neil Kalsi, Washington University Medical School; Jerry Nwobodo, St. Louis University School of Public Health; Angela Woods, Washington University School of Social Work; Jenny Yuda, St. Louis University School of Public Health.
      From the Barnes-Jewish Hospital Obstetrics and Gynecology Clinic: Pat Rekart, OB Clinic Nurse Manager; Sandra Gladney, phlebotomist/recruiter.

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