Erbas B, Chang J-H, Dharmage S, Ong E K, Hyndman R, Newbigin E, Abramson M
Centre for Molecular Environmental Genetic Analytic Epidemiology, School of Population Health, University of Melbourne, Carlton, Vic., Australia.
Clin Exp Allergy. 2007 Nov;37(11):1641-7. doi: 10.1111/j.1365-2222.2007.02818.x. Epub 2007 Sep 17.
The effects of environmental factors and ambient concentrations of grass pollen on allergic asthma are yet to be established.
We sought to estimate the independent effects of grass pollen concentrations in the air over Melbourne on asthma hospital admissions for the 1992-1993 pollen season.
Daily grass pollen concentrations were monitored over a 24-h period at three stations in Melbourne. The outcome variable was defined as all-age asthma hospital admissions with ICD9-493 codes. The ambient air pollutants were average daily measures of ozone, nitrogen dioxide and sulphur dioxide, and the airborne particle index representing fine particulate pollution. Semi-parametric Poisson regression models were used to estimate these effects, adjusted for air temperature, humidity, wind speed, rainfall, day-of-the-week effects and seasonal variation.
Grass pollen was a strong independent non-linear predictor of asthma hospital admissions in a multi-pollutant model (P=0.01). Our data suggest that grass pollen had an increasing effect on asthma hospital admissions up to a threshold of 30 grains/m3, and that the effect remains stable thereafter.
Our findings suggest that grass pollen levels influence asthma hospital admissions. High grass pollen days, currently defined as more than 50 grains/m3, are days when most sensitive individuals will experience allergic symptoms. However, some asthmatic patients may be at a significant risk even when airborne grass pollen levels are below this level. Patients with pollen allergies and asthma would be advised to take additional preventive medication at lower ambient concentrations.
环境因素和草花粉的环境浓度对过敏性哮喘的影响尚未明确。
我们试图评估墨尔本上空空气中草花粉浓度对1992 - 1993年花粉季节哮喘住院率的独立影响。
在墨尔本的三个站点对草花粉浓度进行24小时的每日监测。结果变量定义为所有使用ICD9 - 493编码的全年龄段哮喘住院病例。环境空气污染物为臭氧、二氧化氮和二氧化硫的日均测量值，以及代表细颗粒物污染的空气颗粒物指数。使用半参数泊松回归模型来评估这些影响，并对气温、湿度、风速、降雨量、星期效应和季节变化进行了调整。
在多污染物模型中，草花粉是哮喘住院率的一个强有力的独立非线性预测因子（P = 0.01）。我们的数据表明，草花粉浓度在达到30粒/立方米的阈值之前，对哮喘住院率的影响不断增加，此后影响保持稳定。
我们的研究结果表明草花粉水平会影响哮喘住院率。目前定义为超过50粒/立方米的高草花粉日，是大多数敏感个体将出现过敏症状的日子。然而，即使空气中草花粉水平低于这个水平，一些哮喘患者也可能面临显著风险。建议花粉过敏和哮喘患者在环境浓度较低时服用额外的预防性药物。
