Investigating the impact of London's ultra low emission zone on children's health: children's health in London and Luton (CHILL) protocol for a prospective parallel cohort study.

BACKGROUND: Air pollution harms health across the life course. Children are at particular risk of adverse effects during development, which may impact on health in later life. Interventions that improve air quality are urgently needed both to improve public health now, and prevent longer-term increased vulnerability to chronic disease. Low Emission Zones are a public health policy intervention aimed at reducing traffic-derived contributions to urban air pollution, but evidence that they deliver health benefits is lacking. We describe a natural experiment study (CHILL: Children's Health in London and Luton) to evaluate the impacts of the introduction of London's Ultra Low Emission Zone (ULEZ) on children's health. METHODS: CHILL is a prospective two-arm parallel longitudinal cohort study recruiting children at age 6-9 years from primary schools in Central London (the focus of the first phase of the ULEZ) and Luton (a comparator site), with the primary outcome being the impact of changes in annual air pollutant exposures (nitrogen oxides [NOx], nitrogen dioxide [NO2], particulate matter with a diameter of less than 2.5micrograms [PM2.5], and less than 10 micrograms [PM10]) across the two sites on lung function growth, measured as post-bronchodilator forced expiratory volume in one second (FEV1) over five years. Secondary outcomes include physical activity, cognitive development, mental health, quality of life, health inequalities, and a range of respiratory and health economic data. DISCUSSION: CHILL's prospective parallel cohort design will enable robust conclusions to be drawn on the effectiveness of the ULEZ at improving air quality and delivering improvements in children's respiratory health. With increasing proportions of the world's population now living in large urban areas exceeding World Health Organisation air pollution limit guidelines, our study findings will have important implications for the design and implementation of Low Emission and Clean Air Zones in the UK, and worldwide. CLINICALTRIALS: GOV: NCT04695093 (05/01/2021).

Measurement of pregnancy-related anxiety worldwide: a systematic review.

BACKGROUND: The perinatal period is often characterized by specific fear, worry, and anxiety concerning the pregnancy and its outcomes, referred to as pregnancy-related anxiety. Pregnancy-related anxiety is uniquely associated with negative maternal and child health outcomes during pregnancy, at birth, and early childhood; as such, it is increasingly studied. We examined how pregnancy-related anxiety is measured, where measures were developed and validated, and where pregnancy-related anxiety has been assessed. We will use these factors to identify potential issues in measurement of pregnancy-related anxiety and the geographic gaps in this area of research. METHODS: We searched the Africa-Wide, CINAHL, MEDLINE, PsycARTICLES, PsycINFO; PubMed, Scopus, Web of Science Core Collection, SciELO Citation Index, and ERIC databases for studies published at any point up to 01 August 2020 that assessed pregnancy-related anxiety. Search terms included pregnancy-related anxiety, pregnancy-related worry, prenatal anxiety, anxiety during pregnancy, and pregnancy-specific anxiety, among others. Inclusion criteria included: empirical research, published in English, and the inclusion of any assessment of pregnancy-related anxiety in a sample of pregnant women. This review is registered on PROSPERO (CRD42020189938). RESULTS: The search identified 2904 records; after screening, we retained 352 full-text articles for consideration, ultimately including 269 studies in the review based on the inclusion and exclusion criteria. In total, 39 measures of pregnancy-related anxiety were used in these 269 papers, with 18 used in two or more studies. Less than 20% of the included studies (n = 44) reported research conducted in low- and middle-income country contexts. With one exception, all measures of pregnancy-related anxiety used in more than one study were developed in high-income country contexts. Only 13.8% validated the measures for use with a low- or middle-income country population. CONCLUSIONS: Together, these results suggest that pregnancy-related anxiety is being assessed frequently among pregnant people and in many countries, but often using tools that were developed in a context dissimilar to the participants' context and which have not been validated for the target population. Culturally relevant measures of pregnancy-related anxiety which are developed and validated in low-income countries are urgently needed.

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.

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

BACKGROUND: Whilst there is little uncertainty about the deleterious impact of pollution on human and planetary health, pollution's impact on adolescent mental health is less well understood. This is particularly true for young people in underdeveloped and developing world contexts, about whom research is generally lacking. Furthermore, although adolescent resilience continues to be a research priority, little attention has been paid to adolescent pathways of resilience in the face or aftermath of pollution exposure. The objective of this study will be to examine the associations between pollution and mental health in 10- to 24-year-olds (i.e. adolescents). METHODS: We designed and registered a study protocol for a systematic review of studies which link pollution and mental health in adolescents. We will include observational studies (e.g. cohort, case-control, time series analyses) that assess the associations between exposure to any form of pollution and the mental health of 10- to 24-year-olds. The primary outcome will be symptoms associated with neurodevelopmental disorders; disruptive, impulse-control, and conduct disorders; depressive disorders; anxiety disorders; substance disorders; and schizophrenia. No secondary outcomes will be considered. Literature searches will be conducted in multiple electronic databases (from inception onwards), including PubMed, MEDLINE, SCOPUS, Web of Science, CINAHL, PsycINFO, SciELO, ERIC, and Africa-Wide. Two investigators will independently screen all citations, full-text articles, and abstract data. The methodological quality (or bias) of included studies will be appraised using appropriate tools. We will provide a narrative synthesis of the evidence. DISCUSSION: This systematic review will evaluate the evidence on the associations between pollution and the mental health of 10- to 24-year-olds. Our findings will be of potential interest to multiple audiences (including adolescent patients/clients, their families, caregivers, healthcare professionals, scientists, and policy makers) and could be used to develop prevention and intervention strategies as well as focus future research. Results will be published in a peer-reviewed journal. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020176664.