Toxic metals in toenails as biomarkers of exposure: A review

Toenails have been used as biomarkers of exposure to toxic metals, but their validity for this purpose is not yet clear and might differ depending on the specific agent. To evaluate this issue, we reviewed the literature on: a) the time-window of exposure reflected by toenails; b) the reproducibilit...

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Autores: Salcedo Bellido, Inmaculada, Gómez Ariza, José Luis, García Barrera, Tamara, Pérez Gómez, Beatriz
Tipo de recurso: artículo
Fecha de publicación:2021
País:España
Institución:Universidad de Huelva (UHU)
Repositorio:Arias Montano. Repositorio Institucional de la Universidad de Huelva
Idioma:inglés
OAI Identifier:oai:ariasmontano.uhu.es:10272/20125
Acceso en línea:http://hdl.handle.net/10272/20125
Access Level:acceso abierto
Palabra clave:Toenail
Biomonitoring
Toxic metals
Exposure
Biomarker
23 Química
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spelling Toxic metals in toenails as biomarkers of exposure: A reviewSalcedo Bellido, InmaculadaGómez Ariza, José LuisGarcía Barrera, TamaraPérez Gómez, BeatrizToenailBiomonitoringToxic metalsExposureBiomarker23 QuímicaToenails have been used as biomarkers of exposure to toxic metals, but their validity for this purpose is not yet clear and might differ depending on the specific agent. To evaluate this issue, we reviewed the literature on: a) the time-window of exposure reflected by toenails; b) the reproducibility of toenail toxic-metal levels in repeated measures over time; c) their relationship with other biomarkers of exposure, and; d) their association with potential determinants (i.e. sociodemographic, anthropometric, or lifestyle characteristics) or with sources of exposure like diet or environmental pollution. Thus, we performed a systematic review, searching for articles that provided original data for levels of any of the following toxic metals in toenails: aluminum, beryllium, cadmium, chromium, mercury, nickel, lead, thallium and uranium. We identified 88 articles, reporting data from 67 different research projects, which were quite heterogeneous with regard to population profile, sample size and analytical technique. The most commonly studied metal was mercury. Concerning the time-window of exposure explored by toenails, some reports indicate that toenail cadmium, nickel and lead may reflect exposures that occurred 7–12 months before sampling. For repeated samples obtained 1–6 years apart, the range of intraindividual correlation coefficients of aluminum, chromium and mercury was 0.33–0.56. The correlation of toxic metal concentrations between toenails and other matrices was higher for hair and fingernails than for urine or blood. Mercury levels were consistently associated with fish intake, while other toxic metals were occasionally associated with specific sources (e.g. drinking water, place of residence, environmental pollution, and occupation). The most frequently evaluated health endpoints were cardiovascular diseases, cancer, and central nervous system diseases. Available data suggest that toenail mercury levels reflected long-term exposures and showed positive associations with fish intake. The lack of standardization in sample collection, quality control, analytical techniques and procedures – along with the heterogeneity and conflicting results among studies – mean it is still difficult to conclude that toenails are a good biomarker of exposure to toxic metals. Further studies are needed to draw solid conclusions about the suitability of toenails as biomarkers of exposure to toxic metals.Elsevier20212021-06-0120212021-06-01journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10272/20125reponame:Arias Montano. Repositorio Institucional de la Universidad de Huelvainstname:Universidad de Huelva (UHU)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2Atribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/openAccessoai:ariasmontano.uhu.es:10272/201252026-06-02T14:58:11Z
dc.title.none.fl_str_mv Toxic metals in toenails as biomarkers of exposure: A review
title Toxic metals in toenails as biomarkers of exposure: A review
spellingShingle Toxic metals in toenails as biomarkers of exposure: A review
Salcedo Bellido, Inmaculada
Toenail
Biomonitoring
Toxic metals
Exposure
Biomarker
23 Química
title_short Toxic metals in toenails as biomarkers of exposure: A review
title_full Toxic metals in toenails as biomarkers of exposure: A review
title_fullStr Toxic metals in toenails as biomarkers of exposure: A review
title_full_unstemmed Toxic metals in toenails as biomarkers of exposure: A review
title_sort Toxic metals in toenails as biomarkers of exposure: A review
dc.creator.none.fl_str_mv Salcedo Bellido, Inmaculada
Gómez Ariza, José Luis
García Barrera, Tamara
Pérez Gómez, Beatriz
author Salcedo Bellido, Inmaculada
author_facet Salcedo Bellido, Inmaculada
Gómez Ariza, José Luis
García Barrera, Tamara
Pérez Gómez, Beatriz
author_role author
author2 Gómez Ariza, José Luis
García Barrera, Tamara
Pérez Gómez, Beatriz
author2_role author
author
author
dc.contributor.none.fl_str_mv
dc.subject.none.fl_str_mv Toenail
Biomonitoring
Toxic metals
Exposure
Biomarker
23 Química
topic Toenail
Biomonitoring
Toxic metals
Exposure
Biomarker
23 Química
description Toenails have been used as biomarkers of exposure to toxic metals, but their validity for this purpose is not yet clear and might differ depending on the specific agent. To evaluate this issue, we reviewed the literature on: a) the time-window of exposure reflected by toenails; b) the reproducibility of toenail toxic-metal levels in repeated measures over time; c) their relationship with other biomarkers of exposure, and; d) their association with potential determinants (i.e. sociodemographic, anthropometric, or lifestyle characteristics) or with sources of exposure like diet or environmental pollution. Thus, we performed a systematic review, searching for articles that provided original data for levels of any of the following toxic metals in toenails: aluminum, beryllium, cadmium, chromium, mercury, nickel, lead, thallium and uranium. We identified 88 articles, reporting data from 67 different research projects, which were quite heterogeneous with regard to population profile, sample size and analytical technique. The most commonly studied metal was mercury. Concerning the time-window of exposure explored by toenails, some reports indicate that toenail cadmium, nickel and lead may reflect exposures that occurred 7–12 months before sampling. For repeated samples obtained 1–6 years apart, the range of intraindividual correlation coefficients of aluminum, chromium and mercury was 0.33–0.56. The correlation of toxic metal concentrations between toenails and other matrices was higher for hair and fingernails than for urine or blood. Mercury levels were consistently associated with fish intake, while other toxic metals were occasionally associated with specific sources (e.g. drinking water, place of residence, environmental pollution, and occupation). The most frequently evaluated health endpoints were cardiovascular diseases, cancer, and central nervous system diseases. Available data suggest that toenail mercury levels reflected long-term exposures and showed positive associations with fish intake. The lack of standardization in sample collection, quality control, analytical techniques and procedures – along with the heterogeneity and conflicting results among studies – mean it is still difficult to conclude that toenails are a good biomarker of exposure to toxic metals. Further studies are needed to draw solid conclusions about the suitability of toenails as biomarkers of exposure to toxic metals.
publishDate 2021
dc.date.none.fl_str_mv 2021
2021-06-01
2021
2021-06-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10272/20125
url http://hdl.handle.net/10272/20125
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Atribución-NoComercial-SinDerivadas 3.0 España
http://creativecommons.org/licenses/by-nc-nd/3.0/es/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Atribución-NoComercial-SinDerivadas 3.0 España
http://creativecommons.org/licenses/by-nc-nd/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Arias Montano. Repositorio Institucional de la Universidad de Huelva
instname:Universidad de Huelva (UHU)
instname_str Universidad de Huelva (UHU)
reponame_str Arias Montano. Repositorio Institucional de la Universidad de Huelva
collection Arias Montano. Repositorio Institucional de la Universidad de Huelva
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