| 摘要(英) | Background and Objectives: In June, 2001, the International Agency for Research on cancer affiliated with the World Health Organization reviewed scientific evidence from both epidemiological and animal studies and concluded that exposure to extremely-low-frequency magnetic field (ELF) greater than 4 mili–Gauss (mG) is a possible cause of childhood leukemia. Although on-site measurement, using instrument, can be performed to obtain direct information on ELF exposure, many epidemiological studies still used indirect exposure measures for exposure assessment mainly due to the cost consideration. This study attempts to use the geographic information system (GIS) for calculating high-tension transmission lines density in all townships around the country. Together with cancer incidence data, this study aimed to investigate the association between environmental exposure to ELF indicated by transmission line density and the risk of cancer among children aged less than 15.
Materials and Methods: This study used the 2002 version GIS to analyze the high-tension transmission lines density for all 359 townships in Taiwan; and to calculate the percentage in area within 100 meters (m) on either side of the power lines. Comparisons were made between children in each percentage exposure quartiles; as well as between the children living in townships with percentage exposure ≧90th percentile and those living in areas with a percentage exposure of zero. Additionally, we also compared incidence rate of childhood cancer between children in townships with at least one elementary or junior high school passed over by high-tension transmission lines and those who didn’t have such exposure. The incidence data on childhood cancer were retrieved from the 1991 to 1997 cancer registration. The number of incidence for all cancer and childhood leukemia was 3,684 and 1,122, respectively among children aged 0-14 years. The statistical analyses included calculation of calendar–, age–, and sex–standardized incidence ratio (SIR) for the study subjects living in townships with different exposure classifications with reference to the overall incidence rate of Taiwan. We also used Poisson regression model adjusted for age, sex, calendar year, and level of urbanization, to calculate the rate ratio (RR) of childhood cancer in relation to elevated exposures.
Results: Study subjects in the three higher exposure quartiles (i.e., ≧75th, ≧50th?＜75th, and ＞25th?＜50th) had higher SIRs of all cancer and childhood leukemia than those in the lowest quartile (i.e., <25th). Multivariate regression analysis adjusted for calendar year, sex, age, and level of urbanization showed that as compared to children with the lowest exposure (<25th), children with exposure of ≧75th, ≧50th?＜75th, and ＞25th?＜50th all had non-significantly increased rate ratio (RR) of 1.11 (95％CI＝0.97–1.26), 1.10 (95％CI＝0.96–1.25), and 1.03 (95％CI＝0.89–1.18), respectively. The corresponding figures for childhood leukemia were 1.07 (95％CI＝0.84–1.36), 1.17 (95％CI＝0.92–1.49), and 1.15 (95％CI＝0.89–1.48). Again, these relative risk estimates were also non-significant statistically. Results from trend analyses showed that there was no significant dose gradient between level of exposure and RR of all cancer (p=0.077) and RR of childhood leukemia (p=0.859). Additionally, comparison between children with percentage exposure ≧90th and unexposed children also suggested no significantly increased risk of all cancer (RR=1.26, 95 CI=1.00-1.60) and childhood leukemia (RR=1.46, 95% CI=0.91-2.32). Children living in townships with campuses passed by high-tension transmission lines also did not show significantly increased risks of all cancer (RR=1.05, 95% CI=0.98-1.13) and childhood leukemia (RR=0.99, 95% CI=0.86-1.13).
Conclusion: By using three different strategies in determining ELF exposure level of townships in Taiwan, this study did not disclose any significantly increased risk of childhood leukemia in townships with elevated exposure to ELF. Results from the current analysis are subject to potential information bias due to the fact that the GIS includes only high-tension transmission lines and did not include the information on other environmental source of ELF such as substation, transmission lines, and transformers.
Keywords: childhood leukemia, geographic information system, extremely-low-frequency magnetic field, epidemiology, incidence rate, Poisson regression, relative risk.
|
|---|
| 參考文獻 | Ahlbom A., Day N., Feychting M., Roman E., Skinner J., Dockerty J., Linet M., McBride M., Michaellis J., Olsen J.H., Tynes T., Verkasalo P.K. A pooled analysis of magnetic fields and childhood leukemia. Br J Cancer 2000;83:692-8.
Armstrong B. G., Deadman J., McBride M. L. The determinants of Canadian children's personal exposures to magnetic fields. Bioelectromagnetics 2001;22:161-9.
Armstrong B. G. Comparing standardized mortality ratios. Ann Epidemiol 1995;5:60-4.
Bianchi N, Crosignani P, Rovelli A, Tittarelli A., Carnelli C. A., Rossitto F., Vanelli U., Porro E., Berrino F. Overhead electricity power lines and childhood leukemia: a registry-based, case-control study. Tumori 2000;86:195-8.【In Italian with English abstract】
Blaasaas K. G., Tynes T. Comparison of three different ways of measuring distances between residences and high voltage power lines. Bioelectromagnetics 2002;23:288-91.
Clinard F., Milan C., Harb M., Carli P. M., Bonithon-Kopp C., Moutet J. P., Faivre J., Hillon P. Residential magnetic field measurements in France: comparison of indoor and outdoor measurements. Bioelectromagnetics 1999;20:319-26.
Coghill R. W., Steward J., Philips A. Extra low frequency electric and magnetic fields in the bedplace of children diagnosed with leukaemia: a case-control study. Eur J Cancer Prev 1996;5:153-8.
Coleman M. P., Bell C. M., Taylor H. L., Primic-Zakelj M. Leukaemia and residence near electricity transmission equipment: a case-control study. Br J Cancer 1989;60:793-8.
Copeland K. T., Checkoway H., McMichael A. J., Holbrook R. H. Bias due to misclassification in the estimation of relative risk. Am J Epidemiol 1977;105:488-95.
Dockerty J. D., Elwood J. M., Skegg D. C., Herbison G. P. Electromagnetic field exposures and childhood cancers in New Zealand. Cancer Causes Control 1998;9:299-309.
Draper G., Vincent T., Kroll M. E., Swanson J. Childhood cancer in relation to distance from high voltage power lines in England and Wales: a case-control study. BMJ 2005;330:1290.
Eskelinen T., Keinanen J., Salonen H., Juutilainen J. Use of spot measurements for assessing residential ELF magnetic field exposure: a validity study. Bioelectromagnetics 2002;23:173-6.
Feychting M., Ahlbom A. Magnetic fields and cancer in children residing near Swedish high-voltage power lines. Am J Epidemiol 1993;138:467-81.
Forssen U. M., Ahlbom A., Feychting M. Relative contribution of residential and occupational magnetic field exposure over twenty-four hours among people living close to and far from a power line. Bioelectromagnetics 2002;23:239-44.
Fulton J. P., Cobb S., Preble L., Leone L., Forman E. Electrical wiring configurations and childhood leukemia in Rhode Island. Am J Epidemiol 1980;111:292-6.
Green L. M., Miller A. B., Agnew D. A., Greenberg M. L., Li J., Villeneuve P. J., Tibshirani R. Childhood leukemia and personal monitoring of residential exposures to electric and magnetic fields in Ontario, Canada. Cancer Causes Control 1999;10:233-43.
Greenland S. Multiple-bias modeling for analysis of observation data. J R Stat Soc: Series A 2005;168:267-306
Greenland S., Sheppard A.R., kaune W.T., Poole C., Kelsh M.A. A pooled analysis of magnetic fields, wire codes, and childhood leukemia. Epidemiology 2000;11:624-34.
Gullen W. H., Bearman J. E., Johnson E. A. Effects of misclassification in epidemiologic studies. Public Health Rep 1968;83:914-8.
International Agency for Research on Cancer (IARC). IARC monographs on the evaluation of carcinogenic risks to humans, Vol 80, Leon: IARC, 2001.
International Agency for Research on Cancer（IARC）. IARC monographs on the evaluation of carcinogen risk to human：Complete list of agents evaluated and their classification.（cited 2006 May 23）Available from：URL：http://monographs.iarc.fr/ENG/Classification/index.php
Jones T. L., Shih C. H., Thurston D. H., Ware B. J., Cole P. Selection bias from differential residential mobility as an explanation for associations of wire codes with childhood cancer. J Clin Epidemiol 1993;46:545-8.
Kabuto M., Nitta H., Yamamoto S., Yamaguchi N., Akiba S., Honda Y., Hagihara J., Isaka K., Saito T., Ojima T., Nakamura Y., Mizoue T., Ito S., Eboshida A., Yamazaki S., Sokejima S., Kurokawa Y., Kubo O. Childhood leukemia and magnetic fields in Japan: A case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan. Int J Cancer 2006;119:643-50.
Kaune W. T., Darby S. D., Gardner S. N., Hrubec Z., Iriye R. N., Linet M. S. Development of a protocol for assessing time-weighted-average exposures of young children to power-frequency magnetic fields. Bioelectromagnetics 1994a;15:33-51.
Kaune W. T., Savitz D. A. Simplification of the Wertheimer-Leeper wire code. Bioelectromagnetics 1994b;15:275-82.
Kaune W. T., Stevens R. G., Callahan N. J., Severson R. K., Thomas D. B. Residential magnetic and electric fields. Bioelectromagnetics 1987;8:315-35.
Kheifets L., Shimkhada R. Childhood leukemia and EMF: review of the epidemiologic evidence. Bioelectromagnetics 2005;Suppl 7:S51-9.
Levallois P., Gauvin D., Gingras S., St-Laurent J. Comparison between personal exposure to 60 Hz magnetic fields and stationary home measurements for people living near and away from a 735 kV power line. Bioelectromagnetics 1999;20:331-7.
Li C. Y., Lee W. C., Lin R. S. Risk of leukemia in children living near high-voltage transmission lines. J Occup Environ Med 1998;40:144-7.
Li C. Y., Theriault G., Lin R. S. A validity analysis of residential magnetic fields estimated from high-voltage transmission lines. J Expo Anal Environ Epidemiol 1997a;7:493-504.
Li C. Y., Theriault G., Lin R. S. Residential exposure to 60-Hertz magnetic fields and adult cancers in Taiwan. Epidemiology 1997b;8:25-30.
Lin C. M., Li C. Y., Mao I. F. Birth outcomes of infants born in areas with elevated ambient exposure to incinerator generated PCDD/Fs. Environ Int 2006;32:624-9.
Lin C. M., Li C. Y., Yang G. Y., Mao I. F. Association between maternal exposure to elevated ambient sulfur dioxide during pregnancy and term low birth weight. Environ Res 2004;96:41-50.
Lin R. S., Lee W. C. Risk of childhood leukemia in areas passed by high power lines. Rev Environ Health 1994;10:97-103.
Linet M. S., Hatch E. E., Kleinerman R. A., Robison L. L., Kaune W. T., Friedman D. R., Severson R. K., Haines C. M., Hartsock C. T., Niwa S., Wacholder S., Tarone R. E. Residential exposure to magnetic fields and acute lymphoblastic leukemia in children. N Engl J Med 1997;337:1-7.
London S. J., Thomas D. C., Bowman J. D., Sobel E., Cheng T. C., Peters J. M. Exposure to residential electric and magnetic fields and risk of childhood leukemia. Am J Epidemiol 1991;134:923-37.
McBride M. L., Gallagher R. P., Theriault G., Armstrong B. G., Tamaro S., Spinelli J. J., Deadman J. E., Fincham S., Robson D., Choi W. Power-frequency electric and magnetic fields and risk of childhood leukemia in Canada. Am J Epidemiol 1999;149:831-42.
McDowall M. E. Mortality of persons resident in the vicinity of electricity transmission facilities. Br J Cancer 1986;53:271-9.
Mezei G., Kheifets L. Selection bias and its implications for case-control studies: a case study of magnetic field exposure and childhood leukaemia. Int J Epidemiol 2006;35:397-406.
Mezei G., Li C. Y., Sung F. C., Silva M., Chen P. C., Chen L. M. Survey of residential power frequency magnetic field exposure among children in Taiwan. The Bioelectromagnetics Society (BEMS) 28th Annual Meeting,-Cancun, Mexico, 11-15 June, 2006.
Michaelis J., Schuz J., Meinert R., Menger M., Grigat J. P., Kaatsch P., Kaletsch U., Miesner A., Stamm A., Brinkmann K., Karner H. Childhood leukemia and electromagnetic fields: results of a population-based case-control study in Germany. Cancer Causes Control 1997;8:167-74.
Michaelis J., Schuz J., Meinert R., Zemann E., Grigat J. P., Kaatsch P., Kaletsch U., Miesner A., Brinkmann K., Kalkner W., Karner H. Combined risk estimates for two German population-based case-control studies on residential magnetic fields and childhood acute leukemia. Epidemiology 1998;9:92-4.
Myers A., Clayden A. D., Cartwright R. A., Cartwright S.C. Childhood cancer and overhead powerlines: a case-control study. Br J Cancer 1990;62:1008-14.
Newell D. J. Errors in the interpretation of errors in epidemiology. Am J Public Health 1962;52:1925-8.
Nishchal N. K., Paulraj R., Mishra U. S., Sahu S. K., Lochan R. Electromagnetic field in and around the campus of Jawaharlal Nehru University, New Delhi. Indian J Biochem Biophys 1999;36:374-8.
Olsen J. H., Nielsen A., Schulgen G. Residence near high voltage facilities and risk of cancer in children. BMJ 1993;307:891-5.
Preece A. W., Grainger P., Golding J., Kaune W. Domestic magnetic field exposures in Avon. Phys Med Biol 1996;41:71-81.
Preston-Martin S., Navidi W., Thomas D., Lee P. J., Bowman J., Pogoda J. Los Angeles study of residential magnetic fields and childhood brain tumors. Am J Epidemiol 1996;143:105-19.
Savitz D. A., Wachtel H., Barnes F. A., John E. M., Tvrdik J. G.. Case-control study of childhood cancer and exposure to 60-Hz magnetic fields. Am J Epidemiol 1988;128:21-38.
Schuz J., Grigat J. P., Brinkmann K., Michaelis J. Residential magnetic fields as a risk factor for childhood acute leukaemia: results from a German population-based case-control study. Int J Cancer 2001;91:728-35.
Severson R. K., Stevens R. G., Kaune W. T., Thomas D. B., Heuser L., Davis S., Sever L. E. Acute nonlymphocytic leukemia and residential exposure to power frequency magnetic fields. Am J Epidemiol 1988;128:10-20.
Sun W. Q., H?roux P., Clifford T., Sadilek V., Hamade F. Characterization of the 60-Hz Magnetic Fields in Schools of the Carleton Board of Education. AIHA J 1995;56:1215-24.
Tard?n A., Velarde H., Rodriguez P., Moreno S., Raton M., Munoz J., Fidalgo A. R., Kogevinas M. Exposure to extremely low frequency magnetic fields among primary school children in Spain. J Epidemiol Community Health 2002;56:432-3.
Tarone R. E., Kaune W. T., Linet M. S., Hatch E. E., Kleinerman R. A., Robison L. L., Boice J. D., Jr., Wacholder S. Residential wire codes: reproducibility and relation with measured magnetic fields. Occup Environ Med 1998;55:333-9.
Tomenius L. 50-Hz electromagnetic environment and the incidence of childhood tumors in Stockholm County. Bioelectromagnetics 1986;7:191-207.
Tynes T., Haldorsen T. Electromagnetic fields and cancer in children residing near Norwegian high-voltage power lines. Am J Epidemiol 1997;145:219-26.
UK Childhood Cancer Study Investigators. Childhood cancer and residential proximity to power lines. Investigators. Br J Cancer 2000;83:1573-80.
UK Childhood Cancer Study Investigators. Exposure to power-frequency magnetic fields and the risk of childhood cancer. Lancet 1999;354:1925-31.
Verkasalo P. K., Pukkala E., Hongisto M. Y., Valjus J. E., Jarvinen, P. J., Heikkila, K. V., Koskenvuo, M. Risk of cancer in Finnish children living close to power lines. Br Med J 1993;307:895-9.
Walker A. M. Observation and inference : an introduction to the methods of epidemiology. Epidemiology Resources Inc., 1991.
Wertheimer N. Electrical wiring configurations and childhood leukemia in Rhode Island. Am J Epidemiol 1980;111:461-2.
Wertheimer N., Leeper E. Adult cancer related to electrical wires near the home. Int J Epidemiol 1982;11:345-55.
Wertheimer N., Leeper E. Electrical wiring configurations and childhood cancer. Am J Epidemiol 1979;109:273-83.
江博煌、莫喬治：地理資訊系統與公共衛生。初版。台北：文華圖書管理資訊股份有限公司，2005。
江榮城、王金墩：電磁場概論與暴露限制標準。電機技師雙月刊 2001;15:86-99。
江榮城：電力品質實務（二）。初版。台北市：全華科技股份有限公司，2000。
吳劍秋：基礎電磁學。二版一刷。台北：全華科技圖書股份有限公司，2004。
呂正章：潛談地理資訊系統。CADesigner 2001;164:17-22。
李中一、宋鴻樟、陳富莉：就讀高壓輸電線跨越校園上空學校學童之ㄧ般健康狀態評估。台灣公共衛生雜誌；2006;25:83-92。
李中一、林瑞雄：極低頻電磁場暴露與癌症之流行病學－文獻探討。勞工安全衛生研究季刊 1995;3:1-24。
李中一：國民中小學校園因鄰近變電所或高壓輸電線所造成之環境極低頻磁場暴露－現況調查與管制建議。教育部環保小組委託工作計畫（計畫編號：0920141625），2004a。
李中一：執行非屬原子能游離輻射－高壓輸電線、變電所或行動電話基地台鄰近學校產生電磁場之測量及其對學童健康評估。環保署委託研究計畫（計畫編號：EPA–93–F105–02–106），2004b。
李中一：測量工具的效度與信度。台灣公共衛生雜誌；2004;23:272-81。
李中一：極低頻電磁場之人類致癌效應－回顧近期之流行病學文獻。台灣職業醫學雜誌；2000;7:57-70。
李維進：高壓輸電線電頻磁場暴露與小而白血病之流行病學研究。國防醫學院公共衛生學研究所碩士論文，1994。
周天穎：地理資訊系統理論與實務。再版一刷。台北：儒林圖書有限公司，2003。
林志銘、李中一、毛義方：焚化爐產生之大氣戴奧辛暴露與生殖危害之相關性研究。台灣公共衛生雜誌；2002;21:197-206。
林傑斌、劉明德：地理資訊系統GIS理論與實務。初版。台北：文魁資訊股份有限公司，2002。
林意凡：極低頻磁場暴露之健康風險評估－以台北縣之國小為例。國立台灣大學職業醫學與工業衛生研究所碩士論文，2003，13 p。
邱佳正：時間地理資訊系統建構之研究—以都市土地使用分區變遷為例。國立中山大學海洋環境及工程研究所碩士論文，2003，110 p。
范成楝：空間技術處理技術導論。中央研究院計算中心空間資訊小組。（引用2006?5?16）Available from：URL：http://www.ascc.sinica.edu.tw/gis/NDASupport/class92/fango.files/frame.htm#slide0015.htm
陳建仁：流行病學：原理與方法。初版第四刷。台北：聯經出版事業公司，2000。
陳培君：汐止居民極低頻磁場暴露評估－對於婦女睡眠及生育之影響。國立台灣大學公共衛生學院環境衛生研究所碩士論文，2001，67 p。
黃敏郎、劉守恆、仲琦科技：地理資訊系統基礎操作實務。初版。台北：文魁資訊股份有限公司，2005。
溫在弘、金傳春、蕭朱杏、嚴漢偉、范毅軍、蘇明道：地理資訊系統應用於傳染流行病的疫情偵測、數據分析與速效控制。台灣公共衛生雜誌 2002;21:449-56。
葛維忠：台灣高壓輸電線兩側居民電頻磁場暴露健康風險推估。國立陽明大學環境衛生研究所碩士論文，2003，117 p。
廖勇柏、李文宗、陳建仁：趨勢面分析法在癌症地圖繪製上的應用：以台灣的乳癌死亡率為例。中華公共衛生雜誌；1998;17:474-84。
廖勇柏、陳建仁、李文宗、徐書儀：台灣地區癌症死亡率與發生率電子地圖的建構及使用。台灣公共衛生雜誌；2003;2:227-36。
廖勇柏、鐘雅齡、徐書儀、吳佳芳、鄭瓊珍：台灣地區女性肺癌死亡率之時空變異分析。中山醫學雜誌；2004;15:1-7。
劉介宇、洪永泰、莊義利、陳怡如、翁文舜、洪伊苓、梁賡義：台灣地區鄉鎮市區都市化分層之研究。新竹（元培技術學院）：台灣健康管理學術研討會，2005年6月19日。
劉侑蒼：鋪面養護管理系統與網際網路地理資訊系統之整合研究。國立中央大學機械工程研究所碩士論文，2004，66 p。
賴進貴、葉高華、陳汶軍：地理資訊系統應用於登革熱防治之檢討與建議。環境與世界；2005;11:65-81。
癌症防治組：九十年癌症登記報告記者會新聞稿。台北：行政院衛生署國民健康局，2004年11月18日。
癌症防治組：八十九年癌症登記報告記者會新聞稿。台北：行政院衛生署國民健康局，2003年12月29日。
|
|---|
