Mechanisms of stress, energy homeostasis and insulin resistance in European adolescents – the HELENA study

• Role of stress in obesity development among adolescents is unknown.
• Associations of cortisol with leptin, insulin, glucose and HOMA-IR were explored.
• Cortisol was positively correlated to insulin, glucose and HOMA-IR in boys.
• Cortisol was positively correlated to leptin, insulin and HOMA-IR in girls.
• Stress might facilitate the development of obesity during adolescence.

Background and aimsStress is hypothesized to facilitate the development of obesity, whose the foundations are already set during childhood and adolescence. We investigated the relationship between the stress-system, selected mechanisms of energy homeostasis and insulin resistance (IR) in a sample of European adolescents.Methods and resultsWithin HELENA-CSS, 723 adolescents (12.5–17.5 years) from 10 European cities provided all the necessary data for this study. Fasting blood samples were collected for cortisol, leptin, insulin and glucose analysis. HOMA-IR was calculated from insulin and glucose concentrations. Adolescents' body fat (BF) %, age and duration of exclusive breastfeeding were assessed. For boys and girls separately, the relationship of cortisol with leptin, insulin, glucose and HOMA-IR was examined by computing Pearson correlation coefficients and Hierarchical Linear Models (HLMs), with ‘city’ as cluster unit, adjusting for age, BF% and duration of exclusive breastfeeding. In boys, Pearson correlation coefficients illustrated positive correlations of cortisol with insulin (r = 0.144; p = 0.013), glucose (r = 0.315; p < 0.001) and HOMA-IR (r = 0.180; p = 0.002), whilst in girls, this positive relationship was observed for leptin (r = 0.147; p = 0.002), insulin (r = 0.095; p = 0.050) and HOMA-IR (r = 0.099; p = 0.041), but not for glucose (r = 0.054; p = 0.265). Observed associations were independent of adolescents' age, BF% and duration of exclusive breastfeeding after computing HLMs.ConclusionThis study suggests that the stress-system is positively related to mechanisms of energy homeostasis and IR in European adolescents, and reveals a potential small gender difference in this relationship. The hypothesis that stress might facilitate the development of obesity during adolescence is supported.