Etiology of Lung Cancer among Women in Northern Thailand

根据癌症登记数据，泰国北部，特别是清迈省，已知肺癌发病率非常高，每年都在增加，即，1985年，男性和女性的年龄调整率分别为34.5和26.9; 1992年分别增加到47.7和40.1。特别是，最近清迈55岁以上妇女肺癌发病率的增加是一个严重的问题，沿着整个肺癌的发病率非常高。肺癌的病因是什么？肺癌的病因是什么？本研究项目包括以下三种方法：1）对生活在清迈肺癌高发区和低发区的普通妇女进行比较研究，2）对一家医院进行病例对照研究， ...更多信息 Ital（Maharaj Nakorn Chiang Mai Hospital）的研究，以及3）对在清迈府最大的医院Maharaj Nakorn Chiang Mai医院获得的肺癌标本进行病理学和分子生物学研究。第一种方法包括通过访谈对他们的生活方式进行流行病学调查，对重复膳食进行营养调查，对他们的血清样品进行血清学分析，尿液致突变性试验，痰液和室内空气中漂浮物中细菌和真菌的鉴定。1995年和1996年，我们分别对萨拉皮（高发病率）和Chomtong（低发病率;约为萨拉皮发病率的四分之一）地区的57名和59名年龄在50-74岁之间的妇女进行了调查。Sarapee区目前吸烟率为28.1%，低于Chomtong区的61.0%，这一结果强烈表明，吸烟本身不能解释这两个区之间肺癌发病率的显著差异。萨拉皮县居民绿色和黄色蔬菜和水果的摄入频率和摄入量均低于琼东县，但最显著的差异是良性呼吸道疾病的患病率：萨拉皮县有43.7%的居民患有慢性阻塞性肺疾病，而琼东县只有13.6%。Sarapee的女性吸烟者患有良性呼吸道疾病，血清IgE水平非常高，超过1000 U/ml，表明肺长期暴露于环境物质。此外，在萨拉皮的房屋内的空气中特别发现了某些类型的细菌，特别是犬支原体。沿着方法2）和3），我们分离并培养了这些细菌，用于随后的动物实验，以检查细菌的肿瘤促进活性。少

Nothern part of Thailand, in particular Chiang Mai Province, has been known to show very high incidence rates of lung cancer, which yearly increase, on the basis of the cancer registry data, i.e., the age-adjusted rates were 34.5 and 26.9 in 1985 for men and women, respectively ; those increased to 47.7 and 40.1 in 1992. Particularly, recent increase of lung cancer incidence in Chiang Mai women aged over 55 years is a serious problem to be solved along with the very high incidence of lung cancer as a whole. Only few studies have been so far carried out to find the causes of lung cancer and thus establish preventive measures against lung cancer.We started a research project on the etiology of lung cancer in collaboration with the faculty of medicine, Chaing Mai University, since 1995. This research project entailed the following three approaches :1) a comparative study of general women living in high and low incidence areas of lung cancer in Chiang Mai, 2) a case-control study at a hosp … More ital (Maharaj Nakorn Chiang Mai Hospital) of the faculty of medicine, Chiang Mai University, which is the largest hospital in Chiang Mai Province, and 3) pathological and molecular biological studies on lung cancer specimens obtained at the Maharaj Nakorn Chiang Mai Hospital.The first approach includes a epidemiological survey on their lifestyle by interviewing, nutritional survey on duplicated meals, serological analysis of their serum samples, mutagenicity assay of urine samples, identification of bacteria and fungi in sputum and those floating in the air indoor their houses. We surveyed 57 and 59 women aged at 50-74 years living at Sarapee (high incidence) and Chomtong (low incidence ; about the one-fourth of Sarapee's rate) districts in 1995 and 1996, respectively. Lower rate, 28.1%, of current smokers was observed in Sarapee, compared with 61.0% in Chomtong district.This result strongly implies that cigarette smoking alone can not explain the remarkable difference in lung cancer incidence between these districts. Althoug intake frequency and amount of green & yellow vegetables and fruits was less in Sarapee than that in Chomtong, the most outstanding difference between the districts was prevalence of benigh respiratory diseases : 43.7% in Sarapee experienced benigh respiratory diseases such as clonical bronchitis and COPD in contrast to 13.6% in Chomtong. Those female smokers in Sarapee who experienced benigh respiratory diseases showed very high serum IgE levels over 1000 U/ml, indicating long-term exposure of the lung to environmental substances. Furthermore, some types of bacteria, in particular M.canis, were specifically found in the air inside the houses in Sarapee.Along with the approaches 2) and 3), we isolated and cultured these bacteria for subsequent animal experiments to examine the tumor promotion activity of the bacteria. Less