Abstract：
BACKGROUND: Exposure to ambient fine particulate matter (PM2.5) has been associated with reduced human fecundity. However, the attributable burden has not been estimated for low- and middle-income countries (LMICs), where the exposure-response function between PM2.5 and the infertility rate has been insufficiently studied.
OBJECTIVE: This study examined the associations between long-term exposure to PM2.5 and human fecundity indicators, namely the expected time to pregnancy (TTP) and 12-month infertility rate (IR), and then estimated PM2.5-attributable burden of infertility in LMICs.
METHODS: We analyzed 164,593 eligible women from 100 Demographic and Health Surveys conducted in 49 LMICs between 1999 and 2021. We assessed PM2.5 exposures during the 12 months before a pregnancy attempt using the global satellite-derived PM2.5 estimates produced by Atmospheric Composition Analysis Group (ACAG). First, we created a series of pseudo-populations with balanced covariates, given different levels of PM2.5 exposure, using a matching approach based on the generalized propensity score. For each pseudo-population, we used 2-stage generalized Gamma models to derive TTP or IR from the probability distribution of the questionnaire-based duration time for the pregnancy attempt before the interview. Second, we used spline regressions to generate nonlinear PM2.5 exposure-response functions for each of the two fecundity indicators. Finally, we applied the exposure-response functions to estimate number of infertile couples attributable to PM2.5 exposure in 118 LMICs.
RESULTS: Based on the Gamma models, each 10 µg/m3 increment in PM2.5 exposure was associated with a TTP increase by 1.7 % (95 % confidence interval [CI]: -2.3 %-6.0 %) and an IR increase by 2.3 % (95 %CI: 0.6 %-3.9 %). The nonlinear exposure-response function suggested a robust effect of an increased IR for high-concentration PM2.5 exposure (>75 µg/m3). Based on the PM2.5-IR function, across the 118 LMICs, the number of infertile couples attributable to PM2.5 exposure exceeding 35 µg/m3 (the first-stage interim target recommended by the World Health Organization global air quality guidelines) was 0.66 million (95 %CI: 0.061-1.43), accounting for 2.25 % (95 %CI: 0.20 %-4.84 %) of all couples affected by infertility. Among the 0.66 million, 66.5 % were within the top 10 % high-exposure infertile couples, mainly from South Asia, East Asia, and West Africa.
CONCLUSIONS: PM2.5 contributes significantly to human infertility in places with high levels of air pollution. PM2.5-pollution control is imperative to protect human fecundity in LMICs.
OBJECTIVE: This study examined the associations between long-term exposure to PM2.5 and human fecundity indicators, namely the expected time to pregnancy (TTP) and 12-month infertility rate (IR), and then estimated PM2.5-attributable burden of infertility in LMICs.
METHODS: We analyzed 164,593 eligible women from 100 Demographic and Health Surveys conducted in 49 LMICs between 1999 and 2021. We assessed PM2.5 exposures during the 12 months before a pregnancy attempt using the global satellite-derived PM2.5 estimates produced by Atmospheric Composition Analysis Group (ACAG). First, we created a series of pseudo-populations with balanced covariates, given different levels of PM2.5 exposure, using a matching approach based on the generalized propensity score. For each pseudo-population, we used 2-stage generalized Gamma models to derive TTP or IR from the probability distribution of the questionnaire-based duration time for the pregnancy attempt before the interview. Second, we used spline regressions to generate nonlinear PM2.5 exposure-response functions for each of the two fecundity indicators. Finally, we applied the exposure-response functions to estimate number of infertile couples attributable to PM2.5 exposure in 118 LMICs.
RESULTS: Based on the Gamma models, each 10 µg/m3 increment in PM2.5 exposure was associated with a TTP increase by 1.7 % (95 % confidence interval [CI]: -2.3 %-6.0 %) and an IR increase by 2.3 % (95 %CI: 0.6 %-3.9 %). The nonlinear exposure-response function suggested a robust effect of an increased IR for high-concentration PM2.5 exposure (>75 µg/m3). Based on the PM2.5-IR function, across the 118 LMICs, the number of infertile couples attributable to PM2.5 exposure exceeding 35 µg/m3 (the first-stage interim target recommended by the World Health Organization global air quality guidelines) was 0.66 million (95 %CI: 0.061-1.43), accounting for 2.25 % (95 %CI: 0.20 %-4.84 %) of all couples affected by infertility. Among the 0.66 million, 66.5 % were within the top 10 % high-exposure infertile couples, mainly from South Asia, East Asia, and West Africa.
CONCLUSIONS: PM2.5 contributes significantly to human infertility in places with high levels of air pollution. PM2.5-pollution control is imperative to protect human fecundity in LMICs.
摘要：
背景：暴露于环境细颗粒物（PM2.5）与人类繁殖力降低有关。然而,尚未估计中低收入国家(LMIC)的可归属负担，其中PM2.5和不孕症率之间的暴露反应函数没有得到充分研究。
目的：本研究探讨了长期暴露于PM2.5与人类繁殖力指标之间的关联，即预期怀孕时间(TTP)和12个月不孕率(IR)，然后估计了LMICs不孕的PM2.5归因负担。
方法：我们分析了1999年至2021年间在49个低收入国家进行的100项人口和健康调查中的164,593名合格女性。我们使用大气成分分析小组（ACAG）得出的全球卫星得出的PM2.5估计值评估了怀孕前12个月的PM2.5暴露。首先,我们创建了一系列具有平衡协变量的伪种群，考虑到不同的PM2.5暴露水平，使用基于广义倾向得分的匹配方法。对于每个伪种群，我们使用2阶段广义Gamma模型,从访谈前基于问卷的妊娠持续时间的概率分布推导出TTP或IR.第二,我们使用样条回归为两个繁殖力指标中的每一个生成非线性PM2.5暴露响应函数。最后,我们应用暴露-响应函数来估计118个LMIC中由于PM2.5暴露引起的不育夫妇数量.
结果：基于Gamma模型，PM2.5暴露量每增加10µg/m3,TTP增加1.7%(95%置信区间[CI]:-2.3%-6.0%),IR增加2.3%(95CI:0.6%-3.9%).非线性暴露响应函数表明，对于高浓度PM2.5暴露（>75µg/m3），IR增加具有强大的作用。基于PM2.5-IR函数,在118个低收入国家中，由于PM2.5暴露超过35µg/m3（世界卫生组织全球空气质量指南建议的第一阶段临时目标）而导致的不育夫妇数量为66万（95CI：0.061-1.43），占所有不孕夫妇的2.25%(95CI:0.20%-4.84%)。在66万中，66.5%的人在高暴露不育夫妇中排名前10%，主要来自南亚，东亚,和西非。
结论：在空气污染严重的地方，PM2.5对人类不育症有显著影响。PM2.5污染控制对于保护LMIC中的人类繁殖力至关重要。
目的：本研究探讨了长期暴露于PM2.5与人类繁殖力指标之间的关联，即预期怀孕时间(TTP)和12个月不孕率(IR)，然后估计了LMICs不孕的PM2.5归因负担。
方法：我们分析了1999年至2021年间在49个低收入国家进行的100项人口和健康调查中的164,593名合格女性。我们使用大气成分分析小组（ACAG）得出的全球卫星得出的PM2.5估计值评估了怀孕前12个月的PM2.5暴露。首先,我们创建了一系列具有平衡协变量的伪种群，考虑到不同的PM2.5暴露水平，使用基于广义倾向得分的匹配方法。对于每个伪种群，我们使用2阶段广义Gamma模型,从访谈前基于问卷的妊娠持续时间的概率分布推导出TTP或IR.第二,我们使用样条回归为两个繁殖力指标中的每一个生成非线性PM2.5暴露响应函数。最后,我们应用暴露-响应函数来估计118个LMIC中由于PM2.5暴露引起的不育夫妇数量.
结果：基于Gamma模型，PM2.5暴露量每增加10µg/m3,TTP增加1.7%(95%置信区间[CI]:-2.3%-6.0%),IR增加2.3%(95CI:0.6%-3.9%).非线性暴露响应函数表明，对于高浓度PM2.5暴露（>75µg/m3），IR增加具有强大的作用。基于PM2.5-IR函数,在118个低收入国家中，由于PM2.5暴露超过35µg/m3（世界卫生组织全球空气质量指南建议的第一阶段临时目标）而导致的不育夫妇数量为66万（95CI：0.061-1.43），占所有不孕夫妇的2.25%(95CI:0.20%-4.84%)。在66万中，66.5%的人在高暴露不育夫妇中排名前10%，主要来自南亚，东亚,和西非。
结论：在空气污染严重的地方，PM2.5对人类不育症有显著影响。PM2.5污染控制对于保护LMIC中的人类繁殖力至关重要。
