title: The epidemiology of recent involuntary weight loss in the United States population.
abstract: BACKGROUND
  Although recent involuntary weight loss (RIWL) has been associated with mortality, no national studies described the prevalence among the general population, characteristics and long-term outcomes of people with RIWL.
  
  
  METHODS
  The authors analyzed data from the NHANES II Mortality Study of 5838 individuals 50-74.9 years old who between 1976-1980 underwent a physical examination that included height and weight measurements, biochemical tests and responded to questions about involuntary weight loss within the past six months. Vital status was determined through 1992. Logistic regression was used to examine characteristics associated with RIWL and Cox proportional hazard modeling was used to measure associations between RIWL and mortality.
  
  
  RESULTS
  13.3% of the population reported RIWL with 6.9% reporting > or = 5% RIWL. Obese individuals were at significantly higher risk of RIWL of > or = 5% compared to those with BMI 19-24.9 (OR=1.57. 95% CI: 1.13, 2.18). Other significant risk factors for RIWL included; poor self-reported health, cancer, high white blood cell count, low albumin and low hemoglobin levels, age and current smoking status. RIWL of > or = 5% was significantly associated with mortality (RR=1.24, 95% CI: 1.01, 1.53).
  
  
  CONCLUSIONS
  In summary, RIWL is fairly common among community-dwelling older adults, occurs disproportionately among obese individuals, is associated with characteristics of poor health and independently associated with mortality. These results indicate that RIWL needs to be considered an adverse health indicator even among obese individuals and despite the absence of several clinical indicators of disease.
authors.affiliation: University of Maryland, Department of Nutrition and Food Science, 0112 Skinner building, College Park, MD 20742, USA. nsahyoun@umd.edu
authors.forename: N R
authors.initials: NR
authors.lastname: Sahyoun
authors.forename: M K
authors.initials: MK
authors.lastname: Serdula
authors.forename: D A
authors.initials: DA
authors.lastname: Galuska
authors.forename: X L
authors.initials: XL
authors.lastname: Zhang
authors.forename: E R
authors.initials: ER
authors.lastname: Pamuk
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002423:Cause of Death; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009749:Nutrition Surveys; D009765:Obesity / Q000150:complications* / Q000401:mortality; D011237:Predictive Value of Tests; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D015431:Weight Loss