Overweight, obesity, and elevated serum cystatin C levels in adults in the United States.
BACKGROUND
Although high body mass index (BMI) is a risk factor for hypertension, diabetes, and cardiovascular disease, limited data exist on the association of overweight and obesity with early stages of kidney disease.


METHODS
Cross-sectional data for 5083 participants of the nationally representative Third National Health and Nutrition Examination Survey with an estimated glomerular filtration rate > or = 60 mL/min/1.73 m(2) without micro- or macroalbuminuria were analyzed to determine the association between BMI and elevated serum cystatin C. Normal weight, overweight, class I obesity, and class II to III obesity were defined as a BMI of 18.5 to 24.9 kg/m(2), 25.0 to 29.9 kg/m(2), 30.0 to 34.9 kg/m(2), and > or = 35.0 kg/m(2), respectively. Elevated serum cystatin C was defined as > or = 1.09 mg/L (> or = 99th percentile for participants 20-39 years of age without diabetes, hypertension, micro- or macroalbuminuria, or stage 3-5 chronic kidney disease).


RESULTS
The age-standardized prevalence of elevated serum cystatin C was 9.6%, 12.9%, 17.4%, and 21.5% among adults of normal weight, overweight, class I obesity, and class II to III obesity, respectively (P trend < .001). After multivariate adjustment for demographics, behaviors, systolic blood pressure, and serum biomarkers, and compared with participants of normal weight, the odds ratio (95% confidence interval) of elevated serum cystatin C was 1.46 (1.02-2.10) for overweight, 2.36 (1.56-3.57) for class I obesity, and 2.82 (1.56-5.11) for class II to III obesity.


CONCLUSIONS
A graded association exists between higher BMI and elevated serum cystatin C. Further research is warranted to assess whether reducing BMI favorably affects elevated serum cystatin C and the development of chronic kidney disease.
Muntner
Paul
P
Department of Community and Preventive Medicine, Mt Sinai School of Medicine, New York, NY 10029, USA. paul.muntner@mssm.edu
Winston
Jonathan
J
Uribarri
Jaime
J
Mann
Devin
D
Fox
Caroline S
CS
D000328:Adult; D017677:Age Distribution; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015897:Comorbidity; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D055316:Cystatin C; D015891:Cystatins / Q000032:analysis / Q000097:blood*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood / Q000453:epidemiology; D016017:Odds Ratio; D050177:Overweight / Q000097:blood* / Q000453:epidemiology*; D011379:Prognosis; D012042:Registries; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins