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R esting M etabolic R ate in Old‐Old Women with and without Frailty: Variability and Estimation of Energy Requirements
Author(s) -
Weiss Carlos O.,
Cappola Anne R.,
Varadhan Ravi,
Fried Linda P.
Publication year - 2012
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2012.04101.x
Subject(s) - basal metabolic rate , medicine , confidence interval , odds ratio , gerontology , demography , body mass index , sociology
Objectives To measure resting metabolic rate ( RMR ) in old‐old adults living in the community and examine the association between measured RMR and frailty status and compare it with expected RMR generated by a predictive equation. Design Physiological substudy conducted as a home visit within an observational cohort study. Setting B altimore C ity and C ounty, M aryland. Participants Seventy‐seven women aged 83 to 93 enrolled in the W omen's H ealth and A ging S tudy II . Measurements Resting metabolic rate with indirect calorimetry, frailty status, fat‐free mass, ambient and body temperature, expected RMR according to the Mifflin‐St. Jeor equation. Results Average RMR was 1,119 ± 205 kcal/d (range 595–1,560 kcal/d). Agreement between observed and expected RMR was biased and poor (between‐subject coefficient of variation 38.0%, 95% confidence interval = 35.1–40.8). Variability of RMR was greater in frail individuals (heteroscedasticity F ‐test P = .02). Low and high RMR were associated with being frail (odds ratio 5.4, P = .04) and slower self‐selected walking speed ( P < .001) after adjustment for covariates. Conclusion Equations to predict RMR that are not validated in old‐old adults appear to correlate poorly with measured RMR . RMR is highly variable in old‐old women, with deviations from the mean predicting clinical frailty. These exploratory findings suggest a pathway to clinical frailty through high or low RMR .