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This Article Full Text (Publish Ahead of Print[PDF]) All Versions of this Article: 90/6/1579    most recent ajcn.2009.28047v1 Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Delmonico, M. J Articles by Goodpaster, B. H PubMed PubMed Citation Articles by Delmonico, M. J Articles by Goodpaster, B. H Agricola Articles by Delmonico, M. J Articles by Goodpaster, B. H

Longitudinal study of muscle strength, quality, and adipose tissue infiltration^1,2,3

¹ From the Departments of Epidemiology (MJD, MBC, RB, and ABN) and Medicine (MBC, BHG, and ABN), University of Pittsburgh, Pittsburgh, PA; the Department of Kinesiology, University of Rhode Island, Kingston, RI (MJD); the Laboratory for Epidemiology, Demography and Biometry, National Institute on Aging, Bethesda, MD (TBH); the Institute of Health Sciences, VU University and EMGO Institute, VU Medical Center, Amsterdam, Netherlands (MV); the Department of Internal Medicine, Pochon CHA University, Pochon, Korea (SWP); the Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN (PV-M); the Department of Aging and Geriatric Research, University of Florida, Gainesville, FL (TMM); and the Department of Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, CA (MN).

² Supported by National Institute on Aging contracts N01-AG-6–2101, N01-AG-6–2103, and N01-AG-6–2106 and in part by the Intramural Research Program of the NIH, National Institute on Aging.

³ Address correspondence to MJ Delmonico, MPH Department of Kinesiology, 25 West Independence Way, Room 214, University of Rhode Island, Kingston, RI 02881. E-mail: delmonico{at}uri.edu.

for the Health, Aging, and Body Composition Study

ABSTRACT

Background: Sarcopenia is thought to be accompanied by increased muscle fat infiltration. However, no longitudinal studies have examined concomitant changes in muscle mass, strength, or fat infiltration in older adults.

Objective: We present longitudinal data on age-related changes in leg composition, strength, and muscle quality (MQ) in ambulatory, well-functioning men and women. We hypothesized that muscle cross-sectional area (CSA) and strength would decrease and muscular fat infiltration would increase over 5 y.

Design: Midthigh muscle, subcutaneous fat (SF), and intermuscular fat (IMF) CSAs and isokinetic leg muscle torque (MT) and MQ (MT/quadriceps CSA) were examined over 5 y in the Health, Aging, and Body Composition study cohort (n = 1678).

Results: Men experienced a 16.1% loss of MT, whereas women experienced a 13.4% loss. Adjusted annualized decreases in MT were 2–5 times greater than the loss of muscle CSA in those who lost weight and in those who remained weight-stable. Weight gain did not prevent the loss of MT, despite a small increase in muscle CSA. Only those who gained weight had an increase in SF (P < 0.001), whereas those who lost weight also lost SF (P < 0.001). There was an age-related increase in IMF in men and women (P < 0.001), and IMF increased in those who lost weight, gained weight, or remained weight-stable (all P < 0.001).

Conclusions: Loss of leg MT in older adults is greater than muscle CSA loss, which suggests a decrease in MQ. Additionally, aging is associated with an increase in IMF regardless of changes in weight or SF.

Received for publication May 7, 2009. Accepted for publication September 20, 2009.