Buthelezi Minenhle S, Mentz Graciela, Wright Caradee Y, Phaswana Shumani, Garland Rebecca M, Naidoo Rajen N
Discipline of Occupational and Environmental Health, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa.
Anesthesiology Department, Medical School, University of Michigan, Ann Arbor, Michigan.
Environ Epidemiol. 2024 Oct 30;8(6):e354. doi: 10.1097/EE9.0000000000000354. eCollection 2024 Dec.
Asthma affects millions of people globally, and high levels of air pollution aggravate asthma occurrence. This study aimed to determine the association between short-term lagged PM exposure and airway inflammation, lung function, and asthma symptom scores among schoolchildren in communities in the Highveld high-pollution region in South Africa.
A cross-sectional study was conducted among schoolchildren aged 9-14 years in six communities in the Highveld region in South Africa, between October 2018 and February 2019. A NIOX 200 instrument was used to measure fractional exhaled nitric oxide (FeNO). Lung function indices (forced expiratory volume in one second [FEV]; forced vital capacity [FVC] and FEV/FVC) were collected using spirometry and the percent of predicted of these was based on the reference equations from the Global Lung Initiative, without ethnic correction. These values were further analyzed as binary outcomes following relevant thresholds (lower limits of normal for lung function and a cutoff of 35 ppb for FeNO). Asthma symptoms were used to create the asthma symptom score. Daily averages of PM data for the nearest monitoring station located in each community, were collected from the South African Air Quality Information System and created short-term 5-day lag PM concentrations. Additional reported environmental exposures were collected using standardized instruments.
Of the 706 participating schoolchildren, only 1.13% of the participants had doctor-diagnosed asthma, compared to a prevalence of 6.94% with an asthma symptom score suggestive of asthma. Lag 1 (odds ratio [OR]: 1.01; 95% confidence interval [CI]: 1.00, 1.02, = 0.039) and 5-day average lagged PM (OR: 1.02; 95% CI: 0.99, 1.04, = 0.050) showed increased odds of the FeNO > 35 ppb. Lung function parameters (FEV < lower limit of normal [LLN] [OR: 1.02, 95% CI: 1.00, 1.03, = 0.018], and FEV/FVC < LLN [OR: 1.01; 95% CI: 1.00, 1.02, < 0.001]) and asthma symptom score ≥ 2 (OR: 1.02; 95% CI: 1.00, 1.04, = 0.039) also showed significant associations with lag 2, lag 4 and lag 1 of PM, respectively.
Lagged PM exposure was associated with an increased odds of airway inflammation and an increased odds of lung function parameters below the LLN particularly for the later lags, but a significant dose-response relationship across the entire sample was not consistent.
哮喘影响着全球数百万人，高水平的空气污染会加剧哮喘的发生。本研究旨在确定南非高韦尔德高污染地区社区学龄儿童短期滞后的颗粒物暴露与气道炎症、肺功能及哮喘症状评分之间的关联。
2018年10月至2019年2月期间，在南非高韦尔德地区的六个社区对9至14岁的学龄儿童进行了一项横断面研究。使用NIOX 200仪器测量呼出一氧化氮分数（FeNO）。使用肺量计收集肺功能指标（一秒用力呼气量[FEV]；用力肺活量[FVC]和FEV/FVC），并根据全球肺部倡议的参考方程计算这些指标的预测百分比，未进行种族校正。根据相关阈值（肺功能正常下限和FeNO的35 ppb临界值）将这些值进一步分析为二元结果。使用哮喘症状创建哮喘症状评分。从南非空气质量信息系统收集每个社区最近监测站的每日平均颗粒物数据，并创建短期5天滞后的颗粒物浓度。使用标准化仪器收集其他报告的环境暴露信息。
在706名参与研究的学龄儿童中，只有1.13%的参与者有医生诊断的哮喘，相比之下，哮喘症状评分提示哮喘的患病率为6.94%。滞后1天（比值比[OR]：1.01；95%置信区间[CI]：1.00，1.02，P = 0.039）和5天平均滞后颗粒物（OR：1.02；95%CI：0.99, 1.04，P = 0.050）显示FeNO>35 ppb的几率增加。肺功能参数（FEV<正常下限[LLN][OR：1.02，95%CI：1.00，1.03，P = 0.018]，以及FEV/FVC<LLN[OR：1.01；95%CI：1.00，1.02，P<0.001]）和哮喘症状评分≥2（OR：1.02；95%CI：1.00，1.04，P = 0.039）分别与滞后2天、滞后4天和滞后1天的颗粒物也显示出显著关联。
滞后的颗粒物暴露与气道炎症几率增加以及肺功能参数低于正常下限的几率增加有关，特别是对于后期滞后情况，但整个样本中显著的剂量反应关系并不一致。
