Relation of triglyceride stores in skeletal muscle cells to central obesity and insulin sensitivity in European and South Asian men.
OBJECTIVE
To compare the relation between intramyocellular lipid content, central obesity and insulin sensitivity in Europeans and South Asians.


METHODS
Cross-sectional study of 40 South Asian and European non-diabetic men matched for age and body mass index. We measured intramyocellular lipid by proton magnetic resonance spectroscopy of soleus muscle, insulin sensitivity by the short insulin tolerance test, per cent body fat by dual-energy x-ray absorptiometry and visceral fat by single-slice computed tomography of the abdomen.


RESULTS
South Asians compared with Europeans had a higher mean per cent body fat (26.8% vs 22.5%, p = 0.05) and lower insulin sensitivity (mean +/- SEM 2.4 +/- 0.2 vs 3.4%/min +/- 0.3, p = 0.013). Mean (+/- SEM) intramyocellular lipid content was higher in South Asians than in Europeans (72.1 +/- 7.5 vs 53.6 +/- 4.9 mmol/kg dry weight, p = 0.046). In Europeans intramyocellular lipid was correlated with per cent body fat (r = 0.50, p = 0.028), waist:hip ratio (r = 0.74, p < 0.001), visceral fat (r = 0.62, p = 0.004) and insulin sensitivity (r = -0.53, p = 0.016). In South Asians intramyocellular lipid was not significantly related to insulin sensitivity or obesity, and the strongest associations of insulin sensitivity were with fasting plasma triglyceride and waist:hip ratio.


CONCLUSIONS
The association of intramyocellular lipid with insulin sensitivity and obesity in Europeans is consistent with the hypothesis that muscle triglyceride mediates the effect of obesity on insulin sensitivity. The absence of a similar relation of insulin sensitivity to intramyocellular lipid in South Asians suggests that other mechanisms underlie the high insulin resistance observed in this group.
Forouhi
N G
NG
Epidemiology Unit, London School of Hygiene and Tropical Medicine, UK.
Jenkinson
G
G
Thomas
E L
EL
Mullick
S
S
Mierisova
S
S
Bhonsle
U
U
McKeigue
P M
PM
Bell
J D
JD
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D001208:Asia / Q000208:ethnology; D001786:Blood Glucose / Q000032:analysis; D001824:Body Constitution; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004739:England; D005060:Europe / Q000208:ethnology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000737:chemistry*; D009765:Obesity / Q000145:classification / Q000378:metabolism / Q000503:physiopathology*; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed; D014280:Triglycerides / Q000032:analysis* / Q000097:blood / Q000378:metabolism
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D014280:Triglycerides