title: Energy Metabolism and the Burden of Multimorbidity in Older Adults: Results From the Baltimore Longitudinal Study of Aging.
abstract: Excessively elevated resting metabolic rate (RMR) for persons of a certain age, sex, and body composition is a mortality risk factor. Whether elevated RMR constitutes an early marker of health deterioration in older adult has not been fully investigated. Using data from the Baltimore Longitudinal Study of Aging, we hypothesized that higher RMR (i) was cross-sectionally associated with higher multimorbidity and (ii) predicted higher multimorbidity in subsequent follow-ups. The analysis included 695 Baltimore Longitudinal Study of Aging participants, aged 60 or older at baseline, of whom 248 had follow-up data available 2 years later and 109 four years later. Multimorbidity was assessed as number of chronic diseases. RMR was measured by indirect calorimetry and was tested in regression analyses adjusted for covariates age, sex, and dual-energy x-ray absorptiometry-measured total body fat mass and lean mass. Baseline RMR and multimorbidity were positively associated, independent of covariates (p = .002). Moreover, in a three-wave bivariate autoregressive cross-lagged model adjusted for covariates, higher prior RMR predicted greater future multimorbidity above and beyond the cross-sectional and autoregressive associations (p = .034). RMR higher than expected, given age, sex, and body composition, predicts future higher multimorbidity in older adults and may be used as early biomarker of impending health deterioration. Replication and the development of normative data are required for clinical translation.
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland. Department of Medical and Surgical Sciences, University of Bologna, Italy. elisa.fabbri@nih.gov.
authors.forename: Elisa
authors.initials: E
authors.lastname: Fabbri
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Yang
authors.initials: Y
authors.lastname: An
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Schrack
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Marta
authors.initials: M
authors.lastname: Gonzalez-Freire
authors.affiliation: Department of Medical and Surgical Sciences, University of Bologna, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zoli
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.affiliation: Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.affiliation: Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Boyd
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Studenski
authors.affiliation: Intramural Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D015142:Baltimore; D001823:Body Composition; D002153:Calorimetry, Indirect; D002908:Chronic Disease; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012146:Rest / Q000502:physiology; D012307:Risk Factors
keywords: Aging; Health status; Metabolism.; Multimorbidity; Resting metabolic rate