Exploring the relationship between environmental noise and children’s health outcomes: sleep habits and cortisol levels

Environmental noise is a ubiquitous form of urban exposure and is considered a major environmental risk factor for public health. However, children are often underrepresented in research, and there is limited evidence on its effects among this subpopulation. Given this gap, the primary objective of this thesis is to provide empirical evidence regarding the impact of environmental noise on human health, with a specific focus on children. To achieve this, we conducted several studies utilizing data from the INMA and ATHLETE projects. The objective of the first study was to investigate the impact of environmental noise exposure on children’s sleep habits. The second study sought to identify factors affecting hair cortisol levels in 11-year-old children. The third publication examined the effect of environmental noise exposure on cortisol levels. The fourth and final study investigated the roles of chronic stress, chronic inflammation, and oxidative stress in noise-induced health effects. The results indicate that 60% of children from the INMA-Gipuzkoa cohort experienced day-evening-night noise exposure levels exceeding 55 dB, with no observed socioeconomic differences in noise exposure. No significant association was observed between environmental noise exposure and sleep patterns. The results remained consistent when examining the relationship between environmental noise exposure and cortisol levels in 8-year-old children. However, increased exposure to environmental noise was associated with reduced hair cortisol levels in 11-year-old boys. These findings suggest the need for further epidemiological research to better understand the complex relationship between environmental noise exposure and health outcomes in children.