Reproductive Factors and Risk of Pancreatic Cancer in Women: A Review of the Literature
Received 23 August 2008; accepted 19 November 2008.
Purpose
Pancreatic cancer (PCA) is the fourth leading cause of cancer death in the United States. The male-to-female incidence and mortality ratio of PCA is 1.1–2.0. One possible explanation for this difference is that female hormone exposure is protective for the development of PCA. Several hypotheses were investigated in this systematic review: (1) increased exposure to estrogen through early menarche and later menopause is associated with a decreased risk of PCA; (2) increased exposure to pregnancy is associated with decreased risk of PCA; and (3) increased exposure to oral contraceptives and/or hormone replacement therapy is associated with decreased risk of PCA.
Methods
Of 371 articles identified, 10 case-control and 5 cohort studies met the criteria for our review. Odds ratios for case-control studies and hazard ratios for cohort studies and their accompanying 95% confidence intervals for analyses relevant to our hypotheses were considered in the review.
Results
For all 3 hypotheses, studies displayed inconsistent results, and this may have been due to the diversity of study populations, exposure quantification, analysis approach, confounding and other limitations, and biases across studies.
Conclusions
As there was no strong support for any of the 3 hypotheses, it appears that reproductive factors are not associated with the development of PCA in women.
aMilitary Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA
bDepartment of Epidemiology and Biostatistics, University of South Florida College of Public Health, Tampa
cDepartment of Surgery, University of South Florida College of Medicine, Tampa
dDepartment of Surgery, University of Pennsylvania School of Medicine, West Philadelphia
Address correspondence to: Monika M. Wahi, MPH, CPH, United States Army Research Institute of Environmental Medicine, Kansas St., Bldg. 42, Natick, MA 01760-5007. Tel.: (508) 233-5586; fax: (508) 233-4487.
ABSTRACT