Use of hair cortisol analysis for comparing population status in wild red deer (Cervus elaphus) living in areas with different characteristics

The stress response is subserved by the stress system, which is located both in the central nervous system and the periphery. The principal effectors of the stress system include corticotropin-releasing hormone (CRH); arginine vasopressin; the proopiomelanocortin-derived peptides alpha-melanocyte-stimulating hormone and beta-endorphin, the glucocorticoids; and the catecholamines norepinephrine and epinephrine. Appropriate responsiveness of the stress system to stressors is a crucial prerequisite for a sense of well-being, adequate performance of tasks, and positive social interactions. By contrast, inappropriate responsiveness of the stress system may impair growth and development and may account for a number of endocrine, metabolic, autoimmune, and psychiatric disorders. The development and severity of these conditions primarily depend on the genetic vulnerability of the individual, the exposure to adverse environmental factors, and the timing of the stressful events, given that prenatal life, infancy, childhood, and adolescence are critical periods characterized by increased vulnerability to stressors.

The detrimental effects of stress on human health are being increasingly recognized. There is a critical need for the establishment of a biomarker that accurately measures its intensity and course over time. Such a biomarker would allow monitoring of stress, increase understanding of its pathophysiology and may help identify appropriate and successful management strategies. Whereas saliva and urine cortisol capture real-time levels, hair cortisol analysis presents a complementary means of monitoring stress, capturing systemic cortisol exposure over longer periods of time. This novel approach for cortisol quantification is being increasingly used to identify the effects of stress in a variety of pathological situations, from chronic pain to acute myocardial infarctions. Because of its ability to provide a long-term, month-by-month measure of systemic cortisol exposure, hair cortisol analysis is becoming a useful tool, capable of answering clinical questions that could previously not be answered by other tests. In this paper we review the development, current status, limitations and outstanding questions regarding the use of hair cortisol as a biomarker of chronic stress. Copyright © 2011 Elsevier Ltd. All rights reserved.