Hormonal factors and the risk of invasive ovarian cancer: a population-based case-control study.
OBJECTIVE
To examine the influence of hormone-related factors on the risk of invasive epithelial ovarian cancer (ovarian cancer).


METHODS
Population-based case-control study using in-person interviews.


METHODS
Academic department of preventive medicine.


METHODS
Four hundred seventy-seven ovarian cancer patients and 660 controls.


METHODS
None.


METHODS
Numbers of and ages at births, oral contraceptive use, and use of menopausal hormone therapy.


RESULTS
Compared with nulliparous women, women whose only (last) birth was after age 35 years had an estimated 51% (95% confidence interval: 21%-70%) reduction in risk. If this birth occurred earlier, the reduction in risk was progressively less. Additional (earlier) births reduced the risk further. Oral contraceptive use also reduced risk. Increased body mass index increased risk, but this effect was confined to localized disease and is likely to be a diagnostic bias, as a consequence of other problems associated with being overweight and in itself having no etiological significance.


CONCLUSIONS
If the major protective effect of a late birth can be confirmed, our most challenging task will be to understand the mechanism to develop a chemoprevention approach to exploit this finding.
Pike
Malcolm C
MC
USC/Norris Comprehensive Cancer Center, Keck School of Medicine, Department of Preventive Medicine, University of Southern California, Los Angeles, California 90033, USA. mcpike@usc.edu
Pearce
Celeste L
CL
Peters
Ruth
R
Cozen
Wendy
W
Wan
Peggy
P
Wu
Anna H
AH
D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000494:pharmacology; D005260:Female; D006728:Hormones / Q000097:blood*; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010051:Ovarian Neoplasms / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control*; D018566:Pregnancy, High-Risk; D018570:Risk Assessment; D011795:Surveys and Questionnaires
D003276:Contraceptives, Oral; D006728:Hormones