Serum Cystatin C in the United States: The Third National Health and Nutrition Examination Survey (NHANES III)
Received 2 September 2007; accepted 17 November 2007.
Refers to article:
Cystatin C: Research Priorities Targeted to Clinical Decision Making
Michael G. Shlipak
American Journal of Kidney Diseases
March 2008 (Vol. 51, Issue 3, Pages 358-361) Full Text |
Full-Text PDF (70 KB)
Background
Serum cystatin C increasingly is used as a marker of glomerular filtration rate and cardiovascular risk. However, information for serum cystatin C levels in the general population, specifically across a wide age range and different ethnicities, is lacking.
Objectives
To determine nationally representative serum cystatin C levels, estimate the prevalence of increased cystatin C levels in the general population, and identify factors associated with increased cystatin C levels.
Study Design
Cross-sectional survey.
Setting and Participants
A nationally representative subsample of 7,596 participants aged 12 years or older in the Third National Health and Nutrition Examination Survey conducted in 1988-1994.
Predictors
Age, sex, race/ethnicity, risk factors for chronic kidney disease.
Outcomes
Continuous serum cystatin C levels and serum cystatin C level greater than 1.12 mg/L.
Measurements
Cystatin C was measured in 2006 from stored sera by using an automated particle-enhanced nephelometric assay.
Results
Overall median serum cystatin C level was 0.85 mg/L. Median cystatin C levels increased steeply with age and were greater in males and non-Hispanic white persons, even in a healthy subgroup of 20- to 39-year-olds. Prevalences of increased serum cystatin C levels (>1.12 mg/L) were 1%, 41%, and greater than 50% in all persons aged younger than 20 years, 60 years or older, and 80 years or older. In persons aged 60 years and older, older age, non-Hispanic white ethnicity, hypertension, current smoking, lower levels of education and high-density lipoprotein cholesterol, and increased body mass index, C-reactive protein, and triglyceride values were associated significantly with increased serum cystatin C levels.
Limitations
No measured glomerular filtration rate, single measurement of cystatin C, cross-sectional study design.
Conclusions
Serum cystatin C level is related to sex and ethnicity, even in young healthy individuals. The prevalence of increased cystatin C levels increases dramatically with age, reaching greater than 50% after the age of 80 years in both sexes and all ethnic groups.
1Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD
2Division of Nephrology, Tufts-New England Medical Center, Boston, MA
3Department of Clinical Pathology, Cleveland Clinic Foundation, Cleveland, OH
4Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Hospital, Baltimore, MD
5Department of Medicine, Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Hospital, Baltimore, MD.
Address correspondence to Josef Coresh, MD, PhD, Welch Center for Prevention, Epidemiology & Clinical Research, 2024 E Monument St, Baltimore, MD 21287.
Because an author of this manuscript is an editor for AJKD, the peer-review and decision-making processes were handled entirely by an Associate Editor (Marcello Tonelli, MD, University of Alberta) who served as Acting Editor-in-Chief. Details of the journal’s procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.
ABSTRACT