title: Smoking is a risk factor for the progression of idiopathic membranous nephropathy.
abstract: BACKGROUND
  Multiple studies have shown cigarette smoking to be a risk factor for chronic kidney disease. However, it is unknown whether smoking similarly increases the risk for progression of membranous nephropathy.
  
  
  METHODS
  This study used the Nagoya Nephrotic Syndrome Cohort Study (N-NSCS), including 171 patients with idiopathic membranous nephropathy (IMN) from 10 nephrology centers in Japan. The dose-response relationships between cigarette smoking and the outcomes were assessed by using multivariate Cox proportional hazards models adjusted for clinically relevant factors. The primary outcome was a 30% decline in the estimated glomerular filtration rate (eGFR). The secondary outcome was first complete remission (CR) of proteinuria.
  
  
  RESULTS
  During the observation period (median, 37 months; interquartile range, 16-71 months), 37 (21.6%) patients developed a 30% decline in eGFR and 2 (1.2%) progressed to ESRD. CR occurred in 103 (60.2%) patients. Multivariate Cox proportional hazards models revealed current smoking (adjusted hazard ratio [HR], 7.81 [95% confidence interval (CI), 3.17-19.7]), female sex (adjusted HR, 3.58 [95% CI, 1.87-8.00]), older age (adjusted HR, 1.71 [95% CI, 1.13-2.62] per 10 years), the number of cigarettes smoked daily (adjusted HR, 1.61 [95% CI, 1.23-2.09] per 10 cigarettes daily), and cumulative smoking of ≥40 pack-years (adjusted HR, 5.56 [95% CI, 2.17-14.6]) to be associated with a 30% decline in eGFR. However, smoking was not associated with CR.
  
  
  CONCLUSIONS
  Smoking is a significant and dose-dependent risk factor for IMN progression. All patients with IMN who smoke should be encouraged to quit.
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Makoto
authors: M
authors: Yamaguchi
authors: Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Japan.
authors: Masahiko
authors: M
authors: Ando
authors: Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Suita, Japan.
authors: Ryohei
authors: R
authors: Yamamoto
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Shinichi
authors: S
authors: Akiyama
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Sawako
authors: S
authors: Kato
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Takayuki
authors: T
authors: Katsuno
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Tomoki
authors: T
authors: Kosugi
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Waichi
authors: W
authors: Sato
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Naotake
authors: N
authors: Tsuboi
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Yoshinari
authors: Y
authors: Yasuda
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Masashi
authors: M
authors: Mizuno
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Yasuhiko
authors: Y
authors: Ito
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Seiichi
authors: S
authors: Matsuo
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Shoichi
authors: S
authors: Maruyama
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D015433:Glomerulonephritis, Membranous / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D016896:Treatment Outcome