Relations between Individual and Neighborhood-based Measures of Socioeconomic Position and Bone Lead Concentrations among Community-exposed Men: The Normative Aging Study

Abstract

To examine the association between lead exposure and both individual and geographic area indicators of socioeconomic position, the authors measured tibia 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, occupation, and income were collected by questionnaire. Using subjects' residential addresses at the time of the tibia lead measurements, the authors obtained geographic area-specific measures of education, social class, and poverty by linking records to 1990 US Census block group data. In multivariate linear regression analysis controlling for age and cumulative smoking, tibia lead concentrations were 10.39 microg/g (95% confidence interval (CI) 7.80-12.97) higher in men who did not graduate from high school than in men with > or =4 years of college. Among the former men (non-high school graduates), living in an undereducated area was associated with a 9.28 microg/g (95% CI 1.59-16.97) increase in tibia lead level compared with living in a non-undereducated area; among the latter men (college graduates), 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 socioeconomic position on cumulative lead exposure is modified by geographic area conditions.

Occupational determinants of bone and blood lead levels in middle aged and elderly men from the general community: The Normative Aging Study

“…Despite a strong correlation between education and occupation (Table II), a low educational level (high school or less) was an important risk factor that was shown in our final multivariate regression models (Table VI) to be significantly associated with bone lead concentration independent of occupational category. In a study of socioeconomic position and bone lead concentrations, education, and income were found to be inversely associated with tibia lead concentration, with the effect being strongest for education [Elreedy et al, 1999]. As income correlates with level of education, our finding may reflect the residence of less educated workers with relatively low income in non-modernized areas with greater environmental hazards.…”

Association of Blood Lead and Tibia Lead with Blood Pressure and Hypertension in a Community Sample of Older Adults

“…The first is represented by model B (reciprocal effects) and suggests that socioeconomic status can both influence and be influenced by cumulative lead dose, a role of socioeconomic status that is especially complex. Lower educational level, income, and occupational status are associated with elevated risk of hypertension (36)(37)(38)(39) as well as greater exposure to lead (40). In addition, greater exposure to environmental lead early during brain development can dampen educational achievement, resulting in lowered socioeconomic status in adulthood (41,42).…”

Elevation of Blood Lead Levels in Emergency Department Patients with Extra-articular Retained Missiles

“…Ninety to 95% of the total body lead burden is stored in cortical bone and teeth and very slowly metabolized, reflecting a long-term source of lead exposure. 21,22,27,28,[31][32][33][34][35] One to 5% of total body lead is stored in the soft tissues and more rapidly metabolized, with a mean half-life of 40 days. 21,22,27,28,[31][32][33][34][35] The remaining 1 to 5% of total body lead circulates in erythrocytes, providing a source of lead exposure, with a mean half-life of 35 days.…”

“…WBL levels therefore represent a relatively short-term exposure to lead and do not reflect a patient's total lead burden. 3,12,22,26,27,[31][32][33][34][35][36] ZPP levels, in contrast, reflect the soft tissues' chronic burden of lead and are elevated at toxic concentrations. Lead interferes with the ability of protoporphyrin IX to fix iron for heme synthesis, resulting in a buildup of protoporphyrin levels.…”