title: Dietary pattern and breast cancer risk in Japanese women: the Japan Public Health Center-based Prospective Study (JPHC Study).
abstract: Evidence that diet is associated with breast cancer risk is inconsistent. Most of the studies have focused on risks associated with specific foods and nutrients, rather than overall diet. In this study, we aimed to evaluate the association between dietary patterns and breast cancer risk in Japanese women. A total of 49 552 Japanese women were followed-up from 1995 to 1998 (5-year follow-up survey) until the end of 2012 for an average of 14·6 years. During 725 534 person-years of follow-up, 718 cases of breast cancer were identified. We identified three dietary patterns (prudent, westernised and traditional Japanese). The westernised dietary pattern was associated with a 32 % increase in breast cancer risk (hazard ratios (HR) 1·32; 95 % CI 1·03, 1·70; P trend=0·04). In particular, subjects with extreme intake of the westernised diet (quintile (Q) Q5_5th) had an 83 % increase in risk of breast cancer in contrast to those in the lowest Q1 (HR 1·83; 95 % CI 1·25, 2·68; P trend=0·01). In analyses stratified by menopausal status, postmenopausal subjects in the highest quintile of the westernised dietary pattern had a 29 % increased risk of breast cancer (HR 1·29; 95 % CI 0·99, 1·76; P trend=0·04). With regard to hormone receptor status, the westernised dietary pattern was associated with an increased risk of oestrogen receptor-positive/progesterone receptor-positivetumours (HR 2·49; 95 % CI 1·40, 4·43; P trend<0·01). The other dietary patterns were not associated with the risk of breast cancer in Japanese women. A westernised dietary pattern is associated with an increased risk of breast cancer in Japanese women.
authors.affiliation: 1Graduate School of Medicine,The University of Tokyo,7-3-1 Hongo,Bunkyo-ku,Tokyo 113-0033,Japan.
authors.forename: Sangah
authors.initials: S
authors.lastname: Shin
authors.affiliation: 1Graduate School of Medicine,The University of Tokyo,7-3-1 Hongo,Bunkyo-ku,Tokyo 113-0033,Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Saito
authors.affiliation: 1Graduate School of Medicine,The University of Tokyo,7-3-1 Hongo,Bunkyo-ku,Tokyo 113-0033,Japan.
authors.forename: Manami
authors.initials: M
authors.lastname: Inoue
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.affiliation: 3Department of Nutrition Science,Sagami Women's University,2-1-1 Bunkyo,Minami-ku,Sagamihara 252-0383,Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Ishihara
authors.affiliation: 4Department of Food Science and Nutrition, Faculty of Human Life and Environment,Nara Women's University,Kitauoyanishi-machi,Nara 630-8506,Japan.
authors.forename: Ribeka
authors.initials: R
authors.lastname: Takachi
authors.affiliation: 5Department of Epidemiology and Prevention,International Clinical Research Center,National Center for Global Health and Medicine,1-21-1 Toyama,Shinjuku-ku,Tokyo 162-8655,Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Nanri
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Taichi
authors.identifier: http://orcid.org/0000-0001-6000-9830
authors.initials: T
authors.lastname: Shimazu
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Taiki
authors.initials: T
authors.lastname: Yamaji
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sasazuki
authors.affiliation: 2Epidemiology and Prevention Group,Research Center for Cancer Prevention and Screening,National Cancer Center,5-1-1 Tsukiji,Chuo-ku,Tokyo 104-0045,Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology*; D004032:Diet; D004034:Diet Surveys; D066273:Diet, Western / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D009043:Motor Activity; D015596:Nutrition Assessment; D025341:Principal Component Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011634:Public Health; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: Breast cancer; Cohort studies; Dietary patterns; ER oestrogen receptor; Epidemiological studies; Factor analyses; PR progesterone receptor; Q quintile