title: Serum leptin and adiponectin levels and risk of renal cell carcinoma.
abstract: OBJECTIVE
  The incidence of renal cell carcinoma (RCC) has increased rapidly in the U.S., particularly among African Americans. Despite a well-established link between obesity and RCC, the mechanism through which obesity increases cancer risk has yet to be established. Adipokines, such as leptin and adiponectin, may link obesity and cancer, with different quantitative effects by race.
  
  
  METHODS
  We evaluated the association between leptin and adiponectin concentrations and RCC risk among Caucasians (581 cases, 558 controls) and African Americans (187 cases, 359 controls) in a case-control study conducted in Detroit and Chicago. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated using unconditional logistic regression.
  
  
  RESULTS
  Among controls, Caucasians had higher median adiponectin than African Americans (males: 8.2 vs. 7.0 μg/ml, P = 0.001; females: 13.4 vs. 8.4 μg/ml, P < 0.0001), and lower median leptin than African Americans (males: 11.8 vs. 14.1 ng/ml, P = 0.04; females: 28.3 vs. 45.9 ng/ml, P < 0.0001). Among Caucasians, the ORs for RCC comparing the highest (Q4) to the lowest (Q1) sex-specific quartile of leptin were 3.2 (95% CI: 1.9-5.2) for males and 4.7 (95% CI: 2.6-8.6) for females. Serum leptin was not significantly associated with RCC among African American males (OR 1.5, 95% CI: 0.7-3.1) or females (OR 2.1, 95% CI: 0.8-5.5). Higher adiponectin was associated with RCC risk among African American males (Q4 vs. Q1: OR 2.3, 95% CI: 1.1-4.6) and females (OR 2.1, 95% CI: 1.2-6.7), but not significantly among Caucasian males (OR 1.6, 95% CI: 0.99-2.7) and females (OR 1.6, 95% CI: 0.9-3.1).
  
  
  CONCLUSIONS
  We observed an association between both leptin and adiponectin concentrations and risk of RCC, which may differ by race. Confirmation in further investigations is needed.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA. liaolm@mail.nih.gov
authors.forename: Linda M
authors.initials: LM
authors.lastname: Liao
authors.forename: Kendra
authors.initials: K
authors.lastname: Schwartz
authors.forename: Michael
authors.initials: M
authors.lastname: Pollak
authors.forename: Barry I
authors.initials: BI
authors.lastname: Graubard
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Julie
authors.initials: J
authors.lastname: Ruterbusch
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Rothman
authors.forename: Faith
authors.initials: F
authors.lastname: Davis
authors.forename: Sholom
authors.initials: S
authors.lastname: Wacholder
authors.forename: Joanne
authors.initials: J
authors.lastname: Colt
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Mark P
authors.initials: MP
authors.lastname: Purdue
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001741:Black or African American; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000097:blood* / Q000453:epidemiology*; D016022:Case-Control Studies; D002641:Chicago; D005260:Female; D006801:Humans; D015994:Incidence; D020738:Leptin / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000453:epidemiology; D016017:Odds Ratio; D012307:Risk Factors; D044465:White People; D055815:Young Adult
chemical_list: D052242:Adiponectin; D020738:Leptin