Body mass index is associated with increased creatinine clearance by a mechanism independent of body fat distribution.
BACKGROUND
Although obesity has been, in general, associated with glomerular hyperfiltration, visceral adiposity has been suggested to be associated with reduced glomerular filtration.


OBJECTIVE
The aim of the study was to evaluate the differential effects of obesity and body fat distribution on glomerular filtration.


METHODS
We conducted a cross-sectional study of the Japanese-American community in Seattle, Washington.


METHODS
We studied a representative sample of second-generation Japanese-American men and women with normal glucose tolerance (n = 124) and impaired glucose metabolism (impaired fasting glucose and/or impaired glucose tolerance) (n = 144) residing in King County, Washington.


METHODS
Glomerular filtration rate was estimated by 24-h urinary creatinine clearance, body size by body mass index (BMI), and intra-abdominal fat (IAF), sc fat (SCF), and lean thigh areas by CT scan.


RESULTS
Creatinine clearance was positively correlated with BMI (r = 0.429; P < 0.001), fasting glucose (r = 0.198; P = 0.001), and insulin levels (r = 0.125; P = 0.042), as well as IAF (r = 0.239; P < 0.001), SCF (r = 0.281; P < 0.001), and lean thigh (r = 0.353; P < 0.001) areas. The association between creatinine clearance and BMI remained significant after adjustments for IAF, SCF areas, and fasting insulin levels (r = 0.337; P < 0.001); whereas IAF and SCF areas were not independently associated with creatinine clearance after adjusting for BMI. Creatinine clearance increased with increasing BMI after adjusting for fasting insulin, fasting glucose, IAF and SCF areas in subjects with normal glucose tolerance (r = 0.432; P < 0.001) and impaired glucose metabolism (r = 0.471; P < 0.001).


CONCLUSIONS
BMI rather than body fat distribution is an independent determinant of creatinine clearance in nondiabetic subjects. Lean body mass, rather than adiposity, may explain this association.
Gerchman
Fernando
F
Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, Washington 98108, USA.
Tong
Jenny
J
Utzschneider
Kristina M
KM
Zraika
Sakeneh
S
Udayasankar
Jayalakshmi
J
McNeely
Marguerite J
MJ
Carr
Darcy B
DB
Leonetti
Donna L
DL
Young
Bessie A
BA
de Boer
Ian H
IH
Boyko
Edward J
EJ
Fujimoto
Wilfred Y
WY
Kahn
Steven E
SE
D000328:Adult; D000368:Aged; D001213:Asian; D001786:Blood Glucose / Q000378:metabolism; D050218:Body Fat Distribution; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D005951:Glucose Tolerance Test; D006801:Humans; D050152:Intra-Abdominal Fat; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D050151:Subcutaneous Fat; D014861:Washington
D001786:Blood Glucose; D003404:Creatinine