title: Serum zinc and prostate cancer risk in a nested case-control study: The multiethnic cohort.
abstract: BACKGROUND
  Experimental studies have provided evidence that zinc has a protective effect against development and progression of prostate cancer. However, epidemiological studies have reported inconsistent findings. We evaluated the association between prediagnostic serum zinc and prostate cancer risk in a cohort of multiethnic population.
  
  
  METHODS
  This case-control study is nested within the Multiethnic Cohort of African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites in Hawaii and California. The analysis included 392 prostate cancer cases and 783 controls matched on age, race/ethnicity, date/time of blood draw and fasting status. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI).
  
  
  RESULTS
  The mean serum zinc concentrations did not significantly differ between cases (94.9 µg/dl) and controls (93.9 µg/dl). No association was found between serum zinc levels and prostate cancer either overall or by tumor stage/grade. In ethnic-specific analyses, positive associations were found in Japanese Americans (OR for the highest vs. the lowest tertile = 2.59, 95% CI: 1.09-6.17) and Latinos (OR = 2.74, 95% CI: 1.05-7.10), whereas no association was observed in African Americans and whites.
  
  
  CONCLUSIONS
  We found no evidence to support an inverse relationship between serum zinc and prostate cancer risk, and, to the contrary, found a suggestion in the ethnic-specific results of a possible increase in risk; however, blood concentrations of zinc may not adequately reflect the levels in prostate tissue. Further study with a larger sample size, and if possible, with assessment of zinc tissue levels, is warranted to confirm these findings.
authors.affiliation: Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii, USA. spark@cc.hawaii.edu
authors.forename: Song-Yi
authors.initials: SY
authors.lastname: Park
authors.forename: Lynne R
authors.initials: LR
authors.lastname: Wilkens
authors.forename: J Steven
authors.initials: JS
authors.lastname: Morris
authors.forename: Brian E
authors.initials: BE
authors.lastname: Henderson
authors.forename: Laurence N
authors.initials: LN
authors.lastname: Kolonel
mesh_terms: D001741:Black or African American / Q000208:ethnology; D000368:Aged; D001213:Asian / Q000208:ethnology; D015415:Biomarkers / Q000097:blood; D002140:California; D016022:Case-Control Studies; D015331:Cohort Studies; D006254:Hawaii; D006630:Hispanic or Latino / Q000208:ethnology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D044468:Native Hawaiian or Pacific Islander / Q000208:ethnology; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology*; D012307:Risk Factors; D044465:White People / Q000208:ethnology; D015032:Zinc / Q000097:blood*
chemical_list: D015415:Biomarkers; D015032:Zinc