Biomedical subjects

L Baeksgaard

Publications and source records attributed to L Baeksgaard.

3 recordsLinked to original sources

PubMed2001

Response of cortical bone to antiresorptive treatment.

A total of 113 postmenopausal women (69 controls, 33 using hormone replacement therapy (HRT), and 11 using bisphosphonate) were evaluated twice over 2 years with a new noninvasive, radiogrammetry-based technique called digital X-ray radiogrammetry (DXR) and conventional bone densitometry of the spine, hip, and forearm. Longitudinal changes in bone densitometry were compared with changes captured by DXR: BMD evaluated by DXR (BMDDXR), cortical thickness of the second metacarpal (CTMC2), and porosity of cortical bone. The expected annual postmenopausal reduction in BMD in the control group was detected by BMDspine (-0.8%, P < 0.01), BMDhip (-1.6%, P < 0.001), BMDforearm (-1.5%, P < 0.001), DXR-BMD (-0.8%, P < 0.001), and CTMC2 (-1.1%, P < 0.001). In the HRT group, smaller reductions were seen in BMDDXA, but only significant at the hip (-1.0%, P < 0.01) and distal forearm (-1.0%, P < 0.02). In the bisphosphonate group, cortical porosity was significantly reduced (P < 0.025). Comparing longitudinal changes in age-matched subsamples of controls and bisphosphonate treated, BMDDXR, CTMC2, and porosity of cortical bone all differed significantly (P < 0.01, P < 0.05, P < 0.05, respectively), whereas the BMDDXA measurements did not. In conclusion, DXR provides a densitometry equivalent measurement of the distal forearm and hand and seems to offer new information on the porosity of cortical bone. This may prove useful in the evaluation of bone loss and offer new insight into the effects of different antiresorptive treatment regimens used in the prevention of osteoporosis.

Absorptiometry, Photon↗

PubMed1998

Calcium and vitamin D supplementation increases spinal BMD in healthy, postmenopausal women.

We undertook a double-masked, randomized, placebo-controlled trial to evaluate the effect of a calcium and vitamin D supplement and a calcium supplement plus multivitamins on bone loss at the hip, spine and forearm. The study was performed in 240 healthy women, 58-67 years of age. Duration of treatment was 2 years. Bone mineral density (BMD) was measured at the lumbar spine, hip and forearm. A dietary questionnaire was administered twice during the study and revealed a fairly good calcium and vitamin D intake (919 mg calcium/day; 3.8 micrograms vitamin D/day). An increase in lumbar spine BMD of 1.6% was observed in the treatment group after 2 years (p < 0.002). In the placebo group no significant changes were observed during the 2 years. Lumbar spine BMD was significantly higher in the treatment group at both 1 (p < 0.01) and 2 years (p < 0.05) compared with the placebo group. Though not significant, the same trend was seen at the hip. No significant changes from baseline values were observed at the distal forearm in either the treatment or the placebo group. In conclusion, we found a significant increase in urinary calcium excretion in the treatment group compared with the placebo group. Together with significant changes in serum calcium and serum parathyroid hormone, this indicates that a long-term calcium and vitamin supplement of 1 g elementary calcium (calcium carbonate) and 14 micrograms vitamin D3 increases intestinal calcium absorption. A positive effect on BMD was demonstrated, even in a group of early postmenopausal age, with a fairly good initial calcium and vitamin D status.

Aged↗

PubMed1997

Body composition analysis by DEXA by using dynamically changing samarium filtration.

Dual-energy X-ray absorptiometry (DEXA) has a high accuracy for body composition analysis but is influenced by beam hardening and other error sources in the extremes of measurement. To compensate for beam hardening, the Norland XR-36 introduces a dynamically changing samarium filtration system, which depends on the current-absorber thickness. With this system we found a good agreement (r = 0.99) between reference and measured amounts of tissue or fat percentages in a plastic phantom and in smaller (approximately 0.5-4 kg) and larger (approximately 5-20 kg) piles of tissue (ox muscle and lard). Scans of six healthy volunteers covered with combinations of beef and lard (approximately 5-15 kg) showed a good agreement (r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic filtration) has a high accuracy for body composition analysis. It has a potential for gaining status as a reference method in the future and may presently be used as a supplement to the traditional methods for body composition analysis.

Absorptiometry, Photon↗