First global analysis follows discovery of toxic pollution particles in lungs and brains of foetuses

首次全球分析是在发现胎儿肺部和大脑中的有毒污染颗粒后进行的

Office buildings in Beijing shrouded by pollution haze. Experts say clean air policies, such as those enacted by China, can reduce the number of stillbirths. Photograph: Andy Wong/AP

北京的办公楼被雾霾笼罩。专家说，清洁空气政策，比如中国制定的政策，可以减少死产的数量。

照片：Andy Wong/AP

Almost a million stillbirths a year can be attributed to air pollution, according to the first global study.

根据第一项全球研究，每年有近100万例死产可归因于空气污染。

The research estimated that almost half of stillbirths could be linked to exposure to pollution particles smaller than 2.5 microns (PM2.5), mostly produced from the burning of fossil fuels.

该研究估计，近一半的死产可能与暴露于小于2.5微米(PM2.5)的污染颗粒有关，这些颗粒主要由燃烧化石燃料产生。

The study covered 137 countries in Asia,Africa and Latin America, where 98% of stillbirths occur. Dirty air was already known to increase the risk of stillbirth but the research is the first to assess the number of foetal deaths. The work was based on data from more than 45,000 stillbirths and live births.

这项研究覆盖了亚洲、非洲和拉丁美洲的137个国家，98%的死产发生在这些国家。人们已经知道污浊的空气会增加死产的风险，但这项研究是第一次评估胎儿死亡数量。这项研究基于4.5万多名死产和活产的数据。

Stillbirths were described as a “neglected tragedy” in a 2020 report published by Unicef. The heavy impact of stillbirths on mothers and their families would mean that action to prevent them would boost women’s health and equality, the scientists behind the new work said.

在联合国儿童基金会2020年发布的一份报告中，死产被描述为“被忽视的悲剧”。这项新研究的科学家们表示，死产对母亲及其家人的严重影响意味着，采取措施防止死产将促进女性的健康和平等。

The epidemiological study did not examine how small particle pollution could cause stillbirths. But it followed the revelation in October that toxic air pollution particles werefound in the lungs and brains of foetuses. Air pollution particles were first detected in placentas in 2018 and by then dirty air was known to strongly correlate with increased miscarriages, premature births, low birth weights and disturbed brain development.

流行病学研究没有调查小颗粒污染如何导致死产。但在此之前，今年10月有消息称，胎儿的肺和大脑中发现了有毒空气污染颗粒。2018年，人们首次在胎盘中检测到空气污染颗粒，那时人们已经知道，肮脏的空气与流产、早产、出生体重过低和大脑发育紊乱密切相关。

“Meeting the World Health Organization (WHO) air quality targets could prevent a considerable number of stillbirths,” said the scientists, led by Dr Tao Xue at Peking University inChina. “Current efforts to prevent stillbirth focus on medical service improvements but compared to clinical risk factors, environmental ones are usually unseen.”

中国北京大学的薛涛博士领导的科学家们说:“达到世界卫生组织(WHO)的空气质量目标可以防止相当数量的死产。”“目前预防死胎的努力主要集中在改善医疗服务上，但与临床风险因素相比，环境风险因素通常被忽视。”

The scientists added: “Clean air policies, which have been enacted in some countries, such as China, can prevent stillbirths. In addition, personal protections against air pollution, ie wearing masks, installing air purifiers, avoiding going outside when air pollution occurs could also protect vulnerable pregnant women.”

科学家们补充说:“一些国家，如中国，已经制定了清洁空气政策，可以防止死产。此外，防止空气污染的个人防护措施，如戴口罩、安装空气净化器、在空气污染发生时避免外出，也可以保护脆弱的孕妇。”

The research,published in Nature Communications, used data on stillbirths and air pollution between 1998 and 2016 from 54 low- and middle-income countries (LMIC), including Pakistan, India and Nigeria. This was used to estimate the number of stillbirths attributable to PM2.5 exposure across the 137 LMIC countries, taking into account the fact that the impact of dirty air was greater on older mothers.

这项发表在《自然通讯》上的研究使用了1998年至2016年54个低收入和中等收入国家(LMIC)的死产和空气污染数据，包括巴基斯坦、印度和尼日利亚。该数据用于估计137个LMIC国家中PM2.5暴露导致的死产数量，同时考虑到脏空气对大龄母亲的影响更大这一事实。

Virtually all the mothers in the study were exposed to PM2.5 levels above theWHO’s current guideline level of 5 micrograms per cubic metre (μg/m3). There were 2.09 million stillbirths recorded in the studied countries in 2015, and 950,000 of them (45%) were attributable to exposure above the 5 μg/m3 level, the study estimated.

在这项研究中，几乎所有的母亲都暴露在PM2.5水平高于世界卫生组织目前的指导水平每立方米5微克(μg/m3)的环境中。该研究估计，2015年在受研究国家记录了209万例死产，其中95万例(45%)是由于暴露在5μg/m3水平以上。

The WHO guideline for PM2.5 was 10 μg/m3 until 2021 and 99% of mothers in the study were exposed to higher levels of dirty air. This was linked to 830,000 stillbirths, or 40% of the total, the study found. The proportion of stillbirths attributed to PM2.5 pollution was particularly high in Pakistan,India, Nigeria and China. Overall, the researchers found that an increase in PM2.5 exposure of about 10 µg/m3 was associated with an 11% increase in the risk of stillbirth.

在2021年之前，世界卫生组织的PM2.5指导方针是10μg/m3，研究中99%的母亲暴露在更高水平的脏空气中。研究发现，这与83万死产有关，占死产总数的40%。在巴基斯坦、印度、尼日利亚和中国，PM2.5污染导致的死产比例特别高。总的来说，研究人员发现PM2.5暴露量增加约10μ g/m3与死产风险增加11%相关。

The total number of stillbirths fell from 2.31 million in 2010 to 1.93 million in 2019. The researchers said cuts in air pollution in some countries, such as China, could be a significant reason for this fall. They estimated that reducing air pollution to the 10 ug/m3 level could today prevent 710,000 stillbirths a year. “Due to universal exposure to air pollution, it is one of the most important contributors to global stillbirth,” Xue said.

死产总数从2010年的231万例下降到2019年的193万例。研究人员表示，一些国家(如中国)空气污染的减少可能是这种下降的一个重要原因。他们估计，将空气污染降低到10微克/立方米的水平，现在每年可以防止71万名死产。“由于普遍暴露在空气污染中，这是全球死产最重要的原因之一，”薛说。

How air pollution may cause stillbirths is not yet clear. But the researchers said pollution particles passing through the placenta could cause “irreversible embryonic damage” and could also harm the placenta itself.Air pollution could also restrict the ability of the mother’s body to pass oxygen to the foetus.

空气污染如何导致死胎还不清楚。但研究人员表示，通过胎盘的污染颗粒可能导致“不可逆的胚胎损伤”，也可能伤害胎盘本身。空气污染也会限制母亲的身体向胎儿输送氧气的能力。

The scientists said while the global number of stillbirths was falling, there was no decrease in about half the LMIC countries assessed. They noted that the rate of decline of stillbirths was slower than the decline in mortality for children under five years old. “This suggests that efforts to promote maternal health are unequal for different adverse outcomes, and that interventions relevant to stillbirths are inadequate,” they said.

科学家们说，虽然全球死产数量在下降，但在评估的LMIC国家中，约有一半的国家没有下降。他们指出，死产率的下降速度低于五岁以下儿童死亡率的下降速度。他们说:“这表明，对于不同的不良结果，促进产妇健康的努力是不均衡的，与死产相关的干预措施是不充分的。”

Prof Gregory Wellenius, the director of the Center for Climate and Health at Boston University in the US, who was not involved in the research, said: “This study is novel and demonstrates that at current levels air pollution contributes to a substantial number of stillbirths around the world.

美国波士顿大学气候与健康中心主任Gregory Wellenius教授没有参与这项研究，他说:“这项研究很新颖，它表明，在目前的空气污染水平下，世界各地的死产数量相当巨大。”

“Health impact assessments such as this are always based on a number of important assumptions. Although the fraction of stillbirths that might be prevented through meaningful reductions in PM2.5 is uncertain, the study adds to the abundance of scientific evidence showing that reducing air pollution levels would improve the health of people around the world, particularly among the most vulnerable individuals.”

“像这样的健康影响评估总是基于一些重要的假设。尽管通过大幅度降低PM2.5可以防止死产的比例尚不确定，但这项研究为大量科学证据提供了新的证据，表明减少空气污染水平将改善世界各地人们的健康，特别是最弱势群体的健康。”

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本文作者Damian Carrington，由纽约金融学院推荐，文内涉及各种股票，信息，资讯，仅作为投资者进行证券投资的参考和替代，不作为投资建议。投资者自行承担据此进行投资所产生的风险及后果。