title: Early Life Residence, Fish Consumption, and Risk of Breast Cancer.
abstract: Background:Little is known about fish intake throughout the life course and the risk of breast cancer.Methods:We used data on the first residence of 9,340 women born 1908 to 1935 in the Reykjavik Study as well as food frequency data for different periods of life from a subgroup of the cohort entering the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (n= 2,882).Results:During a mean follow-up of 27.3 years, 744 women were diagnosed with breast cancer in the Reykjavik Study. An inverse association of breast cancer was observed among women who lived through the puberty period in coastal villages, compared with women residing in the capital area [HR, 0.78; 95% confidence interval (CI), 0.61-0.99]. In the subgroup analysis of this Icelandic population, generally characterized by high fish intake, we found an indication of lower risk of breast cancer among women with high fish consumption (more than 4 portions per week) in adolescence (HR, 0.71; 95% CI, 0.44-1.13) and midlife (HR, 0.46; 95% CI, 0.22-0.97), compared with low consumers (2 portions per week or less). No association was found for fish liver oil consumption in any time period, which could be due to lack of a reference group with low omega-3 fatty acids intake in the study group.Conclusions:Our findings suggest that very high fish consumption in early to midlife may be associated with a reduced risk of breast cancer.Impact:Very high fish consumption in early adulthood to midlife may be associated with decreased risk of breast cancer.Cancer Epidemiol Biomarkers Prev; 26(3); 346-54. ©2016 AACR.
authors.affiliation: Faculty of Food Science and Human Nutrition, University of Iceland, Reykjavik, Iceland. alh1@hi.is.|Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Alfheidur
authors.initials: A
authors.lastname: Haraldsdottir
authors.affiliation: Faculty of Food Science and Human Nutrition, University of Iceland, Reykjavik, Iceland.|Unit for Nutrition Research, University of Iceland and Landspitali National University Hospital Reykjavik, Reykjavik, Iceland.
authors.forename: Laufey
authors.initials: L
authors.lastname: Steingrimsdottir
authors.affiliation: Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Unnur A
authors.initials: UA
authors.lastname: Valdimarsdottir
authors.affiliation: Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|The Icelandic Heart Association, Kopavogur, Iceland.
authors.forename: Thor
authors.initials: T
authors.lastname: Aspelund
authors.affiliation: The Icelandic Cancer Registry, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Laufey
authors.initials: L
authors.lastname: Tryggvadottir
authors.affiliation: Laboratory of Epidemiology and Population Sciences, Intramural Research Program, National Institute on Aging, Bethesda, Maryland.
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.affiliation: Laboratory of Epidemiology and Population Sciences, Intramural Research Program, National Institute on Aging, Bethesda, Maryland.
authors.forename: Lenore J
authors.initials: LJ
authors.lastname: Launer
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Lorelei A
authors.initials: LA
authors.lastname: Mucci
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.|Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: Edward L
authors.initials: EL
authors.lastname: Giovannucci
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
authors.affiliation: The Icelandic Heart Association, Kopavogur, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.affiliation: Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|Unit for Nutrition Research, University of Iceland and Landspitali National University Hospital Reykjavik, Reykjavik, Iceland.
authors.forename: Johanna E
authors.initials: JE
authors.lastname: Torfadottir
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000818:Animals; D001943:Breast Neoplasms / Q000453:epidemiology*; D015525:Fatty Acids, Omega-3; D005247:Feeding Behavior; D005260:Female; D005395:Fish Oils; D005399:Fishes; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008137:Longitudinal Studies; D008572:Menarche; D008875:Middle Aged; D011159:Population Surveillance; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012111:Residence Characteristics; D012307:Risk Factors; D017747:Seafood; D011795:Surveys and Questionnaires
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils