Parity and Risk of Pancreatic Cancer Among Premenopausal Women: A Nationwide Cohort Study.

Abstract

To examine the association between parity and pancreatic cancer risk, along with other reproductive factors, in premenopausal women, amid the rising incidence of pancreatic cancer among younger women and concurrent decline in fertility rates. In this nationwide cohort study, 935,345 premenopausal women aged 40-55 years without prior cancer who participated in the 2009 Korean National Cancer Screening Program were followed from January 1, 2009, through December 31, 2019, until pancreatic cancer diagnosis, death, or end of follow-up, whichever came first. Multivariable-adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models. Over a median follow-up of 9.3 years, 2,065 women developed pancreatic cancer (mean age at baseline, 45.0 years [SD, 3.9]). The incidence rate was 30.2 per 100,000 person-years in nulliparous women, compared with 23.6 and 23.4 in women with one and ≥2 births, respectively. Parity was inversely associated with pancreatic cancer risk, with adjusted hazard ratios (aHRs) of 0.72 (95% CI, 0.57-0.91) for one birth and 0.70 (95% CI, 0.57-0.86) for ≥2 births, compared with nulliparity. The associations were consistent across most subgroups, except those stratified by alcohol consumption and hypertension (P for interaction =.001 and 0.02, respectively). Other reproductive factors were not significantly associated with risk. Parity was associated with a reduced risk of pancreatic cancer in premenopausal women after adjustment for multiple potential confounders, suggesting that targeted prevention strategies for nulliparous women may help mitigate the growing burden of this malignancy among younger women.