title: Impact of westernization on fibroblast growth factor 23 levels among individuals of African ancestry.
abstract: BACKGROUND
  The Western diet is associated with high consumption of processed foods preserved with phosphate. Higher dietary phosphate consumption stimulates production of fibroblast growth factor 23 (FGF23), which heightens risk for cardiovascular disease and mortality. We hypothesized that adults living in a more westernized society have higher levels of FGF23 due to increased phosphate consumption as measured by urinary phosphate excretion.
  
  
  METHODS
  We measured plasma C-terminal FGF23 levels and urinary phosphate and creatinine levels in timed urine collections among 100 African adults living in the rural area of Igbo-Ora, Nigeria (52 women, 48 men), and 100 African Americans (32 women, 68 men) living in Maywood, IL, an urban suburb of Chicago, IL, USA. Among these 200 participants, urine collections were adequate in 76 and 68 of the Maywood and Igbo-Ora participants, respectively.
  
  
  RESULTS
  In the total group, the mean age and body mass index, respectively, were 34.6 ± 8.2 years and 22.1 ± 3.9 kg/m(2) in Igbo-Ora, and 42.8 ± 7.2 years and 25.8 ± 6.5 kg/m(2) in Maywood. Demographic characteristics for each site were very similar after excluding participants without adequate urine collections. Among all 200 participants, the median (interquartile range) FGF23 levels were significantly higher in Maywood versus Igbo-Ora [63.8 (45.0-89.9) versus 12.5 RU/mL (8.5-18.5); P < 0.0001] and these differences did not change substantially after excluding nine women from Maywood with FGF23 levels >400 RU/mL or after excluding participants with inadequate urine collections. Among participants with adequate urine collections, the mean 24-h urinary phosphate excretion was significantly higher in Maywood versus Igbo-Ora (810.6 ± 309.0 versus 347.5 ± 153.1 mg; P < 0.001) and FGF23 levels correlated significantly with total urinary phosphate excretion (r = 0.62; P < 0.001) and urinary phosphate-to-creatinine ratios (r = 0.50; P < 0.001).
  
  
  CONCLUSIONS
  Living in a more westernized society may be associated with greater net phosphate absorption, as reflected by higher urinary phosphate excretion, and higher FGF23 levels.
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Eckberg
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA Division of Nephrology and Hypertension, Department of Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Holly
authors.initials: H
authors.lastname: Kramer
authors.affiliation: Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Myles
authors.initials: M
authors.lastname: Wolf
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Ramon
authors.initials: R
authors.lastname: Durazo-Arvizu
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Bamidele
authors.initials: B
authors.lastname: Tayo
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Luke
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Cooper
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D044383:Black People / Q000208:ethnology*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology*; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D066273:Diet, Western / Q000208:ethnology*; D004797:Enzyme-Linked Immunosorbent Assay; D005247:Feeding Behavior; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D010710:Phosphates / Q000652:urine*; D014481:United States / Q000453:epidemiology; D016482:Urinalysis; D001741:Black or African American
chemical_list: D015415:Biomarkers; C000717427:FGF23 protein, human; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D003404:Creatinine
keywords: African diaspora; FGF23; phosphorus excretion; potassium excretion; sodium excretion