Fig 1.
Study design and target analytes.
This study was conducted following the scheme shown in A). All participants started fasting from 9 p.m. and sampling was conducted the next morning. Serum, urine, and saliva were obtained from all participants. All participants answered BJSQ and CES-D items and were interviewed by a medical doctor. All participants received laboratory tests. The target urinary neurotransmitters are shown in B) with their metabolism pathway.
Fig 2.
Comparison between BJSQ and CES-D.
A scatter plot of BJSQ and CES-D total scores is shown in A) with a fitting curve and 95% CI curves. The ratio of four scores, 1 (low stress) to 4 (high stress) are plotted with bar graph B); black (BJSQ), gray (CES-D).
Table 1.
Significant responses of neural transmitters.
Fig 3.
The expressions of six urinary neurotransmitters and their combined index.
The examinees were divided into two groups based on their total BJSQ scores. The box-whisker plots of 5-HIAA, DA, GABA, HVA, 5-HT, and VMA are shown in A). Student’s t-tests were performed for the six urinary neurotransmitters, and p-values below 0.05 are shown in the plots. To generate the stress index, participants were randomly divided into a training (66) or test (34) set, and all analyte concentrations were logarithmically converted and normalized by zero-mean-centering and unit-variance-scaling. The stress index was generated by a linear combination of six normalized values with weight factors. The weight factors were optimized using the Excel-solver program B).
Table 2.
Demographic features.
Table 3.
Average concentrations of urinary neurotransmitters in high and low stress groups.