Abstract
Purpose :
To investigate hair cortisol concentration as a biochemical correlate of chronical psychological stress as a risk factor for keratoconus progression.
Methods :
70 participants were included in this prospective observational study (28 progressive keratoconus (KCp) patients, 27 stable keratoconus (KCs) patients and 15 healthy (H) participants). Hair strands of keratoconus patients and healthy subjects were analyzed in order to compare their hair cortisol concentration as a biomarker of stress. Based on an average hair growth rate of 1 cm/month, hair cortisol of a hair segment of 3 cm length is supposed to represent the stress profile of the last three months. We investigated hair strands of a diameter of approximately 3 mm which were taken scalp-near from a posterior vertex position. Cortisol concentrations were determined from the 3 cm hair segment most proximal to the scalp. Cortisol levels were determined in Institute of Biopsychology of the TU Dresden using a commercially available immunoassay with chemoluminescence detection (CLIA, IBL-Hamburg, Germany). Relevant sociodemographic variables were recorded. An objective standardized questionnaire for chronic stress had to be answered using the Trierer Inventar of chronic stress (TICS) screening scale.
Statistical analysis was performed using SPSS: Chi-square-test and ANOVA were used to determine which parameters differed between the two groups.
Results :
In patients with progressive keratoconus was hair cortisol concentration higher compared to the patients with stable disease and healthy subjects (27.54 (CI 95% 19.31…39.28) vs. 18.2 (14.61…22.66) pg/mg P=0.043). There was no difference between healthy subjects and patients with stable keratoconus (16.33 (CI 95% 10.69 …24.95) vs. 19.28 (14.06 … 26.42) P=0.900). Normal hair cortisol ranges from 5-25 pg/mg. Increased values were found in the group with progressive keratoconus than in the group of healthy participatns and patients with stable keratoconus (50% vs. 33% vs. 13%; P=0.05). The BMI was slightly higher in KCp compared to healthy group and KCs (27.06±7.5 vs. 24.5±4.5 P= 0.086). No difference was found in age, gender, TICS.
Conclusions :
This study showed that increased hair cortisol concentration seemed to be a risk factor for progression of keratoconus and these patients might benefit from avoiding chronical stress.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.