In a study focusing on 11-year-old children, researchers have found a connection between increased behavioral issues and elevated levels of cortisol in hair. The study indicates that certain factors leading to chronic stress could influence the cortisol levels detected in hair samples.
Cortisol is a hormone the body releases in response to stress, making hair cortisol concentrations a valuable indicator for assessing long-term stress levels. “While cortisol can be found in the blood, saliva, and urine, which reflect immediate cortisol levels, its accumulation in hair indicates a more prolonged state of stress, or chronic stress,” explained Ane Arregi-Otxotorena from the UPV/EHU’s Faculty of Psychology. To illustrate the difference between acute stress and chronic stress, Arregi provides the example: “The stress felt when you realize you lack cash to buy bread one day is different from the ongoing stress of knowing you can’t afford bread regularly.”
The researcher from the Basque Environmental Health Research Group (B-EHRG) analyzed hair samples from 11-year-old participants to evaluate chronic stress. She utilized data from the INMA project, which collects extensive information on children and their families starting from the mother’s pregnancy for long-term research insights.
As a result, the findings showed that significant behavioral problems correlate with elevated hair cortisol levels. Furthermore, “we observed that maternal stress impacts children’s behavioral issues, suggesting that a mother’s stress can affect her child’s cortisol levels through their behavior,” Arregi elaborated.
Cortisol levels and environmental noise
Additionally, the study revealed an unexpected finding: “Increased exposure to environmental noise was linked to lower cortisol levels. We noticed that as the noise levels rose, cortisol levels tended to drop. However, this correlation was significant only for boys,” the researchers noted. They suggested that while short-term stress from noise might temporarily elevate cortisol levels, ongoing exposure to high noise could lead to a decrease in cortisol levels. These intriguing results regarding noise will be further explored in a broader study under the European Athlete (Horizon 2020) project.
Influences from various factors
In general, “our research identified these two key factors, but that doesn’t exclude the possibility of other related factors that we didn’t uncover,” Arregi stated. “It’s essential to view this research from a wider lens, considering multiple stress factors simultaneously.” Hence, a model was developed to examine how environmental, social, and individual influences affect the cortisol concentrations in children’s hair. Various potential stressors were accounted for in the literature: access to green and blue spaces, air pollution, environmental noise, family and school dynamics, parental stress, sleep issues, physical activity, age, sex, and so forth.
As highlighted by the UPV/EHU researcher, “there’s still much to learn about what influences hair cortisol levels in children and young people, as previous studies often overlooked the simultaneous impact of several factors.” This model aims to address that gap. Arregi explained that the model will help identify which factors should be prioritized when evaluating hair cortisol levels.
Future studies will need to adopt this more intricate approach to better grasp what determines cortisol levels in children’s hair. The simultaneous effects of various environmental, social, and individual factors may significantly sway cortisol concentrations. Chronic stress in children is linked to numerous health concerns; “childhood and adolescence are particularly sensitive periods as they involve rapid development. Understanding how various factors impact the health of children and adolescents during these times is crucial for fostering healthy adult development,” the researcher emphasized.
“We believe that measuring cortisol in hair could serve as a valuable tool in evaluating the effects of environmental factors on chronic stress. Ultimately, this could inform effective public policy; understanding what causes chronic stress in specific communities may streamline the process of implementing preventative measures,” she concluded.
