Background: Since 1970s, Xuanwei in Yunnan province has been one of the towns with highest lung cancer mortality in China. Moreover, the characters of high female lung cancer mortality and sub-regional clustering high lung cancer mortality have not changed. In this study, we further described the exposure situation of risk factors of lung cancer in Xuanwei nowadays, in order to explore the trend of the distribution of lung cancer there.
Methods: Firstly we divided the 26 towns of Xuanwei city to high-, median- and low- lung cancer areas by the lung cancer mortality in 2010-2012. We chose 2 towns within each area according to topography and orientation, and randomly picked 4 villages in each town to be our study area. We did a questionnaire about lung cancer related risk factors upon the sample population in the study area. We calculated the exposure percentages of each risk factor, in whole sample population and subgroups, for nowadays and for 10 years ago (only living environmental risk factors), and compared them between areas or time points using standardized rates and the statistical test of standardized rate comparison, or chi-square test.
Results: 65%-80% male in the study area has a history of smoking; 60%-90% non-smoker has been exposed to second hand smoke. These situations are worse in high and median lung cancer areas. 50% male in median lung cancer area have coal mining work experience, which is 2 times of the percentages in the other two areas; while 15%-25% people in high lung cancer area have other occupational exposure history to particulate air pollution, which is 3-5 times of the percentages in the other two areas. From ten years ago until nowadays, 80% families in median lung cancer area use 2 tons or more smoky coal per year; more than 90% families burn coal for household heating; more than 60% families suffer from smog in the kitchen during cook; 60% families most frequently use stove in the ground with chimney. Only 20% families in high lung cancer area now use 2 tons or more smoky coal per year. Now 50%-75% families in the study area use 700 kilowatt-hours of electricity per year, much more than ten years ago. 80% residents in low lung cancer area eat fatty or pickled or smoked food at least 3 days per week; while in high and median lung cancer areas the percentages are 50%-60%.
Conclusions: According to data obtained in this survey, current distribution of smoky coal use has differed from the distribution of high-, median- and low- lung cancer areas. Tobacco use and second hand smoke, the use of smoky coal and occupational exposure to particulate matters could be the main risk factors for lung cancer in Xuanwei now. The relations between lung cancer and stove type, dietary habit and so on deserve further study.
背景与目的 自1970年代至今，云南省宣威市始终是我国肺癌高发地区之一，且其女性高发、地区聚集性高发的特征未发生过改变。本研究目的在于进一步关注宣威市普通居民肺癌高发危险因素暴露的变化情况，以预测未来肺癌分布特征。方法 根据2010年-2012年肺癌死亡率将宣威市26个乡镇划分为高、中、低发区后，根据地形和方位选取6个乡镇（高中低发区各2个），并从每个乡镇中随机抽取4个行政村作为调查点。对调查点中居民样本人群进行肺癌危险因素面对面调查。计算高、中、低发区人群危险因素暴露率，以及性别、年龄别亚组人群暴露率，其中生活环境方面危险因素计算现在和十年前。采用标化率和标化率比较的统计学检验或卡方检验，比较区域间或两时间点暴露水平的高低。结果 研究地区65%-80%的男性有吸烟史，60%-90%的从未吸烟者有二手烟暴露史。烟草使用和二手烟暴露均是在肺癌高、中发区明显严重于低发区。中发区50%的男性有煤矿工作经历，是高、低发区的2倍；而高发区15%-25%的人有其他职业烟尘暴露史，是中、低发区的3倍-5倍。从十年前到现在，中发区都有近80%的家庭每年使用2吨或更多烟煤，有超90%的家庭使用燃煤取暖，有60%多的家庭做饭时厨房油烟多，有60%的家庭日常最常使用有烟囱地炉。高发区目前倒只有20%的家庭大量使用烟煤。整个研究地区50%-75%的家庭每年使用700度或更多电，比十年前用电量大增。低发区80%的人经常吃高油脂或腌制熏制食品，高、中发区为50%-60%。结论 从本次调查数据来看，目前烟煤使用情况的分布与肺癌高中低发区的分布已不一致。烟草流行包括二手烟暴露，烟煤使用，职业暴露可能是当前宣威肺癌仍旧高发的原因。炉灶类型、饮食习惯等危险因素与宣威肺癌间的相关性值得进一步研究。.