主动吸烟是导致肺癌的主要原因早已被证实。但最近几年的研究 ,科学家又发现其它引发肺癌的病源学因素 ,特别是在非吸烟的人群中 ,曾经有过肺部非恶性疾病史的病人患肺癌的机会高于无病史者。这项研究是由美国国立卫生研究院与中国工业卫生研究所的科学家在我国甘肃省进行的 , Active smoking is the leading cause of lung cancer has long been proven. However, in recent years, scientists also found other etiological factors that cause lung cancer. Especially in non-smokers, those who had had a history of non-malignant lung disease had a higher chance of developing lung cancer than those without history. This study was conducted by scientists from the National Institutes of Health and China Institute of Industrial Hygiene in Gansu Province, China.