title: Insulin resistance and β-cell function in smokers: results from the EGIR-RISC European multicentre study.
abstract: Tobacco smoking is known to increase the long-term risk of developing Type 2 diabetes mellitus, but the mechanisms involved are poorly understood. This observational, cross-sectional study aims to compare measures of insulin sensitivity and β-cell function in current, ex- and never-smokers.
  
  
  
  The study population included 1246 people without diabetes (mean age 44 years, 55% women) from the EGIR-RISC population, a large European multicentre cohort. Insulin sensitivity was measured using a hyperinsulinaemic, euglycaemic clamp and the homeostatic model assessment - insulin resistance (HOMA-IR) index. Two β-cell function parameters were derived from measures during an oral glucose tolerance test: the early insulin response index and β-cell glucose sensitivity. Additionally, the areas under the curve during the oral glucose tolerance test were calculated for glucose, insulin and C-peptide.
  
  
  
  According to smoking habits, there were differences in insulin sensitivity, which was lower in women who smoked, and in β-cell glucose sensitivity, which was lower in men who smoked, but these associations lost significance after adjustment. However, after adjustment, the areas under the glucose and the C-peptide curves during the oral glucose tolerance test were significantly higher in men who smoked.
  
  
  
  Smoking habits were not independently associated with insulin sensitivity or β-cell function in a healthy middle-aged European population. Health-selection bias, methodological shortcomings or a true lack of causal links between smoking and impaired insulin sensitivity/secretion are possible explanations. The mechanisms behind the observed increased glucose and C-peptide areas under the curve during the oral glucose tolerance test in male smokers need to be further evaluated.
authors.affiliation: Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Gottsäter
authors.affiliation: INSERM U-1018, CESP, Team5 (EpReC, Renal and Cardiovascular Epidemiology), Villejuif, France.
authors.forename: B
authors.initials: B
authors.lastname: Balkau
authors.affiliation: Mater Misericordiae University Hospital, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Hatunic
authors.affiliation: Instituto de Investigación Princesa IP, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Gabriel
authors.affiliation: Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.|Metabolic Unit, Institute of Biomedical Engineering, Padua, Italy.|Mariahilf Community Pharmacy, Arnoldstein, Austria.
authors.forename: C-H
authors.initials: CH
authors.lastname: Anderwald
authors.affiliation: Department of Epidemiology and Biostatistics, VU Medical Centre, Amsterdam, The Netherlands.|EMGO+ Institute for Health and Care Research, VU Medical Centre, Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Dekker
authors.affiliation: University of Belgrade, Clinic for Endocrinology, Diabetes and Metabolic Diseases, Belgrade, Serbia.
authors.forename: N
authors.initials: N
authors.lastname: Lalic
authors.affiliation: Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: P M
authors.initials: PM
authors.lastname: Nilsson
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000378:metabolism; D003430:Cross-Sectional Studies; D005060:Europe; D005260:Female; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012907:Smoking / Q000453:epidemiology* / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin