title: Estimating the risk of cardiovascular disease using an obese-years metric.
abstract: OBJECTIVE
  To examine the association between obese-years and the risk of cardiovascular disease (CVD).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Boston, USA.
  
  
  METHODS
  5036 participants of the Framingham Heart Study were examined.
  
  
  METHODS
  Obese-years was calculated by multiplying for each participant the number of body mass index (BMI) units above 29 kg/m(2) by the number of years lived at that BMI during approximately 50 years of follow-up. The association between obese-years and CVD was analysed using time-dependent Cox regression adjusted for potential confounders and compared with other models using the Akaike information criterion (AIC). The lowest AIC indicated better fit.
  The median cumulative obese-years was 24 (range 2-556 obese-years). During 138,918 person-years of follow-up, 2753 (55%) participants were diagnosed with CVD. The incidence rates and adjusted HR (AHR) for CVD increased with an increase in the number of obese-years. AHR for the categories 1-24.9, 25-49.9, 50-74.9 and ≥75 obese-years were, respectively, 1.31 (95% CI 1.15 to 1.48), 1.37 (95% CI 1.14 to 1.65), 1.62 (95% CI 1.32 to 1.99) and 1.80 (95% CI 1.54 to 2.10) compared with those who were never obese (ie, had zero obese-years). The effect of obese-years was stronger in males than females. For every 10 unit increase in obese-years, the AHR of CVD increased by 6% (95% CI 4% to 8%) for males and 3% (95% CI 2% to 4%) for females. The AIC was lowest for the model containing obese-years compared with models containing either the level of BMI or the duration of obesity alone.
  
  
  CONCLUSIONS
  This study demonstrates that obese-years metric conceptually captures the cumulative damage of obesity on body systems, and is found to provide slightly more precise estimation of the risk of CVD than the level or duration of obesity alone.
authors.affiliation: Department of Biostatistics and Population Health, Faculty of Public Health, University Muhammadiyah Aceh, Banda Aceh, Aceh, Indonesia Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Asnawi
authors.initials: A
authors.lastname: Abdullah
authors.affiliation: Department of Public Health Nutrition, Faculty of Public Health, University Muhammadiyah Aceh, Banda Aceh, Aceh, Indonesia.
authors.forename: Fauzi Ali
authors.initials: FA
authors.lastname: Amin
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Johannes
authors.initials: J
authors.lastname: Stoelwinder
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Tanamas
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Rory
authors.initials: R
authors.lastname: Wolfe
authors.affiliation: School of Population Health, University Queensland, Herston, Queensland, Australia.
authors.forename: Jan
authors.initials: J
authors.lastname: Barendregt
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Peeters
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D013997:Time Factors
keywords: EPIDEMIOLOGY; NUTRITION & DIETETICS; PUBLIC HEALTH; VASCULAR MEDICINE