title: Cortisol level measurements in fingernails as a retrospective index of hormone production.
abstract: 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 rs = 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 rs = 0.50, p < 0.01) and 5 months later (r = 0.45, p < 0.05 and rs = 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.
authors: Health Administration and Psychosocial Factor Research Group, National Institute of Occupational Safety and Health, Kanagawa 2148585, Japan. Electronic address: izawa0810@gmail.com.
authors: Shuhei
authors: S
authors: Izawa
authors: Health Administration and Psychosocial Factor Research Group, National Institute of Occupational Safety and Health, Kanagawa 2148585, Japan.
authors: Keiichi
authors: K
authors: Miki
authors: Health Administration and Psychosocial Factor Research Group, National Institute of Occupational Safety and Health, Kanagawa 2148585, Japan.
authors: Masao
authors: M
authors: Tsuchiya
authors: Hospital of Watanabe, Health Care Facility at Medical Corporation of Doaikai, Ibaragi 3140343, Japan.
authors: Takeshi
authors: T
authors: Mitani
authors: Hospital of Watanabe, Health Care Facility at Medical Corporation of Doaikai, Ibaragi 3140343, Japan.
authors: Toru
authors: T
authors: Midorikawa
authors: Hospital of Watanabe, Health Care Facility at Medical Corporation of Doaikai, Ibaragi 3140343, Japan.
authors: Tatsuya
authors: T
authors: Fuchu
authors: Department of Physical Therapy, School of Health Science, Tokyo University of Technology, Tokyo 1448535, Japan.
authors: Taiki
authors: T
authors: Komatsu
authors: Educational Physiology Laboratory, Graduate School of Education, The University of Tokyo, Tokyo 1130033, Japan.
authors: Fumiharu
authors: F
authors: Togo
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006197:Hair / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism*; D007564:Japan; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000737:chemistry / Q000378:metabolism*; D012189:Retrospective Studies; D012463:Saliva / Q000737:chemistry / Q000378:metabolism
chemical_list: D006854:Hydrocortisone
keywords: Cortisol; Fingernail; Hair; Stress