title: Insulin therapy and colorectal cancer risk among type 2 diabetes mellitus patients: a systemic review and meta-analysis.
abstract: BACKGROUND
  Insulin is widely used in patients with type 2 diabetes mellitus (T2DM). More attention was focused on its higher risk of colorectal cancer (CRC). This meta-analysis examined the relationship between levels of insulin use and the risk of CRC.
  
  
  METHODS
  A meta-analysis using data from 12 published epidemiologic studies (7 case-control, and 5 cohort studies) published before Jan. 2014 was done to examine the association between insulin use and CRC. Random effects analyses were done to calculate relative risk (RR) and 95% confidence intervals (CI). Heterogeneity among studies was measured by the χ2 and I2 statistic.
  
  
  RESULTS
  Overall, the risk of CRC was significantly associated with insulin use to a random-effects model (RR, 1.69; 95% CI, 1.25 -2.27). When subgroup analyses were conducted according to the study types, no associations were detected in cohort group (RR, 1.25; 95% CI, 0.95-1.65; I2, 75.7%); however significant association was detected in case-control group (RR, 2.15; 95% CI, 1.41-3.26; I2, 89.1%).
  
  
  CONCLUSIONS
  A significant harmful effect of insulin, observed mainly among case-control studies, may result from study design differences and amount of included studies. Although these results suggest a harmful effect of insulin use for CRC risk, additional large studies are warranted to support these preliminary evidences.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2194715731194123.
authors.affiliation: Department of Endocrinology, First affiliated hospital of General hospital of PLA, Beijing 100048, China. yinshinan2011@163.com.
authors.forename: Shinan
authors.initials: S
authors.lastname: Yin
authors.forename: Hua
authors.initials: H
authors.lastname: Bai
authors.forename: Danqing
authors.initials: D
authors.lastname: Jing
mesh_terms: D015179:Colorectal Neoplasms / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D007328:Insulin / Q000009:adverse effects*
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin