Insulin, glucose and hepatocellular carcinoma risk in male hepatitis B carriers: results from 17-year follow-up of a population-based cohort

This study aimed to investigate the association of fasting insulin and glucose levels with hepatocellular carcinoma (HCC) risk in a case-cohort study within a cohort (1989-2006) of 2903 male government employees chronically infected with hepatitis B virus (HBV) in Taiwan. Insulin, glucose and HBV-related factors were assayed in baseline plasma among 124 HCC cases and a random subcohort of 1084 of the total cohort. After adjustment for demographics and HBV-related factors, including viral load and genotype, the HCC risk was higher for the highest [>6.10 mu U/ml, hazard ratio (HR) = 2.36, 95% confidence interval (CI): 1.43-3.90] and lowest (<2.75 mu U/ml, HR = 1.57, 95% CI: 0.96-2.58) categories of insulin, compared with insulin of 2.75-4.10 mu U/ml. The dose-response relationship between insulin and HCC varied by follow-up time, with stronger association for the HCC cases that occurred >= 8 years after baseline (P for trend <0.0001). The effect of higher insulin on HCC risk remained after adjustment for other metabolic factors, and was fairly consistent across strata of age, body mass index, and HBV genotypic variants. However, it was more profound among those with viral load <4.39 log(10) copies/ml at recruitment (>6.10 mu U/ml, HR = 6.15, 95% CI: 2.48-15.22). Higher insulin was also associated with an increased risk for cirrhosis diagnosed by ultrasonography and elevated alanine aminotransferase. No association with either cirrhosis or HCC was noted for glucose or diabetes after adjusting for insulin. In conclusion, elevated insulin levels are an independent risk factor for HCC among HBV carriers, especially for those with lower viral load.