title: Pre-illness isoflavone consumption and disease risk of ulcerative colitis: a multicenter case-control study in Japan.
abstract: BACKGROUND
  Previous studies have suggested that estrogens play a role in the development of ulcerative colitis (UC). Because isoflavones have a similar structure to 17β-estradiol, dietary consumption of isoflavones may have similar influences on the development of UC. We examined the association between pre-illness isoflavone consumption and the risk of UC.
  
  
  METHODS
  We conducted a hospital-based case control study, and compared the dietary habits of 126 newly diagnosed UC cases with those of 170 age- and gender-matched hospital controls. Information on dietary factors was collected using a self-administered diet history questionnaire. To consider potential changes in dietary habits due to disease symptoms, the habits were assessed separately during the previous 1 month and at 1 year before the recruitment.
  
  
  RESULTS
  In the assessment of dietary habits during the previous 1 month, the highest tertile of isoflavone consumption revealed an increased odds ratio (OR) for UC (OR = 2.79; 95% confidence interval (CI), 1.39-5.59; Trend P = 0.004). A significant association was also observed for the dietary assessment at 1 year before, when most UC cases had not yet experienced their first disease symptoms (OR = 2.06; 95% CI, 1.05-4.04; Trend P = 0.04). Associations were more pronounced in females (OR in highest tertile of isoflavone consumption at 1 year before = 4.76; 95% CI, 1.30-17.5; Trend P = 0.02) but were obscured in males (corresponding OR = 1.21; 95% CI, 0.49-3.01; Trend P = 0.63).
  
  
  CONCLUSIONS
  Dietary isoflavone consumption may be associated with an increased risk of UC, particularly in females. Prospective cohort studies are warranted to confirm these findings.
authors.affiliation: Department of Public Health, Osaka City University Faculty of Medicine, Osaka, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Ohfuji
authors.affiliation: Department of Public Health, Osaka City University Faculty of Medicine, Osaka, Japan.
authors.forename: Wakaba
authors.initials: W
authors.lastname: Fukushima
authors.affiliation: Department of Gastroenterology, Osaka City University Faculty of Medicine, Osaka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
authors.affiliation: Department of Gastroenterology, Osaka City University Faculty of Medicine, Osaka, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Yamagami
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Nagahori
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Public Health, Osaka City University Faculty of Medicine, Osaka, Japan; Clinical Epidemiology Research Center, Medical Co. LTA, Fukuoka, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hirota
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000209:etiology*; D004032:Diet; D005260:Female; D006801:Humans; D007529:Isoflavones; D007564:Japan; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D055815:Young Adult
chemical_list: D007529:Isoflavones