Elsevier

Steroids

Volume 76, Issues 10–11, September–October 2011, Pages 1032-1036
Steroids

Evaluation of a method to measure long term cortisol levels

https://doi.org/10.1016/j.steroids.2011.04.005Get rights and content

Abstract

Introduction

Elevated levels of cortisol are known to induce various symptoms and diseases, e.g. abdominal obesity, type 2 diabetes, osteoporosis and cardiovascular disease. Measuring serum, saliva and urine cortisol is limited to one time point. Measurement of cortisol in scalp hair is a recently developed method to measure long term cortisol levels. The aim of this study was to investigate whether hair cortisol is a feasible parameter to measure cortisol exposure.

Experimental

We collected hair samples of 195 healthy individuals, 9 hypercortisolemic and one hypocortisolemic patient and measured hair cortisol levels. Cortisol was extracted from scalp hair using methanol and cortisol levels were measured using a salivary ELISA kit. Measurement of waist and hip circumferences and blood pressure was performed in 46 healthy subjects.

Results

We found a positive correlation between hair cortisol and both waist circumference (r = 0.392, p = 0.007) and waist-to-hip ratio (WHR) (r = 0.425, p = 0.003). No correlations were found between hair cortisol levels and BMI, blood pressure or age. There was no decline in cortisol levels in six consecutive hair segments. Hair cortisol levels were elevated in patients with known hypercortisolism (p < 0.0001).

Conclusions

Hair cortisol was positively correlated with WHR, suggesting that hair cortisol reflects cortisol exposure at tissue level, which was also supported by elevated hair cortisol levels in hypercortisolemic patients and concordance between hair cortisol levels and clinical disease course. Cortisol levels in hair are slightly influenced by hair treatment but not by natural hair colour, use of hair products, gender or age.

Graphical abstract

Hair cortisol is positively correlated with waist-to-hip ratio and corresponds with clinical course in a patient with Cushing's disease, suggesting that hair cortisol reflects cortisol exposure at the tissue level.

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Highlights

► Cortisol levels in scalp hair were measured in 195 healthy individuals, 9 hypercortisolemic patients and 1 hypocortisolemic patient. ► Hair cortisol levels are positively correlated with waist-hip-ratio. ► There is no decline in cortisol levels in consecutive segments of long hair. ► Cortisol levels in hair are slightly influenced by hair treatment. ► Cortisol levels in scalp hair of patients with Cushing's syndrome are increased and correspond to clinical course.

Introduction

The stress hormone cortisol has a wide spectrum of physiological effects throughout the human body and is involved in glucose and lipid metabolism, body composition, immunosuppressive and anti-inflammatory actions [1]. The effects of long term exposure to elevated cortisol levels comprise increased visceral fat mass, redistribution of body fat with accumulation of adipose tissue on abdomen and trunk and muscle atrophy. In addition, high levels of cortisol induce hypertension, insulin resistance and dyslipidemia, leading to an increased cardiovascular risk as is seen in Cushing's syndrome, which is a state of cortisol excess, or in use of high doses of exogenous glucocorticoids [2], [3].

Until now, most studies addressed the relationship between total serum cortisol and symptoms or disease. Conflicting data have been published and the exact relationship between cortisol-mediated effects and symptoms or diseases remains to be established. Likely explanations for these conflicting data are the circadian rhythm, the pulsatile secretion of cortisol and the daily variation due to circumstances (e.g. stress or infection). This complicates the use of serum, saliva and urine cortisol in epidemiological studies. Recently, several studies have shown that endogenous cortisol can reliably be measured in scalp hair [4], [5], [6], [7], [8], [9], [10]. Scalp hair grows with an average rate of one centimeter (cm) per month, therefore one cm of scalp hair could represent cortisol levels of one month. This suggests that hair cortisol can be used as a method to retrospectively measure cortisol exposure over the past weeks or months. This offers new potential ways to study the effects of, e.g. chronic stress, which is thought to be accompanied by a hyperactive hypothalamic–pituitary–adrenal (HPA) axis. This has already been evaluated in several studies. In chronic pain patients, cortisol levels were elevated compared to healthy persons [9] and in healthy pregnant women hair cortisol levels were positively correlated with perceived stress scale (PSS) scores [5]. Furthermore, unemployment, which is a chronic stressor, was also associated with increased cortisol levels in hair [11]. Recently, Pereg et al. showed elevated hair cortisol levels in patients with acute myocardial infarction [12].

Although the mechanism of cortisol incorporation into hair is not fully understood, measurement of cortisol levels in scalp hair is a very promising technique. Until now relatively small study populations were used and therefore replication is needed to evaluate the use of hair cortisol as a marker of long term endogenous cortisol levels. Hence, we determined cortisol levels in scalp hair of healthy individuals and patients with hyper- and hypocortisolism. The aim of this study was to investigate whether hair cortisol is a feasible parameter to measure cortisol exposure. We studied this by measuring cortisol levels in scalp hair of healthy individuals, patients with hypercortisolism and one patient with hypocortisolism. Factors that could influence hair cortisol concentrations were determined and we studied whether hair cortisol concentrations were associated with cortisol specific tissue effects such as body composition.

Section snippets

Study population

In total 195 healthy individuals who did not use glucocorticoids participated in this study. All participants had to fill out a questionnaire concerning hair and medical conditions. In the initial group of 149 healthy individuals hair cortisol levels were determined as well as height and weight. This group was extended by an additional 46 persons, in whom also waist and hip circumferences and blood pressure were measured. BMI was calculated as kg/m2. To validate the measurement of cortisol in

Assay recovery

The recovery of 5, 10, 20, 40, 80 and 160 nmol/L cortisol standards from PBS was 122.0%, 95.0%, 86.5%, 85.8%, 90.5% and 89.1%, respectively. When hydrocortisone was added to hair extracts, the mean recovery was 84.5%.

Healthy controls

Baseline characteristics of all healthy individuals are shown in Table 1. We found a significantly higher number of subjects who treated (dyed, bleached or permanent waved/straightened) their hair in women compared to men. Waist circumference, WHR and systolic blood pressure were

Discussion

The focus of this study was to evaluate whether cortisol in hair is a reliable long term cortisol parameter. One of the main findings of this study is the positive correlation between cortisol in hair and both waist circumference and WHR in healthy individuals. There was no correlation between hair cortisol and hip circumference or BMI. This observation is important, since one of the typical effects of cortisol is the accumulation of abdominal fat. BMI is a measure of body weight based on a

Declaration of interest

The authors declare no conflict of interest.

Funding

This work was supported by the NWO (grant number 916.96.069)

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