title: A prospective study of trans-fatty acid levels in blood and risk of prostate cancer.
abstract: BACKGROUND
  Previous studies suggest a positive association between markers of trans-fatty acid intake and prostate cancer. We therefore prospectively evaluated the association between blood trans-fatty acid levels and risk of prostate cancer.
  
  
  METHODS
  We conducted a nested case-control study among 14,916 apparently healthy men who provided blood samples in 1982. Blood fatty acid levels were determined for 476 men diagnosed with prostate cancer during a 13-year follow-up and their matched controls. Controls were individually matched to cases according to age and smoking status at baseline. Conditional logistic regression was used to estimate the relative risk and 95% confidence interval of total, nonaggressive (stage A/B and low grade), and aggressive (stage C/D, high grade, subsequent distant metastasis or death) prostate cancer associated with blood levels of specific trans-fatty acids.
  
  
  RESULTS
  Blood levels of all the trans-fatty acids examined were unrelated to total prostate cancer risk. When results were divided according to tumor aggressiveness, blood levels of 18:1n-9t, all the 18:2t examined, and total trans-fatty acids were positively associated to nonaggressive tumors. The relative risks (95% confidence intervals; P trend) comparing top with bottom quintile trans-fatty acid levels were 2.16 (1.12-4.17; 0.11) for 18:1n-9t, 1.97 (1.03-3.75; 0.01) for total 18:2t, and 2.21 (1.14-4.29; 0.06) for total trans-fatty acids. None of the trans fats examined was associated with aggressive prostate tumors.
  
  
  CONCLUSIONS
  Blood levels of trans isomers of oleic and linoleic acids are associated with an increased risk of nonaggressive prostate tumors. As this type of tumors represents a large proportion of prostate cancer detected using prostate-specific antigen screening, these findings may have implications for the prevention of prostate cancer.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. jchavarr@hsph.harvard.edu
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Chavarro
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Hannia
authors.initials: H
authors.lastname: Campos
authors.forename: Tobias
authors.initials: T
authors.lastname: Kurth
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D006801:Humans; D019787:Linoleic Acid / Q000097:blood*; D008297:Male; D008875:Middle Aged; D019301:Oleic Acid / Q000097:blood*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood* / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology
chemical_list: D019301:Oleic Acid; D019787:Linoleic Acid