title: Changes of body mass index in relation to mortality: results of a cohort of 42,099 adults.
abstract: BACKGROUND
  High Body-Mass-Index (BMI) is associated with increased all-cause mortality, but little is known about the effect of short- and long-term BMI change on mortality. The aim of the study was to determine how long-term weight change affects mortality.
  
  
  RESULTS
  Within a population-based prospective cohort of 42,099 Austrian men and women (mean age 43 years) with at least three BMI measurements we investigated the relationship of BMI at baseline and two subsequent BMI change intervals of five years each with all-cause mortality using Cox proportional Hazard models. During median follow-up of 12 years 4,119 deaths were identified. The lowest mortalities were found in persons with normal weight or overweight at baseline and stable BMI over 10 years. Weight gain (≥0.10 kg/m(2)/year) during the first five years was associated with increased mortality in overweight and obese people. For weight gain during both time intervals mortality risk remained significantly increased only in overweight (Hazard Ratio (HR): 1.39 (95% confidence interval: 1.01; 1.92)) and obese women (1.85 (95% confidence interval: 1.18; 2.89)). Weight loss (< -0.10 kg/m(2)/year) increased all-cause mortality in men and women consistently. BMI change over time assessed using accepted World Health Organisation BMI categories showed no increased mortality risk for people who remained in the normal or overweight category for all three measurements. In contrast, HRs for stable obese men and women were 1.57 (95% CI: 1.31; 1.87) and 1.46 (95% CI: 1.25; 1.71) respectively.
  
  
  CONCLUSIONS
  Our findings highlight the importance of weight stability and obesity avoidance in prevention strategy.
authors.affiliation: Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany ; Clinic for Geriatric Rehabilitation, Robert-Bosch Hospital, Stuttgart, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Klenk
authors.affiliation: Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany ; Clinic for Geriatric Rehabilitation, Robert-Bosch Hospital, Stuttgart, Germany.
authors.forename: Kilian
authors.initials: K
authors.lastname: Rapp
authors.affiliation: Department of Medical Statistics, Informatics and Health Economics, Medical University, Innsbruck, Austria.
authors.forename: Hanno
authors.initials: H
authors.lastname: Ulmer
authors.affiliation: Agency for Preventive and Social Medicine, Bregenz, Austria.
authors.forename: Hans
authors.initials: H
authors.lastname: Concin
authors.affiliation: Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany ; Agency for Preventive and Social Medicine, Bregenz, Austria.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Nagel
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality / Q000639:trends*; D013997:Time Factors