title: Circulating biomarkers of dairy fat and risk of incident stroke in U.S. men and women in 2 large prospective cohorts.
abstract: BACKGROUND
  Previous observational studies of self-reported dairy product consumption and stroke risk have reported mixed findings. Few studies have used circulating biomarkers that provide objective measures of dairy fat intake.
  
  
  OBJECTIVE
  We tested the hypothesis that the circulating biomarkers of dairy fat, pentadecanoic acid (15:0), heptadecanoic acid (17:0), and trans palmitoleate (trans 16:1n-7), were associated with lower incidence of stroke, especially ischemic stroke. Secondarily, we evaluated 14:0, which is obtained from dairy products and beef, and also endogenously synthesized.
  
  
  METHODS
  In participants from 2 large US cohorts (the Health Professionals Follow-Up Study: 51,529 men; the Nurses' Health Study: 121,700 women) with stored blood samples in 1993-1994 (n = 18,225) and 1989-1990 (n = 32,826), respectively, we prospectively identified 594 incident stroke cases (median follow-up: 8.3 y) and matched them 1:1 to risk-set-sampled control subjects by age, sex, race, and smoking. Total plasma and red blood cell (RBC) fatty acids were measured by using gas-liquid chromatography. Covariates were assessed by using validated questionnaires. Stroke events and subtypes were adjudicated by using medical records or other supporting documentation. We used conditional logistic regression to estimate associations of fatty acids with incident stroke, and cohort-specific findings were combined by inverse-variance weights.
  
  
  RESULTS
  After adjustment for demographic characteristics, lifestyle, cardiovascular disease risk factors, diet, and other circulating fatty acids, no significant associations with total stroke were seen for plasma 15:0 (pooled HR for highest compared with lowest quartiles: 0.85; 95% CI: 0.54, 1.33), 17:0 (0.99; 0.67, 1.49), trans 16:1 n-7 (0.89; 0.55, 1.45), or 14:0 (1.05; 0.62, 1.78). Results were similar for ischemic and hemorrhagic stroke subtypes, for RBC fatty acids, and in several different sensitivity analyses.
  
  
  CONCLUSIONS
  In 2 large prospective cohorts, circulating biomarkers of dairy fat were not significantly associated with stroke.
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Mohammad Y
authors.initials: MY
authors.lastname: Yakoob
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Peilin
authors.initials: P
authors.lastname: Shi
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Hannia
authors.initials: H
authors.lastname: Campos
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rexrode
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: E John
authors.initials: EJ
authors.lastname: Orav
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.affiliation: From the Departments of Epidemiology (MYY, PS, and DM) and Nutrition (FBH, HC, and WCW), Harvard School of Public Health, Boston, MA; the Divisions of Preventive Medicine (KMR) and General Internal Medicine (EJO), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA (DM).
authors.forename: Dariush
authors.initials: D
authors.lastname: Mozaffarian
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D003611:Dairy Products; D004032:Diet; D004041:Dietary Fats / Q000097:blood*; D005227:Fatty Acids / Q000097:blood; D005229:Fatty Acids, Monounsaturated / Q000097:blood; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000097:blood* / Q000453:epidemiology*
chemical_list: D015415:Biomarkers; D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; C008757:palmitoleic acid; C117025:pentadecanoic acid; C013102:margaric acid
keywords: biomarkers; dairy fat; hemorrhagic stroke; heptadecanoic acid; ischemic stroke; pentadecanoic acid; red blood cell; stroke; total plasma; trans-palmitoleate