Abstract

Objective: Low-density lipoprotein cholesterol (LDL-C) <2.80 mmol/L was associated with cancer risk in type 2 diabetes mellitus (T2DM). We explored a) interaction between low LDL-C and albuminuria and b) interaction between co-presence of these 2 risk factors and statin use for cancer in T2DM.

Research design and methods: We analyzed prospective data of 3793 Chinese T2DM patients who remained naïve for statin treatment and 1483 patients started on statin during a median follow-up period of 5.24 years. All patients were free of cancer at baseline. Biological interactions were estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (S). RERI >0, AP >0 or S >1 indicates biological interaction.

Results: In 3793 statin-naïve T2DM patients, co-presence of low LDL-C and albuminuria increased cancer risk by 2.8 fold (hazard ratio 2.77, 95% confidence interval [CI] 1.78 to 4.31) with significant biological interactions (RERI: 1.05, 95%CI 0.04 to 2.06; AP: 0.38, 95%CI 0.09 to 0.66). In the whole cohort of 5276 T2DM patients, there were interactions between non-use of statin and co-presence of low LDL-C and albuminuria with increased cancer risk (RERI: 2.87, 95%CI 0.64 to 5.09 and AP: 0.60 95%CI 0.29 to 0.90). Statin non-users with LDL-C <2.80 mmol/L and albumunuria had a 4.9-fold risk of cancer as compared to statin users with or without both risk factors.

Conclusions— In T2DM, there was interaction between low LDL-C and albuminuria with increased cancer risks. The latter was attenuated in the presence of statin treatment.