Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, ON.
Can J Public Health. 2011 Jan-Feb;102(1):35-41. doi: 10.1007/BF03404874.
We calculated the population attributable fraction (PAF) of Canadian childhood asthma due to modifiable environmental exposures, in order to estimate their relative contributions to asthma development based on the current literature.
We conducted a systematic review to determine Canadian childhood asthma incidence, Canadian prevalence of exposure to airborne pollutants and indoor allergens, and international estimates of the risk of developing physician-diagnosed asthma (PDA) associated with each exposure. Combining risk estimates by meta-analysis where possible, PAF was calculated by the formula: PAF = Attributable risk Exposure prevalence 100%/Asthma incidence.
Age-specific Canadian childhood asthma incidence ranged from 2.8%-6.9%. Canadian exposure prevalences were: PM10 16%, PM2.5 7.1%, NO2 25%, environmental tobacco smoke (ETS) 9.0%, cat 22%, dog 12%, mouse 17%, cockroach 9.8%, dust mite 30%, moisture 14% and mould 33%. Relative risk estimates of PDA were: PM10 1.64, PM2.5 1.44, NO2 1.29, ETS 1.40, mouse 1.23, cockroach 1.96, and spanned 1.00 for cat, dog, dust mites, moisture and mould. PAF estimates for incident asthma among preschool children were: PM10 11%, PM2.5 1.6%, NO2 4.0%, ETS 2.9%, mouse 6.5% and cockroach 13%.
This systematic review suggests contributions to childhood asthma development from exposure to particulates, NO2, ETS, mouse and cockroach. The associations appeared to be more complex for cat, dog and dust mite allergens and more variable for mould and moisture. Additional prospective, population-based studies of childhood asthma development with objectively-measured exposures are needed to further quantify these associations.
我们计算了加拿大儿童哮喘归因于可改变的环境暴露的人群归因分数（PAF），以便根据当前文献估算它们对哮喘发展的相对贡献。
我们进行了系统综述，以确定加拿大儿童哮喘的发病率、加拿大空气中污染物和室内过敏原的暴露率以及与每种暴露相关的国际医生诊断哮喘（PDA）风险的估计。尽可能通过荟萃分析合并风险估计值，通过公式计算 PAF：PAF=归因风险×暴露率×100%/哮喘发病率。
特定年龄的加拿大儿童哮喘发病率为 2.8%-6.9%。加拿大的暴露率分别为：PM10 为 16%，PM2.5 为 7.1%，NO2 为 25%，环境烟草烟雾（ETS）为 9.0%，猫 22%，狗 12%，鼠 17%，蟑螂 9.8%，尘螨 30%，湿度 14%和霉菌 33%。PDA 的相对风险估计值分别为：PM10 为 1.64，PM2.5 为 1.44，NO2 为 1.29，ETS 为 1.40，鼠为 1.23，蟑螂为 1.96，猫、狗、尘螨、湿度和霉菌的相对风险估计值均为 1.00。学龄前儿童哮喘发病率的 PAF 估计值分别为：PM10 为 11%，PM2.5 为 1.6%，NO2 为 4.0%，ETS 为 2.9%，鼠为 6.5%，蟑螂为 13%。
本系统综述表明，颗粒物、NO2、ETS、鼠和蟑螂暴露与儿童哮喘的发展有关。猫、狗和尘螨过敏原的关联似乎更为复杂，霉菌和湿度的关联更为多变。需要进行更多的、基于人群的、前瞻性的儿童哮喘发展与客观测量暴露相关的研究，以进一步量化这些关联。
