Low Triglyceride and Nonuse of Statins Is Associated With Cancer in Type 2 Diabetes Mellitus

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) have increased cancer risks. The authors reported nonlinear associations of cancer with triglyceride and other lipids in T2DM. Crosstalk between lipid metabolism and the renin-angiotensin system may increase cancer risk via activation of insulin-like growth factor-1 pathway in T2DM. In this analysis, the authors explored associations of cancer risk with high/low triglyceride in T2DM and possible modifying effects of statins on this risk association, if any. METHODS: A consecutive cohort of 5166 Chinese patients with T2DM, free of cancer at enrollment and not using statins at or before enrollment, was analyzed using Cox models. Biological interactions were estimated using relative excess risk because of interaction, attributable proportion because of interaction, and synergy index. Relative excess risk because of interaction > 0, attributable proportion because of interaction > 0, or synergy index > 1 indicates biological interaction. RESULTS: During 5.25 years of follow-up (median), 4.7% (n = 243) patients developed cancer. Triglyceride < 1.70 mmol/L was associated with increased cancer risk in the entire cohort and in statin nonusers, but not in statin users. Patients with triglyceride < 1.70 mmol/L plus nonuse of statins during follow-up had 2.74-fold increased cancer risk compared with their counterparts with either triglyceride >= 1.70 mmol/L or use of statins or both. There was significant interaction between triglyceride < 1.70 mmol/L and nonuse of statins (relative excess risk because of interaction, 0.99; 95% confidence interval [CI], 0.07-1.90 and attributable proportion because of interaction, 0.36; 95% CI, 0.02-0.70). CONCLUSIONS: In Chinese T2DM patients, triglyceride < 1.70 mmol/L might be associated with increased cancer risk, which was attenuated in the presence of use of statins. Cancer 2011;117:862-71. (C) 2010 American Cancer Society.