Central obesity associates with renal hyperfiltration in the non-diabetic general population: a cross-sectional study.
Obesity is a risk factor for end-stage renal disease. Renal hyperfiltration, defined as an abnormally high glomerular filtration rate (GFR), is a link in the causal chain between diabetes and chronic kidney disease. Whether obesity is associated with hyperfiltration in the non-diabetic general population, remains unresolved due to a lack of consensus regarding the definition of hyperfiltration and the limited precision of high-range GFR estimations with creatinine and/or cystatin C.



1555 middle-aged participants without diabetes, renal or cardiovascular disease were enrolled from the general population in the Renal Iohexol Clearance Survey from the 6th Tromsø Study (RENIS-T6) between 2007 and 2009. Obesity was assessed using the body mass index (BMI), waist circumference (WC) and the waist-hip ratio (WHR). GFR was measured by iohexol clearance. Dichotomous variables for hyperfiltration were based on two alternative definitions using unadjusted GFR (mL/min) above the 90th percentile. The 90th percentile was age-, sex- and height-specific in one definition and age-, sex-, height- and weight-specific in the other.



In multivariable adjusted logistic regression models, only WHR was consistently associated with hyperfiltration based on both definitions. For the definition based on the age-, sex-, height- and weight-specific 90th percentile, the association with the WHR (odds ratios (95 % confidence intervals)) for hyperfiltration was 1.48 (1.08-2.02) per 0.10 WHR increase.



Central obesity is associated with hyperfiltration in the general population. The WHR may serve as a better indicator of the renal effects of obesity than BMI or WC.
Metabolic and Renal Research Group, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway. vidar.stefansson@uit.no.
Vidar Tor Nyborg
VT
Stefansson
Metabolic and Renal Research Group, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
Jørgen
J
Schei
Metabolic and Renal Research Group, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.|Department of Organ Transplantation, Oslo University Hospital, Oslo, Norway.
Trond Geir
TG
Jenssen
Metabolic and Renal Research Group, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.|Section of Nephrology, University Hospital of North Norway, Tromsø, Norway.
Toralf
T
Melsom
Metabolic and Renal Research Group, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.|Section of Nephrology, University Hospital of North Norway, Tromsø, Norway.
Bjørn Odvar
BO
Eriksen
D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000503:physiopathology*; D055105:Waist Circumference; D049629:Waist-Hip Ratio
Body mass index; Chronic kidney disease; Glomerular filtration rate; Glomerular hyperfiltration; Waist circumference; Waist-hip ratio