Effects of pollution on adolescent mental health: a systematic review protocol

Childhood air pollution exposure is related to cognitive, educational and mental health outcomes in childhood and adolescence: A longitudinal birth cohort study

BACKGROUND

A growing body of evidence supports an association between air pollution exposure and adverse mental health outcomes, especially in adulthood however, very little is known about the effects of early life air pollution exposure during childhood. We examined longitudinal associations between the extent and timing of children's annual air pollution exposure from conception to age 10 years and a wide range of cognitive, educational and mental health outcomes in childhood and adolescence that were assessed prospectively as part of a large birth cohort study.

METHODS

We linked historical air pollution data (μg.m-3) from pregnancy to age 10 years (1976-1987) using the addresses of all cohort members (n = 1265) of the Christchurch Health and Development Study (CHDS) who were born in New Zealand in mid-1977. Latent Class Growth Mixture Models were used to characterise different trajectories of air pollution exposure from the prenatal period to age 10 years. We then examined associations between these air pollution exposure trajectories and 16 outcomes in childhood and adolescence using R Studio and Stata V18.

FINDINGS

Four air pollution exposure trajectories were identified: i) low, ii) persistently high, iii) high prenatal and postnatal, and iv) elevated pre-school exposure. While some associations were attenuated, after adjusting for a variety of covariates spanning childhood, family sociodemographic background and family functioning characteristics, several associations remained. Relative to the lowest exposure trajectory, persistently high and high prenatal and postnatal exposure were both related to attentional problems. High prenatal and postnatal was also related to higher risk of substance abuse. Elevated pre-school exposure was associated with conduct problems, lower educational attainment and substance abuse and persistently high childhood exposure increased risk of substance abuse.

CONCLUSIONS

Our study highlights potential adverse and longer-term impacts of air pollution exposure during childhood on subsequent development in later life.

A systematic review of the mental health risks and resilience among pollution-exposed adolescents

Pollution is harmful to human physical health and wellbeing. What is less well established is the relationship between adolescent mental health - a growing public health concern - and pollution. In response, we systematically reviewed studies documenting associations between pollution and mental health in adolescents. We searched Africa Wide, Medline, PsycArticles, PsycInfo, PubMed, CINAHL, ERIC, SciELO, Scopus, and Web of Science Core Collection for studies published up to 10 April 2020 that investigated exposure to any pollutant and symptoms of anxiety; depression; disruptive, impulse-control, and conduct disorders; neurodevelopmental disorders; psychosis; or substance abuse in 10-24-year-olds (i.e., adolescents as per expanded and more inclusive definition of adolescence). This identified 2291 records and we assessed 128 papers for inclusion. We used a narrative synthesis to coalesce the studies' findings. This review is registered on PROSPERO, CRD42020176664. Seventeen studies from Asia, Europe, the Middle East, and North America were included. Air and water pollution exposure was associated with elevated symptoms of depression, generalised anxiety, psychosis, and/or disruptive, impulse control and conduct disorder. Exposure to lead and solvents was associated with neurodevelopmental impairments. Most studies neglected factors that could have supported the mental health resilience of adolescents exposed to pollution. Notwithstanding the limited quality of most reviewed studies, results suggest that pollution exposure is a risk to adolescent mental health. High-quality research is urgently required, including the factors and processes that protect the mental health of pollution-exposed adolescents. Studies with adolescents living in low- and lower middle-income countries and the southern hemisphere must be prioritized.