Cortisol level measurements in fingernails as a retrospective index of hormone production. (April 2015)

• Record Type: Journal Article
• Authors: Izawa, Shuhei; Miki, Keiichi; Tsuchiya, Masao; Mitani, Takeshi; Midorikawa, Toru; Fuchu, Tatsuya; Komatsu, Taiki; Togo, Fumiharu
• Is Part Of: Psychoneuroendocrinology. Volume 54(2015:Apr.)
• Page Start: 24
• Page End: 30
• Publication Date: 2015-04
• Subjects: Cortisol -- Fingernail -- Stress -- Hair; Psychoneuroendocrinology -- Periodicals; Endocrinology -- Periodicals; Neurology -- Periodicals; Psychiatry -- Periodicals; Neuropsychoendocrinologie -- Périodiques; 616.8
• DOI: 10.1016/j.psyneuen.2015.01.015
• Languages: English
• ISSNs: 0306-4530

Abstract

Highlights: Biological validity of fingernail cortisol was studied in the sample of workers. Fingernail cortisol level was moderately associated with hair cortisol level. Fingernail cortisol level was retrospectively correlated with salivary cortisol level. Summary: The cortisol level in fingernails may reflect the hormone's cumulative production over a long period, but the notions have not been fully established. In this study, we investigated the association of cortisol in fingernails with cortisol accumulation over a long period (hair cortisol) and over a relatively short period (salivary cortisol). In study 1, hair and fingernail samples were collected from 58 middle-aged and elderly men. The cortisol level in hair samples was moderately associated with the level in fingernail samples ( r = 0.29, p < 0.05 and r s = 0.36, p < 0.01). In study 2, 37 workers provided 4 saliva samples over the course of one day (at awakening, 30 min after awakening, before lunch, and after work) and another set a month later. Further, the workers were asked to provide fingernail samples during a six-month period. We found that the cortisol level in saliva over the whole day (area under the curve for cortisol) was moderately associated with the cortisol level measured in fingernail samples that were collected 4 months ( r = 0.43, p < 0.05 and r s = 0.50, p < 0.01) and 5 months later ( r = 0.45, p < 0.05 and r s = 0.53, p < 0.01). These results indicated that the cortisol level in fingernail samples might retrospectively represent hormone production during a given period. The cortisol level in fingernail samples may be useful in the investigation of the link between psychosocial stress and health.