Older age at first birth is a risk factor for pancreatic cancer: a meta-analysis.

Background: Some studies found that age at first birth is associated with pancreatic cancer; others did not. The present meta-analysis was to evaluate the relationship between age at first birth and pancreatic cancer in women.

Data Sources: We searched PubMed, Embase, and the Cochrane Library for relevant publications on age at first birth and pancreatic cancer up to April, 2014. The eligible studies (six cohorts and five case-controls) were independently selected by two authors. Pooled relative risk (RR) estimates and corresponding 95% confidence interval (95% CI) were calculated using the inverse-variance method.

Results: The pooled RR of pancreatic cancer risk for the highest versus lowest categories of age at first birth was 1.21 (95% CI: 1.01-1.45, P=0.314, I2=13.7%). Consistent relationships were also observed within subgroup analyses stratified by study design, geographic region, and whether the studies included adjustment for cigarette smoking, diabetes, or all of the confounders. In this meta-analysis, no publication bias among studies was observed using Egger's test (P=0.383) or Begg's test (P=0.436).

Conclusion: Our findings suggest that older age at first birth is associated with an increased risk of pancreatic cancer in women and the exact functional mechanism needs further investigation.