Pancreatic cancer incidence in relation to female reproductive factors: Iowa Women's Health Study.
OBJECTIVE
Motivated by inconsistent literature, we evaluated the association between incident pancreatic cancer and reproductive characteristics.


METHODS
The Iowa Women's Health Study is a large prospective population-based cohort followed from 1986 to 2003. Reproductive information was self-reported.


METHODS
The study population comprised 37,459 women aged 55-69 years at baseline. Over 18 years, 228 incident pancreatic cancers were identified.


RESULTS
In a multivariate-adjusted model there were no associations between incident pancreatic cancer and age at first birth, number of births, age at menarche, or use of hormones. There was a statistically significant inverse association between age at menopause and pancreatic cancer incidence. Compared to menopause less than 45 years, the hazard ratio of pancreatic cancer was 0.61 (95% CI, 0.40-0.94) for menopause at 45-49 years, 0.75 (95% CI, 0.51-1.09) for 50-54 years, and 0.35 (95% CI, 0.18-0.68) for menopause at 55 years or more (P trend=0.005). This association held after restricting the cohort to never smokers. The associations between pancreatic cancer and ages at natural and surgical menopause followed similar patterns. In a parallel fashion, risk of pancreatic cancer was decreased for women with intact ovaries compared to those who had oophorectomy: hazard ratio was 0.70 (95% CI, 0.50-0.99).


CONCLUSIONS
Our results indicate that older age at menopause is associated with reduced pancreatic cancer risk, but further research is warranted.
Prizment
Anna E
AE
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota Minneapolis, MN 55455, USA.
Anderson
Kristin E
KE
Hong
Ching-Ping
CP
Folsom
Aaron R
AR
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008593:Menopause; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000453:epidemiology*; D011446:Prospective Studies; D017584:Reproductive History; D012307:Risk Factors