Toenails as biomarker of exposure to essential trace metals: A review
Metadatos
Mostrar el registro completo del ítemEditorial
Elsevier BV
Materia
Toenail Biomonitoring Biomarker Exposure Essential trace essential metals Systematic review
Fecha
2019Referencia bibliográfica
Gutiérrez-González, E., García-Esquinas, E., de Larrea-Baz, N. F., Salcedo-Bellido, I., Navas-Acien, A., Lope, V., ... & Pérez-Gómez, B. (2019). Toenails as biomarker of exposure to essential trace metals: A review. Environmental research, 108787.
Patrocinador
This work was supported by FIS grants PI12/00150, PI17CIII/00034 & PI18/00287 (Instituto de Salud Carlos III, State Secretary of R + D + I and European Union (ERDF/ESF, "Investing in your future")).Resumen
Health problems associated with essential trace metals can result from both inadequate (i.e., low intake) and
excessive exposures (i.e., from environmental and/or occupational source). Thus, measuring the exposure level
is a real challenge for epidemiologists. Among non-invasive biomarkers that intend to measure long-term exposure
to essential trace metals, the toenail is probably the biological matrix with the greatest potential.
This systematic review collects the current evidence regarding the validity of toenail clippings as exposure
biomarker for trace metals such as boron, cobalt, copper, iron, manganese, molybdenum, selenium, silicon,
vanadium and zinc. Special attention was paid to the time-window of exposure reflected by the toenail, the
intraindividual variability in exposure levels over time in this matrix, and the relationship of toenail with other
biomarkers, personal characteristics and environmental sources.
Our search identified 139 papers, with selenium and zinc being the most studied elements. The variability
among studies suggests that toenail levels may reflect different degrees of exposure and probably correspond to
exposures occurred 3–12 months before sampling (i.e., for manganese/selenium). Few studies assessed the reproducibility
of results over time and, for samples obtained 1–6 years apart, the correlation coefficient were
between 0.26 and 0.66. Trace metal levels in toenails did not correlate well with those in the blood and urine and
showed low-moderate correlation with those in the hair and fingernails.