White blood cell DNA adducts and fruit and vegetable consumption in bladder cancer

The 'Mediterranean diet', a diet rich in cereals, fruit and vegetables, has been associated with lowering the risk of a variety of cancers of the dige stive tract and the bladder, In a previous study, we showed that the high p henolic content these dietary components produce in the urine could be asso ciated with higher antimutagenic properties of the urine and lower arylamin e-DNA adducts in exfoliated bladder cells. We have conducted a case-control study on 162 bladder cancer patients and 104 hospital controls, Total arom atic DNA adducts were measured in white blood cells (WBC) of all subjects b y P-32-post-labelling. Genetically based metabolic polymorphisms were analy sed by PCR-RFLP (NAT2, GSTM1, GSTT1, GSTP1, COMT and NQO1), All subjects we re interviewed about their tobacco use, dietary habits and other risk facto rs. The odds ratio (OR) for the risk of bladder cancer according to the pre sence/absence of WBC DNA adducts (detection limit 0.1 RALX10(8)) was 3.7 [9 5% confidence interval (CI) 2.2-6.3] and a dose-response relationship with levels of adducts was apparent. The association between case/control status and the presence of WBC DNA adducts was significantly stronger in the subj ects who consumed fewer portions of fruit or vegetables per day (OR 7.80, 9 5% CI 3.0-20.30 for 0-1 portions of vegetables) than in the heavy consumers (OR 4.98 for consumers of 2 portions dairy, OR 1.97 for consumers of great er than or equal to 3 portions; similar but lower estimates were found for the intake of fruit). No association was noticed between tobacco smoking an d WBC DNA adducts, Only NAT-2, among the several genotypes considered, was associated in a statistically significant way with the risk of bladder canc er (OR 1.72, 95% CI 1.03-2.87) and with the levels of WBC DNA adducts, Our report suggests that fruit and vegetables could protect against bladder can cer by inhibiting the formation of DNA adducts.