title: Highly elevated PSA and dietary PhIP intake in a prospective clinic-based study among African Americans.
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.
authors.affiliation: Lawrence Livermore National Laboratory, Energy and Environment Directorate, University of California, 7000 East Avenue, Livermore, CA 94550, USA. bogen@LLNL.gov
authors.forename: K T
authors.initials: KT
authors.lastname: Bogen
authors.forename: G A
authors.initials: GA
authors.lastname: Keating
authors.forename: J M
authors.initials: JM
authors.lastname: Chan
authors.forename: L J
authors.initials: LJ
authors.lastname: Paine
authors.forename: E L
authors.initials: EL
authors.lastname: Simms
authors.forename: D O
authors.initials: DO
authors.lastname: Nelson
authors.forename: E A
authors.initials: EA
authors.lastname: Holly
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D002273:Carcinogens; D004032:Diet; D006801:Humans; D007093:Imidazoles; D008297:Male; D008460:Meat; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000453:epidemiology*; D012307:Risk Factors
chemical_list: D002273:Carcinogens; D007093:Imidazoles; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; D017430:Prostate-Specific Antigen