Weight-related differences in glucose metabolism and free fatty acid production in two South African population groups.
Int J Obes Relat Metab Disord
; 25(8): 1196-205, 2001 Aug.
Article
in En
| MEDLINE
| ID: mdl-11477505
ABSTRACT
OBJECTIVE:
The effects of free fatty acids (FFA), leptin, tumour necrosis factor (TNF) alpha and body fat distribution on in vivo oxidation of a glucose load were studied in two South African ethnic groups. DESIGN AND MEASUREMENTS Anthropometric and various metabolic indices were measured at fasting and during a 7 h oral glucose tolerance test (OGTT). Body composition was measured using bioelectrical impedance analysis and subcutaneous and visceral fat mass was assessed using a five- and two-level CT-scan respectively. Glucose oxidation was evaluated by measuring the ratio of (13)CO(2) to (12)CO(2) in breath following ingestion of 1-(13)C-labelled glucose.SUBJECTS:
Ten lean black women (LBW), ten obese black women (OBW), nine lean white women (LWW) and nine obese white women (OWW) were investigated after an overnight fast.RESULTS:
Visceral fat levels were significantly higher (P<0.01) in obese white than black women, despite similar body mass indexes (BMIs). There were no ethnic differences in glucose oxidation however; in the lean subjects of both ethnic groups the area under the curve (AUC) was higher than in obese subjects (P<0.05 for both) and was found to correlate negatively with weight (r=-0.69, P<0.01) after correcting for age. Basal TNF alpha concentrations were similar in all groups. Percentage suppression of FFAs at 30 min of the OGTT was 24+/-12% in OWW and -38+/-23% (P<0.05) in OBW, ie the 30 min FFA level was higher than the fasting level in the latter group. AUC for FFAs during the late postprandial period (120--420 min) was significantly higher in OWW than OBW (P<0.01) and LWW (P<0.01) and correlated positively with visceral fat mass independent of age (r=0.78, P<0.05) in the OWW only. Leptin levels were higher (P<0.01) both at fasting and during the course of the OGTT in obese women from both ethnic groups compared to the lean women.CONCLUSIONS:
Glucose oxidation is reduced in obese subjects of both ethnic groups; inter- and intra-ethnic differences were observed in visceral fat mass and FFA production and it is possible that such differences may play a role in the differing prevalences of obesity-related disorders that have been reported in these two populations.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Black or African American
/
Body Weight
/
Adipose Tissue
/
White People
/
Fatty Acids, Nonesterified
/
Glucose
/
Obesity
Type of study:
Prognostic_studies
Limits:
Adult
/
Female
/
Humans
Country/Region as subject:
Africa
Language:
En
Journal:
Int J Obes Relat Metab Disord
Year:
2001
Document type:
Article
Affiliation country:
South Africa