Prevalence estimate of elevated pediatric blood leads: two Air Force bases

After the occurrence of several cases of lead poisoning at Offutt and Randolph Air Force Bases, a cross-sectional study on all children of age 12 or younger was initiated to identify those children with possibly undue lead exposure. A total of 1102 and 784 children at these two bases, respectively, were tested for blood lead values. The aim of this study was to estimate the prevalence of elevated blood lead levels of young children living in on- or off-base housing at the two air force bases. To account for analytical errors and the within-person variability in blood lead measurements, a bivariate lognormal model was employed to estimate the true blood lead values of those children whose initial measurements were 10 micrograms/dL or greater. As a result of accounting for the analytical errors and within-person variance in blood lead measurements, many cases of elevated blood lead levels turned out to be false positives. It was also shown that the relative risk for young children at the two bases having elevated blood leads was the same regardless of where they lived and how old they were. By pooling together the cases, a point estimate for the prevalence of elevated blood leads among young children was 4.2 per 1000 children, with a 95% confidence interval of 1.8 to 8.4 children per 1000 children.