ABSTRACT
OBJECTIVE: This study aimed to compare the diurnal patterns of three salivary biomarkers (cortisol, amylase, and chromogranin A), as well as the factors affecting their levels. DESIGN: A total of 110 participants with mean age of 26.93 ± 6.05 years old took part in the study. The saliva was collected at awakening, 30 min after awakening, 10:00, 12:00, 16:00, and 19:00 h. Cortisol, amylase, chromogranin A, and total protein levels were determined. RESULTS: The diurnal patterns of three biomarkers were different with cortisol showing the least variance and chromogranin A showing the highest variance among individuals. Participants with lower BMI exhibited higher cortisol levels (p = 0.044). Age oppositely affected amylase and chromogranin A, as being older was associated with higher amylase (p = 0.029) and lower chromogranin A levels (p < 0.01) even though both markers represent the sympathetic activity. Male participants also showed lower chromogranin A levels than females (p = 0.045). Total protein concentration affected chromogranin A levels only around awakening period but not at other time points suggesting that protein adjustment may not be necessary if the experiment is performed during the day. The afternoon was the period where all three biomarkers showed rather stable levels. CONCLUSIONS: These results illustrate the nature of cortisol, amylase, and chromogranin A patterns throughout the day in a normal physiological state and help in choosing the right condition to perform the experiment with these biomarkers.
