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 / North-Western Namibia

Presentation Number: SAT-398
Date of Presentation: March 7th, 2015

Peter Herbert Kann*1, Mark Münzel2, Peyman Hadji3, Hanna Daniel4, Stephan Flache3, Peter Nyarango5 and Anneke Wilhelm3
1University Hospital Marburg, Marburg, Germany, 2University Marburg, Marburg, Germany, 3University Hospital Marburg, 4University Marburg, 5University of Namibia Windhoek

Abstract

Diabetes mellitus is affecting Africa increasingly. This prospective, cross-sectional, diagnostic study was aimed to investigate whether urbanisation of the Ovahimba people in Namibia is associated with an increased prevalence of disorders of glucose metabolism, and may this be attributed to changes of cortisol homeostasis. Two groups of Ovahimba people participated: group 1 ‘urban’, n=60, 42 females, 46.3±11.3 years; group 2 ‘rural/semi-nomadic’ n=63, 44 females, 51.1±12.0 years (semi-nomadic). OGTT, sunrise/sunset saliva cortisol and metabolic parameters were performed/assessed, a questionnaire completed. 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*24h (all p<0.001). Further metabolic parameters were unfavourably changed in the urban group: hip circumference 105.5±14.1 vs. 97.7±10.2 cm (p<0.001), waist circumference 94.1±17.4 vs. 78.0±12.6 cm (p<0.001), body mass index 26.6±6.2 vs. 24.2±4.4 kg/m2 (p=0.014), systolic BP at rest 123.0±20.2 vs. 109.4±16.4 mmHg (p<0.001), diastolic BP at rest 81.7±13.7 vs. 74.8±10.3 mmHg (p=0.002), systolic BP after exercise 154.9±27.3 vs. 137.8±20.0 mmHg (p<0.001), heart rate after exercise 99.8±21.2 vs. 89.2±20.6 bpm (p=0.007), fasting glucose 5.3±0.8 vs. 4.9±0.7 mmol/l (p<0.001), 2-hours-glucose by OGTT 6.7±1.4 vs. 6.0±1.3 mmol/l (p=0.002), triglycerides 1.1±0.8 vs. 0.8±0.4 mmol/l (p=0.04), HDL-cholesterol 1.3±0.4 vs. 1.5±0.4 mmol/l (p=0.014), prevalence of the metabolic syndrome n=19/31.7% vs. n=5/7.9% (p<0.001). Physical activity was higher in the rural group, intake of fastfood and sweets in the urban group. In conclusion, urbanisation of the Ovahimba people is associated with an increasing prevalence of disorders of glucose metabolism and other unfavourable metabolic parameters. Besides changes of lifestyle, this may be attributed to an increased cortisol exposure of the Ovahimba people living in an urban environment.

 

Nothing to Disclose: PHK, MM, PH, HD, SF, PN, AW