以前对白血病发病的研究多集中在接触放射线或逆病毒感染。近来美国学者提出吸烟也是个重要的危险因素。他们分析了22项前瞻性和对比方式的研究课题，发现吸烟者患菌性白血病和急性淋巴细胞性白血病的危险分别上升40％及30％；而且这种危险还直接与吸烟量有关。据作者估计，美 Previous studies of the incidence of leukemia focused on exposure to radiation or retroviral infection. Recently, American scholars proposed smoking is also an important risk factor. They analyzed 22 prospective and comparative studies and found that the risk of smokers with bacterial leukemia and acute lymphoblastic leukemia increased by 40% and 30%, respectively, and the risk was directly linked to smoking. According to the author’s estimation, the United States