A CASE-CONTROL STUDY OF DIET AND LUNG-CANCER IN NORTHEAST CHINA

A case-control study involving interviews with 227 lungcancer cases an d 227 matched hospital controls was conducted in Heilongjiang Province in northeast China to examine the influence of dietary factors on the risk of developing lung cancer. Lung-cancer cases were all incident c ases judged to be suitable candidates for tumor removal by surgery. Co ntrols were selected among hospitalized patients with non-neoplastic a nd non-lung disease. The overall male lungcancer risks associated with cigarette smoking were similar to those reported in other Chinese stu dies but quite low compared to risks in Western countries. However, th e subjects in this study were relatively young (average age 53.2), had started to smoke on average at a relatively old age (21.3 years), and only smoked an average of 18.7 cigarettes per day. Lung-cancer risk w as not strongly associated with any of the nutrients examined, when al l cases were compared to all controls. However, the data were suggesti ve of differences in the relationship of diet to risk among smokers an d nonsmokers. Cautious interpretation is required because of the wide confidence intervals due to limited sample size. Among the smokers, on ly higher beta-carotene was associated with estimates suggesting a low ered risk. Among non-smokers, the evidence suggested that increased ve getable consumption might reduce risk, consumption of any fruit might reduce risk but beta-carotene was unrelated to risk. The differences o bserved in the relationship of diet to lung-cancer risk between Chines e smokers and non-smokers warrant further study. (C) 1997 Wiley-Liss, Inc.