title: Dietary glycemic index, glycemic load, and the risk of breast cancer in an Italian prospective cohort study.
abstract: BACKGROUND
  Interest in the roles of glycemic index (GI) and glycemic load (GL) in breast cancer etiology has been stimulated by indications that disease risk is linked to insulinemia, sex hormone bioavailability, and insulin-like growth factor 1.
  
  
  OBJECTIVE
  We aimed to determine whether GI and GL were associated with the risk of breast cancer in a cohort of Italian women volunteers from Northern Italy, who enrolled between 1987-1992 in the Hormones and Diet in the Etiology of Breast Tumors Study (ORDET Study).
  
  
  METHODS
  Volunteers completed a semiquantitative food-frequency questionnaire, and anthropometric and lifestyle data were collected. Dietary GI and GL in relation to breast cancer risk were examined in 8926 cohort women, including 289 with breast cancer identified after a mean follow-up of 11.5 y.
  
  
  RESULTS
  The relative risk (RR) of breast cancer in the highest (versus lowest) quintiles of GI and GL was 1.57 (95% CI: 1.04, 2.36; P for trend = 0.040) and 2.53 (95% CI: 1.54, 4.16; P for trend = 0.001), respectively. Total carbohydrate intake was not associated with greater breast cancer risk, but high carbohydrate from high-GI foods was. When women were categorized by baseline menopausal status and body mass index (BMI; in kg/m(2)), the increased risk of dietary GL was confined to those who were premenopausal (RR = 3.89; 95% CI: 1.81, 8.34) and who had normal BMI (ie, <25) (RR = 5.79; 95% CI: 2.60, 12.90) (P for trend = 0.001 for both).
  
  
  CONCLUSIONS
  A high-GL diet may increase the risk of breast cancer in Italian women. The effect is particularly evident in premenopausal women and those with BMI < 25.
authors.affiliation: Nutritional Epidemiology Unit, National Cancer Institute, Milan, Italy. sabina.sieri@istitutotumori.mi.it
authors.forename: Sabina
authors.initials: S
authors.lastname: Sieri
authors.forename: Valeria
authors.initials: V
authors.lastname: Pala
authors.forename: Furio
authors.initials: F
authors.lastname: Brighenti
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Pellegrini
authors.forename: Paola
authors.initials: P
authors.lastname: Muti
authors.forename: Andrea
authors.initials: A
authors.lastname: Micheli
authors.forename: Alberto
authors.initials: A
authors.lastname: Evangelista
authors.forename: Sara
authors.initials: S
authors.lastname: Grioni
authors.forename: Paolo
authors.initials: P
authors.lastname: Contiero
authors.forename: Franco
authors.initials: F
authors.lastname: Berrino
authors.forename: Vittorio
authors.initials: V
authors.lastname: Krogh
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000378:metabolism; D015331:Cohort Studies; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000145:classification / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D038321:Glycemic Index; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D010809:Physical Fitness; D017698:Postmenopause; D017697:Premenopause / Q000502:physiology*; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D012739:Gonadal Steroid Hormones; D007328:Insulin; D007334:Insulin-Like Growth Factor I