title: Association among Dietary Flavonoids, Flavonoid Subclasses and Ovarian Cancer Risk: A Meta-Analysis.
abstract: BACKGROUND
  Previous studies have indicated that intake of dietary flavonoids or flavonoid subclasses is associated with the ovarian cancer risk, but presented controversial results. Therefore, we conducted a meta-analysis to derive a more precise estimation of these associations.
  
  
  METHODS
  We performed a search in PubMed, Google Scholar and ISI Web of Science from their inception to April 25, 2015 to select studies on the association among dietary flavonoids, flavonoid subclasses and ovarian cancer risk. The information was extracted by two independent authors. We assessed the heterogeneity, sensitivity, publication bias and quality of the articles. A random-effects model was used to calculate the pooled risk estimates.
  
  
  RESULTS
  Five cohort studies and seven case-control studies were included in the final meta-analysis. We observed that intake of dietary flavonoids can decrease ovarian cancer risk, which was demonstrated by pooled RR (RR = 0.82, 95% CI = 0.68-0.98). In a subgroup analysis by flavonoid subtypes, the ovarian cancer risk was also decreased for isoflavones (RR = 0.67, 95% CI = 0.50-0.92) and flavonols (RR = 0.68, 95% CI = 0.58-0.80). While there was no compelling evidence that consumption of flavones (RR = 0.86, 95% CI = 0.71-1.03) could decrease ovarian cancer risk, which revealed part sources of heterogeneity. The sensitivity analysis indicated stable results, and no publication bias was observed based on the results of Funnel plot analysis and Egger's test (p = 0.26).
  
  
  CONCLUSIONS
  This meta-analysis suggested that consumption of dietary flavonoids and subtypes (isoflavones, flavonols) has a protective effect against ovarian cancer with a reduced risk of ovarian cancer except for flavones consumption. Nevertheless, further investigations on a larger population covering more flavonoid subclasses are warranted.
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Hua
authors.affiliation: Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Lili
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Ruxu
authors.initials: R
authors.lastname: You
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liao
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, PR China.
authors.forename: Lixiu
authors.initials: L
authors.lastname: Yu
mesh_terms: D000818:Animals; D004032:Diet; D005260:Female; D005419:Flavonoids / Q000378:metabolism*; D006801:Humans; D010051:Ovarian Neoplasms / Q000453:epidemiology*; D012307:Risk Factors
chemical_list: D005419:Flavonoids