Diabetes mellitus and risk of endometrial cancer: a meta-analysis.
OBJECTIVE
Diabetes has been associated with a statistically significantly increased risk of endometrial cancer in most, but not all studies. To provide a quantitative assessment of the association between diabetes and risk of endometrial cancer, we conducted a meta-analysis of case-control studies and cohort studies.


METHODS
We identified studies by a literature search of PubMed and Embase through to January 2007 and by searching the reference lists of relevant articles. Summary relative risks (RRs) with 95% CIs were calculated using random-effects model.


RESULTS
The analysis of diabetes (largely type 2) and endometrial cancer is based on 16 studies (three cohort and 13 case-control studies), including 96,003 participants and 7,596 cases of endometrial cancer. Twelve of the studies showed a statistically significantly increased risk and four a non-significant increased risk of endometrial cancer. In our meta-analysis we found that diabetes was statistically significantly associated with an increased risk of endometrial cancer (summary RR 2.10, 95% CI 1.75-2.53). The risk estimates were somewhat stronger among case-control (RR 2.22, 95% CI 1.80-2.74) than among cohort studies (RR 1.62, 95% CI 1.21-2.16), stronger among studies adjusting only for age (RR 2.74, 95% CI 1.87-4.00) compared with multivariate adjustment (RR 1.92, 95% CI 1.58-2.33) and slightly lower in studies performed in the USA than in those performed Europe. The analysis of type 1 diabetes and endometrial cancer was based on three studies and found a statistically significant positive association (summary RR 3.15, 95%CI 1.07-9.29).


CONCLUSIONS
Results from the meta-analysis support a relationship between diabetes and increased risk of endometrial cancer.
Friberg
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Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, PO Box 210, 171 77, Stockholm, Sweden. emilie.friberg@ki.se
Orsini
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Mantzoros
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CS
Wolk
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D048909:Diabetes Complications / Q000209:etiology*; D003920:Diabetes Mellitus / Q000175:diagnosis*; D016889:Endometrial Neoplasms / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D012306:Risk