[The association between aflatoxin exposure and primary hepatocellular carcinoma risks: a case-control study in Chongqing]. Objective: To investigate the association between aflatoxin exposure and primary hepatocellular carcinoma (PHC) development.  Methods: From December 2013 to May 2016, we selected 214 patients newly diagnosed with PHC as cases, and 214 patients as controls from three hospitals in Chongqing.  Cases were confirmed with PHC diagnosis standard.  And cases caused by clear reasons such as drug-induced liver injury, alcoholic liver damage, fatty liver and gallstones etiology, were excluded.  Controls were included with no cancer and no digestive system disease, and recruited simultaneously with cases.  Cases and controls were frequency-matched (1∶1) by same gender and age (±3 years).  Peripheral blood and random urine samples were collected and analyzed for serum HBsAg status by biochemistry analyzer, and serum AFB(1)-ALB adduct and urinary AFB(1)-N(7)-GUA adduct by ELISA.  Basic information, living habits and history of disease for patients were obtained by questionnaires.  We used wilcoxon rank sum test to compare the median of serum AFB(1)-ALB adduct and urinary AFB(1)-N(7)-GUA adduct in cases and controls.  Logistic regression analyses were performed to assess risk factors for PHC, and synergism index (S) of aflatoxin with other factors was estimated by the method of Andersson.  Results: There was no significant difference in age between PHC cases (50.74±9.67) years and controls (51.15±9.90) years.  Logistic regression showed that the odds ratio of HBV infection for PHC development was 46.3 (95% CI: 23.3-88.0).  There was a significant difference in median concentrations of serum AFB(1)-ALB adduct (cases vs controls: 146.23 vs 74.42 ng/g albumin, P<0.001), but no difference in median concentrations of urinary AFB(1)-N(7)-GUA adduct was observed (cases vs controls: 0.17 vs 0.14 ng/mg creatinine, P<0.210).  The odd ratios for PHC risk after adjustment were 1.9 (95%CI: 1.1-3.4) for AFB(1)-ALB adduct, and 2.1 (95%CI: 1.0-4.2) for AFB(1)-N(7)-GUA adduct.  Moreover, we observed a positive interaction of aflatoxin exposure with HBV, alcohol drinking, and diabetes.  The S was 4.7 (95%CI: 2.8-7.9), 3.5 (95%CI: 1.0-12.0), and 12.4 (95%CI: 1.8-84.2), respectively for serum AFB(1)-ALB adduct with each of the three factors mentioned, and was 1.9 (95%CI:1.1-3.1), 2.0 (95%CI: 1.1-3.6), and 2.0 (95%CI: 1.1-3.6), respectively for urinary AFB(1)-N(7)-GUA adduct with each of the three factors mentioned.  Conclusion: HBV was still the main risk factor, and AFB(1) exposure was also an independent risk factor for PHC in Chongqing.  There was a positive interaction of aflatoxin with HBV, alcohol drinking, and diabetes.
C