A central body fat distribution is related to renal function impairment, even in lean subjects.
BACKGROUND
Overweight and obesity are believed to be associated with renal damage. Whether this depends on fat distribution is not known. We hypothesize that in addition to overweight, fat distribution may be associated with renal function abnormalities.


METHODS
We studied the relation between body weight and fat distribution and microalbuminuria and elevated or diminished filtration in 7,676 subjects without diabetes. Microalbuminuria is defined as urinary albumin excretion (UAE) of 30 to 300 mg/24 h. Elevated and diminished filtration are defined as filtration plus or minus 2 SDs of a nondiabetic lean group with a peripheral fat distribution and UAE of 0 to 15 mg/24 h, corrected for age and sex. The total population was divided into six groups according to body weight (overweight is defined as body mass index [BMI] > 25 and < or = 30 kg/m2; obesity, as BMI > 30 kg/m2) and fat distribution.


RESULTS
In logistic regression analysis, obese subjects with central fat distribution had a greater risk for microalbuminuria (relative risk, 1.7; 95% confidence interval, 1.19 to 2.35). Obese subjects with either peripheral or central fat distribution had a greater risk for elevated filtration (relative risk, 3.2; 95% confidence interval, 1.19 to 8.47; relative risk, 2.6; 95% confidence interval, 1.59 to 4.28, respectively). Furthermore, subjects with central fat distribution, either lean, overweight, or obese, had a greater risk for diminished filtration (relative risk, 1.9; 95% confidence interval, 1.19 to 3.12; relative risk, 2.0; 95% confidence interval, 1.19 to 3.19; and relative risk, 2.7; 95% confidence interval, 1.46 to 4.85, respectively). Finally, by dividing waist-hip ratio (WHR) into quartiles, greater WHR was associated with a greater risk for diminished filtration, even when corrected for BMI.


CONCLUSIONS
Not only overweight and obese subjects, but also lean subjects with central fat distribution are at risk for diminished filtration. Therefore, a central pattern of fat distribution, not overweight or obesity by itself, seems to be important for renal impairment.
Pinto-Sietsma
Sara-Joan
SJ
Division of Nephrology, Department of Internal Medicine, University Hospital Groningen, Groningen, The Netherlands. pintosj@hotmail.com
Navis
Gerjan
G
Janssen
Wilbert M T
WM
de Zeeuw
Dick
D
Gans
Reinhold O B
RO
de Jong
Paul E
PE
D000005:Abdomen; D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000453:epidemiology*; D001786:Blood Glucose / Q000032:analysis; D001824:Body Constitution / Q000502:physiology*; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology; D012044:Regression Analysis; D012306:Risk; D013851:Thinness / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology; D013909:Thorax
D001786:Blood Glucose; D002784:Cholesterol; D003404:Creatinine