Salivary cortisol and nitrite concentrations in school teachers: A longitudinal pilot study.
Level 4 - case-series / case-control
Single-cohort longitudinal observational pilot study without a comparison group
PubMed 31517603 · doi:10.2478/enr-2018-0015
What was done
Saliva samples were collected from 13 secondary school teachers across five schools at three time points (6:30 a.m., 11:30 a.m., and 5:30 p.m.) across three months of the academic year (March, July, and December). Salivary cortisol was measured via enzyme immunoassay and nitric oxide was assessed via nitrite quantification. Total daily exposure was calculated as area under the curve with respect to ground (AUC).
What was found
Neither salivary cortisol nor nitrite concentrations showed statistically significant differences across the three sampling months. Daily cortisol and nitrite concentrations demonstrated a weak, statistically significant positive correlation (r = 0.3455, p = 0.0336).
Why it matters
This pilot study provides initial preliminary evidence that salivary nitrite correlates weakly with salivary cortisol, suggesting salivary nitric oxide could be explored alongside cortisol in occupational stress research.
Limits
The sample size is extremely small (n = 13), limiting statistical power and generalizability. There was no control group, dietary nitrate intake was not reported, and subjective stress or cardiovascular outcomes were not directly measured.