title: Dietary protein intake and change in estimated GFR in the Cardiovascular Health Study.
abstract: OBJECTIVE
  With aging, kidney function declines, as evidenced by reduced glomerular filtration rate. It is controversial whether or not high protein intake accelerates this decline. The aim of this study was to determine whether high protein intake was associated with declines in kidney function among older patients.
  
  
  METHODS
  We examined whether dietary protein is associated with change in kidney function (mean follow-up 6.4 y [SD = 1.4, range = 2.5-7.9] in the Cardiovascular Health Study (N = 3623). We estimated protein intake using a food frequency questionnaire and estimated glomerular filtration rate from cystatin C. Associations between protein intake and kidney function were determined by linear and logistic regression models.
  
  
  RESULTS
  Average protein intake was 19% of energy intake (SD = 5%). Twenty-seven percent (n = 963) of study participants had rapid decline in kidney function, as defined by (ΔeGFRcysC > 3 mL•min•1.73 m(2)). Protein intake (characterized as g/d and % energy/d), was not associated with change in estimated glomerular filtration rate (P > 0.05 for all comparisons). There were also no significant associations when protein intake was separated by source (animal and vegetable).
  
  
  CONCLUSIONS
  These data suggest that higher protein intake does not have a major effect on kidney function decline among elderly men and women.
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, USA. Electronic address: jeannette.beasley@einstein.yu.edu.
authors.forename: Jeannette M
authors.initials: JM
authors.lastname: Beasley
authors.affiliation: Collaborative Health Studies Coordinating Center, University of Washington, Seattle, Washington, USA.
authors.forename: Ronit
authors.initials: R
authors.lastname: Katz
authors.affiliation: Department of Medicine, UCSF School of Medicine, San Francisco, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Shlipak
authors.affiliation: Division of Nephrology University of California-San Diego, San Diego, California, USA.
authors.forename: Dena E
authors.initials: DE
authors.lastname: Rifkin
authors.affiliation: School of Public Health, University of Washington, Seattle, Washington, USA.
authors.forename: David
authors.initials: D
authors.lastname: Siscovick
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Kaplan
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D005247:Feeding Behavior; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006262:Health; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D012044:Regression Analysis; D011795:Surveys and Questionnaires
chemical_list: D004044:Dietary Proteins
keywords: Animal protein; Glomerular filtration rate; Kidney; Macronutrients; Vegetable protein