A new method to measure the amount of the stress hormone cortisol found in the body over the long term could lead to new research avenues to study the development of common conditions, such as heart disease, diabetes and depression. In results announced at the European Congress of Endocrinology, researchers found that hair can be used to create a retrospective timeline of exposure to cortisol. Cortisol is implicated in the development of many common conditions and this new technique could allow us to study its role better.
Cortisol is a hormone produced by the adrenal glands and its primary role is to help maintain body metabolism. If the body is put under (psychological or physical) stress, cortisol levels increase to allow the body to respond to the situation. Currently the standard method to measure cortisol levels is to take a blood or saliva sample. However, since cortisol is released in a circadian rhythm and with pulses throughout the day, levels can fluctuate considerably, meaning it is difficult to estimate an individual's long-term exposure to cortisol through blood and saliva tests alone. Finding a new non-invasive method to measure long-term cortisol exposure could have a major impact on our ability to determine the role of cortisol in the development of many common diseases, such as cardiovascular disease, diabetes and depression.
Dr Laura Manenschijn and her team from Erasmus MC in The Netherlands collected scalp hair samples from 195 healthy individuals and from 11 patients with Cushing's syndrome (a condition where the adrenal glands produce too much cortisol) and 3 patients with Addison's disease (a condition where the adrenal glands are unable to produce cortisol) and tested their cortisol levels. All participants filled out a questionnaire to assess what products and treatments they used on their hair. A subset of 46 participants also had their waist and hip measurements taken.
The team found that hair cortisol levels correlated positively with waist to hip ratio (r=0.425, p=0.003) and waist circumference (r=0.392, p=0.007), meaning people with higher exposure to cortisol showed higher abdominal obesity. In individuals with Cushing's syndrome the levels of cortisol in hair were significantly higher than in healthy individuals (p