title: The protective effects of a novel fitness-fatness index on all-cause mortality among adults with cardiovascular disease.
abstract: BACKGROUND
  We evaluated the specific association between a fitness-fatness index (FFI) and all-cause mortality among a national sample of US adults with coronary artery disease, congestive heart failure, or myocardial infarction. This FFI has recently emerged in the literature as a novel index of health.
  
  
  OBJECTIVE
  We hypothesize that FFI will be inversely associated with mortality risk.
  
  
  METHODS
  The FFI was calculated as cardiorespiratory fitness divided by waist-to-height ratio. Data from the 1999-2006 National Health and Nutrition Examination Survey were used to identify 1206 participants, ages 20 to 85. Person-months of follow-up were calculated from the date of interview until date of death or censoring on December 31, 2011, whichever came first.
  
  
  RESULTS
  In a Cox proportional hazards model, for every 1-FFI-unit increase, participants had a 6% reduced all-cause mortality rate (hazard ratio [HR]: 0.94, 95% confidence interval [CI]: 0.91-0.97, P = 0.001; N = 1206). Results were similar among those diagnosed with coronary artery disease (HR: 0.94, 95% CI: 0.90-0.98, P = 0.007), congestive heart failure (HR: 0.95, 95% CI: 0.91-0.99, P = 0.02), or myocardial infarction (HR: 0.96, 95% CI: 0.92-0.99, P = 0.04). When examined in isolation, only fitness (and not fatness) was linked with survival benefits.
  
  
  CONCLUSIONS
  In this national sample, increased FFI was associated with reduced risk of all-cause mortality; this association was driven by the beneficial effects of fitness. This underscores the importance of tailored cardiac rehabilitation programs designed to promote fitness, in particular, among cardiac populations.
authors.affiliation: Physical Activity Epidemiology Laboratory, Exercise Psychology Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, Mississippi.
authors.forename: Emily
authors.initials: E
authors.lastname: Frith
authors.affiliation: Physical Activity Epidemiology Laboratory, Exercise Psychology Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, Mississippi.
authors.forename: Paul D
authors.identifier: http://orcid.org/0000-0001-7711-4741
authors.initials: PD
authors.lastname: Loprinzi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D002423:Cause of Death / Q000639:trends; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000534:rehabilitation; D010809:Physical Fitness / Q000502:physiology*; D018570:Risk Assessment; D012307:Risk Factors; D040242:Risk Reduction Behavior; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D055815:Young Adult
keywords: Cardiac rehabilitation; Epidemiology; chronic disease; obesity; physical activity