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Environ Int. 2018 Sep;118:86-91. doi: 10.1016/j.envint.2018.05.030. Epub 2018 May 29.

Urine and toenail cadmium levels in pregnant women: A reliability study.

Author information

1
Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA. Electronic address: Alexandra.white@nih.gov.
2
Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA; Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
3
Department of Earth Sciences, Dartmouth College, Hanover, NH, USA.
4
Department of Epidemiology and Children's Environmental Health and Disease Prevention Research Center at Dartmouth, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA.

Abstract

BACKGROUND:

Cadmium, as measured in human tissue, has been associated with numerous health outcomes. However, few studies have evaluated the reliability of cadmium measurements across different biologic samples. We evaluated toenail cadmium levels over time and compared toenail cadmium to urinary cadmium. We also evaluated the relationship between biomarker concentrations and cigarette smoking, a known source of cadmium exposure.

METHODS:

Cadmium was assessed in urine and toenail samples collected from 1338 pregnant women participating in the New Hampshire Birth Cohort Study. Each participant was asked to provide a urine and a toenail sample at enrollment (between 24 and 28 weeks gestation) and another toenail sample 2-8 weeks postpartum. Cadmium concentrations were determined using inductively-coupled plasma mass spectrometry. Spearman correlations were assessed for cadmium in the toenails across the two-time points and comparing toenail and urine levels. Smoking status was evaluated as a predictor of cadmium levels.

RESULTS:

Toenail cadmium assessed during pregnancy and postpartum were modestly correlated (R = 0.3, p < 0.0001). However, urine and toenail cadmium levels were unrelated (R = -0.03, p = 0.46). Both toenail and urinary cadmium levels were associated with women's smoking status.

CONCLUSION:

Our findings suggest that both toenail and urinary cadmium concentrations reflect the major source of exposure - cigarette smoking. Toenail cadmium concentrations are modestly reproducible pre- and postpartum; but do not appear to be related to urinary cadmium and thus likely represent different windows and chronicity of exposure among pregnant women.

KEYWORDS:

Biomarker; Cadmium; Pregnancy; Reliability; Toenail; Urine

PMID:
29857281
PMCID:
PMC6045451
DOI:
10.1016/j.envint.2018.05.030
[Indexed for MEDLINE]
Free PMC Article

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