Seasonal and biological variation of urinary epinephrine, norepinephrine, and cortisol in healthy women

Am. Hansen et al., Seasonal and biological variation of urinary epinephrine, norepinephrine, and cortisol in healthy women, CLIN CHIM A, 309(1), 2001, pp. 25-35
Citations number
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
ISSN journal
0009-8981 → ACNP
Year of publication
25 - 35
SICI code
Background: There is a significant circadian and seasonal periodicity in va rious endocrine functions. The present study describes the within-day and s easonal fluctuation for urinary catecholamines and cortisol and estimates t he within-(CVi) and between-subject (CVg) coefficients of variation for hea lthy women undertaking their routine work. In addition, index of individual ity (I-i) and power calculations were derived. Methods: Eleven healthy fema les undertaking their routine life-style at work participated in the study. Each subject collected six samples during 24 h 15 days over a year, giving a total number of 990 samples. Using a random effect analysis of variance, we estimated CVg and total within-subject variation (CVti), i.e. combined within-subject and analytical variation, from logarithmically transformed d ata. Analytical variation was subtracted from CVti to give CVi. CVi was est imated from samples collected monthly during 1 year(CViy), weekly during 1 month (CVim), and six to eight times/day (CVid), Results: A seasonal variat ion was demonstrated for excretion of epinephrine, norepinephrine, and cort isol standardized with creatinine. Concentrations of urinary epinephrine we re higher during June and July compared to the rest of the year, whereas co ncentrations of urinary cortisol were higher during December and January co mpared to the rest of the year. Excretion of norepinephrine was lower durin g working hours and higher during hours off work for June and July compared to the rest of the year. There was a high within- and between-subject vari ation, which could not be explained by menstrual cycle, behavioral, emotion al, or cognitive stress reactions. Conclusions: Despite high biological var iation a reasonably low sample size, e.g. 10-50 individuals, is adequate fo r practical applicability, i.e. studying differences above 150%. The presen t study recommends to include the sampling time in the statistical evaluati on of data and to be aware of the changes in diurnal variations over season s. When single measurements are to be evaluated, reference intervals are re commended. (C) 2001 Elsevier Science B,V. All rights reserved.