title: Physical activity and renal cell carcinoma among black and white Americans: a case-control study.
abstract: BACKGROUND
  Renal cell carcinoma (RCC) has a higher incidence in blacks than in whites. Physical activity may influence the risk of renal cell cancer, but the evidence is inconsistent. No previous study has investigated this relationship in the black population.
  
  
  METHODS
  We examined the association between self-reported physical activity at different ages and risk of RCC in a population based case-control study of 1217 cases (361 black, 856 white) and 1235 controls (523 black, 712 white) frequency-matched on age, race, and gender. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression.
  
  
  RESULTS
  Among whites, increased risks of RCC were observed among participants reporting low levels of transportation-related activity in their 20's (OR <1 hr/wk vs >7 hr/wk (95% CI): 1.42 (1.10, 1.83)) and leisure time activity in their 50's (OR <1 hr/wk vs >7 hr/wk (95% CI): 1.49 (1.00, 2.20)). We found no association between physical activity and RCC risk among blacks.
  
  
  CONCLUSIONS
  Our results suggest that physical activity may be inversely associated with RCC risk in whites, but there was no evidence of such an association in blacks. As this is the first study evaluating the effect of physical activity on RCC risk among blacks, further investigations are needed to clarify the relationship in this population.
authors.affiliation: Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. qian.xiao@nih.gov.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xiao
authors.forename: Linda
authors.initials: L
authors.lastname: Liao
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Faith
authors.initials: F
authors.lastname: Davis
authors.forename: Kendra
authors.initials: K
authors.lastname: Schwartz
authors.forename: Mark
authors.initials: M
authors.lastname: Purdue
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Hofmann
authors.forename: Joanne
authors.initials: J
authors.lastname: Colt
mesh_terms: D000328:Adult; D001741:Black or African American; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011159:Population Surveillance; D012307:Risk Factors; D044465:White People; D055815:Young Adult