title: Smoking and progression of diabetic nephropathy in patients with type 1 diabetes.
abstract: OBJECTIVE
  To evaluate the effect of cumulative smoking on the development of diabetic nephropathy.
  
  
  METHODS
  Study included 3613 patients with type 1 diabetes, participating in the Finnish Diabetic Nephropathy Study. The 12-year cumulative risk of microalbuminuria, macroalbuminuria and end-stage renal disease (ESRD) was estimated for current, ex- and nonsmokers. Cox regression analyses, with multivariable adjustments for other risk factors for diabetic nephropathy, were used to evaluate the risk at different stages of diabetic nephropathy based on the cumulative amount of smoking in pack-years.
  
  
  RESULTS
  The 12-year cumulative risk of microalbuminuria was 18.9 % (95 % CI 14.6-23.0, P < 0.0001) for current smokers and 15.1 % (10.3-19.6, P = 0.087) for ex-smokers, compared with 10.0 % (7.8-12.1) for nonsmokers. The corresponding risks of macroalbuminuria were 14.4 % (95 % CI 10.8-17.9, P < 0.0001), 6.1 % (3.5-8.6, P = 0.082) and 4.7 % (3.0-6.4), respectively. The 12-year cumulative risk of ESRD was 10.3 % (95 % CI 8.4-12.4, P < 0.0001) for current smokers and 10.0 % (7.9-12.3, P < 0.0001) for ex-smokers, compared with 5.6 % (4.6-6.7) for nonsmokers. In the current smokers, one pack-year increased the risk of macroalbuminuria with a HR of 1.025 (1.010-1.041) and the risk of ESRD with a HR of 1.014 (1.001-1.026) compared with nonsmokers, in the fully adjusted model. In the ex-smokers, the risk of macroalbuminuria and ESRD was no different from the risk in nonsmokers after multivariable adjustment.
  
  
  CONCLUSIONS
  Current smoking is a risk factor for the progression of diabetic nephropathy and the risk increases with the increasing dose of smoking. Ex-smokers seem to carry a similar risk of progression of diabetic nephropathy as nonsmokers.
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Maija
authors.initials: M
authors.lastname: Feodoroff
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.|Diabetes Prevention Unit, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Valma
authors.initials: V
authors.lastname: Harjutsalo
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Carol
authors.initials: C
authors.lastname: Forsblom
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Lena
authors.initials: L
authors.lastname: Thorn
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Johan
authors.initials: J
authors.lastname: Wadén
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Tolonen
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
authors.forename: Raija
authors.initials: R
authors.lastname: Lithovius
authors.affiliation: Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014, Helsinki, Finland. per-henrik.groop@helsinki.fi.|Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. per-henrik.groop@helsinki.fi.|Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland. per-henrik.groop@helsinki.fi.|The Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia. per-henrik.groop@helsinki.fi.
authors.forename: Per-Henrik
authors.initials: PH
authors.lastname: Groop
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000209:etiology* / Q000652:urine; D018450:Disease Progression; D005260:Female; D005387:Finland; D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology; D008297:Male; D012044:Regression Analysis; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
keywords: Diabetic nephropathy; End-stage renal disease; Macroalbuminuria; Microalbuminuria; Smoking; Smoking cessation; Type 1 diabetes