Relations between individual and neighborhood-based measures of socioeconomic position and bone lead concentrations among community-exposed men - TheNormative Aging Study

To examine the association between lead exposure and both individual and ge ographic area indicators of socioeconomic position, the authors measured ti bia lead concentration, a biomarker of cumulative lead exposure, using K x- ray fluorescence in a cross-sectional survey of 538 white males aged 50-92 years who were healthy when enrolled in the Normative Aging Study (Boston, Massachusetts) in the 1960s. Data on individual risk factors, education, oc cupation, and income were collected by questionnaire. Using subjects' resid ential addresses at the time of the tibia lead measurements, the authors ob tained geographic area-specific measures of education, social class, and po verty by linking records to 1990 US Census block group data. In multivariat e linear regression analysis controlling for age and cumulative smoking, ti bia lead concentrations were 10.39 mu g/g (95% confidence interval (CI) 7.8 0-12.97) higher in men who did not graduate from high school than in men wi th greater than or equal to 4 years of college. Among the former men (non-h igh school graduates), living in an undereducated area was associated with a 9.28 mu g/g (95% CI 1.59-16.97) increase in tibia lead level compared wit h living in a non-undereducated area; among the latter men (college graduat es), no difference existed by residential area education (beta = 0.72, 95% CI -5.35 to 6.78). The authors conclude that the influence of individual so cioeconomic position on cumulative lead exposure is modified by geographic area conditions.