UCSF

Background

Although metals can adversely impact children's health, the distribution of exposures to many metals, particularly among vulnerable subpopulations, is not well characterized.

Objectives

We sought to determine whether neighborhood deprivation was associated with urinary concentrations of thirteen metals and whether observed relationships varied by race/ethnicity.

Methods

We obtained neighborhood characteristics from the 2005-2009 American Community Survey. Demographic information and urine samples from 400 healthy young girls in Northern California were obtained during a clinical visit. Urine samples were analyzed for metals using inductively-coupled plasma-mass spectrometry and levels were corrected for creatinine. We ran analysis of variance and generalized linear regression models to estimate associations of urinary metal concentrations with neighborhood deprivation and race/ethnicity and stratified multivariable models to evaluate possible interactions among predictors on metals concentrations.

Results

Urinary concentrations of three metals (barium, lead, antimony) varied significantly across neighborhood deprivation quartiles, and four (barium, lead, antimony, tin) varied across race/ethnicity groups. In models adjusted for family income and cotinine, both race/ethnicity (F3,224=4.34, p=0.01) and neighborhood deprivation (F3,224=4.32, p=0.01) were associated with antimony concentrations, but neither were associated with lead, barium, or tin, concentrations. Examining neighborhood deprivation within race/ethnicity groups, barium levels (pinteraction<0.01) decreased with neighborhood deprivation among Hispanic girls (ptrend<0.001) and lead levels (pinteraction=0.06) increased with neighborhood deprivation among Asian girls (ptrend=0.04).

Conclusions

Our results indicate that children's vulnerability to some metals varies by neighborhood deprivation quartile and race/ethnicity. These differential distributions of exposures may contribute to environmental health disparities later in life.