title: Insulin resistance and systemic inflammation, but not metabolic syndrome phenotype, predict 9 years mortality in older adults.
abstract: BACKGROUND
  Although metabolic syndrome (MS) is a typical condition of middle-aged/older person, the association between MS and mortality risk has not been confirmed in people over 65 years. We hypothesized that while in the elderly MS phenotype might lose its value in predicting mortality risk, the two core factors of MS, i.e. insulin resistance (IR) and low grade systemic inflammation (LGSI) would not.
  
  
  METHODS
  1011 community-dwelling older individuals (InCHIANTI study) were included. MS phenotype was defined by NCEP-ATP-III criteria. IR was calculated by HOMA; high-sensitivity C reactive protein was measured by ELISA. Subjects were divided into four groups based on presence/absence of IR (HOMA ≥ 2.27) and LGSI (hs-CRP ≥ 3 g/L): Group 1: no IR/LGSI (reference); Group 2: LGSI only; Group 3: IR only; Group 4: IR + LGSI. Hazard Ratios (HR) for 9-years cardiovascular (CVD) and total mortality, according to IR/LGSI groups, were estimated in subjects with (n.311) and without MS by Cox model.
  
  
  RESULTS
  31.8% of subjects with MS phenotype had no IR, 45.3% had no LGSI; moreover, 51% of subjects with both IR and LGSI didn't display the MS phenotype. MS phenotype was not associated with CVD (HR: 1.29; 95%C.I.:0.92-1.81) or total (HR: 1.07; 95%C.I.:0.86-1.34) mortality risk, whereas the presence of IR plus LGSI was associated with increased CVD (no MS: HR 2.07, 95%CI: 1.12-3.72; MS: HR 9.88, 95%CI: 2.18-4), and overall (no MS: HR 1.72, 95%CI: 1.001-3.17; MS: HR 1.51, 95%CI: 1.02-2.28) mortality risk. The presence of IR (HR: 6.90, 95%CI: 1.45-32) or LGSI (HR 7.56, 95%CI: 1.63-35) was associated with CVD mortality, only among individuals with MS phenotype.
  
  
  CONCLUSIONS
  Among community-dwelling older individuals, IR and LGSI, but not MS phenotype, was associated with 9-years overall and CVD mortality risk. Since a reduced "overlap" between MS phenotype and its physiopathological core (IR and LGSI) might be present with aging, we suggest that the definition of MS might be more holistic in advanced age, and probably comprise the measurement of IR and LGSI.
authors: Department of Medical Sciences, Section of Internal and CardioRespiratory Medicine, University of Ferrara, Italy. Electronic address: gzuliani@hotmail.com.
authors: Giovanni
authors: G
authors: Zuliani
authors: Department of Medical Sciences, Section of Internal and CardioRespiratory Medicine, University of Ferrara, Italy.
authors: Mario Luca
authors: ML
authors: Morieri
authors: Department of Medical Sciences, Section of Internal and CardioRespiratory Medicine, University of Ferrara, Italy.
authors: Stefano
authors: S
authors: Volpato
authors: Department of Internal Medicine and Biomedical Sciences, Section of Geriatrics, University of Parma, Italy.
authors: Marcello
authors: M
authors: Maggio
authors: Institute of Gerontology and Geriatrics, INNRCA, Ancona, Italy.
authors: Antonio
authors: A
authors: Cherubini
authors: Department of Medical Sciences, Section of Internal and CardioRespiratory Medicine, University of Ferrara, Italy.
authors: Daniela
authors: D
authors: Francesconi
authors: ASF Geriatric Rehabilitation, Florence, Italy; Tuscany Regional Health Agency, I.O.T., Florence, Italy.
authors: Stefania
authors: S
authors: Bandinelli
authors: Department of Gerontology, Geriatrics and Metabolic Diseases, Second University of Naples, Italy.
authors: Giuseppe
authors: G
authors: Paolisso
authors: Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
authors: Jack M
authors: JM
authors: Guralnik
authors: Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, NIH, Baltimore, MD, USA.
authors: Luigi
authors: L
authors: Ferrucci
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000401:mortality*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications / Q000401:mortality*; D007333:Insulin Resistance; D007558:Italy / Q000453:epidemiology; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000401:mortality*; D010641:Phenotype; D012306:Risk
chemical_list: D002097:C-Reactive Protein
keywords: C reactive protein; Elderly; Insulin resistance; Metabolic syndrome; Mortality