title: Association Between Serum β2-Microglobulin Levels and Prevalent and Incident Physical Frailty in Community-Dwelling Older Women.
abstract: OBJECTIVE
  To investigate whether higher serum β2-microglobulin (B2M) levels, a kidney function marker, are associated with prevalent and incident frailty in community-dwelling older women.
  
  
  METHODS
  Cross-sectional and longitudinal analyses of a prospective cohort.
  
  
  METHODS
  Population-based cohort study in Tokyo, Japan.
  
  
  METHODS
  Community-dwelling women aged 75 and older with adequate data for assessing frailty status (N = 1,191) and a subset of participants without baseline frailty but with repeated frailty assessment at 2 and 4 years of follow-up.
  
  
  METHODS
  The primary predictor was B2M level. Outcomes were prevalent and incident frailty during the 4-year follow-up period. Frailty was defined as presence of three of the five Fried criteria: weight loss, exhaustion, weakness, slowness, and low physical activity. Adjusted odds ratios for the main confounders were obtained using logistic regression. Discrete-time Cox proportional hazards models were used to determine the risk of developing frailty.
  
  
  RESULTS
  The study included 241 (20.2%) women with prevalent frailty at baseline and 139 (21.1%) with incident frailty during the 4-year follow-up. On multivariate analysis adjusted for multiple potential confounders, the odds of prevalent frailty were 2.5 times as great with B2M levels of 1.9 to 2.1 mg/L as with levels less than 1.6 mg/L and 2.0 times as great with B2M levels of 2.2 mg/L or more. In the unadjusted model, B2M levels of 1.9 to 2.1 mg/L were associated with a greater incidence of frailty than B2M levels of less than 1.6 mg/L (hazard ratio = 1.72, 95% confidence interval = 1.04-2.86). In the multivariate analysis adjusted for potential confounders, no significant association was noted between the highest B2M quartile and incident frailty.
  
  
  CONCLUSIONS
  Higher B2M levels were independently associated with greater frailty at baseline in older adults but only slightly associated with greater risk of incident frailty over 4 years of follow-up.
authors.affiliation: East-West Medical Research Institute, Kyung Hee University, Seoul, Korea.
authors.forename: Miji
authors.initials: M
authors.lastname: Kim
authors.affiliation: National Center for Geriatrics and Gerontology, Aichi, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors.forename: Narumi
authors.initials: N
authors.lastname: Kojima
authors.affiliation: Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors.forename: Hideyo
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Hirano
authors.affiliation: College of Medicine, Kyung Hee University, Seoul, Korea.
authors.forename: Chang Won
authors.initials: CW
authors.lastname: Won
authors.affiliation: Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors.forename: Hunkyung
authors.initials: H
authors.lastname: Kim
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment; D006801:Humans; D015994:Incidence; D007564:Japan; D008137:Longitudinal Studies; D015995:Prevalence; D012307:Risk Factors; D001613:beta 2-Microglobulin / Q000097:blood*
chemical_list: D015415:Biomarkers; D001613:beta 2-Microglobulin
keywords: aging; beta-2-microglobulin; epidemiology; frailty; kidney function