British Journal of Nutrition

Behaviour, Appetite and Obesity

Longitudinal changes in body composition associated with healthy ageing: men, aged 20–96 years

Andrew S. Jacksona1 c1, Ian Janssena2a3, Xuemei Suia4, Timothy S. Churcha5 and Steven N. Blaira4a6

a1 Department of Health and Human Performance, University of Houston, Houston, TX 77204, USA

a2 School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada

a3 Department of Community Health and Epidemiology, Queen's University, Kingston, ON, Canada

a4 Department of Exercise Science, University of South Carolina, Columbia, SC, USA

a5 Pennington Biomedical Research Center, Baton Rouge, LA, USA

a6 Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA


Obesity and sarcopenia are health problems associated with ageing. The present study modelled the longitudinal changes in body composition of healthy men, aged from 20 to 96 years, and evaluated the fidelity of BMI to identify age-dependent changes in fat mass and fat-free mass. The data from 7265 men with multiple body composition determinations (total observations 38 328) were used to model the age-related changes in body mass, fat mass, fat-free mass, BMI and percentage of body fat. Changes in fat mass and fat-free mass were used to evaluate the fidelity of BMI and to detect body composition changes with ageing. Linear mixed regression models showed that all trajectories of body composition with healthy ageing were quadratic. Fat mass, BMI and percentage of body fat increased from age 20 years and levelled off at approximately 80 years. Fat-free mass increased slightly from age 20 to 47 years and then declined at a non-linear rate with ageing. Levels of aerobic exercise had a positive influence on fat mass and a slight negative effect on fat-free mass. BMI and percentage of body fat were sensitive in detecting the increase in fat mass that occurred with healthy ageing, but failed to identify the loss of fat-free mass that started at age 47 years.

(Received November 18 2010)

(Revised June 08 2011)

(Accepted June 13 2011)

(Online publication August 03 2011)


c1 Corresponding author: Dr A. S. Jackson, fax +1 713 743 9860, email


Abbreviations: ACLS, Aerobics Center Longitudinal Study; DXA, dual-energy X-ray absorptiometry; LMM, linear mixed models; PAI, physical activity index