title: Age Differences in the Association Between Body Mass Index Class and Annualized Medicare Expenditures.
abstract: OBJECTIVE
  The aim of the study is to assess the relationship between body mass index (BMI) class and Medicare claims among young-old (65-69), old (70-74), and old-old (75+) adults over a 10-year period.
  
  
  METHODS
  We assessed costs by BMI class and age group among 9,300 respondents to the 1998 Health and Retirement Study (HRS) with linked 1998-2008 Medicare claims data. BMI was classified as normal (18.5-24.9), overweight (25-29.9), mild obesity (30-34.9), or severe obesity (35 or above).
  
  
  RESULTS
  Annualized total Medicare claims adjusted for age, gender, ethnicity, education, and smoking history were 109% greater for severely obese young-old adults in comparison with normal weight young-old adults (US$9,751 vs. US$4,663). Total annualized claim differences between the normal weight and severely obese in the old and old-old groups were not statistically significant.
  
  
  CONCLUSIONS
  Excess Medicare expenditures related to obesity may be concentrated among severely obese young-old adults. Preventing severe obesity among middle and older aged adults may have large cost implications for society.
authors.affiliation: Indiana University, Indianapolis, USA Regenstrief Institute, Inc., Indianapolis, IN, USA Indiana University Center for Aging Research, Indianapolis, USA daniclar@iupui.edu.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Clark
authors.affiliation: Indiana University, Indianapolis, USA.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Lane
authors.affiliation: Regenstrief Institute, Inc., Indianapolis, IN, USA.
authors.forename: Roberta
authors.initials: R
authors.lastname: Ambuehl
authors.affiliation: Indiana University, Indianapolis, USA Regenstrief Institute, Inc., Indianapolis, IN, USA.
authors.forename: Wanzhu
authors.initials: W
authors.lastname: Tu
authors.affiliation: Indiana University, Indianapolis, USA.
authors.forename: Chiung-Ju
authors.initials: CJ
authors.lastname: Liu
authors.affiliation: Indiana University, Indianapolis, USA Regenstrief Institute, Inc., Indianapolis, IN, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Unroe
authors.affiliation: Indiana University, Indianapolis, USA Regenstrief Institute, Inc., Indianapolis, IN, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Callahan
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D005260:Female; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D006278:Medicare / Q000191:economics*; D009765:Obesity / Q000191:economics; D014481:United States
keywords: Medicare; expenditures; obesity; older adults