Relationship between reduced serum IGF-I levels and accumulation of visceral fat in Japanese men.
OBJECTIVE
To investigate whether the changes in IGF-I concentrations after weight reduction in Japanese overweight men are associated with changes in visceral and subcutaneous fat.


METHODS
Cross-sectional and longitudinal clinical intervention study with exercise education.


METHODS
One-hundred and twelve Japanese overweight men aged 30-59 y (body mass index (BMI) 28.4+/-2.5 kg/m(2)) and 33 normal-weight men aged 30-39 y (BMI 22.1+/-1.5 kg/m(2)) at baseline. From the participants, 56 randomly selected overweight men (BMI 28.8+/-2.8) were further enrolled into a 1 y exercise program.


METHODS
Fat distribution was evaluated by visceral fat (V) and subcutaneous fat (S) areas measured with computed tomography scanning at umbilical levels, metabolic parameters and hormones including insulin, leptin and IGF-I at baseline and after 1 y.


RESULTS
In 112 overweight subjects at baseline, insulin (10.5+/-5.0 microU/ml) and leptin (6.4+/-3.7 ng/ml) significantly correlated with both V (r=0.260, P=0.0073; r=0.410, P<0.0001) and S areas (r=0.377, P<0.0001; r=0.613, P<0.0001), respectively. IGF-I (156.8+/-48.7 microU/ml) significantly and negatively correlated with V area (r=-0.242, P=0.0125) and age (r=-0.192, P=0.0480). In normal-weight men aged 30-39 y (n=33) and age-matched subjects (n=30) selected from the 112 overweight men, the serum IGF-I further tightly correlated with V area (r=-0.467, P<0.0001). Visceral fat area and age were independently related to serum IGF-I levels by multiple regression analysis. By intervention with exercise education, 56 overweight subjects showed an increase in daily steps (6224+/-2781 to 7898+/-4141 steps/day) and reduction of BMI (28.8+/-2.8 to 27.7+/-2.9). deltaIGF-I significantly correlated with deltaV area (r=-0.432, P=0.0009) but not with DeltaS area or deltaBMI.


CONCLUSIONS
The present study indicated a negative correlation between IGF-I levels and visceral fat at baseline as well as an association between the reduction in visceral fat and increase in IGF-I levels after an exercise intervention.
Kunitomi
M
M
Department of Medicine III, Okayama University Medical School, Okayama, Japan.
Wada
J
J
Takahashi
K
K
Tsuchiyama
Y
Y
Mimura
Y
Y
Hida
K
K
Miyatake
N
N
Fujii
M
M
Kira
S
S
Shikata
K
K
Maknio
H
H
D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D020738:Leptin / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed; D014781:Viscera; D015431:Weight Loss
D007328:Insulin; D020738:Leptin; D007334:Insulin-Like Growth Factor I