title: Nighttime eating and breast cancer among Chinese women in Hong Kong.
abstract: A novel line of research suggests that eating at nighttime may have several metabolic consequences that are highly relevant to breast cancer. We investigated the association between nighttime eating habits after 10 p.m. and breast cancer in Hong Kong women.
  
  
  
  A hospital-based case-control study was conducted during 2012-2015. A total of 922 patients with incident breast cancer (cases) and 913 hospital controls were recruited and interviewed using a standard questionnaire including information on eating behavior during both daytime and nighttime. We collected the timing, duration, types and frequencies of food intake of eating at nighttime. Odds ratios (ORs) for the risk of breast cancer in relation to nighttime eating-related variables were calculated by unconditional multivariable logistic regression.
  
  
  
  Eating at night after 10 pm was significantly associated with breast cancer with an adjusted OR of 1.50 (95% confidence interval (CI) 1.06-2.12, P = 0.02), and the associations were stronger in women who had the longest duration of nighttime eating (≥20 years) (adjusted OR = 2.28 (95% CI 1.13-4.61, P = 0.02) and who ate late (midnight to 2 a.m.) (adjusted OR = 2.73, 95% CI 1.01-6.99, P = 0.04). Interestingly, nighttime eating was only associated with breast cancer among women who consumed staple foods (OR = 2.16, 95% CI 1.42-3.29, P < 0.001) but not those who ate vegetables or fruits as nighttime meals. The significant association between nighttime eating and breast cancer was observed among women with body mass index (BMI) <25 (OR = 2.29, 95% CI 1.48-3.52, P < 0.001) but not among women with BMI ≥25.
  
  
  
  Results from this study suggest a possible association between nighttime eating behavior and breast cancer. These findings need to be confirmed by independent large studies.
authors.affiliation: JC School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Mengjie
authors.initials: M
authors.lastname: Li
authors.affiliation: JC School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, China. shelly@cuhk.edu.hk.
authors.forename: Lap Ah
authors.initials: LA
authors.lastname: Tse
authors.affiliation: Department of Surgery, North District Hospital, Hong Kong SAR, China.
authors.forename: Wing-Cheong
authors.initials: WC
authors.lastname: Chan
authors.affiliation: Department of Oncology, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: Chi-Hei
authors.initials: CH
authors.lastname: Kwok
authors.affiliation: Department of Surgery, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China.
authors.forename: Siu-Lan
authors.initials: SL
authors.lastname: Leung
authors.affiliation: Department of Pathology, North District Hospital, Hong Kong SAR, China.
authors.forename: Cherry
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Medicine, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: Wai-Cho
authors.initials: WC
authors.lastname: Yu
authors.affiliation: JC School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Priscilla Ming-Yi
authors.initials: PM
authors.lastname: Lee
authors.affiliation: Department of Pathology, Yan Chai Hospital, Hong Kong SAR, China.
authors.forename: Koon-Ho
authors.initials: KH
authors.lastname: Tsang
authors.affiliation: Department of Surgery, Yan Chai Hospital, Hong Kong SAR, China.
authors.forename: Sze-Hong
authors.initials: SH
authors.lastname: Law
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Vermeulen
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, USA.
authors.forename: Fangyi
authors.initials: F
authors.lastname: Gu
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, USA.
authors.forename: Neil E
authors.initials: NE
authors.lastname: Caporaso
authors.affiliation: JC School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ignatius Tak-Sun
authors.initials: IT
authors.lastname: Yu
authors.affiliation: JC School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, USA.
authors.forename: Xiaohong Rose
authors.initials: XR
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D015897:Comorbidity; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011159:Population Surveillance; D012306:Risk; D013997:Time Factors; D055815:Young Adult
keywords: Breast cancer; Dietary factors; Nighttime eating behavior