Prediagnostic level of dietary and urinary isoflavonoids in relation to risk of liver cancer in Shanghai, China
Couplée aux données d'une étude chinoise portant sur 217 patients atteints d'un cancer du foie et 427 témoins, cette étude analyse, en fonction du sexe, l'association entre les niveaux d'isoflavones, mesurés dans les urines ou estimés dans l'alimentation, et le risque de développer la maladie
Background : No epidemiological studies have directly assessed the association between dietary and urinary of isoflavonoids and risk of liver cancer in humans. Methods : A nested case-control study including 217 incident cases of liver cancer and 427 individually matched control subjects was conducted in Shanghai, China. Dietary isoflavonoids intakes were assessed through a validated food-frequency questionnaire and the Chinese Food Composition Tables. Urinary excretion levels of four major isoflavonoids were measured by the reversed-phase high-performance liquid chromatography. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived using conditional logistic regression models. Results : The adjusted ORs (95% CIs) for liver cancer across increasing quartiles of urinary genistein levels were 1.00 (reference), 0.55 (95% CI = 0.22 to 1.36), 0.57 (95% CI = 0.23 to1.43) and 0.19 (95% CI = 0.06 to 0.59) (P=0.008 for trend) in women and 1.00 (reference), 1.22(0.52，2.86), 1.17(0.47，2.90), 1.23 (0.55-2.76) in men, respectively. These associations were consistent by limiting the cases to primary malignant neoplasm of liver or malignant neoplasms of the intrahepatic bile ducts, or among participants without self-reported liver disease or cirrhosis at the baseline survey. No associations were found between dietary isoflavonoids and liver cancer risk. Conclusions : Our study suggests for the first time that urinary excretion of genistein may be associated with reduced risk of liver cancer in women. Impact : In this nested case-control study in China, we found that urinary excretion of genistein was associated with lower risk of liver cancer in women, and not in men.