Olaniyan Toyib, Jeebhay Mohamed, Röösli Martin, Naidoo Rajen, Baatjies Roslynn, Künzil Nino, Tsai Ming, Davey Mark, de Hoogh Kees, Berman Dilys, Parker Bhawoodien, Leaner Joy, Dalvie Mohamed Aqiel
Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa.
Swiss Tropical and Public Health Institute, Socinstrasse 57, P.O. Box 4002, Basel, Switzerland.
BMC Public Health. 2017 Sep 16;17(1):712. doi: 10.1186/s12889-017-4726-5.
There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements.
METHODS/DESIGN: A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop).
This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.
现有文献表明，幼儿期暴露于环境空气污染物中可能在哮喘发作和其他呼吸道症状中起重要作用，对哮喘儿童的影响更大。然而，关于环境空气污染物暴露在儿童哮喘患病率增加及哮喘诱发方面的作用，证据尚无定论。在人群层面，由于这种关联在不受控制的现实生活环境中带来挑战，关于花粉过敏原与空气污染物之间潜在协同效应的了解甚少。特别是，撒哈拉以南非洲的数据稀缺，在居住于非正式居住点的人群中几乎没有相关数据。
方法/设计：在南非西开普省对居住在四个潜在环境空气污染物暴露水平不同的非正式定居点地区的600名学童进行一项前瞻性队列研究。该研究有两个相隔至少六个月的随访期，包括夏季和冬季的嵌入式面板研究。暴露评估部分使用土地利用回归模型（LUR）对四个研究区域在研究期间的空气质量时空变异性进行建模。此外，记录研究区域的每日花粉水平（霉菌孢子、树木、草和杂草花粉）。在面板研究中，每天记录三次哮喘症状和连续峰值流量测量结果，以确定冬季和夏季10天内与环境空气质量和花粉变化相关的短期连续气道变化。队列研究的健康结局部分包括：使用标准化的国际儿童哮喘和过敏研究（ISAAC）问卷确定哮喘的存在、肺功能测定、呼出一氧化氮分数（FeNO）以及特应性（Phadiatop）的存在。
本研究应用最先进的暴露评估方法来描述环境空气污染物对儿童呼吸健康的影响，特别关注南非非正式定居点地区的哮喘和气道炎症标志物（FeNO），同时考虑花粉计数和气象因素。该研究将生成撒哈拉以南非洲低收入环境中空气污染与哮喘的关键数据，而这在国际文献中是缺乏的。
