Estrogen-Containing Contraceptive Use and Blood Lead Concentrations in a Cohort of Young Women [ID 2683459

Abstract

INTRODUCTION: Toxic metal lead is stored in the skeleton and, with increased bone turnover, is mobilized to systemic circulation. Given the bone-conserving properties of estrogens, we hypothesized that current users of estrogen-containing contraception would have lower blood lead concentrations. METHODS: We conducted a cross-sectional analysis using baseline data from the Study of Environment, Lifestyle & Fibroids (SELF). During 2010–2012 (baseline), 1,693 self-identified Black women, ages 23–35, enrolled. Data on contraceptive use were ascertained by interview. We quantified lead concentrations in whole blood using inductively coupled plasma mass spectrometry (ICP-MS). Among 1,555 participants, we estimated the percent difference in blood lead concentrations and 95% CIs between current users and nonusers of estrogen-containing contraception using multivariable linear regression, adjusting for potential confounders. RESULTS: The geometric mean blood lead concentrations for estrogen-containing contraceptive users and nonusers were 0.41 micrograms/dL (95% CI: 0.39, 0.43) and 0.51 micrograms/dL (95% CI: 0.50, 0.52), respectively. After adjustment, current use of estrogen-containing contraception was associated with 10% lower blood lead concentrations (95% CI: −15%, −4%). Considering estrogen-containing contraceptive type, compared to nonusers, combined oral contraceptive users (n=187) had 9% lower blood lead concentrations (95% CI: −15%, −2%) and vaginal ring/transdermal patch users (n=33) had 17% lower blood lead concentrations (95% CI: −29%, −4%). CONCLUSION: As hypothesized, we observed lower blood lead concentrations with current use of estrogen-containing contraception. Further research is warranted to confirm the results and to understand the relationship between lead exposure, hormonal contraception, and bone health to limit systemic lead exposure.