title: Body mass index effects on risk of ovarian cancer: a meta- analysis.
abstract: OBJECTIVE
  The association between body mass index (BMI) and ovarian cancer risk is unclear and requires further investigation. The present meta-analysis was conducted to assess the effect of overweight and obesity on ovarian cancer risk in the premenopausal and postmenopausal periods.
  
  
  METHODS
  Major electronic databases were searched until February 2014 including Medline and Scopus. Reference lists and relevant conference databases were searched and the authors were contacted for additional unpublished references.
  
  
  METHODS
  All cohort and case-control studies addressing the effect of BMI on ovarian cancer were included, irrespective of publication date and language. The effect measure of choice was risk ratio (RR) for cohort studies and odds ratio (OR) for case-control studies. The results were reported using a random effects model with 95% confidence intervals (CIs).
  
  
  RESULTS
  Of 3,776 retrieved studies, 19 were ultimately analyzed including 10 cohort studies involving 29,237,219 person-years and 9 case-control studies involving 96,965 people. The results of both cohort and case-control studies showed being overweight and obesity increased the risk of ovarian cancer compared to women with normal weight during both premenopausal and postmenopausal periods: RR=1.08 (95%CI: 0.97, 1.19) and OR=1.26 (95%CI: 0.97, 1.63) for overweight and RR=1.27 (95%CI: 1.16, 1.38) and OR=1.26 (95%CI: 1.06, 1.50) for obesity.
  
  
  CONCLUSIONS
  There is sufficient evidence that an increase in BMI can increase the risk of ovarian cancer regardless of the menopausal status, mimicking a dose-response relationship although the association is not very strong.
authors.affiliation: Modeling of Noncommunicable Diseases Research Center, Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran E-mail : en.jenabi@yahoo.com.
authors.forename: Jalal
authors.initials: J
authors.lastname: Poorolajal
authors.forename: Ensiyeh
authors.initials: E
authors.lastname: Jenabi
authors.forename: Seyyedeh Zahra
authors.initials: SZ
authors.lastname: Masoumi
mesh_terms: D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D009765:Obesity / Q000150:complications*; D010051:Ovarian Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D017698:Postmenopause / Q000502:physiology; D017697:Premenopause / Q000502:physiology; D011379:Prognosis; D012307:Risk Factors