Highly elevated PSA and dietary PhIP intake in a prospective clinic-based study among African Americans

Prostate Cancer Prostatic Dis. 2007;10(3):261-9. doi: 10.1038/sj.pcan.4500941. Epub 2007 Jan 16.

Abstract

African-American men die from prostate cancer (PC) nearly twice as often as white US men and consume about twice as much of the predominant US dietary heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a genotoxic rat-prostate carcinogen found primarily in well-cooked chicken and beef. To investigate the hypothesis that PhIP exposure increases PC risk, an ongoing prospective clinic-based study compared PC screening outcomes with survey-based estimates of dietary PhIP intake among 40-70-year-old African-American men with no prior PC in Oakland, CA. They completed food-frequency and meat-cooking/consumption questionnaires and had a prostate-specific antigen (PSA) test and digital-rectal exam. Results for 392 men indicated a 17 (+/-17) ng/kg day mean (+/-1 s.d.) daily intake of PhIP, about twice that of white US men of similar age. PhIP intake was attributable mostly to chicken (61%) and positively associated (R(2)=0.32, P<0.0001) with saturated fat intake. An odds ratio (95% confidence interval) of 31 (3.1-690) for highly elevated PSA > or =20 ng/ml was observed in the highest 15% vs lowest 50% of estimated daily PhIP intake (> or =30 vs < or =10 ng/kg day) among men 50+ years old (P=0.0002 for trend) and remained significant after adjustment for self-reported family history of (brother or father) PC, saturated fat intake and total energy intake. PSA measures were higher in African-American men with positive family history (P=0.007 all men, P<0.0001 highest PSA quartile). These preliminary results are consistent with a positive association between PhIP intake and highly elevated PSA, supporting the hypothesis that dietary intervention may help reduce PC risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • African Americans*
  • Aged
  • Carcinogens*
  • Diet*
  • Humans
  • Imidazoles*
  • Male
  • Meat
  • Middle Aged
  • Prospective Studies
  • Prostate-Specific Antigen / blood*
  • Prostatic Neoplasms / epidemiology*
  • Risk Factors

Substances

  • Carcinogens
  • Imidazoles
  • 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine
  • Prostate-Specific Antigen