室外空氣汙染和結核病之相關性研究

Association between Ambient Air Pollution and Tuberculosis: Prospective Cohort Study

賴亭君(Ting-Chun Lai)

指導教授 ： 林先和

共同指導教授 ： 詹長權

國立臺灣大學/公共衛生學院/流行病學與預防醫學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.10017

摘要

背景
近年來發現有許多和肺結核相關的呼吸道危險因子，但目前並沒有關於室外空氣汙染是否為肺結核重要危險因子的流行病學證據。室外空氣汙染在開發中國家相當嚴重，而這些國家又是結核病發生率較高的國家，因此這兩者之間的相關性是很值得重視的議題。

方法
本研究是前瞻性的世代研究，對象為104196位居住在新北市29個地區參加整合式健康篩檢的民眾，收案期間從2005年到2008年，一直追蹤到2011年止。在空氣汙染暴露的推估方面使用了三種不同的測量方式，利用受試著的住家地址推估個人空氣汙染暴露量。最近測站法是利用受試著的住家地址將他們分配到所屬的最近測站，使用測站的資料當作個人的空氣汙染暴露值。第二種方法是使用歐盟空氣汙染世代研究所建立的土地利用回歸模式，加入了土地利用和交通道路資訊去推估個人空氣汙染暴露量。第三種方式是土地利用回歸模式中有使用的交通道路相關預測變項當作空氣污染暴露的替代指標。最後結果的部分是串連疾病管制局結核病通報登記系統的資料。統計分析部分使用存活分析中的比例風險模式，調整可能的干擾因子。

結果
研究平均追蹤了5.4年，104196位受試著中共有312位結核病病人，發生率為十萬分之五十八人。調整過可能的干擾子後發現住家附近半徑三百公使內道路越多或是半徑五百公尺內主要道路越多，發生結核病的風險也越大。另外，使用最近測站法也發現，暴露濃度越高的NO2和NOx會增加得到結核病的危險性。

討論
這是第一篇關於室外空氣汙染和結核病之間相關性的流行病學研究。研究發現住家附近道路以及主要道路越多會增加發生結核病的風險，長期暴露於高濃度的NO2和NOx也會提高得到結核病的危險性。本研究最大的優勢是使用前瞻性的世代研究方法以及在暴露的推估上使用三種不同的方式做比較。本研究的限制在於空氣汙染研究的結果需要比較大的樣本數才可以看出顯著的相關性，另外不管使用何種空氣汙染暴露的推估，都還是存在著暴露錯分的問題。未來的研究應該增加樣本數以及重新建立可以代表新北市地區的土地利用回歸模式，用來了解室外空氣汙染和結核病之間更清楚的相關性。

關鍵字

室外空氣汙染 ； 結核病 ； 前瞻性世代研究 ； 最近測站法 ； 土地利用回歸模式

並列摘要

Background:
Several respiratory risk factors have been report to be possibly associated with tuberculosis (TB). To our knowledge, there was no study on the association between ambient air pollution and risk of TB. Since the problem of air pollution is serious in developing countries where the burden of TB is high, there is a need to understand the association between ambient air pollution and TB.

Design/Methods:
We included 104,196 participants (>=30 years of age) who were enrolled in community integrated health screening service in New Taipei City from 2005~2008. All participants were followed up to the end of 2011. Using the home address of participants, we estimated the individual-level of ambient air pollution by three methods. In the nearest station method, the level of pollutant for each participant was assigned based on the pollution level in the monitoring station that was closest to the individual’s address. Secondly, we applied the land use regression model that was developed and validated in the previous European Study of Cohorts for Air Pollution Effects project to estimate the level of pollutant at the individual level. Lastly, we used heavily trafficked roadway proximity to be a proxy measure of air pollution. The occurrence of TB disease during follow-up was ascertained by linking the health screening database to national TB registry of Taiwan Centers for Disease Control. Cox proportional hazards model was used to estimate the association between ambient air pollution and active TB, adjusting for potential confounders.

Results:
After median follow-up of 5.4 years, 312 cases of incident TB occurred among 104,196 participants (incidence rate: 58/100, 000). After adjusting for potential confounders, the length of road in buffer 300m (adjusted HR, 1.12[1.02, 1.23]) and the length of major road in buffer 500m (adjusted HR, 1.10[1.02, 1.19]), a proxy measure of air pollution were associated with increased risk of TB incidence. In the nearest station method, NO2 (adjusted HR, 1.29[0.98, 1.69]) and NOx (adjusted HR, 1.21[1.02, 1.43]) were shown to increase TB risk. The results for pulmonary TB were similar to that from the main analysis. However we found HRs increased for culture-confirmed TB in all pollutants and positive air pollution predictors. In the subgroup analysis, we restricted the study population to the urban districts and found these regions were homogeneous in baseline characteristics. In the subgroup analysis, the association between air pollution measured by land use regression and risk of TB became stronger. On the other hand, the association between air pollution measured by the nearest station method and TB did not become stronger in subgroup analysis.

Conclusions:
To our knowledge, our study is the first epidemiological study on ambient air pollution and TB. The length of road and length of major road in the close proximity, and NO2 and NOx were found to be associated with increased risk of TB. Further studies of larger sample size and accurate land use regression model will help clarify the impact of air pollution on TB.

並列關鍵字

ambient air pollution ； tuberculosis ； prospective cohort study ； nearest station method ； land use regression model

參考文獻

31. Centor for Disease Control, R.O.C., 感染控制雜誌 第十六卷 第一期.

1. World Health Organization, GLOBAL TUBERCULOSIS REPORT. WHO, 2012.

2. Lienhardt, C., From exposure to disease: The role of environmental factors in susceptibility to and development of tuberculosis. Epidemiologic Reviews, 2001. 23(2): p. 288-301.

3. Lonnroth, K., et al., Drivers of tuberculosis epidemics: the role of risk factors and social determinants. Soc Sci Med, 2009. 68(12): p. 2240-6.

4. Lin, H.H., M. Ezzati, and M. Murray, Tobacco smoke, indoor air pollution and tuberculosis: A systematic review and meta-analysis. Plos Medicine, 2007. 4(1): p. 173-189.