[Lung cancer and vegetable consumption in Asturias, Spain. A case control study].

BACKGROUND: Lung cancer in Asturias (Northern Spain) exceeds the Spanish average by 1.4 times. While the proportion of smokers is similar, consumption of vegetables is the lowest of Spain. The objective of the study was to examine the relationship between lung cancer and vegetable consumption in Asturias. PATIENTS AND
METHOD: This was an incident, hospital-based, case-control study. Cases were newly diagnosed lung cancer patients and controls were patients from surgical wards. Diet habits were obtained by means of a food frequency questionnaire with one year recall time. Information was also sought on smoking, occupational exposure and demographic variables.
RESULTS: 197 cases and 196 controls were included in the study. Those at the 80th percentile of cruciferous (e.g, cabbage, broccoli) consumption had half the risk of lung cancer, other than adenocarcinoma, as compared to those at the 20th percentile [OR = 0.47; 95% CI, 0.23-0.95 in the crude analysis]. However, when adjusting for smoking and social class, the association was no longer significant, possibly due to a low power of the study. A high vegetable, vitamin A or betacarotene consumption was not associated with a lower risk of lung cancer.
CONCLUSIONS: This study points towards a protective effect of cruciferous vegetables in lung cancer, other than adenocarcinoma. However, even in the case such a vegetable were protective, it could not explain by itself the existing differences in lung cancer rates between Asturias and the the rest of Spain.