Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA.
Glob Health Sci Pract. 2020 Sep 30;8(3):372-382. doi: 10.9745/GHSP-D-20-00011.
Few randomized trials have assessed the impact of reducing household air pollution from biomass stoves on adverse birth outcomes in low-income countries.
Two sequential trials were conducted in rural low-lying Nepal. Trial 1 was a cluster-randomized step-wedge trial comparing traditional biomass stoves and improved biomass stoves vented with a chimney. Trial 2 was a parallel household-randomized trial comparing vented biomass stoves and liquid petroleum gas (LPG) stoves with a year's supply of gas. Kitchen particulate matter of 2.5 μm or less (PM) and carbon monoxide (CO) were assessed before and after stove installation. Prevalent and incident pregnancies were enrolled at baseline and throughout the trials. Birth anthropometry was compared across differing exposure times in pregnancy.
In trial 1, the mean 20-hour kitchen PM concentration was reduced from 1380 µg/m to 936 µg/m. Among infants born before the intervention, mean birth weight and gestational age were 2627 g (SD=443) and 38.8 weeks (SD=3.1), and 39% were low birth weight (LBW), 22% preterm, and 55% small for gestational age (SGA). Adverse birth outcomes were not significantly different with increasing exposure to improved stoves during pregnancy. In trial 2, the mean 20-hour PM concentration was 885 µg/m in households with vented biomass and 442 µg/m in those with LPG stoves. Mean birth weight was 2780 g (SD=427) and 2742 g (SD=431), among households with vented and LPG stoves, respectively. Respective percentages for LBW, SGA, and preterm were 23%, 13%, and 42% in the vented stove group and not statistically different from 31%, 17%, and 42% in the LPG group.
Improved biomass or LPG stoves did not reduce adverse birth outcomes. PM and CO following improved stove installation remained well above the World Health Organization indoor air standard of 25 µg/m or intermediate air quality guideline of 37.5 µg/m. Trials that lower indoor air pollution further are needed.
很少有随机试验评估减少低收入国家家庭生物质炉灶空气污染对不良生育结局的影响。
在尼泊尔农村低地进行了两项连续试验。试验 1 是一项比较传统生物质炉灶和带有烟囱通风的改良生物质炉灶的集群随机分步试验。试验 2 是一项比较通风生物质炉灶和液化石油气 (LPG) 炉灶与一年供应气体的平行家庭随机试验。在炉灶安装前后评估了 2.5μm 或以下的厨房颗粒物 (PM) 和一氧化碳 (CO)。在基线和整个试验期间招募了现患和新发妊娠。在妊娠期间比较了不同暴露时间的出生人体测量结果。
在试验 1 中，20 小时厨房 PM 浓度的平均值从 1380μg/m 降至 936μg/m。在干预前出生的婴儿中，平均出生体重和胎龄分别为 2627g（SD=443）和 38.8 周（SD=3.1），55%为小于胎龄儿（SGA）。妊娠期间暴露于改良炉灶的程度增加，不良出生结局并无显著差异。在试验 2 中，通风生物质炉灶家庭的 20 小时 PM 浓度平均值为 885μg/m，LPG 炉灶家庭为 442μg/m。通风炉灶和 LPG 炉灶家庭的平均出生体重分别为 2780g（SD=427）和 2742g（SD=431）。通风炉灶组的 LBW、SGA 和早产的比例分别为 23%、13%和 42%，与 LPG 组的 31%、17%和 42%无统计学差异。
改良生物质或 LPG 炉灶并不能降低不良生育结局的发生。改良炉灶安装后 PM 和 CO 仍远高于世界卫生组织室内空气质量标准的 25μg/m 或中间空气质量指南的 37.5μg/m。需要进一步降低室内空气污染的试验。
