title: Normal weight obesity: a risk factor for cardiometabolic dysregulation and cardiovascular mortality.
abstract: OBJECTIVE
  We hypothesized that subjects with a normal body mass index (BMI), but high body fat (BF) content [normal weight obesity (NWO)], have a higher prevalence of cardiometabolic dysregulation and are at higher risk for cardiovascular (CV) mortality.
  
  
  RESULTS
  We analysed 6171 subjects >20 years of age from the Third National Health and Nutrition Examination Survey (NHANES III) and the NHANES III mortality study, whose BMI was within the normal range (18.5-24.9 kg/m(2)), and who underwent a complete evaluation that included body composition assessment, blood measurements, and assessment of CV risk factors. Survival information was available for >99% of the subjects after a median follow-up of 8.8 years. We divided our sample using sex-specific tertiles of BF%. The highest tertile of BF (>23.1% in men and >33.3% in women) was labelled as NWO. When compared with the low BF group, the prevalence of metabolic syndrome in subjects with NWO was four-fold higher (16.6 vs. 4.8%, P < 0.0001). Subjects with NWO also had higher prevalence of dyslipidaemia, hypertension (men), and CV disease (women). After adjustment, women with NWO showed a significant 2.2-fold increased risk for CV mortality (HR = 2.2; 95% CI, 1.03-4.67) in comparison to the low BF group.
  
  
  CONCLUSIONS
  Normal weight obesity, defined as the combination of normal BMI and high BF content, is associated with a high prevalence of cardiometabolic dysregulation, metabolic syndrome, and CV risk factors. In women, NWO is independently associated with increased risk for CV mortality.
authors.affiliation: Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Abel
authors.initials: A
authors.lastname: Romero-Corral
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
authors.forename: Justo
authors.initials: J
authors.lastname: Sierra-Johnson
authors.forename: Yoel
authors.initials: Y
authors.lastname: Korenfeld
authors.forename: Simona
authors.initials: S
authors.lastname: Boarin
authors.forename: Josef
authors.initials: J
authors.lastname: Korinek
authors.forename: Michael D
authors.initials: MD
authors.lastname: Jensen
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Parati
authors.forename: Francisco
authors.initials: F
authors.lastname: Lopez-Jimenez
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000401:mortality*; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism / Q000401:mortality*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult