Evaluation of salivary cortisol as a biomarker of self-reported mental stress in field studies

This study examine's the association between self-reported mental stress and the salivary cortisol response via a systematic literature review by using recommendations from the Cochrane Collaboration. Literature in different databases was screened and articles were selected on the basis of a set of inclusion criteria. Each article was assigned a total score on the basis of a rating system including objective and design of the studies, description of possible confounders, sampling strategy, description of psychosocial factors, and statistical analysis. The findings of the studies were considered to be inconsistent if less than 75 per cent of the high and medium quality studies reported the same conclusion. The literature search revealed a total of 73 studies. According to the inclusion criteria 14 field studies were selected for further evaluation. According to the rating system, seven studies were considered to be of high quality and seven studies of medium quality. No studies were considered to be of low quality. Four studies reported a positive association; two studies reported negative association and eight reported no association between self-reported mental stress and the cortisol response. Accordingly, the evaluation of the studies in this paper showed insufficient evidence for an association between self-reported mental stress and the cortisol response in field studies. Possibly the large diversity in study designs, the types and measures of mental stress, and the various salivary cortisol sampling strategies obscure any potential relationship. Copyright (C) 2004 John Wiley Sons, Ltd.