title: Body mass index and health-related quality of life among young Swiss men.
abstract: BACKGROUND
  Studies about the association between body mass index (BMI) and health-related quality of life (HRQOL) are often limited, because they 1) did not include a broad range of health-risk behaviors as covariates; 2) relied on clinical samples, which might lead to biased results; and 3) did not incorporate underweight individuals. Hence, this study aims to examine associations between BMI (from being underweight through obesity) and HRQOL in a population-based sample, while considering multiple health-risk behaviors (low physical activity, risky alcohol consumption, daily cigarette smoking, frequent cannabis use) as well as socio-demographic characteristics.
  
  
  METHODS
  A total of 5 387 young Swiss men (mean age = 19.99; standard deviation = 1.24) of a cross-sectional population-based study were included. BMI was calculated (kg/m²) based on self-reported height and weight and divided into 'underweight' (<18.5), 'normal weight' (18.5-24.9), 'overweight' (25.0-29.9) and 'obese' (≥30.0). Mental and physical HRQOL was assessed via the SF-12v2. Self-reported information on physical activity, substance use (alcohol, cigarettes, and cannabis) and socio-demographic characteristics also was collected. Logistic regression analyses were conducted to study the associations between BMI categories and below average mental or physical HRQOL. Substance use variables and socio-demographic variables were used as covariates.
  
  
  RESULTS
  Altogether, 76.3% were normal weight, whereas 3.3% were underweight, 16.5% overweight and 3.9% obese. Being overweight or obese was associated with reduced physical HRQOL (adjusted OR [95% CI] = 1.58 [1.18-2.13] and 2.45 [1.57-3.83], respectively), whereas being underweight predicted reduced mental HRQOL (adjusted OR [95% CI] = 1.49 [1.08-2.05]). Surprisingly, obesity decreased the likelihood of experiencing below average mental HRQOL (adjusted OR [95% CI] = 0.66 [0.46-0.94]). Besides BMI, expressed as a categorical variable, all health-risk behaviors and socio-demographic variables were associated with reduced physical and/or mental HRQOL.
  
  
  CONCLUSIONS
  Deviations from normal weight are, even after controlling for important health-risk behaviors and socio-demographic characteristics, associated with compromised physical or mental HRQOL among young men. Hence, preventive programs should aim to preserve or re-establish normal weight. The self-appraised positive mental well-being of obese men noted here, which possibly reflects a response shift, might complicate such efforts.
authors.affiliation: Institute of Social and Preventive Medicine, University of Zurich, Hirschengraben 84, Zurich 8001, Switzerland. michelle.dey@uzh.ch.
authors.forename: Michelle
authors.initials: M
authors.lastname: Dey
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gmel
authors.forename: Meichun
authors.initials: M
authors.lastname: Mohler-Kuo
mesh_terms: D000428:Alcohol Drinking / Q000453:epidemiology; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology; D050177:Overweight / Q000453:epidemiology; D011788:Quality of Life; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013557:Switzerland / Q000453:epidemiology; D013851:Thinness / Q000453:epidemiology; D055815:Young Adult