Biomedical subjects

C Bergot

Publications and source records attributed to C Bergot.

At least 19 recordsLinked to original sources

PubMed2006

Volumetric quantitative computed tomography of the proximal femur: relationships linking geometric and densitometric variables to bone strength. Role for compact bone.

INTRODUCTION: In assessing cervical fractures of the proximal femur, this in vitro quantitative computed tomography (QCT) study had three objectives: to compare QCT to dual-energy X-ray absorptiometry (DXA) for predicting the failure load of the proximal femur, to compare the contributions of density and geometry to bone failure load, and to compare the contributions of cortical and trabecular bone to bone failure load. A novel three-dimensional (3D) analysis tool [medical image analysis framework (MIAF-Femur)] was used to analyze QCT scans. METHODS: The proximal ends of 28 excised femurs were studied (1) using QCT to separately measure bone mineral density (BMD) and geometric variables of trabecular and cortical bone, (2) using mechanical tests to failure in a stance configuration, and (3) using DXA to measure BMD. The variables were described with mean, standard deviation, and range. Correlation matrix and multivariate linear models were computed. RESULTS: Among correlations, cortical thicknesses of the femoral neck were significantly correlated with femoral failure load, especially of the inferoanterior quadrant (r2=0.41; p<0.001), as was cortical volume at the "extended neck" (r2=0.41; p<0.001). Femoral failure load variance was best explained by a combination of QCT variables. Combining densitometric and geometric variables measured by QCT explained 76% of femoral failure load variance compared with 69% with the DXA model. Geometric variables (measured by QCT) explained 43% of femoral failure load variance compared with 72% for densitometric variables (measured by QCT). A model including only trabecular variables explained 52% of femoral failure load variance compared with 59% for a model including only cortical variables. CONCLUSION: The QCT-MIAF reported here provides analysis of both geometric and densitometric variables characterizing cortical and trabecular bone. Confirmation of our results in an independent sample would suggest that QCT may better explain failure load variance for cervical fracture than the gold standard DXA-provided BMD.

Absorptiometry, Photon↗

PubMed2006

Evidence of a marked 25-hydroxyvitamin D deficiency in patients with congenital ichthyosis.

BACKGROUND: Vitamin D is essential for bone mineralization, and its deficiency may be the cause of skeletal fractures and osteomalacia. Geographical or ethnic factors may modulate the cutaneous synthesis of vitamin D. We hypothesized that major changes in keratinization may similarly alter the cutaneous synthesis of vitamin D. OBJECTIVES: To explore calciotrophic hormones, parameters of bone remodelling and bone mineral density (BMD) in nine patients with non-bullous congenital ichthyosis. PATIENTS AND METHODS: Six patients were European, three were North African. Four had received acitretin over a long period of time. A complete biological investigation, including serum and urinary calcium and phosphorus, calciotrophic hormones [intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25-(OH)D) and 1,25-dihydroxyvitamin D (1,25-(OH)2D)], bone formation and resorption markers, was performed on all patients during the winter season and repeated among four patients after summer. BMD was measured in all patients. RESULTS: All patients had a marked 25-(OH)D deficiency, clearly below the deficiency threshold of 25 nmol/L. Patients from North Africa had a greater deficiency than European patients, perhaps because of the difference in skin pigmentation. iPTH remained normal in European patients but was elevated among the North Africans. After sun exposure, an improvement in vitamin status was visible in only one patient. Bone formation and resorption markers remained normal. Femoral neck osteodensitometry indicated values near the osteopaenic threshold in two young North African females. No deleterious effect of retinoids on vitamin D metabolism was observed. CONCLUSION: Patients, and in particular pigmented patients, with congenital ichthyosis present a severe deficiency in vitamin D. Care provided to protect the skeletal future of these patients involves measuring BMD and prescribing supplementation.

Adolescent↗

PubMed2006

In vitro ultrasonic characterization of human cancellous femoral bone using transmission and backscatter measurements: relationships to bone mineral density.

Thirty-eight slices of pure trabecular bone 1-cm thickness were extracted from human proximal femurs. A pair of 1-MHz central frequency transducers was used to measure quantitative ultrasound (QUS) parameters in transmission [normalized broadband ultrasound attenuation (nBUA), speed of sound (SOS)] and in backscatter [broadband ultrasound backscatter (BUB)]. Bone mineral density (BMD) was measured using clinical x-ray quantitative computed tomography. Site-matched identical region of interest (ROIs) of 7 x 7 mm2 were positioned on QUS and QCT images. This procedure resulted in 605 ROIs for all the specimens data pooled together. The short-term precision of the technique expressed in terms of CV was found to be 2.3% for nBUA, 0.3% for SOS and 4.5% for BUB. Significant linear correlation between QUS and BMD were found for all the 605 ROIs pooled, with r2 values of 0.73, 0.77, and 0.58 for nBUA, SOS, and BUB, respectively (all p < 0.05). For the BUB, the best regression was obtained with a polynomial fit of second order (r2 = 0.63). An analysis of measurements errors was developed. It showed that the residual variability of SOS is almost completely predicted by measurements errors, which is not the case for BUA and BUB, suggesting a role for micro-architecture in the determination of BUA and BUB.

Aged↗

PubMed2003

Evaluation of bone mineral density and fat-lean distribution in patients with multiple myeloma in sustained remission.

To study the usefulness of bone mineral density (BMD) in the follow-up of myeloma (MM) patients, BMD was evaluated in 44 MM patients in sustained remission for at least 2 years (35.4 +/- 10.5 months) after high-dose or conventional chemotherapy in a retrospective study. Patients never received bisphosphonates before or during the follow-up. Patients underwent lumbar spine (LS) BMD and a whole body (WB) BMD testing before therapy and at least once in the remission period. At baseline, mean LS BMD was 0.863 +/- 0.026 g/cm2, mean lumbar Z-score was -1.45 SD. LS BMD significantly increased from baseline by 5 +/- 1.8%, 9.3 +/- 1.7%, and 14 +/- 1.9% at 1, 2, and 3 years, respectively. The percentage of patients with a T-score below 2.5 SD decreased from 39% at baseline to 18.5% at 3 years. Compared with baseline, WB BMD decreased by -2.8 +/- 0.5%, -2.6 +/- 0.7%, and -1.7 +/- 0.6% at 1, 2, and 3 years, respectively. Mean percentage change of the fat compartment increased from baseline by +28.4 +/- 7.1% at the trunk, and +17.1 +/- 5% in peripheral areas at 3 years. In conclusion, in MM patients in remission after chemotherapy, LS BMD progressively increased after a mean follow-up of 3 years. These patients never received bisphosphonates, so this increase was related to the anti-myeloma treatment. The major effect on BMD was observed at the LS, which is primarily composed of trabecular bone containing the bone marrow. Interestingly, a drastic increase of the fat content was also observed. These results underlined that BMD and fat-lean evaluation could be of interest in the follow-up of MM patients.

Adipose Tissue↗

PubMed2002

Hip fracture risk and proximal femur geometry from DXA scans.

In this retrospective study of hip fracture risk evaluation from hip dual-energy X-ray absorptiometry (DXA) scans, our objectives were to determine which part of the femoral neck length contributes most to the fracture risk and to define a geometric parameter better than hip axis length (HAL) for discriminating hip fracture patients. Forty-nine Caucasian women with a nontraumatic femoral neck fracture were matched on age to 49 normal women and on both age and femoral neck bone mineral density (BMD) to 49 unfractured women. In addition to BMD, geometric parameters including neck-shaft angle, neck width and several HAL segments were evaluated by discriminant analysis to determine which was the best hip fracture discriminator. Neck-shaft angle had a limited influence on the hip fracture risk. Age-related bone loss was associated with a neck width increase in unfractured and fractured patients. HAL was significantly longer in fractured patients and was a significant discriminator between fractured patients and normal controls. HAL was not significant as a discriminator between fractured and low-BMD unfractured patients. The intertrochanter-head center distance (from the intertrochanteric line to the femoral head center) coincides with the femoral lever arm and includes no segments that adapt to BMD changes, such as the greater trochanter-intertrochanter distance. Among all tested lengths, this segment was the part of HAL that discriminated best between fractured and low-BMD unfractured patients. A longer intertrochanter-head center distance increased the risk of femoral neck fracture among low-BMD patients. Including automatic measurement of this segment in standard DXA protocols may prove useful in identifying patients at high risk for hip fracture. At present, HAL remains the easier neck length to measure, but automatic evaluation of the intertrochanter-head center distance must be a goal for future image analysis development.

Absorptiometry, Photon↗

PubMed2001

A comparison of spinal quantitative computed tomography with dual energy X-ray absorptiometry in European women with vertebral and nonvertebral fractures.

Quantitative computed tomography (QCT) was compared to dual X-ray absorptiometry (DXA) measured in the lumbar spine of 508 European women defined as normal without fracture (NoF), or osteoporotic (OP), with either vertebral fracture (VF), or peripheral fracture (PF). The correlations between QCT and DXA BMD measurements were significantly different in normal and in osteoporotic patients, indicating that the two exams do not measure the same bone aspects. According to ROC curves results, QCT Z-scores separate OP from NoF with better sensitivity than all other measurements. A threshold to differentiate OP from NoF was chosen at Z-score = -1 for DXA-BMD and -1.5 for QCT-BMD. VF patients showed a highly significant decrease in BMD by DXA or QCT. PF patients revealed measurements lower than those of normal subjects but greater than those of VF, calling into question the idea of a diffuse osteoporosis causing nonvertebral fractures that is measurable by spinal DXA or QCT. DXA is weakly dependent upon age, and T-score or Z-score are equivalent for evaluating osteoporosis. QCT depends greatly upon age, and Z-score appears to be more efficient.

Absorptiometry, Photon↗

PubMed2001

Distribution of intracortical porosity in human midfemoral cortex by age and gender.

The purpose of this study was to describe the age-specific distribution of midfemoral intracortical porosity throughout the cortical width in males and females. Microradiography and an automated image analysis system were used to study midfemoral cortical bone specimens from 163 white people, including 77 males and 86 females, in a recent anthropological collection covering a broad age range. In each specimen, porosity (percentage of the cortical bone area occupied by pores), pore number, and pore size were measured throughout the entire cortex and in three cortical subregions of equal width labeled the periosteal, midcortical, and endosteal subregions. For each gender, relationships linking age to porosity, pore number, and mean pore size were assessed using regression analysis. In addition, age- and site-related changes in these three variables were tested for significance using two-way analysis of variance (ANOVA). Age explained 52% of the porosity variance in females and 13.5% in males. In each gender, there were significant age- and site-related differences in porosity, pore number, and pore size. In adults aged 60 years or younger, both pore size and pore number increased with increasing age, whereas in adults older than 60 years, pore size continued to increase but pore number decreased. In males, the age-related changes in pore size and pore number were proportionally similar in the three cortical subregions. In females, in contrast, the changes predominated in the endosteal subregion and resulted in significant cortical thinning.

Adolescent↗

PubMed2000

CT of the middiaphyseal femur: cortical bone mineral density and relation to porosity.

PURPOSE: To determine whether computed tomography (CT) can be used to quantify age- and site-related changes in cortical bone mineral density (cBMD) at the middiaphyseal femur and whether cBMD differences are related to intracortical porosity. MATERIALS AND METHODS: Cortical bone specimens from 163 femurs were studied with CT and microradiography. Femurs were from 77 males and 86 females in a white anthropologic collection covering a broad age spectrum. In each sample, the cBMD was measured in the entire cortical width and in periosteal, midcortical, and endosteal subregions of interest. Age- and site-related changes in cBMD were tested for significance by using a two-way analysis of variance for both sexes. By using linear regression, cBMD was compared with porosity in the entire cortical width and in each subregion. RESULTS: There were significant age-related differences in cBMD (P <.001 in females, P =.008 in males). In addition, cBMD values were significantly different between the three cortical subregions (P <.001 for both sexes), decreasing from the periosteum to the midcortex to the endosteum. The cBMD values were closely related to porosity, and porosity contributed to 71.6% of the variance in cBMD in the overall population. CONCLUSION: CT is effective in the measurement of age- and site-related changes in cBMD. Decreases in cBMD are closely correlated with increased cortical porosity.

Adolescent↗

PubMed1999

Prognostic value of vertebral lesions detected by magnetic resonance imaging in patients with stage I multiple myeloma.

We assessed the role of spinal magnetic resonance imaging (MRI) and bone densitometry as prognostic factors in patients with asymptomatic stage I multiple myeloma (MM) and negative skeletal survey. 55 consecutive patients underwent spinal MRI and 41 of them underwent bone densitometry by dual-energy X-ray absorptiometry (DEXA). Spinal MRI studies showed evidence of bone marrow involvement in 17/55 patients (31%). A diffuse pattern was present in three patients and a focal pattern in 14 patients, nine of them with only one nodular lesion. During a median follow-up of 25 months, 10 patients had disease progression, 8/17 patients with abnormal MRI and 2/38 patients with normal MRI. Median time to disease progression was not reached in both groups but was significantly different for patients with normal and those with abnormal patterns on MRI (P < 0.0001). Lumbar BMD was only slightly decreased compared with normal people (median lumbar Z score -0.43) and was not of prognostic value. Using a multivariate analysis the only two independent significant prognostic parameters were abnormal MRI (P<0.001, HR 30.4, 95% CI 4.3-213) and bone marrow plasmacytosis >20% (P=0.004, HR 16.4, 95% Cl 2.6-104). Thus, spinal MRI but not bone densitometry, appeared to be justified in patients with stage I asymptomatic MM and negative skeletal survey.

Absorptiometry, Photon↗

PubMed1995

Evolution of bone densitometry in patients with myeloma treated with conventional or intensive therapy.

BACKGROUND: Demineralization is a common hallmark of multiple myeloma (MM) that can be evaluated by dual-energy X-ray absorptiometry (DEXA). The evolution of lumbar and whole body bone density were investigated by DEXA in patients with MM treated by conventional or intensive therapy supported by autologous blood stem cell transplantation. METHODS: Sixty six patients younger than 66 years with MM were randomly assigned to either conventional (30 patients, Group A) or intensive therapy supported by autologous blood stem cell transplantation (36 patients, Group B). For all patients, lumbar bone mineral density (BMD) was measured by DEXA at diagnosis and 13.2 +/- 4.2 months after the initiation of treatment. Whole body examinations were performed in 45 patients; in addition to whole body BMD, independent BMD values were recorded for various skeletal sites. RESULTS: At diagnosis, mean lumbar Z score (lumbar mean BMD value) was low (-1.24 +/- 1.45) without any significant difference between the 2 groups. Under treatment, lumbar BMD increased 0.7% in Group A and 4.6% in Group B (P = 0.02). This difference was mainly related to nonresponders in group A who featured a lumbar BMD change of -3.9%, whereas patients in remission in both groups displayed a 4.1% increase (P < 0.001). There was a correlation between the variation of lumbar BMD and the decrease of the serum or urinary monoclonal component (r = 0.34, P = 0.006). After intensive therapy, increase of lumbar BMD was higher in men than in women (7.2% vs. 1%, P = 0.005) perhaps because of variations in hormonal status in women. Unexpectedly, whole body BMD decreased in responders (-3%) because of a decrease in appendicular BMD outweighing the increase in axial BMD. This suggests a redistribution from cortical to cancellous bone in patients with MM responsive to chemotherapy. CONCLUSION: Bone densitometry is a marker of treatment response that may be particularly useful in nonsecretory and light chain MM. Moreover, it provides new information on bone remodeling in patients treated for MM, which may have therapeutic consequences.

Absorptiometry, Photon↗

PubMed1995

Bone resorption at the femoral neck is dependent on local factors in nonosteoporotic late postmenopausal women: an in vitro-in vivo study.

Local mediators of bone resorption may be involved in bone loss in recently postmenopausal women and in osteoporosis. In the present study, we investigated the production of cytokines and the formation of osteoclast-like cells in marrow cultures from 16 late postmenopausal nonosteoporotic women (mean age: 66 +/- 8 years; time after menopause: 15 +/- 8 years) undergoing hip replacement for arthrosis. Marrow adherent mononuclear cells (MMNC) isolated from femoral diaphysis marrow were cultured for 10 days in the absence or in the presence of 1,25(OH)2D3. In vivo bone resorption was concomitantly assessed by histomorphometry on femoral neck bone sections. The number of TRAP+ multinucleated cells obtained after 10 days in MMNC cultured in the presence of 1,25(OH)2D3 correlated with the number of osteoclasts measured on the bone femoral neck biopsies (r = 0.65, p < 0.01), suggesting that the formation of multinucleated cells in vitro could reflect the osteoclast differentiation in vivo. Furthermore, the number of osteoclasts was related to the eroded volume and the trabecular separation of the femoral neck bone biopsies. Finally, the release of interleukin-1 (IL-1), IL-6, and TNF-alpha by cultures of peripheral blood mononuclear cells (PBMC) and MMNC was measured by radioimmunoassay. The cytokine levels of basal and 1,25(OH)2D3-treated MMNC decreased from days 2 to 5 and then reached a plateau to day 10. The number of TRAP+ multinucleated cells obtained after 10 days in MMNC cultures correlated with the basal IL-6 release in the same cultures determined at day 2 (r = 0.55, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1995

Dual-energy X-ray absorptiometry of the calcaneus: comparison with vertebral dual-energy X-ray absorptiometry and quantitative computed tomography.

The purpose of this study was to determine the efficacy of using bone mineral measurements of the calcaneus to evaluate osteoporosis. Dual energy X-ray absorptiometry (DXA) of the calcaneus was compared with posteroanterior lumbar absorptiometry (DXA) and vertebral quantitative computed tomography (QCT) measurements in 171 white women (78 normal and 93 osteoporotic). DXA measurement of os calcis mineralization decreased significantly in osteoporosis, but to a lesser extent than in vertebral sites. In normal subjects, good correlations were observed between calcaneal and lumbar DXA (0.69) and QCT (0.56). In subjects with vertebral fractures, there was also good correlation between calcaneal DXA and QCT (0.59-0.69). This suggests that trabecular bone in calcaneus and vertebrae have related involution in cases of vertebral osteoporosis. However, the extent of bone loss is less marked in the calcaneus than in the vertebrae and is not sufficient to be accurately measured over time. We conclude, therefore, that although the global densitometric measurement at this site is not sufficiently sensitive for general use, it can be useful as a epidemiological research tool.

Absorptiometry, Photon↗

PubMed1993

[Measurement of vertebral bone density. Quantitative tomodensitometry or dual-photon absorptiometry?].

We have compared vertebral bone density measurements (QCT and DXA) in women in the postmenopausal period who underwent both examinations. Our aim was to study the results and to define the respective indications of QCT and DXA in various clinical pictures of osteoporosis. The subjects of the study were distributed into various groups according to the presence or absence of vertebral collapse and/or peripheral fractures. The results of the measurements were expressed as Z-scores (deviation from age-normal average) to suppress the age effect and to make comparison between both methods possible. The values of both measurements are significantly lower in case of vertebral involvement. QCT is more sensitive than DXA to discriminate vertebral collapse. A vertebral fragility threshold was defined at a Z-score of -1 with DXA and -1.25 with QCT, corresponding to the best sensitivity for an acceptable specificity. The results of densitometry suggest that there is a peripheral osteoporosis, different from vertebral osteoporosis, as early as the postmenopausal period. Since DXA is easy to implement, it can be used to screen osteoporosis. When the vertebral measurement with DXA is normal although osteoporosis is obvious (previous collapse or fracture), QCT must be used as it is more sensitive.

Absorptiometry, Photon↗

PubMed1992

CT image analysis of the vertebral trabecular network in vivo.

A method of computed tomography (CT) image analysis of lumbar vertebrae has been developed, providing a visualization of the trabecular network as it is represented in a 1.5 mm-thick CT image. We measured the length of the network and the number of discontinuities found in the image. The ratio of these measurements was called the "trabecular fragmentation index" (TFI). CT images from 71 women between the ages of 50 and 59, and 94 women between the ages of 60 and 69 were divided into three groups according to quantitative computed tomography (QCT) vertebral density and to the presence or absence of crushing and fractures. The measure of the network length versus the vertebral area was significantly higher in normal subjects than in osteoporotics. A TFI threshold at 0.195 could separate the normal subjects, regardless of the decade, from osteoporotic ones. In females between 50 and 69 years of age, TFI was 0.166 (SD = 0.031) for the normal group and 0.248 (SD = 0.082) for osteoporotics. The osteopenic group without fractures but low bone mineral density (BMD) showed an intermediate TFI of 0.195 (SD = 0.05), placing this population on both sides of the threshold. Correlation between TFI and BMD was only -0.60. TFI could provide new information in vivo about the state of trabecular structure, particularly in the osteopenic group.

Aged↗

PubMed1992

[Vertebral density of hypercalciuric lithiasis. Its relation to calcium-protein intake and vitamin D metabolism].

Forty-two patients with calcium calculi were selected based on calciuria > 0.1 mmol/kg/d on an uncontrolled diet. To measure excretion of sodium, calcium, phosphates and hydroxyproline, a 24-hr urine sample was collected on the 4th day of a milk product-free diet, a fasting urine specimen was collected on the morning of the 5th day and another sample was taken 4 hr after the oral administration of calcium. On the 5th day, plasma levels of calcium, phosphates, intact parathyroid hormone (PTH), calcidiol and calcitriol were determined on an empty stomach and after administration of a calcium load. The results, compared to those of healthy subjects evaluated under the same conditions, enabled classification of the stone-formers as having dietary hypercalciuria (n = 18), when calciuria returned to normal on a low calcium diet, and idiopathic hypercalciuria (n = 24), when the urinary calcium level remained high. Patients with idiopathic hypercalciuria were then classified, according to Pak's criteria, as having absorptive hypercalciuria (n = 8), when the fasting calciuric levels was normal, renal hypercalciuria (n = 1), when fasting hypercalciuria with elevated circulating PTH was controlled by a calcium load, or undetermined hypercalciuria (n = 15) for those individuals with fasting hypercalciuria and normal plasma PTH levels. In addition, vertebral density was measured tomodensitometrically and expressed as a percentage of the normal as a function of sex and age based on a regression line calculated with the results of 239 normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗

PubMed1991

Diet, vitamin D and vertebral mineral density in hypercalciuric calcium stone formers.

To elucidate the pathophysiology of dietary calcium independent hypercalciuria, 42 calcium stone formers (Ca SF) were selected because they had on free diet a calciuria greater than 0.1 mmol/kg/day. For four days they were put on a diet restricted in calcium (Ca RD) by exclusion of the dairy products. They collected 24 hour urines on free diet and on day 4 of Ca RD as well as the two-hour fasting urines on the morning of the day 5 and the four-hour urines passed after an oral calcium load of 1 g, for measurement of creatinine, Ca, PO4, urea and total hydroxyprolinuria (THP). On day 5 fasting plasma concentrations of Ca, PO4, intact PTH, Gla protein, calcidiol and calcitriol were measured. The patients were firstly classified into dietary hypercalciuria (DH, 18 patients) and dietary calcium-independent hypercalciuria (IH, 24 patients) on the basis of the disappearance or not of hypercalciuria on Ca RD. Then the patients with IH were subclassified into absorptive hypercalciuria (AH) because of normal fasting calciuria (8 patients) and into fasting hypercalciuria (16 patients). Fasting hypercalciuric patients were subsequently divided according to the PTH levels into renal hypercalciuria (RH, 1 patient) with elevated fasting PTH becoming normal after the Ca load and undetermined hypercalciuria (UH, 15 patients) with normal PTH levels. Furthermore, their vertebral mineral density (VMD) was measured by quantitative computerized tomography which was normal in DH (91 +/- 6% of the normal mean for age and sex) but was decreased in IH to 69 +/- 4%. No difference in VMD was observed between AH and UH. Urinary excretions of urea, phosphate and THP was higher in IH than in DH and comparable in AH and UH. Sodium excretion Ca RD was the same in all groups and subgroups as well as the plasma parameters. Plasma calcitriol was increased in IH and DH comparatively to normal in spite of normal plasma calcidiol. Calciuria increase after oral calcium load, an index of Ca absorption, was higher in IH than in controls and comparable in IH and DH as well as in the three subgroups of IH. From these data and correlation studies in IH it is concluded: (1.) VMD is decreased in Ca stone formers with IH but not in those with DH, making the distinction of these two groups of hypercalciuria patients clinically relevant.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1990

[Changes in bone volume and mineral density during aging in humans. In vitro study on 80 subjects].

The extent of bone loss was measured and compared at three characteristic skeletal sites: the humerus, iliac crest and vertebrum. The most important effect of ageing is the fall in bone volume: reduction of bone trabeculae, thinning of compact bone and increase in intracortical porosity. Between 40 and 80 years of age, women lose 42 percent of their vertebral spongy tissue, 29 percent of their iliac spongy tissue and 31 percent of humerus cortical bone. The mean degree of mineralization of bone tissue remains constant between 40 and 80 years of age. Cortical bone is mineralized to a greater extent than spongy bone: 1.20 g/cm3 versus 1.0 g/cm3. Bone loss from different skeletal sites varies; within a given bone-organ it varies from one point to another. The mineral content of the iliac crest differs from that of the vertebrum, but the change is parallel at these two sites.

Adult↗

PubMed1988

Measurement of anisotropic vertebral trabecular bone loss during aging by quantitative image analysis.

Age-dependent variations in the architecture of vertebral trabeculae in both the vertical and horizontal planes were characterized by quantitative image analysis. Images were obtained from autopsy specimens of the third lumbar vertebrae in 61 subjects (30 men and 31 women) whose ages ranged between 33 and 89 years). All subjects had died acutely either after trauma or illnesses unrelated to the skeleton. Using mathematical morphology techniques, we measured total bone area and perimeter, and the width of trabecular particles and medullary spaces in each slice. Between the age intervals 33-49 and 80-89 years: total bone loss in the vertical and horizontal planes was 51 and 64% for women, and 38 and 29% for men, respectively. Mean trabecular width (MTW) in the vertical plane decreased from 172 to 128 micron in women and from 181 to 144 micron in men; MTW in the horizontal plane fell from 144 to 112 micron in women and remained at 114 micron in men. Maximum trabecular width decreased with age in both planes in both sexes. The mode for trabecular width was 111 micron in both sexes for all ages and in both planes. The total number of trabeculae decreased only for women in the vertical plane. Intertrabecular spaces enlarged reciprocally as the trabeculae became thinner, but the widening of spaces was much greater than that expected with trabecular thinning alone. We conclude that age-related bone loss is comprised of two processes: reduction of MTW and fragmentation and complete loss of some trabeculae. We found no evidence of vertical trabeculae thickening during normal aging.

Adult↗