title: Longitudinal associations of nutritional factors with glycated hemoglobin in youth with type 1 diabetes: the SEARCH Nutrition Ancillary Study.
abstract: BACKGROUND
  Improved glycated hemoglobin (Hb A1c) delays the progression of microvascular and macrovascular complications in individuals with type 1 diabetes (T1D). We previously showed that higher baseline intakes of n-3 (ω-3) fatty acids and leucine are associated with preserved β cell function 2 y later in youth with T1D.
  
  
  OBJECTIVE
  In the current study, we extend this work to explore the longitudinal associations of nutritional factors with Hb A1c in youth with T1D.
  
  
  METHODS
  We included 908 T1D youth with baseline and follow-up Hb A1c measurements. Nutritional factors assessed at baseline were as follows: breastfeeding status and timing of complimentary food introduction; intakes of leucine, carbohydrates, protein, fat, and fiber estimated from a food-frequency questionnaire (FFQ); and plasma biomarkers for vitamins D and E, eicosapentaenoic acid (EPA), and docosahexaenoic acid. We fit linear regression models adjusted for baseline Hb A1c, sociodemographic variables, diabetes-related variables, time between baseline and follow-up visits, saturated fat, physical activity, and for FFQ-derived nutrients, total calories. The vitamin D model was further adjusted for season and body mass index z score.
  
  
  RESULTS
  The mean ± SD age and diabetes duration at baseline was 10.8 ± 3.9 y and 10.1 ± 5.8 mo, respectively. A total of 9.3% of participants had poor Hb A1c (value ≥9.5%) at baseline, which increased to 18.3% during follow-up (P < 0.0001). Intakes of EPA (β = -0.045, P = 0.046), leucine (β = -0.031, P = 0.0004), and protein (β = -0.003, P = 0.0002) were significantly negatively associated with follow-up Hb A1c after adjustment for confounders. Intake of carbohydrates was significantly positively (β = 0.001, P = 0.003) associated with follow-up Hb A1c after adjustment for confounders.
  
  
  CONCLUSIONS
  Several nutritional factors may be associated with Hb A1c during early stages of disease progression in youth recently diagnosed with T1D. In addition to the overall role of major macronutrients such as carbohydrates and protein, leucine and n-3 fatty acid intakes, such as of EPA, may be important for long-term glycemic control.
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ). archana_lamichhane@unc.edu.
authors.forename: Archana P
authors.initials: AP
authors.lastname: Lamichhane
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ).
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Crandell
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ).
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Jaacks
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ).
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Couch
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ).
authors.forename: Jean M
authors.initials: JM
authors.lastname: Lawrence
authors.affiliation: From the Department of Nutrition, Gillings School of Global Public Health (APL), the Department of Nutrition, Gillings School of Global Public Health and School of Medicine (EJM-D), and the Departments of Nursing and Biostatistics (JLC), University of North Carolina, Chapel Hill, NC; the Department of Nutritional Sciences, University of Cincinnati Medical Center, Cincinnati, OH (SCC); the Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA (JML), and the Hubert Department of Global Health, Emory University, Atlanta, GA (LMJ).
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Mayer-Davis
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004281:Docosahexaenoic Acids / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000097:blood; D002149:Energy Intake; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007930:Leucine / Q000008:administration & dosage; D008137:Longitudinal Studies; D008297:Male; D015596:Nutrition Assessment; D009752:Nutritional Status; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood; D014810:Vitamin E / Q000097:blood
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D006442:Glycated Hemoglobin; D007930:Leucine; D014807:Vitamin D; D014810:Vitamin E
keywords: Hb A1c; infant feeding practices; macronutrients; nutrient biomarkers; type 1 diabetes