title: Male sex and vascular risk factors affect cystatin C-derived renal function in older people without diabetes or overt vascular disease.
abstract: OBJECTIVE
  to explore the effect of ageing on renal function with cystatin C as the marker of glomerular filtration rate (GFR) in the general population without vascular disease or diabetes.
  
  
  METHODS
  a cross-sectional analysis of a healthy subset from the Good Aging in Skåne-cohort study representative of the Swedish general population.
  
  
  METHODS
  1252 participants without vascular disease and diabetes (43.9% men) of whom 203 were over 80 years old were included from the original cohort of 2931.
  
  
  METHODS
  plasma cystatin C and plasma creatinine were used as markers for GFR. Estimated GFR (eGFR) was calculated with three chronic kidney disease epidemiology collaboration (CKD-EPI) formulas involving cystatin C, creatinine or both.
  
  
  RESULTS
  the median for plasma cystatin C was 0.93 mg/l (60-69 years old), 1.04 (70-79 years old) and 1.24 (80+ years old). The difference in mg/l between the 5th and 95th percentile was 0.46, 0.62 and 0.90 for these age groups. Male sex increased the age effect on plasma cystatin C levels with 0.004 mg/l/year (P = 0.03), adjusted for vascular risk factors. Smoking, lower HDL and higher diastolic blood pressure were associated with higher cystatin C levels. 54.7% (CKD-EPI creatinine) to 73.9% (CKD-EPI cystatin C) of the 80+ had an eGFR < 60 ml/min/1.73 m2.
  
  
  CONCLUSIONS
  non-diabetics without overt vascular disease exhibit an age related but heterogeneous decline in renal function. The ageing effect is more pronounced in men. At least half of healthy 80+ years old could be expected to have at least CKD Stage 3 with eGFR < 60 ml/min/1.73 m2.
authors: Department of Health Sciences, Lund University, Geriatriska kliniken Jan Waldenströmgata 35, Malmö 205 02, Sweden.
authors: Karin Birgitta
authors: KB
authors: Werner
authors: Sölve
authors: S
authors: Elmståhl
authors: Anders
authors: A
authors: Christensson
authors: Mats
authors: M
authors: Pihlsgård
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013223:Statistics as Topic; D013548:Sweden / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine
keywords: ageing; cystatin C; epidemiology; kidney function; sex