Life Unleaded: measuring the impact of lead reduction in water supplies

铅是一种毒性很强的元素，即使浓度很低，也会对婴儿和儿童的健康产生不利影响。在20世纪70年代，大多数人-包括怀孕的母亲-生活在格拉斯哥将饮用自来水，其中含有5倍的铅水平比目前接受的。当铅的毒性开始被广泛认识时，有时是在民间团体的运动之后，英国监管机构制定了减少并最终逐步淘汰水管和汽油中铅的计划和政策。该项目将研究从供水中去除铅的特定干预措施对怀孕结果的影响（例如，活产、出生体重、死产、流产）和婴儿死亡率。这项分析将研究1978年和1989年在格拉斯哥成功降低自来水中铅含量的两个水处理方案。该项目已获得公共利益和隐私小组的批准，苏格兰政府和格拉斯哥大学之间的数据共享协议也已签署。这些数据的处理符合《数据保护法》附表2第6条和附表3第8条的规定。格拉斯哥从特罗萨克斯的洛赫卡特琳水库取水。铅管道与洛赫湖的软水相结合，意味着格拉斯哥水中的铅含量被认为是不安全的。进行了两次铅处理，以提高供水的pH值，从而降低铅含量。第一次是在1978年，在供水系统中加入石灰。第二次是在1989年，石灰与正磷酸盐结合。这些成功地降低了格拉斯哥水中的铅含量。然而，没有研究这种铅治疗对格拉斯哥人群的影响。使用一个独特的数据集，我将利用个人暴露于铅污染的水的变化，以检查这对一系列结果的影响。关于妊娠结局的信息，如活产、死产和流产，将从不同的记录中收集：SMR 02、SMR 01（ISD）和死亡、出生和死产登记（NRS）。数据将涵盖1975年至2000年期间。活产将与死亡登记联系起来，以确定儿童是否在5岁前死亡。将单独分析每个关注的结局，如出生体重、胎龄、流产、5岁前死亡。作为对照的变量是性别和母亲的特征，如年龄、身高、吸烟史和既往产科史（如有）。这些记录将在可能的情况下与出生记录（NRS）联系起来，以提供有关父母职业和背景的信息，这些信息可用作额外的控制。为了改善混杂因素集，将与1981年和1991年的卡斯泰尔斯评分相关的其他信息与邮政编码区联系起来。将寻求关于教育和犯罪结果的进一步数据，这些数据可以与出生记录联系起来。这将用于了解铅治疗在健康结果之外的更广泛影响。铅已被证明会影响儿童的认知发展，这可能会影响教育成果。还有一些证据表明，铅暴露会降低对暴力的抑制，并导致冲动控制的丧失。因此，减少铅暴露可能会导致个人犯罪倾向的减少，特别是暴力犯罪。研究的第二个目的是利用铅影响的发现来预测供水中可能仍然存在高铅水平的地方。21世纪初在爱丁堡建造的新房屋以及密歇根州弗林特高度宣传的案例中发现了水中的铅污染。利用现代机器学习技术，我将建立一个预测模型，旨在找到供水中可能存在高铅含量的地方。

Lead is a very toxic element that can have adverse consequences on babies and children's health, even at low concentrations. In the 1970s, the majority of people - including pregnant mothers - living in Glasgow would drink tap water that contained 5 times the level of lead than is currently accepted. When the toxicity of lead started to be widely recognised, sometimes after campaigns by civic groups, the UK regulators set up programmes and policies to reduce and eventually phase out lead from water pipes and petrol. This project will examine the influence of specific interventions to remove lead from the water supply on pregnancy outcomes (e.g., live births, birth weight, stillbirths, miscarriage) and infant mortality by combining historical and administrative health data. The analysis will study two water treatment programmes that successfully reduced lead content in tap water in Glasgow in 1978 and 1989. The project has been approved by the Public Benefits and Privacy Panel and a data sharing agreement between Scottish Government and the University of Glasgow has been signed. The processing of these data meet the Data Protection Act Schedule 2, section 6 and Schedule 3, section 8. Glasgow receives its water from Loch Katrine reservoir in the Trossachs. Lead piping combined with the soft water of the loch meant that lead levels in Glasgow's water were considered unsafe. Two lead treatments were carried out to raise the pH of the water supply, so that lead levels were reduced. The first, in 1978, was the addition of lime to the water supply. The second, in 1989, was lime combined with orthophosphate. These successfully reduced lead levels in Glasgow's water. However, no research was carried out on what the effects of this lead treatment were for the population of Glasgow. Using a unique dataset, I will exploit the variation in individual's exposure to lead contaminated water to examine the impact of this on a range of outcomes. Information on pregnancy outcomes such as live births, stillbirths and miscarriages and will be gathered from different records: SMR02, SMR01 (ISD), and Death, Birth and Stillbirths Registrations (NRS). The data will cover the period from 1975 to 2000. Live births will be linked to death registration to identify if the child died before age 5. Every outcome of interest, such as birth weight, gestational age, miscarriages, death before the age 5 will be analysed separately. Variables that will be useful as controls are gender and mother's characteristics such as age, height, smoking history and previous obstetric history (if available). These records will be linked to birth records (NRS) when possible to provide information on parental occupation and backgrounds that could be used as additional controls. With an effort to improve the set of confounders, additional information related to Carstairs scores from 1981 and 1991 will be linked to postcode sector. Further data will be sought on education and crime outcomes that can be linked to birth records. This will be used to understand the wider effects of the lead treatment beyond health outcomes. Lead has been shown to affect cognitive development in children which may affect educational outcomes. There is also some evidence that lead exposure reduces inhibitions against violence and leads to loss of impulse control. Reduced exposure to lead may therefore cause a reduction in individual's propensity to commit a crime, especially violent crime.A secondary aim of the research will be to use the findings of the effects of lead to predict where high lead levels may still be present in the water supply. Lead contamination in water has been found in new houses built in Edinburgh in the early 2000's as well as in the highly publicised case of Flint, Michigan. Using modern machine learning techniques, I will build a forecasting model that aims to find where there is likely to be high levels of lead in the water supply.