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Understanding the Exposome
The Role of Life Course
Childhood may be viewed as a succession of phases or stages with distinguishable anatomical, physiological, and psychological characteristics. A child’s exposure and vulnerability to physical, social, and internal components vary over developmental phases, ranging from preconception, foetal period, neonatal period, infant, toddler, early childhood, middle childhood and early and late adolescence (e.g. Cohen et al., 2014).
Over these time periods, children are subjected to a wide diversity of physical and social expo-sures in places and times, exposures over which they have little control. A child’s individual vulnerability varies across time due to their extensive bio-psycho-social development. Children also have a comparatively higher uptake of substances due to their physiology and less devel-oped detoxification metabolism, making them more vulnerable to environmental and chemical exposures than adults. Equal-Life adopted a simplified classification of age span with six age groups: prenatal, 0-3 years, 4-6 years, 7-12 years, 13-16 years and 17 and older. The exact age categories varied between the different analyses due to deviating classification in the cohorts, in-depth studies etc.
Results from literature review show that age-specific exposures are related to child outcomes.
Prenatal exposures to e.g. smoking, maternal mental health issues or air pollution have long time effects on mental health and cognitive development. Partly, this is associated with low birth weight. Early exposures are therefore crucial for mental health later in life.
Among children aged 5–7 years, parent-reported well-being and mental health, as well as children’s preschool well-being, are, according to the literature, associated with several factors: parental stress and support, neighbourhood quality, environmental risks, and the number of children in the household. Children's well-being is significantly lower in contexts with higher environmental risk exposure. Interestingly, a greater number of children in the household was associated with better performance in non-speech sound detection in noise (SDT). Additionally, children's ability to perceive speech in noisy environments was a significant predictor of their phonological awareness and reading abilities one year later
In children aged 8–12 years, the analysis of exposures and outcomes focused on mental health, well-being, cognition, and sleep. Perceived neighbourhood quality and road safety contributed valuable insights into the pathways linking the social exposome to developmental outcomes. In addition, exposures such as access to green spaces and the quality of family relationships emerged as particularly influential factors, highlighting the importance of both environmental and social dimensions in shaping children’s health and development.
For adolescents, key exposures related to mental health, well-being, cognition, and sleep include perceived socioeconomic position, environmental noise and light, and access to green spaces. Proteomic biomarkers, air pollution, and media use also emerged as important factors, reflecting the multifaceted nature of environmental and biological influences during this critical developmental period.