50年代以来采取了降低卷烟烟雾中焦油和尼古丁浓度的措施。为了验证这一措施是否在吸烟者支气管上皮的组织变化中有所反映,从445名尸检(非死于肺癌者)的支气管做了共20,424张切片,随机地进行镜检。211例死于1955～1960年,其中154例一贯吸烟;234例死于1970～1977年,其中181例一贯吸烟。所观察的变化包括:基底细胞增生、纤毛脱失和具有不典型刻的细胞。在两个时期内,经过年龄校正,上述组织改变在不吸烟者中远远少于吸卷烟者,其发生 Since the 1950s measures have been taken to reduce tar and nicotine concentrations in cigarette smoke. In order to verify whether this measure is reflected in the tissue changes in the bronchial epithelium of smokers, a total of 20,424 slices of bronchi from 445 autopsies (those not died of lung cancer) were randomly selected for microscopic examination. Of the 211 patients who died in 1955-60, 154 were consistently smokers and 234 died in 1970-1977, of whom 181 consistently smoked. Observed changes include: basal cell proliferation, cilia loss and with atypical cells. In both periods, after age correction, the above-mentioned organizational changes were far fewer among non-smokers than those who smoked cigarettes, and their occurrence