Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Asian Pac J Allergy Immunol. 2016 Dec;34(4):284-289. doi: 10.12932/AP0668.
Seasonal smog produces particulate matters that are less than 10 microns in diameter (PM₁₀), which are known to have several impacts on the respiratory system.
This study was to determine the association of an increased PM10 level due to seasonal smog in Chiang Mai and emergency visits for asthma and chronic obstructive pulmonary disease (COPD) exacerbations.
A retrospective cross-sectional study was conducted between the months of January and March from 2006 until 2009. The association of an increased PM₁₀ level and the daily number of asthma and COPD exacerbations were analyzed using a generalized linear model; a Poisson regression model was fit to the number of daily emergency visits using predictor variables: lags of PM10, day of the week, and time.
There were a total of 917 emergency visits for acute exacerbations of asthma and COPD, with a median of 2 visits per day (range 0-10). The median PM₁₀ level during the same interval was 64.5 microgram per cubic meter (μg/m3) (16-304). For every 10 μg/m3 rise in PM10 concentration, there was a lag time of 6 days for asthma exacerbations [Adjusted relative risk (RR)=1.020; 95% confident interval (CI), 1.001-1.040; (p=0.014)], 7 days for COPD exacerbations [RR=1.030; 95%CI, 1.010-1.050 (p=0.024)] and 7 days for all exacerbations [RR=1.030 95%CI, 1.010-1.040 (p<0.001)].
This study confirms the effect of increasing PM₁₀ concentrations from seasonal smog on asthma and COPD exacerbations. However, there was an approximately 1 week lag time between the elevated PM₁₀ levels and time to emergency visits due to disease exacerbation.
季节性烟雾会产生直径小于 10 微米的颗粒物 (PM₁₀)，已知这些颗粒物会对呼吸系统造成多种影响。
本研究旨在确定清迈季节性烟雾导致的 PM₁₀ 水平升高与哮喘和慢性阻塞性肺疾病 (COPD) 加重急诊就诊之间的关联。
本研究采用回顾性病例交叉研究设计，于 2006 年至 2009 年 1 月至 3 月进行。使用广义线性模型分析 PM₁₀ 水平升高与哮喘和 COPD 加重每日就诊人数之间的关系；使用泊松回归模型，采用 PM₁₀、星期几和时间的滞后变量来拟合每日急诊就诊次数。
共有 917 例哮喘和 COPD 急性加重的急诊就诊，中位数为每天 2 次就诊（范围 0-10 次）。同期 PM₁₀ 中位数为 64.5 微克/立方米（μg/m³）（16-304）。PM₁₀ 浓度每升高 10μg/m³，哮喘加重的滞后时间为 6 天[调整后的相对风险 (RR)=1.020；95%置信区间 (CI)，1.001-1.040；(p=0.014)]，COPD 加重的滞后时间为 7 天[RR=1.030；95%CI，1.010-1.050 (p=0.024)]，所有加重的滞后时间为 7 天[RR=1.030 95%CI，1.010-1.040 (p<0.001)]。
本研究证实了季节性烟雾中 PM₁₀ 浓度升高对哮喘和 COPD 加重的影响。然而，PM₁₀ 水平升高与因疾病加重而导致的急诊就诊之间存在约 1 周的滞后时间。
