American Journal of Epidemiology Advance Access originally published online on June 10, 2008
American Journal of Epidemiology 2008 168(3):278-288; doi:10.1093/aje/kwn119
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ORIGINAL CONTRIBUTIONS |
Non-Hodgkin Lymphoma in Women: Reproductive Factors and Exogenous Hormone Use
1 Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California Davis, Sacramento, CA
2 Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA
3 Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA
Correspondence to Dr. Paige M. Bracci, Department of Epidemiology and Biostatistics, University of California San Francisco, 3333 California Street, Suite 280, San Francisco, CA 94118-1944.
Received for publication October 17, 2007. Accepted for publication April 7, 2008.
Few studies of reproductive hormone exposures and non-Hodgkin lymphoma (NHL) have examined NHL subtypes. Associations between reproductive hormonal factors and risk of all NHL and of two predominant subtypes, diffuse large-cell lymphoma (DLCL) (n = 233) and follicular lymphoma (n = 173), were investigated among women (n = 581) in a large, population-based, case-control study (1,591 cases, 2,515 controls). Controls (n = 836) identified by random digit dialing were frequency matched by age and county to incident NHL cases ascertained in the San Francisco Bay Area of California in 1988–1993. Adjusted unconditional logistic regression was used to obtain odds ratios. More than four pregnancies indicated a possible lower risk of all NHL (odds ratio (OR) = 0.81, 95% confidence interval (CI): 0.55, 1.2; p-trend = 0.06) and of DLCL (OR = 0.53, 95% CI: 0.31, 0.90; p-trend = 0.01). Exclusive use of menopausal hormone therapy for 
5 years was associated with a reduced risk of all NHL (OR = 0.68, 95% CI: 0.48, 0.98) and of DLCL (OR = 0.50, 95% CI: 0.30, 0.85). Oral contraceptive use indicated a lower risk of all NHL (OR = 0.68, 95% CI: 0.49, 0.94), and perhaps DLCL (OR = 0.79, 95% CI: 0.51, 1.2), and of follicular lymphoma (OR = 0.75, 95% CI: 0.46, 1.2). Results suggest that endogenous and exogenous reproductive hormones confer different risks by NHL subtype and are associated with a reduced risk of DLCL in women.
case-control studies; contraception; estrogens; hormone replacement therapy; lymphoma, non-Hodgkin; menopause; pregnancy; reproduction
Abbreviations: DLCL, diffuse large-cell lymphoma; HT, menopausal hormone therapy; NHL, non-Hodgkin lymphoma