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Distribution characteristics of salivary cortisol measurements in a healthy young male population

BACKGROUND: Salivary cortisol has been used in various fields of science as a non-invasive biomarker of stress levels. This study offers the normative reference values of cortisol measurement for healthy young males. FINDINGS: Salivary cortisol levels were measured in 267 healthy young males (age: 2...

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Autores principales: Kobayashi, Hiromitsu, Miyazaki, Yoshifumi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4543482/
https://www.ncbi.nlm.nih.gov/pubmed/26286592
http://dx.doi.org/10.1186/s40101-015-0068-0
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author Kobayashi, Hiromitsu
Miyazaki, Yoshifumi
author_facet Kobayashi, Hiromitsu
Miyazaki, Yoshifumi
author_sort Kobayashi, Hiromitsu
collection PubMed
description BACKGROUND: Salivary cortisol has been used in various fields of science as a non-invasive biomarker of stress levels. This study offers the normative reference values of cortisol measurement for healthy young males. FINDINGS: Salivary cortisol levels were measured in 267 healthy young males (age: 21.7 ± 1.5 years) in the early morning on two consecutive days and were analyzed by radioimmunoassay. Frequency distribution analysis was conducted with mean values of the measurements taken on the 2 days. The mean salivary cortisol level was 20.39 ± 7.74 nmol/l (median: 19.31 nmol/l). The skewness and kurtosis of the distribution of the raw data were 0.72 and 0.68, respectively. They were both improved by a square root transformation but not by a logarithmic transformation. CONCLUSIONS: The skewness of the distribution for salivary cortisol measured in the early morning is considerably smaller than that previously reported from afternoon measurements. A “floor effect” may be an explanation for the difference in the distribution characteristics of salivary cortisol.
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spelling pubmed-45434822015-08-22 Distribution characteristics of salivary cortisol measurements in a healthy young male population Kobayashi, Hiromitsu Miyazaki, Yoshifumi J Physiol Anthropol Short Report BACKGROUND: Salivary cortisol has been used in various fields of science as a non-invasive biomarker of stress levels. This study offers the normative reference values of cortisol measurement for healthy young males. FINDINGS: Salivary cortisol levels were measured in 267 healthy young males (age: 21.7 ± 1.5 years) in the early morning on two consecutive days and were analyzed by radioimmunoassay. Frequency distribution analysis was conducted with mean values of the measurements taken on the 2 days. The mean salivary cortisol level was 20.39 ± 7.74 nmol/l (median: 19.31 nmol/l). The skewness and kurtosis of the distribution of the raw data were 0.72 and 0.68, respectively. They were both improved by a square root transformation but not by a logarithmic transformation. CONCLUSIONS: The skewness of the distribution for salivary cortisol measured in the early morning is considerably smaller than that previously reported from afternoon measurements. A “floor effect” may be an explanation for the difference in the distribution characteristics of salivary cortisol. BioMed Central 2015-08-19 /pmc/articles/PMC4543482/ /pubmed/26286592 http://dx.doi.org/10.1186/s40101-015-0068-0 Text en © Kobayashi and Miyazaki. 2015 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Short Report
Kobayashi, Hiromitsu
Miyazaki, Yoshifumi
Distribution characteristics of salivary cortisol measurements in a healthy young male population
title Distribution characteristics of salivary cortisol measurements in a healthy young male population
title_full Distribution characteristics of salivary cortisol measurements in a healthy young male population
title_fullStr Distribution characteristics of salivary cortisol measurements in a healthy young male population
title_full_unstemmed Distribution characteristics of salivary cortisol measurements in a healthy young male population
title_short Distribution characteristics of salivary cortisol measurements in a healthy young male population
title_sort distribution characteristics of salivary cortisol measurements in a healthy young male population
topic Short Report
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4543482/
https://www.ncbi.nlm.nih.gov/pubmed/26286592
http://dx.doi.org/10.1186/s40101-015-0068-0
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