title: Smoking is associated with more abdominal fat in morbidly obese patients.
abstract: BACKGROUND
  While the association between cigarette smoking and abdominal fat has been well studied in normal and overweight patients, data regarding the influence of tobacco use in patients with morbid obesity remain scarce. The aim of this study is to evaluate body fat distribution in morbidly obese smokers.
  
  
  METHODS
  We employed a cross-sectional study and grouped severely obese patients (body mass index [BMI] >40 kg/m2 or >35 kg/m2 with comorbidities) according to their smoking habits (smokers or non-smokers). We next compared the anthropometrical measurements and body composition data (measured by electric bioimpedance) of both groups. We analyzed the effect of smoking on body composition variables using univariate and multiple linear regression (MLR); differences are presented as regression coefficients (b) and their respective 95% confidence intervals.
  
  
  RESULTS
  We included 536 morbidly obese individuals, 453 (84.5%) non-smokers and 83 (15.5%) smokers. Male smokers had a higher BMI (b=3.28 kg/m2, p=0.036), larger waist circumference (b=6.07 cm, p=0.041) and higher percentage of body fat (b=2.33%, p=0.050) than non-smokers. These differences remained significant even after controlling for confounding factors. For females, the only significant finding in MLR was a greater muscle mass among smokers (b=1.34kg, p=0.028). No associations were found between tobacco load measured in pack-years and anthropometric measures or body composition.
  
  
  CONCLUSIONS
  Positive associations between smoking and BMI, and waist circumference and percentage of body fat, were found among male morbidly obese patients, but not among females. To the best of our knowledge, this study is the first investigation of these aspects in morbidly obese subjects. We speculate that our findings may indicate that the coexistence of morbid obesity and smoking helps to explain the more serious medical conditions, particularly cardiovascular diseases and neoplasms, seen in these patients.
authors.affiliation: Center of Obesity and Metabolic Syndrome, Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Post-Graduation Program in Medicine and Health Science, School of Medicine Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Raquel
authors.initials: R
authors.lastname: Chatkin
authors.affiliation: Post-Graduation Program in Medicine and Health Science, School of Medicine Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Chatkin
authors.affiliation: Department of Psychiatry, Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Lucas
authors.initials: L
authors.lastname: Spanemberg
authors.affiliation: Center of Obesity and Metabolic Syndrome, Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Casagrande
authors.affiliation: Post-Graduation Program in Medicine and Health Science, School of Medicine Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Mario
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Center of Obesity and Metabolic Syndrome, Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Post-Graduation Program in Medicine and Health Science, School of Medicine Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Cláudio
authors.initials: C
authors.lastname: Mottin
mesh_terms: D050153:Abdominal Fat / Q000473:pathology*; D000328:Adult; D001823:Body Composition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000150:complications* / Q000473:pathology; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*