title: Menstrual and Reproductive Factors and Risk of Gastric and Colorectal Cancer in Spain.
abstract: BACKGROUND
  Sex hormones play a role in gastric cancer and colorectal cancer etiology, however, epidemiological evidence is inconsistent. This study examines the influence of menstrual and reproductive factors over the risk of both tumors.
  
  
  METHODS
  In this case-control study 128 women with gastric cancer and 1293 controls, as well as 562 female and colorectal cancer cases and 1605 controls were recruited in 9 and 11 Spanish provinces, respectively. Population controls were frequency matched to cases by age and province. Demographic and reproductive data were directly surveyed by trained staff. The association with gastric, colon and rectal cancer was assessed using logistic and multinomial mixed regression models.
  
  
  RESULTS
  Our results show an inverse association of age at first birth with gastric cancer risk (five-year trend: OR = 0.69; p-value = 0.006). Ever users of hormonal contraception presented a decreased risk of gastric (OR = 0.42; 95%CI = 0.26-0.69), colon (OR = 0.64; 95%CI = 0.48-0.86) and rectal cancer (OR = 0.61; 95%CI = 0.43-0.88). Postmenopausal women who used hormone replacement therapy showed a decreased risk of colon and rectal tumors. A significant interaction of educational level with parity and months of first child lactation was also observed.
  
  
  CONCLUSIONS
  These findings suggest a protective role of exogenous hormones in gastric and colorectal cancer risk. The role of endogenous hormones remains unclear.
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.|Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS Puerta de Hierro (IDIPHIM), Madrid 28222, Spain.
authors: Virginia
authors: V
authors: Lope
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Nerea
authors: N
authors: Fernández de Larrea
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.|Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS Puerta de Hierro (IDIPHIM), Madrid 28222, Spain.
authors: Beatriz
authors: B
authors: Pérez-Gómez
authors: Grupo de Investigación en Interacciones Gen-Ambiente y Salud, Universidad de León, León 24071, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Vicente
authors: V
authors: Martín
authors: IDIBELL-Catalan Institute of Oncology, L'Hospitalet de Llobregat, Barcelona 08907, Spain.|Department of Clinical Sciences, Faculty of Medicine, University of Barcelona, L'Hospitalet del Llobregat, Barcelona 08907, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Victor
authors: V
authors: Moreno
authors: Unit of Infections and Cancer, Cancer Epidemiology Research Programme, IDIBELL, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Barcelona 08907, Spain.|Department of Medicine, University of Barcelona, L'Hospitalet del Llobregat, Barcelona 08907, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Laura
authors: L
authors: Costas
authors: Medical Oncology Department, Hospital Universitario Ramón y Cajal, Madrid 28034, Spain.
authors: Federico
authors: F
authors: Longo
authors: Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA)-Granada Health Research Institute (ibs.GRANADA), Granada 18012, Spain.|Department of Preventive Medicine and Public Health, University of Granada, Granada 18016, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: José Juan
authors: JJ
authors: Jiménez-Moleón
authors: Universidad de Cantabria-IDIVAL, Santander 39011, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Javier
authors: J
authors: Llorca
authors: Navarra Breast Cancer Screening Programme, Public Health Institute, Pamplona 31003, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Nieves
authors: N
authors: Ascunce
authors: Cancer and Public Health Area, Fundación Para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO), Valencia 46020, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Rosana
authors: R
authors: Peiró-Pérez
authors: Public Health Division of Gipuzkoa, Donostia 20013, San Sebastián, Spain.|Biodonostia Research Institute, Donostia 20014, San Sebastián, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Jone M
authors: JM
authors: Altzibar
authors: Instituto Universitario de Oncología, Universidad de Oviedo, Oviedo 33006, Asturias, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Adonina
authors: A
authors: Tardón
authors: Centro de Investigación en Salud y Medio Ambiente (CYSMA), Universidad de Huelva, Huelva 21071, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Juan
authors: J
authors: Alguacil
authors: Department of Epidemiology, Murcia Regional Health Council, IMIB-Arrixaca, Murcia 30008, Spain.|Department of Health and Social Sciences. Universidad de Murcia, Murcia 30003, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Carmen
authors: C
authors: Navarro
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.|Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS Puerta de Hierro (IDIPHIM), Madrid 28222, Spain.
authors: Ángeles
authors: Á
authors: Sierra
authors: Gastroenterology, Hospital de Viladecans, Viladecans, Barcelona 08840, Spain.
authors: Ana Belén
authors: AB
authors: Vega
authors: Servicio de Cirugía, Complejo Asistencial Universitario de León, León 24071, Spain.
authors: Amaya
authors: A
authors: Villafañe
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona 08003, Spain.|IMIM (Hospital del Mar Medical Research Institute), Barcelona 08003, Spain.|Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Gemma
authors: G
authors: Castaño-Vinyals
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona 08003, Spain.|IMIM (Hospital del Mar Medical Research Institute), Barcelona 08003, Spain.|Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.
authors: Manolis
authors: M
authors: Kogevinas
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.|Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS Puerta de Hierro (IDIPHIM), Madrid 28222, Spain.
authors: Marina
authors: M
authors: Pollán
authors: Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid 28029, Spain.|Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública, CIBERESP), Madrid 28029, Spain.|Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS Puerta de Hierro (IDIPHIM), Madrid 28222, Spain.
authors: Nuria
authors: N
authors: Aragonés
mesh_terms: D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008598:Menstruation; D017584:Reproductive History; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000503:physiopathology