title: Body mass index and renal cell cancer: the influence of race and sex.
abstract: BACKGROUND
  Obesity is a risk factor for renal cell (or renal) cancer. The increasing prevalence of obesity may be contributing to the rising incidence of this cancer over the past several decades. The effects of early-age obesity and change in body mass index (BMI) on renal cancer have been studied less thoroughly, and the influence of race has never been formally investigated.
  
  
  METHODS
  Using data gathered as part of a large case-control study of renal cancer (1214 cases and 1234 controls), we investigated associations with BMI at several time points, as well as with height. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed using logistic regression modeling. Race- and sex-stratified analyses were conducted to evaluate subgroup differences.
  
  
  RESULTS
  Obesity (BMI ≥ 30 kg/m) early in adulthood (OR = 1.6 [95% CI = 1.1 to 2.4]) and 5 years before diagnosis (1.6 [1.1 to 2.2]) was associated with renal cancer. The association with early-adult obesity was stronger among whites than blacks (test for interaction, P = 0.006), whereas the association with obesity near diagnosis was marginally stronger in women than men (test for interaction, P = 0.08). The strongest association with renal cancer was observed for obese whites both in early adulthood and before interview (2.6 [1.5 to 4.4]); this association was not present among blacks. Estimates of the annual excess rate of renal cancer (per 100,000 persons) attributed to both overweight and obesity (BMI > 25 kg/m) ranged from 9.9 among black men to 5.6 among white women.
  
  
  CONCLUSIONS
  Obesity, both early and later in life, is associated with an increased risk of renal cancer. The association with early obesity seems to be stronger among whites than blacks.
authors.affiliation: Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, USA. dimmerj@karmanos.org
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Beebe-Dimmer
authors.forename: Joanne S
authors.initials: JS
authors.lastname: Colt
authors.forename: Julie J
authors.initials: JJ
authors.lastname: Ruterbusch
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Keele
authors.forename: Mark P
authors.initials: MP
authors.lastname: Purdue
authors.forename: Sholom
authors.initials: S
authors.lastname: Wacholder
authors.forename: Barry I
authors.initials: BI
authors.lastname: Graubard
authors.forename: Faith
authors.initials: F
authors.lastname: Davis
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Kendra L
authors.initials: KL
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D044383:Black People / Q000706:statistics & numerical data*; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000453:epidemiology*; D016022:Case-Control Studies; D015984:Causality; D015897:Comorbidity; D004522:Educational Status; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D015994:Incidence; D007680:Kidney Neoplasms / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015146:Midwestern United States / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology*; D012307:Risk Factors; D017678:Sex Distribution; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult; D001741:Black or African American