title: Preventable smoking and exercise-related hospital admissions. A model based on the NHEFS.
abstract: BACKGROUND
  The NHANES I Epidemiologic Follow-Up Study (NHEFS), a longitudinal study of a representative sample of U.S. adults, makes it possible for the first time to develop a simulation model relating hospital admissions to baseline clinical risk factors for the general adult population. The model is presented here and used to project the impact on hospital admissions of changes in smoking behavior and sedentary lifestyle.
  
  
  METHODS
  Three kinds of projections were calculated for the cohort of adults aged 45 to 74 at baseline: projections of hospital admissions in the absence of the risk factor; projections that reflect a 10-year lag between behavior change and full health benefit; and projections that reflect both lag and incomplete adherence to behavior change. For incomplete adherence we assumed that only 10% of the at-risk population changed their behavior.
  
  
  RESULTS
  Tests of the simulation model showed that it agreed with a Cox analysis of the hospital data and accurately projected observed hospital admissions over the study period. The projections showed that eliminating smoking would reduce annual rates of all-cause hospitalization among older adults by 8.9% 20 years after baseline. Eliminating inactivity would reduce them 4.6%. Introducing a lag of 10 years between behavior modification and full benefit delayed the impact on hospitalization rates but the effect at 20 years was the same. When only 10% of the population at risk stopped smoking or became physically active, a percentage that reflects the effectiveness of current interventions, annual hospitalization rates at 20 years fell by 0.9% and 0.5%, respectively.
  
  
  CONCLUSIONS
  Substantial reductions in hospital admissions can be achieved by interventions to prevent smoking, help smokers quit, or encourage inactive persons to become active. Improving adherence can markedly improve the impact on hospitalizations. The costs of these efforts would be rewarded not only by better health, but by lower expenditures for hospitalization.
authors.affiliation: Institute for Health, Health Care Policy, and Aging Research, Rutgers University, New Brunswick, New Jersey 08901, USA. lrussell@rci.rutgers.edu
authors.forename: L B
authors.initials: LB
authors.lastname: Russell
authors.forename: S M
authors.initials: SM
authors.lastname: Teutsch
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: A
authors.initials: A
authors.lastname: Dey
authors.forename: E
authors.initials: E
authors.lastname: Milan
mesh_terms: D017677:Age Distribution; D000368:Aged; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D015438:Health Behavior; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D011322:Primary Prevention / Q000379:methods*; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D018570:Risk Assessment; D017678:Sex Distribution; D012907:Smoking / Q000401:mortality; D016540:Smoking Cessation / Q000379:methods / Q000706:statistics & numerical data*; D000074606:Smoking Prevention; D016019:Survival Analysis