Cortisol levels in hair linked to heart attack risk

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Cortisol levels in hair may be the first biomarker to measure chronic stress, which is linked to a higher risk of having a heart attack (acute myocardial infarction), according to a new study published in the medical journal Stress. Employment, marital, bereavement, and financial problems are examples of stressors that have been associated with a higher heart attack risk, say the authors. But no previous study has come up with a biological market to measure chronic stress.

Investigators from Canada and Israel developed a way of measuring hair cortisol levels, providing an accurate measurement of stress levels in the months preceding an acute event, such as a heart attack.

Cortisol is a stress hormone – we secrete it when they are under stress. Traditional measurements of stress do not show stress levels over long periods. Typically, cortisol levels have been measured using serum, saliva or urine tests. However, cortisol is captured in the hair shaft, giving us an idea of its levels in the human body over longer periods.

Gideon Koren, who holds the Ivey Chair in Molecular Toxicology at Western’s Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada, said: “Intuitively we know stress is not good for you, but it’s not easy to measure. We know that on average, hair grows one cm a month, and so if we take a hair sample six cm long, we can determine stress levels for six months by measuring the cortisol level in the hair”.

The researchers collected three centimeter-long hair samples from 56 adult males who had been hospitalised at the Meir Medical Centre, Kfar-Saba, Israel, following a heart attack. They also collected samples from a control group consisting of 56 men who had also been hospitalised, but not for heart attacks. They discovered that hair cortisol levels during the last three months before hospitalisation were clearly higher in the heart attack patients than in the control group. The heart attack and control groups had similar heart attack factors, such as hypertension, smoking and family histories of coronary artery disease. The investigators did find more cholesterol problems among the heart attack patients.

After taking into account known risk factors, the scientists report that cortisol content emerged as the strongest predictor of heart attack. Koren said: “Stress is a serious part of modern life affecting many areas of health and life. This study has implications for research and for practice, as stress can be managed with lifestyle changes and psychotherapy”.