title: Dietary carbohydrates, fiber, and breast cancer risk in Chinese women.
abstract: BACKGROUND
  Few studies have investigated the association of dietary carbohydrate and fiber intake with breast cancer risk in women in China, where carbohydrate intake is traditionally high.
  
  
  OBJECTIVE
  The objective was to prospectively evaluate the association of dietary carbohydrates, glycemic index, glycemic load, and dietary fiber with breast cancer risk and to determine whether the effect of these dietary intakes is modified by age and selected insulin- or estrogen-related risk factors.
  
  
  METHODS
  A total of 74,942 women aged 40-70 y were recruited into the Shanghai Women's Health Study, a population-based cohort study. Dietary intake was assessed by in-person interviews. A Cox proportional hazards regression model was used to evaluate associations.
  
  
  RESULTS
  During an average of 7.35 y of follow-up, 616 incident breast cancer cases were documented. A higher carbohydrate intake was associated with a higher risk of premenopausal breast cancer (P for trend = 0.002). Compared with the lowest quintile, the hazard ratios (and 95% CIs) were 1.47 (1.00, 2.32) and 2.01 (1.26, 3.19) for the fourth and fifth quintiles, respectively. A similar pattern was found for glycemic load. The association between carbohydrate intake and breast cancer was significantly modified by age; the increased breast cancer risk associated with carbohydrate intake was restricted to women who were younger than 50 y. No significant association of breast cancer risk with glycemic index or dietary fiber intake was found.
  
  
  CONCLUSIONS
  Our data suggest that a high carbohydrate intake and a diet with a high glycemic load may be associated with breast cancer risk in premenopausal women or women <50 y.
authors.affiliation: Vanderbilt Epidemiology Center, Vanderbilt University Medical Center, Nashville, TN 37203-1738, USA. wanqing.wen@vanderbilt.edu
authors.forename: Wanqing
authors.initials: W
authors.lastname: Wen
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Honglan
authors.initials: H
authors.lastname: Li
authors.forename: Gong
authors.initials: G
authors.lastname: Yang
authors.forename: Bu-Tian
authors.initials: BT
authors.lastname: Ji
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000008:administration & dosage*; D004967:Estrogens / Q000378:metabolism; D005260:Female; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood; D008875:Middle Aged; D016017:Odds Ratio; D017697:Premenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D004967:Estrogens; D007328:Insulin