NDT Advance Access published online on September 11, 2009
Nephrology Dialysis Transplantation, doi:10.1093/ndt/gfp474
Age and cystatin C in healthy adults: a collaborative study
1 Department of Epidemiology, School of Public Health, University of California, Berkeley 2 Department of General Internal Medicine, University of California, San Francisco, CA, USA 3 Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands 4 Collaborative Health Studies Coordinating Center, University of Washington, Seattle, WA 5 Renal Section, Veterans Affairs Pittsburgh Healthcare System 6 Department of Epidemiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 7 Departments of Medicine and Nephrology, University of Tennessee Health Science Center, Memphis, TN 8 Laboratory of Epidemiology, Demography, and Biometry Program, National Institute on Aging, NIH, Bethesda, MD 9 Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA 10 Departments of Medicine and Epidemiology, University of Washington, Seattle WA 11 Departments of Medicine, Epidemiology and Biostatistics, University of California, San Francisco 12 Department of General Internal Medicine, San Francisco VA Medical Center, San Francisco, CA, USA
Correspondence and offprint requests to: Michelle C. Odden; E-mail: michelle.odden{at}ucsf.edu
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Abstract |
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Background. Kidney function declines with age, but a substantial portion of this decline has been attributed to the higher prevalence of risk factors for kidney disease at older ages. The effect of age on kidney function has not been well described in a healthy population across a wide age spectrum.
Methods. The authors pooled individual-level cross-sectional data from 18 253 persons aged 28–100 years in four studies: the Cardiovascular Health Study; the Health, Aging and Body Composition Study; the Multi-Ethnic Study of Atherosclerosis and the Prevention of Renal and Vascular End-Stage Disease cohort. Kidney function was measured by cystatin C. Clinical risk factors for kidney disease included diabetes, hypertension, obesity, smoking, coronary heart disease, cerebrovascular disease, peripheral arterial disease and heart failure.
Results. Across the age range, there was a strong, non-linear association of age with cystatin C concentration. This association was substantial, even among participants free of clinical risk factors for kidney disease; mean cystatin C levels were 46% higher in participants 80 and older compared with those <40 years (1.06 versus 0.72 mg/L, P < 0.001). Participants with one or more risk factors had higher cystatin C concentrations for a given age, and the age association was slightly stronger (P < 0.001 for age and risk factor interaction).
Conclusions. There is a strong, non-linear association of age with kidney function, even in healthy individuals. An important area for research will be to investigate the mechanisms that lead to deterioration of kidney function in apparently healthy persons.
Keywords: ageing; chronic kidney disease; cystatin C; epidemiology
Received for publication: 13. 5.09
Accepted in revised form: 17. 8.09