Metabolomics of mouth-rinsed water for assessing psychophysiological stress in office workers

Workplace stress impacts productivity and health, necessitating non-invasive, rapid, and objective assessment methods. This study investigates the potential of metabolite profiling of mouth-rinsed water (MW)-an oral biofluid collected in just 10 s-as a screening tool for psychophysiological stress among office workers. Thirty-two participants were classified into high-stress and control groups based on the State-Trait Anxiety Inventory and the Brief Job Stress Questionnaire, and objective physiological measures. MW samples were collected at four time points, including before and after brief mental stress tasks. Biochemical features were profiled using capillary electrophoresis-mass spectrometry and liquid chromatography-mass spectrometry. A total of 559 analytes, including 532 water-soluble metabolites, 25 steroids, and 2 salivary proteins, were measured, of which 127 analytes with acceptable analytical precision were selected for subsequent analyses. Statistically significant differences in numerous metabolites indicated stress-associated alterations in metabolic activity. Notably, a predictive model using the ratio of N-acetyl-β-alanine to asymmetric dimethylarginine achieved high accuracy, with an area under the receiver operating characteristic curve (AUC) of 0.845 for identifying high stress. The distinct metabolite dynamics under varying stress conditions suggest multiple stress-response mechanisms. These findings underscore MW metabolite profiling as a promising approach for assessing and managing workplace stress.