Aims: The study aimed to investigate the relationship between metabolic syndrome (MS) and risk of cancer in patients with type 2 diabetes (T2DM). 
Methods: We enrolled 6587 patients with T2DM who were hospitalized in Qingdao Endocrine and Diabetes Hospital from Feb 2005 to Jan 2016. According to the number of MS component each patient had, they were divided into isolated T2DM, T2DM plus 1 component，2 components, 3 components and 4 components, respectively. The IDF Worldwide Definition of the Metabolic Syndrome was applied. Information on the diagnosis of cancer was obtained by matching ICD-10 codes recorded in local Healthcare medical records database. Prevalence of cancer was compared using Chi-square test. Logistic regression model was used to evaluate risk of cancer associated with MS.
Results: The prevalence of cancer was 4.2% among 6587 patients with T2DM. Female patients had higher prevalence than did male in total or in the MS subgroup. The prevalence of cancer were 3.8%, 3.9%, 3.8%, 5.1% and 5.0% in isolated DM, T2DM plus 1 component of MS, T2DM plus 2, T2DM plus 3 and T2DM plus 4 components, respectively (P for trend <0.05). Compared with those with less than 3 components, T2DM plus 3 or 4 components had increased risk of having cancer (OR=1.32, 95% CI: 1.04-1.69). Among T2DM patients who had more than 3 components of MS, a specific cluster of increased waist, elevated triglycerides (TG) and decreased High-Density Lipoprotein Cholesterol (HDL-C) was associated with the highest prevalence of cancer (10.7%), followed by 8.3% in T2DM patients plus hypertension, elevated TG and decreased HDL-C and 3.2% in T2DM patients plus hypertension, increased waist and elevated TG (χ2=26.6, P<0.05).  
Conclusions: A cluster of metabolic disorders consisting of increased waist, elevated TG and decreased HDL-C seems to be oncogenic among Chinese patients with T2DM. For patients in combination with 3 or 4 MS components, it is important to conduct early cancer screening and prevention.

Cluster of metabolic disorders in relation to risk of cancer in Chinese patients with type 2 diabetes