title: Obesity is associated with increased relative risk of diffuse large B-cell lymphoma: a meta-analysis of observational studies.
abstract: BACKGROUND
  The relation between body mass index (BMI) and incidence of diffuse large B-cell lymphoma (DLBCL) has been suggested, but no systematic review has been undertaken.
  
  
  METHODS
  We performed a literature search through December 2012. Meta-analyses were performed to quantify the relative risk (RR) of DLBCL incidence in overweight and obese persons compared with normal weight individuals using the random-effects model. Subset analyses were performed according to study design, sex, and geographic region. Overweight was defined as a BMI 25 to 29.9 kg/m(2), and obesity was defined as a BMI of 30 kg/m(2). Meta-regression, using an unrestricted maximum likelihood model, was performed to evaluate the linear association between BMI and odds of DLBCL.
  
  
  RESULTS
  Our study included 6 case-control and 10 cohort studies. The RR of DLBCL in overweight individuals was 1.14 (95% confidence interval [CI], 1.04-1.24; P = .004), and in obese individuals, RR was 1.29 (95% CI, 1.16-1.43; P < .001). The RR of DLBCL in overweight men and women was 1.22 and 1.27, respectively. In overweight individuals, both prospective and case-control studies showed an RR of 1.13. The RR of DLBCL in obese men and women was 1.40 and 1.34, respectively. In obese individuals, the RR in prospective studies was 1.25 and in case-control studies it was 1.33. Meta-regression analysis showed a 14% increase in DLBCL incidence for each 10 kg/m(2) increase in BMI.
  
  
  CONCLUSIONS
  An increased BMI is associated with higher RR of DLBCL regardless of sex. Also, there seems to be a linear association between BMI and DLBCL incidence.
authors.affiliation: Division of Hematologic Malignancies, Dana Farber Cancer Institute, Boston, MA. Electronic address: jorgej_castillo@dfci.harvard.edu.
authors.forename: Jorge J
authors.initials: JJ
authors.lastname: Castillo
authors.affiliation: Division of Hematology and Oncology, Rhode Island Hospital, Providence, RI.
authors.forename: Randall R
authors.initials: RR
authors.lastname: Ingham
authors.affiliation: Division of Hematology and Oncology, Rhode Island Hospital, Providence, RI.
authors.forename: John L
authors.initials: JL
authors.lastname: Reagan
authors.affiliation: Department of Medicine, Rhode Island Hospital, Providence, RI.
authors.forename: Michael
authors.initials: M
authors.lastname: Furman
authors.affiliation: Division of Hematology and Oncology, Moffitt Cancer Center and Research Institute, Tampa, FL.
authors.forename: Samir
authors.initials: S
authors.lastname: Dalia
authors.affiliation: Service of Endocrinology, Prima CARE, Fall River, MA.
authors.forename: Joanna
authors.initials: J
authors.lastname: Mitri
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000209:etiology*; D008297:Male; D009765:Obesity / Q000150:complications*; D064887:Observational Studies as Topic; D050177:Overweight / Q000150:complications; D012044:Regression Analysis; D012307:Risk Factors
keywords: Body mass index; Epidemiology; Lymphoma; Meta-analysis; Obesity