Mental health consequences of exposure to air pollution over the life course

世界卫生组织（世卫组织）和经济合作与发展组织（经合组织）将空气污染列为全球过早死亡的主要环境原因，并得出结论认为，通过降低空气污染水平，各国每年可减轻疾病负担，净收益为1.0822亿英镑。这些估计是根据长期和短期接触空气污染与不良心肺发病率和死亡率之间的既定联系作出的。目前，全球开展的研究已将交通衍生空气污染暴露与儿童神经发育障碍（Raz等人2015年）、抑郁和焦虑（Braithwaite等人2019年）、精神病（Newbury等人2019年）和神经退行性疾病（Chen等人2017年）的风险增加联系起来，并提出了潜在的因果途径（Block等人2009年）。这些神经系统影响意味着目前在世卫组织和经合组织的评估中未包括的重大额外经济和社会成本。然而，尽管为改善空气质量作出了相当大的努力，但世界上大多数城市人口呼吸的空气仍不符合以健康为基础的世卫组织空气质量准则。需要一种严格的方法来改进目前的证据基础：这些基于人群的研究结果的强度往往受到以下限制：1)精神健康和精神疾病的简短精神健康和精神筛查工具或代理措施（例如药物处方）的简单性；Ii)过度简化的暴露估计和替代空气污染措施（例如靠近主要道路）；Iii)未考虑空气污染与区域或个人层面指标的相互作用（例如，社会经济地位较低的社区往往居住在交通繁忙的地方）；Iv)未能测量来自多个来源的一系列空气污染物的纵向暴露；v)未能探索空气污染与心理健康之间关联的潜在途径和机制。需要更好地了解空气污染对心理健康的敏感期、累积和极长期影响：越来越多的证据表明，空气污染对死亡率有长期和极长期（25年以上）影响。然而，只有一项研究探讨了这些与25年以上的心理健康结果之间的联系，而且这只与精神分裂症有关（Antonsen et al, 2021）。同样，年轻人可能特别容易受到空气污染的有害影响，因此，重要的是要捕捉生命早期接触污染的情况，并在整个生命过程中纵向探索与心理健康的关系，并检查接触的时间和持续时间是否重要。需要更好地了解暴露于空气污染中的长期社会经济不平等：全球有越来越多的证据表明，与较富裕的社区相比，脆弱社区更有可能暴露于较高的空气污染水平，这可能导致健康受损（Pinault et al . 2016）。迄今为止，很少有研究从生命历程的角度来了解空气污染不平等的动态及其对健康的影响，以便公共卫生研究人员和政策制定者能够了解其社会和经济影响，以便进行干预。目的：在多个英国纵向出生队列（国家健康与发展调查（NSHD），环境风险（E-Risk）纵向双胞胎研究）中，调查空气污染暴露与生命过程中广泛的心理健康结果之间的联系，以及政策和服务提供的不利关联的潜在影响。

The World Health Organisation (WHO) and Organization for Economic Co-operation and Development (OECD) rank air pollution as the main environmental cause of premature death globally and concluded that by reducing air pollution levels countries can alleviate the burden of disease by a net benefit of 108.22 million GB£ annually. These estimates are based on the established associations between long and short-term air pollution exposures and adverse cardiopulmonary morbidity and mortality. Studies conducted globally have now linked traffic-derived air pollution exposures with increased risk of neurodevelopmental disorders in children (Raz et al 2015), depression and anxiety (Braithwaite et al 2019), psychosis (Newbury et al 2019) and neurodegenerative conditions (Chen et al 2017), and potential causal pathways have been suggested (Block et al 2009). These neurological impacts imply significant additional economic and societal costs not currently represented in the WHO and OECD assessments. Yet, despite considerable efforts to improve air quality, the majority of the world's urban populations still breathe air failing to meet the health-based WHO Air Quality Guidelines. A rigorous methodology to improve the current evidence base is needed: The strength of the findings from these population-based studies are often limited by i) the simplicity of brief mental health and psychiatric screening instruments or proxy measures (e.g. prescription of medication) of mental health and psychiatric disorders; ii) over-simplified exposure estimates and surrogates of air pollution measures (e.g. proximity to major roads); iii) not taking into account interactions of air pollution with area- or individual-level indicators (e.g. communities of low socioeconomic status tend to live close to heavy traffic); iv) failure to measure longitudinal exposures from a range of air pollutants from multiple sources; and v) failure to explore potential pathways and mechanisms that are implicated in the association between air pollution and mental health. A better understanding is needed of sensitive periods, accumulation and very long-term impacts of air pollution on mental health: There is growing evidence of long-term and very long-term (25+) impacts of air pollution on mortality. However, only a single study has explored these associations with mental health outcomes beyond a 25-year time-period and this related only to schizophrenia (Antonsen et al 2021). Similarly, young people may be particularly susceptible to the harmful effects of air pollution, so it is important to capture early life exposures to pollution and explore longitudinally the associations with mental health across the life-course and examine whether timing and duration of exposure matters. A better understanding is needed of the long-term socioeconomic inequalities in exposure to air pollution: There is a growing body of global evidence that vulnerable communities are more likely to be exposed to higher air pollution levels which could result in impaired health compared to their more affluent counterparts (Pinault et al 2016). Few studies to date have applied a life course perspective to understand the dynamics of air pollution inequalities and their impacts on health so that public health researchers and policymakers can understand the societal and economic implications in order to intervene. AIM To investigate the link between air pollution exposure and a broad range of mental health outcomes over the life-course in multiple UK-based longitudinal birth cohorts (National Survey of Health and Development (NSHD), Environmental Risk (E-Risk) longitudinal twin study) and the potential implications of adverse associations for policy and service provision.