Blood lead levels in a continuity clinic population.

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Lead toxicity is well recognized as a significant cause of morbidity in children, especially those under the age of six years. While lead toxicity has not been recognized as a public health problem in Houston, it is possible that children in the area suffer from low-level lead effects on the central nervous system. To detect asymptomatic cases of lead toxicity in one population of Houston children and to assess the effectiveness of the lead risk questionnaire. Venous blood samples for quantitative lead were analyzed utilizing the Anodic Stripping Voltameter. The Centers for Disease Control's lead risk assessment questionnaire was administered to each patient. Baylor College of Medicine Continuity Clinic at Texas Children's Hospital. All patients, ages 9-72 months, seen for routine care between December 1992 and June 1994 were screened once. Blood lead levels were obtained on 801 children; all but 47 completed lead risk questionnaires. The mean age of the study group was 2.37 years (SD 1.84) and they were 54% male. They were 39% Hispanic, 39% Black, and 18% White. Eighty-eight percent reported an annual income of < $20,000. They lived in 127 separate zip codes. Twenty-five (3.1%) patients had elevated blood lead, 21 between 10-14 micrograms/dL and 4 between 15-19 micrograms/dL. No patients had blood lead levels of > or = 20 micrograms/dL. No statistically significant differences were found between patients with blood lead < 10 micrograms/dL and those with > or = 10 micrograms/dL when comparing for age, sex, ethnicity, income, and zip code. Only those children living in or regularly visiting a pre-1960 home with peeling or chipping paint were significantly more likely to have elevated blood lead (p = .045). Although the majority of children in our setting were poor and urban, the prevalence of blood lead > or = 10 micrograms/dL was 3.1%, well below the estimated 17% quoted by the Centers for Disease Control in recommending stringent screening guidelines. The lead risk assessment questionnaire failed to identify 32% of children with elevated blood lead levels. Since this questionnaire is critical to screening populations at low risk for lead toxicity, it is important to determine whether a revised questionnaire or a more careful elicitation of parental responses will improve identification of those children at risk.