Decreased β-Cell Function Is Associated with Reduced Skeletal Muscle Mass in Japanese Subjects without Diabetes.
BACKGROUND
Decreased insulin secretion has a great impact on the incidence of type 2 diabetes in Japanese subjects. It is not clear whether β-cell function is related to muscle mass in subjects without diabetes. We investigated the relationship between β-cell function and skeletal muscle mass in Japanese subjects without diabetes.


METHODS
The study included 1098 subjects (538 men and 560 women) aged 40 to 79 years, without diabetes (fasting glucose lower than 126 mg/dL and glycosylated hemoglobin lower than 6.5%), who consulted Osaka Medical College Health Science Clinic for a medical examination. Appendicular muscle mass was measured by bioelectrical impedance analysis. Appendicular muscle mass index was calculated as appendicular muscle mass divided by height squared (kg/m2). The homeostatic model assessment of β-cell function was used to assess β-cell function. The homeostatic model assessment of insulin resistance was used as a measure of insulin resistance. The association between appendicular muscle mass index and clinical parameters of β-cell function and insulin resistance was examined.


RESULTS
Log-transformed homeostatic model assessment of β-cell function and Log-transformed homeostatic model assessment of insulin resistance showed a normal distribution. In both men and women, there was a significant positive correlation between appendicular muscle mass index and clinical parameters of β-cell function and insulin resistance. Tertile analysis, following stratification according to appendicular muscle mass index, found that low appendicular muscle mass index was significantly associated with the Log homeostatic model assessment of β-cell function and Log-transformed homeostatic model assessment of insulin resistance.


CONCLUSIONS
This study shows that decreased β cell function is associated with reduced skeletal muscle mass in Japanese subjects without diabetes.
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Satoshi
S
Sakai
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Keiji
K
Tanimoto
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Ayumi
A
Imbe
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Yuiko
Y
Inaba
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Kanako
K
Shishikura
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Yoshimi
Y
Tanimoto
Health Science Clinic, Osaka Medical College, Takatsuki City, Osaka, 569-1121, Japan.
Takahisa
T
Ushiroyama
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Jungo
J
Terasaki
Department of Internal Medicine (I), Osaka Medical College, Takatsuki City, Osaka, 569-8686, Japan.
Toshiaki
T
Hanafusa
D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism; D005215:Fasting / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*
D006442:Glycated Hemoglobin; D007328:Insulin