title: Reproductive factors and lymphoid neoplasms in Europe: findings from the EpiLymph case-control study.
abstract: BACKGROUND
  The study of lymphomagenesis has rarely focused on hormonal factors. Higher incidence rates are observed for many lymphoma subtypes in men compared with women suggesting an underlying association. Our goal was to investigate the association between reproductive factors and lymphomas.
  
  
  METHODS
  The Epilymph study is a multicenter case-control study carried out in six European countries from 1998 to 2004. Female cases of mature T-cell neoplasms (n = 52), Hodgkin lymphoma (n = 147), and mature B-cell neoplasms (n = 795), including its common subtypes, and their respective controls (n = 1,141) frequency matched by age, gender, and center were considered.
  
  
  RESULTS
  An odds reduction of 29% (95% CI -46 to -6%) was observed for mature T-cell neoplasms for each child increase among parous women and of 13% (95% CI -19 to -7%) for mature B-cell neoplasms; while no association was observed for Hodgkin lymphoma. By B-cell neoplasm subtypes, these associations were found for chronic lymphocytic leukemia/small lymphocytic lymphoma (-21%, 95% CI -31 to -9%) and diffuse large B-cell lymphoma (DLBCL; -14%; 95% CI -23 to -3%). Overall, no associations were observed with age at first and last pregnancy, and ever use of hormonal contraceptives and lymphoma. Higher odds ratios for a short-term use of hormonal contraceptives (<5 years), but not for a long-term use, were observed for mature B-cell neoplasms, DLBCL, and follicular lymphoma compared with never use.
  
  
  CONCLUSIONS
  These data support the hypothesis that increased parity confers a protective effect against lymphoma. Less clearly, our results also indicate that hormonal contraceptives could play a role.
authors: Unit of Infections and Cancer, Cancer Epidemiology Research Programme, Institut Català d' Oncologia, IDIBELL, Av Gran Via de l'Hospitalet 199-203, 08908, L'Hospitalet de Llobregat, Barcelona, Spain. lcostas@iconcologia.net
authors: Laura
authors: L
authors: Costas
authors: Delphine
authors: D
authors: Casabonne
authors: Yolanda
authors: Y
authors: Benavente
authors: Nikolaus
authors: N
authors: Becker
authors: Paolo
authors: P
authors: Boffetta
authors: Paul
authors: P
authors: Brennan
authors: Pierluigi
authors: P
authors: Cocco
authors: Lenka
authors: L
authors: Foretova
authors: Marc
authors: M
authors: Maynadié
authors: Anthony
authors: A
authors: Staines
authors: Eleanor
authors: E
authors: Kane
authors: Alexandra
authors: A
authors: Nieters
authors: Silvia
authors: S
authors: de Sanjosé
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D016403:Lymphoma, Large B-Cell, Diffuse / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011252:Pregnancy Complications, Neoplastic / Q000453:epidemiology; D015995:Prevalence; D017584:Reproductive History; D012307:Risk Factors; D055815:Young Adult