title: Normal weight obesity and functional outcomes in older adults.
abstract: BACKGROUND
  Obesity defined by body mass index (BMI) is associated with higher levels of functional impairment. However, BMI strata misrepresent true adiposity, particularly in those with a normal BMI but elevated body fat (BF%) (normal weight obesity [NWO]) whom are at higher metabolic and mortality risk. Whether this subset of patients is associated with worsening functional outcomes is unclear.
  
  
  METHODS
  Subjects aged ≥60 years with a BMI ≥18.5 kg/m(2) from NHANES III (1988-1994) were included. We created sex-specific tertiles of BF%. Data on physical limitations (PL), instrumental (IADL) and basic activities of daily living (BADL) were obtained. The analysis focused on the association between NWO and these outcomes. Comparative rates among each tertile using logistic regression (referent=lowest tertile) were assessed, incrementally adding co-variates.
  
  
  RESULTS
  Of the 4484 subjects aged ≥60 years, 1528 had a normal BMI, and the range of the mean age of tertiles was 69.9-71.2 years. Lean mass was lowest in the elevated BF% group than in the middle or low tertiles (42.6 vs 44.9 vs 45.8; p<0.001). Those with NWO had higher PL risk than the referent in females only in our adjusted model (males OR 1.18 [0.63-2.21]; females OR 1.90 [1.04-3.48]) but not after incorporating lean mass (males OR 1.11[0.56-2.20]; females (1.73 [0.92-3.25]). Neither sex with high BF% had higher IADL risk than the corresponding tertiles (males OR 0.67 [0.35-1.33]; females OR 1.20 [0.74-1.93]). NWO was protective in males only (OR 0.28 [0.10-0.83]) but not in females (OR 0.64 [0.40-1.03]).
  
  
  CONCLUSIONS
  NWO is associated with increased physical impairment in older adults in females only, highlighting the importance of recognizing the association of obesity with disability in elders.
authors.affiliation: Section of General Internal Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States; Geisel School of Medicine at Dartmouth, Hanover, NH, United States; Dartmouth Centers for Health and Aging, Dartmouth College, Hanover, NH, United States. Electronic address: john.batsis@gmail.com.
authors.forename: John A
authors.initials: JA
authors.lastname: Batsis
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, Mayo Clinic, Rochester, MN 55905, United States.
authors.forename: Karine R
authors.initials: KR
authors.lastname: Sahakyan
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, Mayo Clinic, Rochester, MN 55905, United States.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Rodriguez-Escudero
authors.affiliation: Geisel School of Medicine at Dartmouth, Hanover, NH, United States; Dartmouth Centers for Health and Aging, Dartmouth College, Hanover, NH, United States.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Bartels
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, Mayo Clinic, Rochester, MN 55905, United States.
authors.forename: Francisco
authors.initials: F
authors.lastname: Lopez-Jimenez
mesh_terms: D000203:Activities of Daily Living; D050154:Adiposity; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D005260:Female; D006801:Humans; D056865:Ideal Body Weight; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009765:Obesity / Q000453:epidemiology*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055105:Waist Circumference; D049629:Waist-Hip Ratio
keywords: Elderly; Epidemiology; Functional performance; Obesity