Salivary concentration of progesterone and cortisol significantly differs across individuals after correcting for blood hormone values
Article first published online: 24 JUL 2012
Copyright © 2012 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 149, Issue 2, pages 231–241, October 2012
How to Cite
Konishi, S., Brindle, E., Guyton, A. and O'Connor, K. A. (2012), Salivary concentration of progesterone and cortisol significantly differs across individuals after correcting for blood hormone values. Am. J. Phys. Anthropol., 149: 231–241. doi: 10.1002/ajpa.22114
- Issue published online: 14 SEP 2012
- Article first published online: 24 JUL 2012
- Manuscript Accepted: 12 JUN 2012
- Manuscript Received: 16 DEC 2011
- KAKENHI. Grant Number: 21790572
- NICHD. Grant Number: R24 HD42828
- steroid hormone;
- dried blood spot
Between-individual variation of salivary progesterone (P4) and cortisol levels does not always closely reflect blood hormone concentrations. This may be partly a function of individual differences in salivary hormone excretion. We tested whether time of day at sampling and ethnicity contributed to individual variation in salivary hormones after adjusting for blood hormone levels. Forty-three Caucasian and 15 Japanese women (18–34 years) collected four sets of matched dried blood spot (DBS) and saliva specimens across a menstrual cycle (N = 232 specimen sets). Linear fixed-effects (LFE) models were used to estimate the effects of diurnal variation and ethnicity on salivary P4 and cortisol while adjusting for DBS levels. For each hormone, women with exclusively positive or negative residuals (unexplained variance) from the LFE models were categorized as high- or low-saliva-to-DBS hormone ratio (SDR; high or low salivary secretors), respectively. We found that salivary P4 (P < 0.05) was significantly higher in early morning compared to the afternoon, after controlling for DBS levels, ethnicity, and BMI. After further adjusting for this diurnal effect, significant individual variation in salivary P4 and cortisol remained: sixteen and nine women, respectively were categorized as low or high salivary secretors for both hormones (P < 0.001), suggesting systematic individual-specific variation of salivary hormonal concentration. We conclude that when saliva is used to quantify P4 or cortisol levels, time of day at sampling should be controlled. Even with this adjustment, salivary P4 and cortisol do not closely mirror between- individual variation of serum P4 and cortisol in a substantial proportion of individuals. Am J Phys Anthropol 149:231–241, 2012. © 2012 Wiley Periodicals, Inc.