Evaluation of certain risk factors for lung cancer in Cracow (Poland)--a case-control study

The relationship of lung cancer risk to cigarette smoking, occupational exposure, air pollution at permanent residence and usual frequency of consumption of fruits and vegetables was analysed in a case control study in Cracow, Poland. The cases were 176 male lung cancer patients diagnosed in 1992-1994 with histological confirmation of the diagnosis, obtained from the population-based Cracow Cancer Registry, and 341 controls randomly selected from the general population. Classification of exposure to outside air pollution was based on measured level of total suspended particular matter and sulphur dioxide by particular districts of town (from 1973 to 1980). Except calculation of odds ratios for male lung cancer associated with exposures among all study subjects, the association between lung cancer risk and frequency of consumption of fruit and vegetables was examined among drinkers of vodka above average. Risk of lung cancer was increased significantly with increasing number of pack-years of smoking (OR = 18.7 for more than 40 pack-years). The significant inverse association of frequent usual consumption of boiled vegetables was present both among all subjects and among vodka drinkers (OR = 4.6 and 12.5, respectively, for a rare consumption). The risk of male lung cancer was negatively associated with the level of air pollution but positively with the percentage of occupationally exposed. Our study provides no evidence of a significant harmful effect of air pollution and found a strong inverse association between frequent fruit and vegetables consumption and lung cancer risk.