title: Alterations of cortisol homeostasis may link changes of the sociocultural environment to an increased diabetes and metabolic risk in developing countries: a prospective diagnostic study performed in cooperation with the Ovahimba people of the Kunene region/northwestern Namibia.
abstract: BACKGROUND
  Diabetes mellitus is increasingly affecting Africa.
  
  
  OBJECTIVE
  Urbanization of the Ovahimba people in Namibia is associated with an increased prevalence of disorders of glucose metabolism, and may thus be attributed to changes of cortisol homeostasis.
  
  
  METHODS
  A prospective, cross-sectional, diagnostic study was applied.
  
  
  METHODS
  The study was conducted in the field. Location of the Diabetes Epidemic: Africa and Namibia.
  
  
  METHODS
  Ovahimba people: group 1 "urban" n = 60, 42 females, 46.3 ± 11.3 years (town); group 2 "rural" n = 63, 44 females, 51.1 ± 12.0 years (seminomadic).
  
  
  METHODS
  oGTT, sunrise and sunset saliva cortisol, metabolic parameters, questionnaire.
  
  
  METHODS
  The prevalence of disorders of glucose metabolism (DM, IGT, IFT).
  
  
  RESULTS
  The prevalence of disorders of glucose metabolism differed significantly: urban group n = 17(28.3%) vs rural group n = 8(12.7%) (P = 0.04). The saliva cortisol concentrations also differed significantly: sunrise 0.34 ± 0.18 vs 0.12 ± 0.15 μg/dL, sunset 0.18 ± 0.20 vs 0.07 ± 0.09 μg/dL, area under the curve 6.16 ± 3.48 vs 2.28 ± 2.56 μg/dL * 24 h (all P < 0.001). Further metabolic parameters were unfavorably changed in the urban group: hip circumference (P < 0.001), waist circumference (P < 0.001), body mass index (P = 0.014), systolic BP at rest (P < 0.001), diastolic BP at rest (P = 0.002), systolic BP after exercise (P < 0.001), heart rate after exercise (P = 0.007), fasting glucose (P < 0.001), 2-h-glucose by OGTT (P = 0.002), triglycerides (P = 0.04), HDL-cholesterol (P = 0.014), prevalence of the metabolic syndrome (P < 0.001). Physical activity was higher in the rural group, and intake of fast food and sweets were higher in the urban group.
  
  
  CONCLUSIONS
  Urbanization of the Ovahimba people is associated with an increasing prevalence of disorders of glucose metabolism and other unfavorable metabolic parameters. Besides changes of lifestyle, this may be attributed to an increased cortisol exposure of the Ovahimba people living in an urban environment.
authors.affiliation: Division of Endocrinology and Diabetology (P.H.K., S.F., A.W.), Institute of Cultural and Social Anthropology (P.H.K., M.M.), Department of Gynecology (P.H.), Institute of Medical Biometry and Epidemiology (H.D.), Philipp's University Marburg, D 35033 Marburg, Germany; Department of Surgery (S.F.), Asklepios Hospital, Naumburger Str. 76, D 06667 Weißenfels, Germany; Dean, Faculty of Medicine (P.N.), University of Namibia, 140 Mandume Ndemufayo Avenue, Pioneerspark, Private Bag 13301, Windhoek, Namibia.
authors.forename: Peter Herbert
authors.initials: PH
authors.lastname: Kann
authors.forename: Mark
authors.initials: M
authors.lastname: Münzel
authors.forename: Peyman
authors.initials: P
authors.lastname: Hadji
authors.forename: Hanna
authors.initials: H
authors.lastname: Daniel
authors.forename: Stephan
authors.initials: S
authors.lastname: Flache
authors.forename: Peter
authors.initials: P
authors.lastname: Nyarango
authors.forename: Anneke
authors.initials: A
authors.lastname: Wilhelm
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003469:Culture; D003906:Developing Countries / Q000706:statistics & numerical data; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006706:Homeostasis; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007391:International Cooperation; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000209:etiology*; D008875:Middle Aged; D009276:Namibia / Q000453:epidemiology / Q000208:ethnology; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D012931:Social Environment; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D006854:Hydrocortisone