Type 2 Diabetes and Risk of Incident Cancers in China: A Prospective Study among 0.5 Million Chinese Adults

Abstract

Using data from the China Kadoorie Biobank study, we conducted a prospective investigation on the association between type 2 diabetes mellitus (T2DM) and cancer risk in Chinese adults. A total of 508,892 participants (mean (standard deviation) age = 51.5 (10.7) years) without prior cancer diagnosis at baseline (2004–2008) were included. We documented 17,463 incident cancer cases during follow-up until December 31, 2013. Participants with T2DM had increased risks of total and certain site-specific cancers, and the hazard ratio (HR) was 1.13 (95% confidence interval (CI): 1.07, 1.19) for total cancer, 1.51 (1.29, 1.76) for liver cancer, 1.86 (1.43, 2.41) for pancreatic cancer, and 1.21 (1.01, 1.47) for female breast cancer. The associations were largely consistent when doctor-diagnosed and screen-detected T2DM were analyzed separately, except for colorectal cancer (HR = 0.91 (95% CI: 0.73, 1.13) for doctor-diagnosed T2DM, and HR = 1.44 (95% CI: 1.18, 1.77) for screen-detected T2DM). In participants without prior diagnosis of T2DM, higher random blood glucose levels were positively associated with risk of total cancer, liver cancer, and female breast cancer (all P for trend ≤0.02). In conclusion, T2DM is associated with an increased risk of new-onset cancer in China, particularly cancers of the liver, pancreas, and female breast.