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Am J Clin Nutr. 2009 Dec;90(6):1579-85. doi: 10.3945/ajcn.2009.28047. Epub 2009 Oct 28.

Longitudinal study of muscle strength, quality, and adipose tissue infiltration.

Author information

  • 1Department of Epidemiology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA. delmonico@uri.edu

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.

PMID:
19864405
[PubMed - indexed for MEDLINE]
PMCID:
PMC2777469
Free PMC Article

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