Prospective evaluation of type 2 diabetes mellitus on the risk of primary liver cancer in Chinese men and women.

Background: No prospective study has investigated the relationship between type 2 diabetes mellitus (T2DM) and the risk of primary liver cancer (PLC) in mainland China, and little is known about the effect of diabetes duration on PLC risk.
Design: Data from two population-based cohorts (the Shanghai Men's Health Study, SMHS, 2002-2006 and the Shanghai Women's Health Study, SWHS, 1996-2000) were thus used to assess the associations among T2DM, diabetes duration and PLC risk in Chinese population.
Results: During follow-up through 2009, 344 incident PLC cases were identified among 60 183 men and 73 105 women. T2DM is significantly associated with the increased risk of PLC in both men [hazard ratio (HR) = 1.63, 95% confidence interval (CI) 1.06-2.51] and women (HR = 1.64, 95% CI 1.03-2.61). The highest risk of incident liver cancer was observed in the first 5 years after diabetes diagnosis, and decreased substantially with the prolonged diabetes duration (P(trend) < 0.001). No synergistic interaction in the development of PLC was found between diabetes and other known risk factors.
Conclusions: T2DM is associated with the increased risk of subsequent liver cancer within 5 years after diagnosis in Chinese population, suggesting that hyperinsulinaemia rather than hyperglycaemia is more likely to be a primary mediator for this association.