DEVELOPMENT OF A POPULATION-SPECIFIC RISK ASSESSMENT TO PREDICT ELEVATED BLOOD LEAD LEVELS IN SANTA-CLARA COUNTY, CALIFORNIA

Objectives. To determine: (1) the prevalence of a blood lead level (Pb B) of 10 mu g/dL or greater and 20 mu g/dL or greater among children a ged 6 to 72 months attending the Santa Clara County (SCC), California, public clinics, (2) risk factors for elevated PbB in this population, and (3) whether an SCC public clinic population-specific risk-assessm ent tool and a five-question lead poisoning questionnaire developed by the Centers for Disease Control and Prevention are useful for prospec tively identifying children at higher risk for elevated PbB. Methods. We tested for PbB 3630 children aged 6 to 72 months attending SCC publ ic outpatient clinics between August 8, 1991, and September 1, 1992. W e then conducted two matched case-control studies. Five local risk-fac tor questions were combined with the CDC's five-question lead poisonin g questionnaire, and from May 1, 1993, to June 30, 1993, we conducted risk assessments on 247 children tested for PbB. Results. Two hundred twenty-two of 3630 children (6.1%) had a PbB of 10 mu g/dL or greater. Thirty-nine (1.1%) had a PbB at least 20 mu g/dL. Seventy-nine percen t of the children screened and 91.0% of the children with PbB at least 10 mu g/dL were Hispanic. Twenty percent of Mexican-born Hispanic chi ldren had a PbB of 10 mu g/dL or greater, versus 7% of U.S.-born Hispa nic children. Several factors were associated with elevated PbB among Hispanic children. For identifying children with a PbB of at least 10 mu g/dL, the sensitivity and predictive value negative for the CDC's ' 'high risk'' definition were 30% and 93%, respectively, whereas for th e SCC population-specific high-risk definition, the sensitivity was 90 % and the predictive value negative was 98%. Conclusions. Hispanic chi ldren attending SCC public clinics have risk factors for elevated PbB that were not included in the CDC's lead poisoning questionnaire. Meth ods for prioritizing the frequency of lead screening may be improved b y combining the CDC's questions with a population-specific risk assess ment.