CENSUS TRACT ANALYSIS OF LEAD-EXPOSURE IN RHODE-ISLAND CHILDREN

There has been increasing interest in a targeted approach to the scree ning and prevention of lead exposure in children. Targeted screening r equires an understanding of variation in lead exposure in individual c hildren or by region. In order to better understand variation by regio n, we studied Rhode Island lead poisoning screening data, examining av erage lead exposure to children living in 136 Providence County census tracts (CTs). The study population included 17,956 children aged 59 m onths and under, who were screened between May 1, 1992, and April 30, 1993. We evaluated the relationship between the percentage of children with blood lead greater than or equal to 10 mu g/dL (pe10) and sociod emographic and housing characteristics, derived from United States 199 0 Census data, of these CTs. CT descriptors included population densit y, percentage of households receiving public assistance income, median per capita income, percentage of households female headed, percentage of houses owner occupied, percentage of houses built before 1950, per centage of houses vacant, percentage of population Black, percentage o f recent immigrants, and intraurban mobility. On average, 109 children were screened in each census tract; mean screening rate was 44%. Ther e was wide variation in average lead exposure among census tracts, wit h pe10 ranging from 3 to 60% of screened children (mean 27%). Individu al census variables explained between 24 and 67% of the variance in pe 10 among CTs. A multiple regression model including percentage screene d, percentage of households receiving public assistance, percentage of houses built before 1950. In (percentage of houses vacant), and perce ntage of recent immigrants explained 83% of variance in pe10. The perc entage of houses built before 1950, a variable which models the presen ce of lead paint in old houses, displayed the largest adjusted effect on pe10 over the range observed for that variable in RI CTs. The perce ntage of houses vacant was also a highly significant and robust predic tor; we suggest that vacancy is an ecological marker for the deteriora tion of lead-based paint, with higher vacancy neighborhoods containing houses in poorer condition. In Rhode Island, census tracts with high vacancy rates also have high rates of recent immigration, making immig rant groups vulnerable to lead exposure. Small-areas analysis may be u seful in directing resources to high risk areas, explaining the socioc ultural forces which produce such exposure and analyzing the effects o f housing policy over time in states with high screening penetration. (C) 1997 Academic Press.