Discordance in the decline in regional lean and bone mass with advancing age.
OBJECTIVE
To investigate whether regional mineral-free lean mass (lean mass) and bone mineral density (BMD) decrease equally with advancing age.


METHODS
Subjects were 420 premenopausal women and 239 postmenopausal women with right-side dominance. Age, height, weight, and body mass index were recorded. Lean mass of the arms, trunk and legs were measured by dual-energy X-ray absorptiometry (DEXA). BMD of the same segmental regions was measured by DEXA.


RESULTS
Trunk and bilateral leg lean mass were inversely correlated to age (r = -0.240, P < 0.0001, -0.167, P < 0.0001, and -0.183, P < 0.0001, respectively), but arm lean mass did not decrease with aging. Regional lean mass was positively correlated to regional BMD (r = 0.284-0.449, P < 0.0001). BMD was inversely correlated to age in all segmental regions (r = -0.586 to -0.449, P < 0.0001).


CONCLUSIONS
Decline in regional lean mass and decline in BMD with advancing age are discordant. Arm lean mass may not contribute to 'age-related decline' in arm BMD, because arm lean mass does not decrease with advancing age in the general population of women.
Kuwahata
Riki
R
Department of Obstetrics and Gynecology, Kagoshima University Medical and Dental Hospital, Kagoshima, Japan.
Kuwahata
Tomoki
T
Iwamoto
Ichiro
I
Douchi
Tsutomu
T
D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism* / Q000473:pathology*; D001823:Body Composition; D015519:Bone Density; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000209:etiology