Increasing air pollution in low- and middle-income countries (LMICs) may be contributing to worsening respiratory health, yet to date most relevant studies have been conducted in industrialized nations. Particularly, there are few studies for India, the world’s second most populated country, and on this country’s poorest populations, who may be at the highest risk. We investigated the influence of long-term nitrogen dioxide (NO₂) exposure at residential location on lung function decline over a 5-year period in a cohort of low-income adults in Mysore, Karnataka, India. In 2012–2014 and in 2017–2018, we conducted standardized interviews and performed in-home field spirometry before and after bronchodilation. We estimated annual average NO₂ in 2017 based on interpolation of seasonal air pollution sampling and used linear mixed effects models with a person-specific random effect to estimate NO₂ versus lung function cross-sectionally at baseline and longitudinally, adjusting for potential confounders (age at baseline, sex, smoking status, and long-term seasonality). Among healthy participants (with no COPD or asthma based on lung function tests), NO₂ levels were associated with a decline in lung function pre- and post-bronchodilation (−21.7 ml [95% CI: −42.1, −1.3] for FEV1 and −22.2 ml [95% CI: −46.8, 2.3] for FVC pre-bronchodilation, −25.2 ml [95% CI: −48.4, −4.1] for FEV1 and −26.6 ml [95% CI: −51.1, −2.2] for FVC post-bronchodilation) per interquartile range (10 ppb) increase in NO₂. Longitudinal impacts of air pollution on lung function were not statistically significant. Results suggest that air pollution exposure is associated with worse lung function among apparently healthy individuals among urban poor communities in India. Future studies should further characterize time-varying air pollution exposures and collect further longitudinal health data in these understudied communities.

中低收入国家 (LMIC) 日益严重的空气污染可能导致呼吸系统健康恶化，但迄今为止，大多数相关研究都是在工业化国家进行的。特别是，关于印度这个世界上人口第二多的国家以及该国最贫困人口可能面临最高风险的研究很少。我们调查了印度卡纳塔克邦迈索尔的一组低收入成年人在 5 年内居住地点长期接触二氧化氮 (NO ₂ ) 对肺功能下降的影响。在 2012-2014 年和 2017-2018 年，我们进行了标准化访谈，并在支气管扩张前后进行了家庭肺活量测定。我们估计年平均 NO ₂2017 年基于季节性空气污染采样的插值，并使用具有特定个人随机效应的线性混合效应模型来估计 NO ₂与肺功能的横断面基线和纵向，调整潜在的混杂因素（基线年龄、性别、吸烟状态和长期季节性）。在健康参与者（根据肺功能测试没有 COPD 或哮喘）中，NO ₂水平与支气管扩张前后肺功能下降有关（FEV1 为 -21.7 ml [95% CI：-42.1, -1.3] -22.2 ml [95% CI: -46.8, 2.3] 用于 FVC 预​​支气管扩张，-25.2 ml [95% CI: -48.4, -4.1] 用于 FEV1 和 -26.6 ml [95% CI: -51.1, -2.2] ] 对于 FVC 支气管扩张后）每四分位距 (10 ppb) 增加 NO ₂. 空气污染对肺功能的纵向影响没有统计学意义。结果表明，空气污染暴露与印度城市贫困社区表面健康个体的肺功能恶化有关。未来的研究应进一步表征随时间变化的空气污染暴露，并在这些研究不足的社区中收集进一步的纵向健康数据。