滇东产(燃)煤区农民肺癌流行病学调查

Descriptive Study on the Epidemiology of Lung Cancer in Coal-producing Area in Eastern Yunnan, China

背景与目的云南省宣威市位于滇东黔西晚二叠纪聚煤区,当地肺癌死亡率居全国首位,研究显示宣威农民肺癌高发与室内烟煤燃烧产生的多环芳烃等污染物有关。近年来宣威周边产煤地区环境污染和肺癌高发问题引起国内外关注,滇东其它地区居民肺癌流行水平与发病原因是否与宣威相似未见报道。本研究旨在探索滇东产(燃)煤地区农民肺癌流行状况和发病原因。方法采用多阶段、分层、整群、概率抽样方法随机抽取滇东产(燃)煤382个调查小区,对其中30岁-79岁常住居民进行X线胸片肺癌筛查和相关因素调查,筛查阳性疑似肺癌进行CT复查,诊断为肺癌的病例进行痰癌细胞检查和随访。采用世界肿瘤研究中心标化率比对不同地区肺癌筛查阳性率进行显著性检验分析、调整合并为A区、B区、C区、D区等4层,并进行肺癌相关因素分析。结果共筛查和问卷调查52,833名农村居民,X线胸片筛查疑似肺癌阳性604例,541例经过CT复查,诊断为肺癌363例(其中组织学确诊109例),CT复查校正筛查阳性率763.08/10万,世界人口标化率426.28/10万(95%CI:381.51/10万-471.05/10万),男性482.78/10万,女性387.98/10万,男女比值1.24。各层肺癌流行强度差别较大,从A区→B区→C区→D区,肺癌筛查世标率逐渐减少,男女比值逐渐增大。筛查世标率最高的A区是最低D区的6.97倍。肺癌筛查阳性率与煤炭资源分布有关,调查对象肺癌筛查阳性率与烟煤使用率和使用量成正比,而与无烟煤使用率和使用量无明显关联。调查地区居民早期火塘使用率80%以上,其下无进气口,上无烟囱,煤炭燃烧不完全,加重煤烟废气污染。家族成员肺癌死亡率与肺癌筛查阳性率的分布一致,肺癌筛查阳性率随家族成员肺癌死亡率增加而增加。男性吸烟率85.08%,平均吸烟量16.12支/天;约50%从事过采煤、炼焦等工作。女性吸烟率1.37%,主要从事农业生产和做饭、喂养生猪等室内家务工作,吸烟、职业危害不是女性肺癌的主要发病因素,但可能是男性肺癌发病比女性严重的影响因素。结论肺癌高发与室内外烟煤污染、家族易感性有关联,吸烟、采煤、炼焦不是女性肺癌的主要因素。

Background and objective Xuanwei county is located at Late Permian coal-accumulating area in eastern Yunnan and western Guizhou, China. The lung cancer mortality rate in Xuanwei county is among the highest in China and has been attributed to exposure to indoor smoky coal emissions that contain very high levels of polycyclic aromatic hydrocarbons （PAHs）. Recent years, the pollution and the higher mortality rate of lung cancer has been watched in the area around Xuanwei, and there is no report about whether the epidemic levels and the pathogen of lung cancer in other area of eastern Yunnan is similar to that in xuanwei. The aim of this study is to epidemic levels and cause of lung cancer in coal-producing area in the east of Yunnan province. Methods 382 study units （nature villages） were selected by stratified cluster random sampling from coalproducing area in eastern Yunnan province, China. The villagers who were aged 30-79 years with no history of lung cancer were enrolled. All the participants received an initial single-view posterior-anterior chest radiograph and administered a questionnaire survey （which involves the information of demography, household and fuel use, lifestyle, tobacco and occupational exposure history, family and personal medical history, etc. The subjects with a positive screen by chest x-ray underwent to have a computed tomography scan of the chest and biopsy examination. The confidence interval of the standardized rate ratio were adopted to evalu-ate the statistical significance of differences in different regions. Results 52,833 villagers were surveyed and screened with X-ray. 604 of them were suspicious lung cancer with an initial chest radiograph, 541 underwent CT scan （362 were diagnosed by CT and 109 were diagnosed by histology）. The adjusted positive rates for lung cancer screening with CT is 763.08 per 100,000, the age-standardized rate （ASR） with the world standard population is 426.28 per 100,000 （95% confidence interval=381.51/10 per 100,000 to 471.05 per 100,000）, 482.78 per 100,000 for man, 387.98 per 100,000 for woman, male-to-female （M：F） rate ratios is 1.24. The intensity of lung cancer had significant difference between different study units. The ASR for lung cancer screening from A, B, C to D areas decreased in turn, and the area A was the highest of all, which was 6.97 times higher than the lowest area D, and the ratio between male and female was increased gradually. The positive rate for lung cancer was related to the distribution of coal and in direct proportion to the amount of smoky coal burning, but not associated with smokeless coal combustion. There are above 80% residents who burned ＂smoky＂ coal in indoor firepits which generated very high levels of air pollution. Lung cancer mortality of family members has the same distribution to positive rates of lung cancer screening, and they are in proportion to each other. 85% men smoke 16.12 cigarettes per day, averagely. About 50% of them did the job like coking, mining coal and so forth. Smoking rate of woman is 1.37%, they always did housework such as cooking, raising pigs and so on. Though the smoking and occupational hazard factors were not the major reasons for women to get lung cancer, they were possible reasons for men. Conclusion In Xuanwei country of China, lung cancer was associated with exposure to smoky coal emissions and family susceptibility. Smoking, coking and mining were not the major risk factors lead to lung cancer for women.