Newsletter No. 400

6 No. 400, 19.6.2012 校 園 消 息 CAMPUS NEWS 粗顆粒污染物影響健康 • Coarse Particulate Pollutants Affect Health 香 港空氣質素近年持續下降，對巿民健康的損害亦 日趨嚴重。學術界以往普遍認為，空氣污染物中會 危害呼吸系統的可吸入性顆粒物，以微細顆粒（PM 2.5 ，即 空氣動力學直徑小於2.5微米，本港稱「微細懸浮粒子」） 為主，以其較容易進入呼吸道深處和肺泡，引起呼吸系統 病變。中大賽馬會公共衞生及基層醫療學院職業和環境 健康學部余德新教授（ 左 ）領導的研究團隊和博士研究 生邱宏女士（ 右 ）進行了一項流行病學研究，探討2000至 05年間香港的急症入院情況，發現除了微細顆粒，粗顆粒 （PM 10 ，即空氣動力學直徑介於2.5和10微米之間，本港稱 「可吸入顆粒物」或「可吸入懸浮粒子」）對呼吸系統健康 的危害同樣不容忽視。 研究發現，經校正微細顆粒和其他氣態污染物的影響後， 粗顆粒污染物的濃度每增加 10 μ g/m 3 （微克／立方米空 氣），呼吸系統疾病的急症入院率便會增加1%，慢性阻塞 性肺部疾病的急症入院率亦上升1.6%。換言之，粗顆粒污 染物的濃度每增加10 μ g/m 3 ，因呼吸系統疾病而急症入 院人數便會每年增加八百三十人，同時，因慢性阻塞性肺 部疾病急症入院的人數亦每年多出四百八十二人。 中大最新發布的研究「粗顆粒污染物對呼吸系統健康的 危害」，是目前為止在單一城市進行的最大型研究，涵蓋 超過五十萬名六年內因呼吸系統急症入院的病人。研究結 果已刊載於權威國際學術期刊《環境與健康展望》。中大 並建議特區政府環境保護署將來制訂空氣質素指標時應 考慮PM 10 的危害作用。 I n Hong Kong, air quality has been deteriorating over the years and presents a serious threat to the health of its citizens. It is commonly accepted that the associations between the respirable suspended particles and adverse respiratory health effects are mainly attributable to the fine particles (PM 2.5 , particles with an aerodynamic diameter of less than 2.5 μ m), because of their higher number (count) concentration, larger surface area and deeper lung deposition. An epidemiological research led by Prof. Yu Tak-sun Ignatius ( left ), head, and Ms. Qiu Hong ( right ) (PhD candidate) of the Division of Occupational and Environmental Health, the Jockey Club School of Public Health and Primary Care at CUHK, examined emergency hospital admissions in Hong Kong between 2000 and 2005 and reported that the effects of coarse particles (PM 10 , particles with an aerodynamic diameter between 2.5 and 10 μ m), should not be ignored. CUHK’s research discovered that a 10 μ g/m 3 (micrograms per cubic metre of air) increase of coarse particles was associated with about 1% increase of emergency hospital admissions for total respiratory diseases and 1.6% increase for chronic obstructive pulmonary diseases (COPD). In other words, a 10 μ g/m 3 increase of coarse particles led to 830 additional emergency hospital admissions for respiratory diseases per year, of which 482 admissions were due to COPD during the study period. This study is the largest single-city study to date on the effects of coarse particles on emergency hospital admissions for respiratory diseases, involving over half a million admissions over the six-year period. The report was recently published in Environmental Health Perspectives , the top international journal in environmental health. CUHK also suggests the Environmental Protection Department of the HKSAR Government to take into consideration the adverse effects of PM 10 when reviewing Air Quality Objectives in future. 改良肥胖者無創肝纖維化檢查 • Enhancing Assessment of Liver Fibrosis in Obese Patients 內科及藥物治療學系教授陳力元教授與黃麗虹教授展示無創肝纖維化掃瞄器的加大碼探頭 （左）和正常探頭（右) Prof. Chan Lik-yuen Henry and Prof. Wong Lai-hung Grace of the Department of Medicine and Therapeutics show the new XL probe (left) and the regular M probe (right) of Fibroscan 中 大與法國波爾多大學最近進行了一項合作研究， 率先引入加大碼探頭為肥胖病人進行肝纖維化檢 查，證實能有效深入肥胖人士的皮下脂肪層，準確量度其 肝纖維化的程度。 肥胖容易引致肝臟疾病，八成肥胖人士同時患有脂肪肝， 嚴重者可能演變成肝纖維化及肝癌。透過評估患者的肝纖 維化程度，醫護人員可以及早預斷和提供合適治療。 肝穿刺是現時評估肝纖維化程度的黃金標準，但具創傷 性。近年，肝纖維掃瞄器已發展為量度肝纖維化和肝硬化 程度最準確而無創傷的檢查方法。掃瞄器藉着切變波的 原理去量度肝臟的軟硬程度，然而，由於肥胖人士的皮下 脂肪層較厚，約三分一患者在檢查時不能顯示實際數據。 有見及此，專為肥胖人士檢測肝臟軟硬程度的加大碼探頭 便應運而生。 中大與波爾多大學於2009至2011年進行一項突破性研 究，利用原有的正常探頭及新引進的加大碼探頭為二百 八十六名病人量度。結果發現，使用加大碼探頭成功為 98%的病人取得可靠數據，使用正常探頭時的可靠數據則 減至92%。身高質量指數高於 30 kg/m 2 的肥胖患者，如使 用正常探頭量度肝纖維化程度，只有74%患者能取得可靠 數據，但當轉用加大碼探頭，數據準確度則提升至94%。 T he Chinese University and the University of Bordeaux in France have recently conducted a collaborative research to pioneer the use of the new XL probe to assess liver fibrosis among obese subjects with a deeper penetrance of measurement, and which can also enhance the performance of Fibroscan. Obesity is closely associated with liver diseases and up to 80% of obese people may have fatty liver, which may lead to cirrhosis and liver cancer. By assessing the severity of liver fibrosis, medical professionals can predict the prognosis of patients and give proper treatment. Liver biopsy is a traditional standard test to assess liver fibrosis but it is an invasive procedure. Over the last few years, liver stiffness measurement by Fibroscan, an accurate, reproducible and non-invasive test using Doppler ultrasound technique, has been developed to detect liver fibrosis and cirrhosis. But Fibroscan fails to give reliable results in about 30% of obese patients due to their thick subcutaneous fat layer. In view of this, a new XL probe was developed for liver stiffness measurement in obese patients. From 2009 to 2011, CUHK and the University of Bordeaux conducted a research on liver stiffness measurements on 286 patients by both the new XL probe and the original M probe. Valid measurements were obtained in 98% of patients using the XL probe, compared to 92% when the M probe was in use. Among obese patients with a body mass index above 30 kg/m 2 , 94% valid measurements were obtained by the XL probe and 74% by the M probe.