Preventive Medicine, University of Southern California, 1441 Eastlake Ave, Los Angeles, CA, United States.
Urinary bladder cancer is two-to-four times more common among men than women, a difference in risk not fully explained by established risk factors. Our objective was to determine whether hormonal and reproductive factors are involved in female bladder cancer.
We analyzed data from two population-based studies: the Los Angeles-Shanghai Bladder Cancer Study, with 349 female case-control pairs enrolled in Los Angeles and 131 female cases and 138 frequency-matched controls enrolled in Shanghai, and the California Teachers Study (CTS), a cohort of 120,857 women with 196 incident cases of bladder urothelial carcinoma diagnosed between 1995 and 2005. We also conducted a meta-analysis summarizing associations from our primary analyses together with published results.
In primary data analyses, parous women experienced at least 30% reduced risk of bladder cancer compared with nulliparous women (Shanghai: OR=0.38, 95%CI: 0.13-1.10; CTS: RR=0.69, 95%CI: 0.50-0.95) consistent with results of a meta-analysis of nine studies (summary RR=0.73, 95%CI: 0.63-0.85). The CTS, which queried formulation of menopausal hormone therapy (HT), revealed a protective effect for use of combined estrogen and progestin compared with no HT (RR=0.60, 95%CI: 0.37-0.98). Meta-analysis of three studies provided a similar effect estimate (summaryRR=0.65, 95%CI: 0.48-0.88).
A consistent pattern of reduced bladder cancer risk was found among parous women and those who used estrogen and progestin for HT.
These results suggest that more research is warranted to investigate hormonal and reproductive factors as possible contributors to bladder cancer risk.
Written by:
Davis-Dao CA, Delellis Henderson K, Sullivan-Halley J, Ma H, West DW, Xiang YB, Gago-Dominguez M, Stern MC, Castelao JE, Conti DV, Pike MC, Bernstein L, Cortessis VK. Are you the author?
Reference: Cancer Epidemiol Biomarkers Prev. 2011 Apr 14. Epub ahead of print.
doi: 10.1158/1055-9965.EPI-11-0017
PubMed Abstract
PMID: 21493870
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