Abstract

Background:

Millions of rural U.S. households are heated with wood stoves. Wood stove use can lead to high indoor concentrations of fine particulate matter [airborne particles $\le 2.5\mathrm{\mu }\mathrm{m}$ in aerodynamic diameter (${\mathrm{PM}}_{2.5}$)] and is associated with lower respiratory tract infection (LRTI) in children.

Objectives:

We assessed the impact of low-cost educational and air filtration interventions on childhood LRTI and indoor ${\mathrm{PM}}_{2.5}$ in rural U.S. homes with wood stoves.

Methods:

The Kids Air Quality Interventions for Reducing Respiratory Infections (KidsAIR) study was a parallel three-arm (education, portable air filtration unit, control), post-only randomized trial in households from Alaska, Montana, and Navajo Nation (Arizona and New Mexico) with a wood stove and one or more children $<5\text{\hspace{0.17em}years}$ of age. We tracked LRTI cases for two consecutive winter seasons and measured indoor ${\mathrm{PM}}_{2.5}$ over a 6-d period during the first winter. We assessed results using two analytical frameworks: a) intervention efficacy on LRTI and ${\mathrm{PM}}_{2.5}$ (intent-to-treat), and b) association between ${\mathrm{PM}}_{2.5}$ and LRTI (exposure–response).

Results:

There were 61 LRTI cases from 14,636 child-weeks of follow-up among 461 children. In the intent-to-treat analysis, children in the education arm [$\text{odds ratio\hspace{0.17em}}\left(\text{OR}\right)=0.98$; 95% confidence interval (CI): 0.35, 2.72] and the filtration arm ($\text{OR}=1.23$; 95% CI: 0.46, 3.32) had similar odds of LRTI vs. control. Geometric mean ${\mathrm{PM}}_{2.5}$ concentrations were similar to control in the education arm (11.77% higher; 95% CI: $-16.57$, 49.72) and air filtration arm (6.96% lower; 95% CI: $-30.50$, 24.55). In the exposure–response analysis, odds of LRTI were 1.45 times higher (95% CI: 1.02, 2.05) per interquartile range ($25{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$) increase in mean indoor ${\mathrm{PM}}_{2.5}$.

Discussion:

We did not observe meaningful differences in LRTI or indoor ${\mathrm{PM}}_{2.5}$ in the air filtration or education arms compared with the control arm. Results from the exposure–response analysis provide further evidence that biomass air pollution adversely impacts childhood LRTI. Our results highlight the need for novel, effective intervention strategies in households heated with wood stoves. https://doi.org/10.1289/EHP9932

中文翻译：

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空气过滤和教育干预对用木炉加热的美国农村家庭中室内细颗粒物和儿童下呼吸道感染的效果：KidsAIR 随机试验的结果

摘要

背景：

数以百万计的美国农村家庭用柴炉取暖。使用柴炉会导致室内细颗粒物浓度升高 [空气中的颗粒物$\le 2.5\mathrm{\mu }\mathrm{米}$气动直径 (${\mathrm{下午}}_{2.5}$)] 并且与儿童下呼吸道感染 (LRTI) 相关。

目标：

我们评估了低成本教育和空气过滤干预措施对儿童 LRTI 和室内${\mathrm{下午}}_{2.5}$在有木炉的美国农村家庭中。

方法：

减少呼吸道感染的儿童空气质量干预 (KidsAIR) 研究是一项平行的三臂（教育、便携式空气过滤装置、控制）、仅在阿拉斯加、蒙大拿州和纳瓦霍族（亚利桑那州和新墨西哥州）的家庭中进行的随机试验) 带柴火炉和一个或多个孩子$<5\text{\hspace{0.17em}年}$年龄。我们连续两个冬季跟踪 LRTI 病例并在室内测量${\mathrm{下午}}_{2.5}$在第一个冬天的 6 天时间里。我们使用两个分析框架评估结果：a）对 LRTI 的干预效果和${\mathrm{下午}}_{2.5}$(intent-to-treat), 和b ) 之间的关联${\mathrm{下午}}_{2.5}$和 LRTI（曝光-响应）。

结果：

在 461 名儿童的 14,636 个儿童周的随访中，有 61 例 LRTI 病例。在意向治疗分析中，教育部门的儿童 [$\text{优势比\hspace{0.17em}}\left(\text{或者}\right)=0.98$; 95% 置信区间 (CI): 0.35, 2.72] 和过滤臂 ($\text{或者}=1.23$; 95% CI: 0.46, 3.32) LRTI 与对照组的几率相似。几何平均数${\mathrm{下午}}_{2.5}$浓度与教育部门的对照组相似（高出 11.77%；95% CI：$-16.57$, 49.72) 和空气过滤臂 (降低 6.96%; 95% CI:$-30.50$, 24.55)。在暴露-反应分析中，LRTI 的几率是每四分位间距的 1.45 倍（95% CI：1.02, 2.05）（$25{\mathrm{\mu }\mathrm{G}/\mathrm{米}}^3$) 平均室内增加${\mathrm{下午}}_{2.5}$.

讨论：

我们没有观察到 LRTI 或室内的有意义的差异${\mathrm{下午}}_{2.5}$在空气过滤或教育臂与控制臂相比。暴露反应分析的结果提供了进一步的证据，表明生物质空气污染对儿童 LRTI 产生不利影响。我们的研究结果强调了对用柴炉取暖的家庭采取新颖、有效的干预策略的必要性。https://doi.org/10.1289/EHP9932