Insulin therapy and colorectal cancer risk among type 2 diabetes mellitus patients: a systemic review and meta-analysis
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Department of Endocrinology, First affiliated hospital of General hospital of PLA, Beijing 100048, China
Diagnostic Pathology 2014, 9:91 doi:10.1186/1746-1596-9-91Published: 12 May 2014
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.
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.
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%).
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 webcite.