Lifestyle factors associated with age-related differences in body composition: the Florey Adelaide Male Aging Study.
BACKGROUND
Age-related change in body composition is associated with adverse health outcomes, including functional decline, disability, morbidity, and early mortality. Prevention of age-related changes requires a greater understanding of the associations among age, lifestyle factors, and body composition.


OBJECTIVE
We aimed to comprehensively determine lifestyle factors associated with age-related differences in body composition assessed by using dual-energy X-ray absorptiometry.


METHODS
We analyzed baseline (cross-sectional) data collected from 2002 to 2005 for approximately 1200 men in the Florey Adelaide Male Aging Study, a regionally representative cohort of Australian men aged 35-81 y.


RESULTS
Mean values for whole-body lean mass (LM) and areal bone mineral density (aBMD) decreased, whereas mean values for abdominal fat mass (FM) and whole-body and abdominal percentage FM (%FM) increased with age. No significant age-related differences were found for whole-body FM. Multiple adjusted odds of being in the highest tertiles for whole-body and abdominal %FM decreased for smokers (63-71%) but increased with age group and for lowest energy (43-50%), carbohydrate (92-107%), and fiber (107%) intake tertiles. Multiple adjusted odds of being in the highest aBMD tertile decreased for lowest body mass (92%) and carbohydrate intake (63%) tertiles and for men aged > or = 75 y (78%) but increased for Australian birth (58%) and for participation in vigorous physical activities (82%).


CONCLUSIONS
Age-related differences in body composition indicate that whole-body FM remains stable but increases viscerally and that whole-body %FM is confounded by LM, whereas aBMD decreases with age. Age-related differences in %FM and aBMD are associated with demographic and lifestyle factors.
Atlantis
Evan
E
Exercise, Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Sydney, Australia. e.atlantis@usyd.edu.au
Martin
Sean A
SA
Haren
Matthew T
MT
Taylor
Anne W
AW
Wittert
Gary A
GA
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001315:Australia; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003710:Demography; D004032:Diet; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D016017:Odds Ratio; D012907:Smoking