title: Different association of cigarette smoking with GFR estimated from serum creatinine and that from serum cystatin C in the general population.
abstract: BACKGROUND
  Previous studies have shown that GFR estimated from serum creatinine (eGFRcr) is higher in smokers although the implications remain unclear. We aimed to clarify the associations of smoking with eGFRcys (GFR estimated from serum cystatin C) and eGFRcr, cys (the surmised most precise GFR estimate based on serum creatinine and cystatin C) in a working population.
  
  
  METHODS
  Cross-sectional observation in 1,587 male workers aged 25-64 years. For eGFRcr, JEQcr proposed by the Japanese Society of Nephrology (JSN) and jEPIcr by the Chronic Kidney Disease Epidemiological Collaboration (CKD-EPI) modified for Japanese, and for eGFRcys, JEQcys proposed by JSN and EPIcys by CKD-EPI were calculated together with eGFRcr,cys of JEQaver (the average of JEQcr and JEQcys) and jEPIcr,cys by CKD-EPI modified for Japanese.
  
  
  RESULTS
  Mean JEQcys was 95.1 mL/min/1.73 m(2) in contrast to 80.9 in JEQcr, with this difference considerable. Serum cystatin C was higher in smokers and obese subjects while serum creatinine was lower in smokers and slender subjects. JEQcys and EPIcys were lower in smokers while JEQcr and jEPIcr were higher in smokers adjusting for body mass index (BMI). eGFRcr,cys (JEQaver and jEPIcr,cys) did not differ between the never smokers and current smokers. eGFRcr,cys predicted by the equations composed of eGFRcr, BMI, and smoking habits showed a good accordance with calculated eGFRcr,cys.
  
  
  CONCLUSIONS
  Either eGFRcr, eGFRcys or both were not reliable indicators of renal function in workers who smoked. The possibly more precise estimate of eGFRcr,cys could be predicted by eGFRcr, BMI and smoking in such a generally healthy population.
authors.affiliation: Department of Social and Environmental Medicine, Kanazawa Medical University School of Medicine, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan, u1yamada@kanazawa-med.ac.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yamada
authors.forename: Yuka
authors.initials: Y
authors.lastname: Noborisaka
authors.forename: Masao
authors.initials: M
authors.lastname: Ishizaki
authors.forename: Michiko
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Ryumon
authors.initials: R
authors.lastname: Honda
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kakuma
mesh_terms: D000328:Adult; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000453:epidemiology; D012907:Smoking / Q000097:blood / Q000503:physiopathology*
chemical_list: D055316:Cystatin C; D003404:Creatinine