Diabetes mellitus as a risk factor for pancreatic cancer. A meta-analysis.

OBJECTIVE

To evaluate diabetes mellitus as a risk factor for pancreatic cancer with the consideration that diabetes may also be a consequence of pancreatic cancer.

DATA SOURCES

Pertinent studies of diabetes mellitus and pancreatic cancer published between 1975 and 1994 were identified from a MEDLINE search and from citations in articles and books.

STUDY SELECTION

Twenty of a total of 30 case-control and cohort studies met the two inclusion criteria: cases with a duration of diabetes of at least 1 year prior to either pancreatic cancer diagnosis or death and the ability to calculate an appropriate relative risk (RR) estimate and variance.

DATA EXTRACTION AND SYNTHESIS

The pooled RR and 95% confidence interval (CI) of pancreatic cancer for diabetics relative to nondiabetics was 2.1 (1.6 to 2.8). There was a tendency for a higher RR for the nine cohort studies (RR, 2.6; 95% CI, 1.6 to 4.1) than for the 11 case-control studies (RR, 1.8; 95% CI, 1.1 to 2.7). Requiring diabetes duration of at least 5 years resulted in an RR of 2.0 (95% CI, 1.2 to 3.2).

CONCLUSION

Pancreatic cancer occurs with increased frequency among persons with long-standing diabetes.