title: Reliability of fatty acid composition in human serum phospholipids.
abstract: OBJECTIVE
  We examined the reliability of the fatty acid composition of serum phospholipids in the New York University Women's Health Study, a prospective study of sex hormones, diet and breast cancer.
  
  
  METHODS
  Non-fasting serum samples collected at three yearly visits, in 46 healthy women, and stored at -80 degrees C for 7-12 y, were included in the study. Serum phospholipid fatty acid composition was measured by capillary gas chromatography.
  
  
  RESULTS
  For the 20 individual fatty acids measured, the reliability coefficients were less than 0.50 for four, between 0.50 and 0.70 for nine, and greater than 0.70 for seven. Among the major fatty acids, arachidonic and alpha-linolenic acids had high reliability coefficients (0.71 and 0. 72, respectively), palmitic, oleic, linoleic, eicosapentaenoic and docosahexaenoic acids had intermediate coefficients (0.57, 0.69, 0. 62, 0.64 and 0.66, respectively), whereas stearic acid had the lowest coefficient (0.15). The reliability coefficients for total monounsaturated fats, omega-6 and omega-3 fatty acids were moderately high (0.66, 0.53 and 0.66, respectively), whereas the coefficients for total saturated fats and total polyunsaturated fats were low (0.31 and 0.43, respectively).
  
  
  CONCLUSIONS
  These results indicate that the fatty acid composition of serum phospholipids can be a useful tool in epidemiologic studies, although for most fatty acids a single determination is associated with some error in measurement that should be taken into account at the design and analysis stages. Storage for up to 12 y at -80 degrees C preserved polyunsaturated fatty acids from oxidation very well.
authors.affiliation: Nelson Institute of Environmental Medicine, New York University Medical Center, New York, NY 10016-3240, USA. jacqua02@popmail.med.nyu.edu
authors.forename: A
authors.initials: A
authors.lastname: Zeleniuch-Jacquotte
authors.forename: V
authors.initials: V
authors.lastname: Chajès
authors.forename: A L
authors.initials: AL
authors.lastname: Van Kappel
authors.forename: E
authors.initials: E
authors.lastname: Riboli
authors.forename: P
authors.initials: P
authors.lastname: Toniolo
mesh_terms: D000328:Adult; D000368:Aged; D016718:Arachidonic Acid / Q000097:blood; D002849:Chromatography, Gas / Q000379:methods; D015930:Diet Records; D004041:Dietary Fats / Q000008:administration & dosage; D005227:Fatty Acids / Q000097:blood*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood*; D011446:Prospective Studies; D011786:Quality Control; D015203:Reproducibility of Results; D017962:alpha-Linolenic Acid / Q000097:blood
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D010743:Phospholipids; D017962:alpha-Linolenic Acid; D016718:Arachidonic Acid