title: The relationship between anthropometric measures, blood gases, and lung function in morbidly obese white subjects.
abstract: BACKGROUND
  Obesity may cause adverse effects on the respiratory system. The main purpose of this study was to investigate how various measures of obesity are related to arterial blood gases and pulmonary function.
  
  
  METHODS
  This is a cross-sectional study of consecutive morbidly obese patients with normal lung function. Blood gas samples were taken from the radial artery after 5 min of rest with subjects sitting upright. Lung function measurements included dynamic spirometry, static lung volumes, and gas diffusing capacity.
  
  
  RESULTS
  The 149 patients (77% women) had a mean (SD) age of 43 years (11 years) and BMI of 45.0 kg/m(2) (6.3 kg/m(2)). The mean expiratory reserve volume (ERV) was less than half (49%) of predicted value, whilst most other lung function values were within predicted range. Forty-two patients had an abnormally low pO2 value (<10.7 kPa [80 mmHg]), while eight patients had a high pCO2 value (>6.0 kPa [45 mmHg]). All anthropometric measures correlated significantly with decreasing pO2 and increasing pCO2 (all P values < 0.05). BMI, neck circumference (NC), and waist circumference (WC) were negatively correlated with ERV (r = -0.25, -0.19, -0.21, respectively, all P values < 0.05). Multiple linear regression showed that BMI, WC, and NC were significantly associated with pO2 after adjustments for age, gender, and pack-years (all P values < 0.001). The models explained 34-36% of the variations in pO2. BMI, NC, and WC were also significantly associated with pCO2 (all P values < 0.05).There was no significant association between waist-to-hip ratio and blood gases (both P values > 0.27).
  
  
  CONCLUSIONS
  Both central and overall obesity were associated with unfavorable blood gases and low ERV.
authors.affiliation: The Morbid Obesity Center, Vestfold Hospital Trust, Box 2168, 3103, Tønsberg, Norway.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Gabrielsen
authors.forename: May Brit
authors.initials: MB
authors.lastname: Lund
authors.forename: Johny
authors.initials: J
authors.lastname: Kongerud
authors.forename: Karl Erik
authors.initials: KE
authors.lastname: Viken
authors.forename: Jo
authors.initials: J
authors.lastname: Røislien
authors.forename: Jøran
authors.initials: J
authors.lastname: Hjelmesæth
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis; D015992:Body Mass Index; D049628:Body Size; D002245:Carbon Dioxide / Q000097:blood*; D003430:Cross-Sectional Studies; D005105:Expiratory Reserve Volume; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000208:ethnology / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood*; D012129:Respiratory Function Tests; D044465:White People
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen