aDivision of Molecular Genetic Epidemiology, German Cancer Research Center, DKFZ, Heidelberg, Germany.
Eur J Cancer Prev. 2010 Jul;19(4):275-9. doi: 10.1097/cej.0b013e3283387728.
Environmental risk factors, particularly tobacco smoking, are important for transitional-cell carcinoma of the bladder. Studies in migrants may provide valuable insight into the environmental and genetic etiology of cancer. The nationwide Swedish Family-Cancer Database was used to calculate standardized incidence ratios (SIRs) for transitional-cell carcinoma among the immigrants compared with native Swedes. SIRs for lung cancer were also calculated as a proxy for smoking prevalence. Significantly decreased risks of bladder cancer were observed for male (SIR=0.89) and female (0.71) Finns and male East Asian (0.39) first-generation immigrants. Male immigrants from many countries showed increased risks, ranging from 1.18 to 2.29. Only female immigrants from Denmark (1.40) and Norway (1.27) had increased risks. The risks for bladder and lung cancers correlated, except for Finnish and Iranian men. The sons of immigrants born in high-risk countries had an increased SIR (1.51) whereas the daughters of immigrants born in low-risk countries had a decreased risk (0.32). The risk in the second-generation immigrants born in Sweden was equal to that of natives. In conclusion, the observed bladder cancer risks in the first-generation immigrants, the changes in risks in the second-generation immigrants, and the covariation of the risk patterns of bladder and lung cancers suggested a main contribution by tobacco smoking. The exceptional patterns among the Finns and Iranians may point to the existence of modifying factors. The changes in incidence in second-generation immigrants, yet based on small case numbers, lend little support to the involvement of genetic factors.
环境风险因素，特别是吸烟，对膀胱移行细胞癌很重要。移民研究可能为癌症的环境和遗传病因学提供有价值的见解。利用全国性的瑞典家庭癌症数据库，计算了与土生土长的瑞典人相比，移民中膀胱癌的标准化发病比（SIR）。还计算了肺癌的 SIR 作为吸烟流行率的替代指标。与男性（SIR=0.89）和女性（0.71）芬兰移民以及第一代东亚移民（0.39）相比，男性和女性移民患膀胱癌的风险显著降低。来自许多国家的男性移民的风险增加，范围从 1.18 到 2.29。只有来自丹麦（1.40）和挪威（1.27）的女性移民的风险增加。除了芬兰和伊朗男性外，膀胱癌和肺癌的风险相关。出生在高风险国家的移民的儿子的 SIR 增加（1.51），而出生在低风险国家的移民的女儿的风险降低（0.32）。在瑞典出生的第二代移民的风险与本地人相同。总之，第一代移民中观察到的膀胱癌风险、第二代移民中风险的变化以及膀胱癌和肺癌风险模式的相关性表明，吸烟是主要原因。芬兰人和伊朗人例外的模式可能表明存在修饰因素。第二代移民发病率的变化，但基于病例数量较少，几乎没有支持遗传因素的参与。
