New research shows how people who suffer long-term stress may also be prone to obesity.
The claim comes from a study into levels of cortisol in hair, which showed a correlation between high levels of the hormone over a few months with being overweight.
The researchers at University College, London, UK, published their findings in Obesity.
The study involved 2,527 men and women aged 54 and older taking part in the English Longitudinal Study of Ageing, and differs from previous studies, which focused on measuring the hormone in blood, saliva or urine, the researchers say.
For this study, the research team took from each participant a 2cm lock of hair, which was cut as close possible to a person’s scalp, equating to about two months’ hair growth. Each study subject was weighed and had their BMI and waist circumference measured.
The team found that people who had high levels of cortisol in their hair tended to have larger waist circumference measurements, were heavier, and had a higher BMI. Those classed as obese on the basis of their BMI or waist circumference had particularly high levels of hair cortisol.
Dr Sarah Jackson, UCL Epidemiology and Public Health, who led the research, said the results provided “consistent evidence that chronic stress is associated with higher levels of obesity."
“People who had higher hair cortisol levels also tended to have larger waist measurements, which is important because carrying excess fat around the abdomen is a risk factor for heart disease, diabetes, and premature death,” she explained.
“Hair cortisol is a relatively new measure which offers a suitable and easily obtainable method for assessing chronically high levels of cortisol concentrations in weight research and may therefore aid in further advancing understanding in this area.”
While there were limitations to the study, the team said more research was needed to establish if levels of cortisol are different in younger adults and in people from different ethnic origins. Studies should also examine if chronically elevated cortisol levels are a cause or a consequence of obesity.
Jackson SE, Kirschbaum C, Steptoe A. Hair Cortisol and Adiposity in a Population-Based Sample of 2,527 Men and Women Aged 54 to 87 Years. Obesity. 23 February 2017; doi: 10.1002/oby.21733
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