Anderson H R, Ponce de Leon A, Bland J M, Bower J S, Emberlin J, Strachan D P
Department of Public Health Sciences, St George's Hospital Medical School, London, UK.
Thorax. 1998 Oct;53(10):842-8. doi: 10.1136/thx.53.10.842.
A study was undertaken to investigate the relationship between daily hospital admissions for asthma and air pollution in London in 1987-92 and the possible confounding and modifying effects of airborne pollen.
For all ages together and the age groups 0-14, 15-64 and 65+ years, Poisson regression was used to estimate the relative risk of daily asthma admissions associated with changes in ozone, sulphur dioxide, nitrogen dioxide and particles (black smoke), controlling for time trends, seasonal factors, calendar effects, influenza epidemics, temperature, humidity, and autocorrelation. Independent effects of individual pollutants and interactions with aeroallergens were explored using two pollutant models and models including pollen counts (grass, oak and birch).
In all-year analyses ozone was significantly associated with admissions in the 15-64 age group (10 ppb eight hour ozone, 3.93% increase), nitrogen dioxide in the 0-14 and 65+ age groups (10 ppb 24 hour nitrogen dioxide, 1.25% and 2.96%, respectively), sulphur dioxide in the 0-14 age group (10 micrograms/m3 24 hour sulphur dioxide, 1.64%), and black smoke in the 65% age group (10 micrograms/m3 black smoke, 5.60%). Significant seasonal differences were observed for ozone in the 0-14 and 15-64 age groups, and in the 0-14 age group there were negative associations with ozone in the cool season. In general, cumulative lags of up to three days tended to show stronger and more significant effects than single day lags. In two-pollutant models these associations were most robust for ozone and least for nitrogen dioxide. There was no evidence that the associations with air pollutants were due to confounding by any of the pollens, and little evidence of an interaction between pollens and pollution except for synergism of sulphur dioxide and grass pollen in children (p < 0.01).
Ozone, sulphur dioxide, nitrogen dioxide, and particles were all found to have significant associations with daily hospital admissions for asthma, but there was a lack of consistency across the age groups in the specific pollutant. These associations were not explained by confounding by airborne pollens nor was there convincing evidence that the effects of air pollutants and airborne pollens interact in causing hospital admissions for asthma.
开展了一项研究，以调查1987 - 1992年伦敦哮喘患者每日住院情况与空气污染之间的关系，以及空气中花粉可能产生的混杂和修正作用。
针对所有年龄段以及0 - 14岁、15 - 64岁和65岁及以上年龄组，使用泊松回归来估计与臭氧、二氧化硫、二氧化氮和颗粒物（黑烟）变化相关的每日哮喘住院相对风险，并对时间趋势、季节因素、日历效应、流感流行、温度、湿度和自相关进行控制。使用双污染物模型以及包含花粉计数（禾本科、栎属和桦属）的模型，探讨了单个污染物的独立效应以及与气传变应原的相互作用。
在全年分析中，臭氧与15 - 64岁年龄组的住院情况显著相关（8小时臭氧浓度每增加10 ppb，增加3.93%），二氧化氮与0 - 14岁和65岁及以上年龄组相关（24小时二氧化氮浓度每增加10 ppb，分别增加1.25%和2.96%），二氧化硫与0 - 14岁年龄组相关（24小时二氧化硫浓度每增加10微克/立方米，增加1.64%），黑烟与65岁及以上年龄组相关（黑烟浓度每增加10微克/立方米，增加5.60%）。在0 - 14岁和15 - 64岁年龄组中观察到臭氧存在显著的季节差异，在0 - 14岁年龄组中，寒冷季节臭氧与住院情况呈负相关。一般来说，长达三天的累积滞后效应往往比单日滞后效应更强且更显著。在双污染物模型中，这些关联对于臭氧最为稳健，对于二氧化氮最不稳健。没有证据表明与空气污染物的关联是由任何一种花粉造成的混杂所致，除了儿童中二氧化硫与禾本科花粉的协同作用（p < 0.01）外，几乎没有证据表明花粉与污染之间存在相互作用。
臭氧、二氧化硫、二氧化氮和颗粒物均与哮喘患者每日住院情况显著相关，但不同年龄组在具体污染物方面缺乏一致性。这些关联无法通过空气中花粉的混杂来解释，也没有令人信服的证据表明空气污染物和气传花粉在导致哮喘住院方面存在相互作用。
