Preventable smoking and exercise-related hospital admissions - A model based on the NHEFS

Background: The NHANES I Epidemiologic Follow-Up Study (NHEFS), a longitudi nal study of a representative sample of U.S. adults, makes it possible for the first time to develop a simulation model relating hospital admissions t o baseline clinical risk factors for the general adult population. The mode l is presented here and used to project the impact on hospital admissions o f changes in smoking behavior-and sedentary lifestyle. Methods: Three kinds of projections were calculated for the cohort of adult s aged 45 to 74 at baseline: projections of hospital admissions in the abse nce Of the risk factor; projections that reflect a 10-year lag between beha vior change and full health benefit; and projections that reflect both lag and incomplete adherence to: behavior change. For incomplete adherence we a ssumed that only 10% of the at-risk population changed their behavior. Results: Tests of the simulation model showed that it agreed with a Cox ana lysis of the hospital data and accurately projected observed hospital admis sions over the study period. The projections showed that eliminating smokin g 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 ye ars was the same. When only 10% of the population at risk stopped smoking o r 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 inacti ve persons to become active. Improving adherence can markedly improve the i mpact on hospitalizations. The costs of these efforts would be rewarded not only by better health, but by lower expenditures for hospitalization. (C) 2001 American Journal of Preventive Medicine.