The aim of the present study was to compare bone mineral density (BMD
in g/cm(2)) in the lumbar spine and three hip regions of male spinal c
ord injured subjects at various times post injury to age-matched able-
bodied controls and to correlate their BMDs to their age and level of
their spinal cord lesion. Patients and controls were stratified into t
hree 20 year age groups (20-39, 40-59, and 60(+) years of age). BMD me
asurements were obtained using dual energy X-ray absorptiometry (DEXA,
Lunar Model DPX). BMD levels taken within the first year of injury we
re not significantly lower than the age-matched able-bodies controls.
The 20-39 year old patients injured longer than 1 year had significant
ly lower (P less than or equal to 0.01) BMDs in their femoral region t
han both their age matched controls and the 20-39 year old acutely inj
ured (injured for less than 1 year) patients. Although femoral BMDs of
both paraplegic and quadriplegic patients 40-59 and 60(+) years of ag
e decreased over time, none showed significant bone loss in this regio
n until 10 years after their injury. These results indicate that spina
l cord injury associated bone loss occurs most dramatically in the fem
oral region of young men. These results also indicate that initial bon
e mass loss does not occur prior to 1 year post-injury to the extent t
hat it is detectable by densitometry, or at least it did not occur in
our patients.