title: Serum pentadecanoic acid (15:0), a short-term marker of dairy food intake, is inversely associated with incident type 2 diabetes and its underlying disorders.
abstract: BACKGROUND
  Growing evidence suggests that dairy consumption is associated with lower type 2 diabetes risk. However, observational studies have reported inconsistent results, and few have examined dairy's association with the underlying disorders of insulin resistance and β-cell dysfunction.
  
  
  OBJECTIVE
  We investigated the association of the dairy fatty acid biomarkers pentadecanoic acid (15:0) and trans-palmitoleic acid (trans 16:1n-7) with type 2 diabetes traits by evaluating 1) prospective associations with incident diabetes after 5 y of follow-up and 2) cross-sectional associations with directly measured insulin resistance and β-cell dysfunction.
  
  
  METHODS
  The study analyzed 659 adults without diabetes at baseline from the triethnic multicenter Insulin Resistance Atherosclerosis Study (IRAS). Diabetes status was assessed by using oral-glucose-tolerance tests. Frequently sampled intravenous-glucose-tolerance tests measured insulin sensitivity (SI) and β-cell function [disposition index (DI)]. Serum fatty acids were quantified by using gas chromatography. Logistic and linear regression models were adjusted for demographic, lifestyle, and dietary variables.
  
  
  RESULTS
  Serum 15:0 was a significant biomarker for total dairy intake in the IRAS cohort. It was associated with a decreased incident diabetes risk (OR: 0.73, P = 0.02) and was positively associated with log SI (β: 0.84, P = 0.03) and log DI (β: 2.21, P = 0.02) in fully adjusted models. trans 16:1n-7 was a marker of total partially hydrogenated dietary fat intake and was not associated with outcomes in fully adjusted models.
  
  
  CONCLUSIONS
  Serum 15:0, a marker of short-term intake of this fatty acid, was inversely associated with diabetes risk in this multiethnic cohort. This study may contribute to future recommendations regarding the benefits of dairy products on type 2 diabetes risk.
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Ingrid D
authors.initials: ID
authors.lastname: Santaren
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Steven M
authors.initials: SM
authors.lastname: Watkins
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Angela D
authors.initials: AD
authors.lastname: Liese
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagenknecht
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Rewers
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Steven M
authors.initials: SM
authors.lastname: Haffner
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Carlos
authors.initials: C
authors.lastname: Lorenzo
authors.affiliation: From the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (IDS and AJH); Lipomics, a Division of Metabolon Inc., West Sacramento, CA (SMW); the Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC (ADL); the Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (LEW); Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO (MJR); the Division of Clinical Epidemiology, University of Texas Health Sciences Center, San Antonio, TX (SMH and CL); the Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (AJH); and Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada (AJH).
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hanley
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D003430:Cross-Sectional Studies; D003611:Dairy Products; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004041:Dietary Fats / Q000097:blood*; D005006:Ethnicity; D005227:Fatty Acids / Q000097:blood*; D005229:Fatty Acids, Monounsaturated / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism; D008019:Life Style; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; C008757:palmitoleic acid; C117025:pentadecanoic acid
keywords: dairy; epidemiology; fatty acids; nutrition; type 2 diabetes