Measurement of bone mineral content (BMC) of the lumbar spine, I. Theory and application of a new two-dimensional dual-photon attenuation method

Bone mineral density (aBMD) is equivalent to bone mineral content (BMC) divided by area. We rechecked the significance of aBMD changes in aging by examining BMC and area separately. Subjects were 1167 community-dwelling Japanese men and women, aged 40–79 years. ABMDs of femoral neck and lumbar spine were assessed by DXA twice, at 6-year intervals. The change rates of BMC and area, as well as aBMD, were calculated and described separately by the age stratum and by sex. In the femoral neck region, aBMDs were significantly decreased in all age strata by an increase in area as well as BMC loss in the same pattern in both sexes. In the lumbar spine region, aBMDs decreased until the age of 60 in women, caused by the significant BMC decrease accompanying the small area change. Very differently in men, aBMDs increased after their 50s due to BMC increase, accompanied by an area increase. Separate analyses of BMC and area change revealed that the significance of aBMD changes in aging was very divergent among sites and between sexes. This may explain in part the dissociation of aBMD change and bone strength, suggesting that we should be more cautious when interpreting the meaning of aBMD change.

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Physical Exercise as Prophylaxis against Involutional Vertebral Bone Loss: A Controlled Trial

Clinical Science ◽

10.1042/cs0640541 ◽

1983 ◽

Vol 64 (5) ◽

pp. 541-546 ◽

Cited By ~ 292

Author(s):

Bjørn Krølner ◽

Birte Toft ◽

Stig Pors Nielsen ◽

Erik Tøndevold

Keyword(s):

Lumbar Spine ◽

Bone Loss ◽

Physical Exercise ◽

Bone Mineral Content ◽

Bone Mineral ◽

Mineral Content ◽

Controlled Trial ◽

Exercise Group ◽

Control Group ◽

Normal Women

1. The skeletal effects of physical training were studied in a controlled trial involving 31 healthy women (aged 50–73 years) with previous Colles' fracture of the forearm. The bone mineral content of the lumbar spine and both distal forearms was measured by dual-photon (153Gd) absorptiometry. 2. The participants were allocated to either a physical exercise group or a control group. The former group followed a standardized exercise programme, exercising for 1 h twice weekly during 8 months. 3. Twenty-seven women completed the study. Lumbar spine bone mineral content of the exercise group increased by 3.5%, whereas that of the control group decreased by 2.7%. The rate of bone loss in the control group equalled that of age-matched normal women. 4. The changes in forearm bone mineral content appeared to be independent of the exercise. The bone mineral content of the previously fractured forearm remained nearly unchanged. The bone mineral content of the uninjured forearm decreased on average by 3.5%. 5. The data suggest that physical exercise can inhibit or reverse the involutional bone loss from the lumbar vertebrae in normal women. Physical exercise may prevent spinal osteoporosis.

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