Sequence and seasonal effects of salivary cortisol

Assessments of cortisol levels in saliva have been widely used by both rese archers and clinicians as an index of adrenal functioning. quarterly measur ements of morning and evening cortisol levels were determined in a longitud inal study of 147 participants (72 women and 75 men)followed for I year eac h. The analysis of salivary cortisol revealed no significant gender or age differences in the sample. There was a sequence effect in quarterly cortiso l values with a progressive decrease in serial measurements, especially not able in the morning values, as well as a seasonal variation in cortisol lev els with significantly higher levels found in winter and fall, compared wit h spring and summer. The findings in this study suggest that repeated saliv a sampling and seasonal variation in cortisol levels may independently affe ct adrenal response and, therefore, need to be accounted for in longitudina l studies.