Abstract # 1697 Hair cortisol concentrations associate with hair growth rate

There is a growing interest in hair cortisol analysis as a valuable biomarker for assessment of chronic stress. However, several methodological variations in hair cortisol analysis raise questions about result validity and equivalency between assays. Those debated points include determining the effects of cosmetic hair treatments and frequency of hair washing on hair cortisol concentrations (HCC), whether HCC remain constant along the length of hair shaft, and the relationship between HCC and hair growth rate. The specific goals of the study were to address these points. Fifty-three normal participants were recruited and hair segments proximal to the scalp were collected from each individual. A cost effective ball mill was used for preparation of hair samples and cortisol levels were measured by ELISA. Results show that frequency of hair washing affects HCC. The group that washed hair everyday had significantly lower HCC than that of not-everyday ( p  = 0.004). There was no significant difference between cosmetic treated and non-treated hair samples. Study also shows that HCC in the first 3 cm hair segments proximal to the scalp were equivalent with hair growth rate based on 1 cm/month ( p  = 0.030). Thus, HCC of a 3 cm proximal hair segment may represent cumulative stress exposure over the previous 3 months. These findings will allow more widespread research to validate the utility of HCC as a potential biomarker for assessing chronic stress.