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PubMed2006

[Hormonal activity of the hypophysial-gonadal axis versus the mineral bone density and specific markers of bone turnover in haemodialysis population].

UNLABELLED: Among the numerous complications associated with chronic renal disease both bone and hormonal disturbances have long been recognized. The aim of this study was to assess the relations between bone mineral density, gonadal status and specific markers of bone turnover in haemodialysis (HD) population. MATERIAL AND METHODS: We performed a cross-sectional study involving 40 HD patients: 27 men (mean age 54 +/- 14, 2 years) and 13 women (mean age 58.9 +/- 9.8 years), mean HD time 68 +/- 43 months. Serum levels of testosterone, estradiol, LH, FSH, osteocalcin (OC), beta-CrossLaps, iPTH and alkaline phosphatase (ALP) were measured. Bone mineral density (BMD) was estimated in the lumbar spine and in the femoral neck using dual energy absorptiometry (DXA). RESULTS: 67.5% of HD patients showed a low BMD. Diagnostic criteria of osteoporosis were fulfilled by 32.5% of subjects, they were found more frequently in women (38.5%) than in men (29.6%). Osteopenia was observed in 35% of patients, more frequent in women (46.2%) than in men (29.6%). Mean serum levels of FSH and LH were above the normal range and they were higher in women that in men. The serum levels of estradiol in women were below normal range in 11 from 13 subjects (84.6%). The mean serum testosterone concentrations in HD men were in normal range. We also observed a positive correlation between serum beta-CrossLaps concentrations and PTH (in men p < 0.001, r = 0.66; in women p < 0.006, r = 0.71) and between serum OC levels and PTH (in men p < 0.02, r = 0.44; in women p < 0.01, r = 0.65), respectively. CONCLUSIONS; The frequency of low bone mineral density in haemodialysis patients is high, more common in women. Hypergonadotropic hypogonadism that occurs in dialysis patients may be one of the main risk factors of bone disturbances in these patients. The levels of bone turnover markers are mainly determined by the severity of hyperparathyroidism.

Adult↗
PubMed1997

An experimental study of lumbar destabilization. Restabilization and bone density.

STUDY DESIGN: An investigation of the effects of bone density on lumbar spine stability using destabilizing and restabilizing procedures. OBJECTIVES: To measure cadaveric vertebral bone densities computed tomographic scans and to correlate the measured densities with lumbar spine stability in the intact and during sequential destabilization and restabilization. SUMMARY OF BACKGROUND DATA: The stabilizing effects of lumbar pedicle screw fixation have been widely described. Numerous construct failure mechanisms have been observed, including screw loosening in osteoporosis. Although previous studies have analyzed the effect of bone density on the compression strength of bone similar to that used in interbody fusion and the relationship of pedicle screw pull-out strength to vertebral bone density, a combined study of bone density and construct stability using an interbody bone spacer with pedicle fixation has not been performed. METHODS: Bone densities were measured in 20 human cadaveric lumbar spines using computed tomography scans and a hydroxyapatite phantom. After the specimens were mounted in a testing frame, the L4-L5 motion segments were subjected to cyclic axial compression-torsional loads, and axial and rotational intervertebral displacements were monitored. Laminectomy, facetectomy, and pedicle screw-plate fixation were performed sequentially in three specimens. Ten others underwent these procedures with an additional destabilization procedure, discectomy, after facetectomy. Seven others underwent the same sequence as the previous group, followed by the insertion of interbody bone. Cyclic testing was resumed after each procedure. RESULTS: Average bone densities varied widely among the specimens. Average bone densities of the pedicle and of the vertebral body for individual specimens were well-correlated (r = 0.897). Displacements were recorded as a percentage of the intact state before destabilization; average percentages are reported as follows: axial displacements increased after facetectomy (145%) and subsequent discectomy (251%), and rotational displacements increased after facetectomy (295%) and discectomy (390%). Instrumentation without interbody bone resulted in specimens with decreased axial (126%) and rotational (156%) displacements. The addition of interbody bone further decreased axial (111%) and rotational (117%) displacements. The rotational stabilization provided by instrumentation was well-correlated with vertebral bone density (r = 0.804). This correlation was enhanced by the use of interbody bone (r = 0.939). CONCLUSION: The unstable lumbar spine can be partially stabilized using fixation. Interbody bone provides additional stability. The immediate stability provided by pedicle screws is greater in lumbar vertebrae with higher bone density.

Adult↗
PubMed2004

Hypergonadotropic amenorrhea and bone density: new approach to an old problem.

Amenorrhea can cause bone loss, but not all mechanisms in this process are known. The degree of bone loss in amenorrheic women is determined by the cause of the amenorrhea. The aim of this study was to investigate the influence of secondary amenorrhea on bone density and to compare the bone density between hypogonadotropic amenorrheic women and hypergonadotropic amenorrheic women. Twenty-two amenorrheic and 12 eumenorrheic women under the age of 40 were involved in this study. Every woman underwent measurements of lumbar spine and femoral neck bone density, body mass index (BMI), and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, and prolactin. According to FSH levels, we divided the women with amenorrhea into two groups: hypergonadotropic (n = 7; FSH, >40 IU/l) and hypogonadotropic (n = 15; FSH, < or =40 IU/l) amenorrheic women. Amenorrheic women had a lower lumbar spine bone density than eumenorrheic controls (P = 0.002). Hypergonadotropic amenorrheic women had lower lumbar spine bone density (P = 0.026) than hypogonadotropic ameneorrheic women. In the hypergonadotropic group, only FSH level had a correlation (negative) with lumbar spine bone density (P = 0.05), but in the hypogonadotropic group, there was no correlation between hormonal levels, BMI, age, or duration of amenorrhea. BMI was positively correlated with lumbar spine bone density in amenorrheic women (P < 0.025). Amenorrheic women had lower bone density than eumenorrheic women, but hypergonadotropic amenorrheic women had lower bone density than hypogonadotropic women. The greater bone loss in the hypergonadotropic amenorrheic group could have been caused by a potential direct effect of FSH on bone metabolism.

Age Factors↗
PubMed1990

Fluoride therapy for osteoporosis promotes a progressive increase in spinal bone density.

Since osteoporosis is a disease of diminished bone density, and since osteoporotic fractures occur most commonly in the spine, the ideal therapeutic agent for osteoporosis is one which can increase spinal bone density and thereby reduce the risk for vertebral fractures. In the current study we sought to examine the effect of fluoride therapy on spinal bone density utilizing quantitative computed tomography to measure changes in vertebral trabecular bone density during treatment with fluoride. A group of 61 postmenopausal osteoporotic females, aged 70 +/- 9 years, were treated with 34 +/- 7 mg elemental fluoride/day (equivalent to 75 +/- 15 mg NaF/day) and 1500 mg calcium/day for 19 +/- 6 months. Spinal bone density was increased within the first 6 months of fluoride therapy by 42% or 10 +/- 13 mg/cm3 (p less than 0.001) and continued to increased throughout 2 years of observation. The skeletal response to fluoride therapy was also associated with an early increase in serum alkaline phosphatase activity (p less than 0.001), which was related to the increase in spinal bone density (r = .58, p less than 0.001). Large interpatient variation was observed in the spinal bone response to fluoride therapy, which was not explained by variations in the pretreatment spinal bone density (r = .04), age of the patient (r = .15), or dose of fluoride (r = .16). Results from these studies demonstrate (1) the therapeutic value of fluoride to increase trabecular bone density linearly for 2 years in the osteoporotic spine and (2) the clinical value of measuring spinal bone density and/or serum alkaline phosphatase activity as indices of the skeletal response to fluoride.

Aged↗
PubMed1998

[Effects of pregnancy and lifestyles including food intake on bone density of pregnant women].

Bone densities measured by ultrasound at the calcaneus, and urinary hydroxyproline (H.P) and calcium (Ca) concentrations adjusted for creatinine (Cre) were measured in 79 pregnant women, aged 20 to 38 years, at 5-40 weeks of gestation. Stiffness calculated from the combined value of speed of sound and broadband ultrasound attenuation was used as an index of bone density. The relationships between Stiffness and period of gestation, urinary H.P/Cre and Ca/Cre, and such lifestyles as current and past food intake frequency, physical activity and history of participating in sports obtained by questionnaire were examined using stepwise multiple regression analysis, including age and weight as independent variables. 1) The means of Stiffness in women with the gestation period of more than 20 weeks (primipara 79.6, multipara 83.4) are a little lower than those of non-pregnant and healthy women within the same age range. 2) Period of gestation showed a significant negative correlation to Stiffness. Significant positive correlations were found between urinary H.P/Cre and period of gestation. These results suggest that bone resorption increases with stage of gestation and causes bone loss in pregnant women. 3) Significant relationships with Stiffness was found only in frequency of cow's milk intake before pregnancy among various lifestyle factors. Stiffness of the subjects who took cow's milk every day before pregnancy was significantly higher than those who took less than 2-3 times per week or none. This result indicates that cow's milk and dairy products intake before pregnancy may be important for bone mineral maintenance during pregnancy.

Adult↗
PubMed1989

Effects of age and sex on bone density in the rhesus monkey.

Normative data for bone density of cortical and trabecular bone in the rhesus monkeys is described in the present study. Changes of bone density (g/cm2) for the humerus, the third lumbar vertebra, and the eighth caudal vertebra of the rhesus monkey show differences due to age and sex of the subjects (males n = 57; females n = 49). In general, bone density increased with age and then reached a plateau at approximately 3 to 4 years in all bones measured. In the humerus, older females (greater than 30 years) had a significantly lower bone density than females of 4 to 24 years, while bone density in older males did not decrease. In the vertebrae, some evidence of advanced age-related decreases in bone density was found in both sexes. These results indicate that the rhesus monkey shows a natural pattern of change in bone mineralization which parallels that seen in humans. The physiological similarity between the rhesus monkey and human further suggests a potential role for this species in the future investigation of osteoporosis.

Aging↗
PubMedDate not supplied

[Bone density in swimmers].

Bone mineral density of the non-dominant forearm was measured by single-photon absorptiometry at a proximal site (PBMD) and at a more distal site (DBMC) in 9 competitive male swimmers, aged 18 to 23 years, who had been training for 12 +/- 2 years, 10.3 +/- 5.6 hours a week. The results were compared with 25 age-matched controls. PBMD was m +/- SD 0.57 +/- 0.02 g/cm2 in the swimmers and 0.57 +/- 0.05 g/cm2 in the controls. DBMD was 0.45 +/- 0.02 g/cm2 in the swimmers and 0.45 +/- 0.03 g/cm2 in the controls. No difference was found between the two groups. We can therefore conclude that swimming, in absence of gravity, didn't provide our athletes with an effective mechanical load capable to increase bone density of the forearm.

Absorptiometry, Photon↗
PubMed1991

Fluoride therapy in postmenopausal osteopenic women: effect on vertebral and femoral bone density and prediction of bone response.

Fifty-two postmenopausal women (mean age 60 +/- 5 years) with low BMD (less than -2SD of young adult values) but who had not experienced previous crush fracture were treated with 50 mg of sodium fluoride (NaF), 1 g of calcium and 400 IU of vitamin D2 per day for 2 years. Repeated vertebral and femoral BMD measurements were made and compared with those of a control group consisting of 16 untreated women. Serum alkaline phosphatase and osteocalcin, blood and urinary fluoride levels were measured regularly to determine their predictive value on bone response. 18 of 52 (35%) of the treated patients experienced side effects (29% gastric, 4% lower extremity pain syndrome) but only in 6 cases (12%) was it necessary to discontinue treatment. In neither of the two groups was any fracture recorded (vertebral or otherwise). Among the 43 women who were treated for at least 2 years, 21 (49%) were considered to have responded (i.e., with an increase of vertebral BMD greater than 0.043 g/cm2). There was a mean linear increase in BMD in this group of 0.0041 g/cm2 per month (i.e., 5.5% per year). On the other hand in the non-responder group and in the control group, vertebral BMD either remained stable or decreased. However no difference was detected between the two groups (treated and controls) at the femoral site after 2 years; both groups showed a significant decrease in BMD. The responders had a lower initial osteocalcin level and treatment led to a relatively greater increase in osteocalcin.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1999

Correlation between pre-operative periprosthetic bone density and post-operative bone loss in THA can be explained by strain-adaptive remodelling.

Periprosthetic adaptive bone remodelling after total hip arthroplasty can be simulated in computer models, combining bone remodelling theory with finite element analysis. Patient specific three-dimensional finite element models of retrieved bone specimens from an earlier bone densitometry (DEXA) study were constructed and bone remodelling simulations performed. Results of the simulations were analysed both qualitatively and quantitatively. Patterns of predicted bone loss corresponded very well with the DEXA measurements on the retrievals. The amount of predicted bone loss, measured quantitatively by simulating DEXA on finite element models, was found to be inversely correlated with the initial bone mineral content. It was concluded that the same clinically observed correlation can therefore be explained by mechanically induced remodelling. This finding extends the applicability of numerical pre-clinical testing to the analysis of interaction between implant design and initial state of the bone.

Absorptiometry, Photon↗
PubMed1996

Bone density of class II furcation lesions treated by guided tissue regeneration. A follow-up study by digital analysis of superimposable radiographs.

12 buccal or lingual class II furcation lesions were selected in the lower molars of 7 patients after treatment by routine scaling. In each of the 7 patients, 1 lesion was treated by guided tissue regeneration (GTR) with expanded polytetrafluoroethylene membranes, while 5 neighbouring molars underwent conventional flap operations. The index of gingival inflammation, the plaque index, the depths of the pockets, the horizontal and vertical attachment levels were measured before and 6 months, 1 year and 2 years after surgery. Standardized reproducible radiographs were taken before treatment, post-operatively (at the time of membrane removal for the GTR treated sites), at 6 months, 1 year and 2 years after treatment. The density of bone was quantified in several areas by using high-resolution digital analysis. With the exception of the higher gain in horizontal attachment observed in the GTR treated furcations, the improvement of clinical parameters was similar in all sites during the 2 years of follow-up. The radiographical analysis showed no statistically significant changes neither in the GTR nor in the conventionally treated lesions over this period of time, even when they were compared to untreated bone control areas. However, in this study limited to 7 patients, the interdental bone next to the GTR treated furcations showed significant signs of remodeling.

Absorptiometry, Photon↗
PubMed2005

Clinical applications of bone density testing for osteoporosis.

Bone mineral density (BMD) testing is a clinical tool to diagnose osteoporosis or low bone density, predict fracture risk, and monitor changes in bone density over time. Non-invasive measurement of BMD is done with a variety of technologies for many different skeletal sites. Dual-energy X-ray absorptiometry (DXA) is the gold-standard for diagnosing osteoporosis and monitoring changes in BMD over time. Optimal use of DXA requires staff training and standard operating procedures that include quality controls for instrument maintenance, patient education, indications and contraindications for testing, precision assessment, scan acquisition, analysis, interpretation, and reporting. Other technologies, as well as DXA, are used to estimate the risk of fracture. BMD is commonly expressed as a T-score, the standard deviation variance of the patient's BMD compared to a young-normal reference population. In untreated postmenopausal women, there is a strong correlation between T-score and fracture risk, with fracture risk increasing about two-fold for every standard deviation decrease in bone density. BMD in postmenopausal women is classified as normal, osteopenia, or osteoporosis according to criteria established by the World Health Organization. BMD testing, combined with assessment of clinical risk factors for fracture, allows healthcare providers to identify patients who may benefit from pharmacologic therapy to reduce the risk of future fractures. Clinical applications of BMD testing are presented in this review.

Absorptiometry, Photon↗
PubMed1996

Evaluation of bone density in newborn infants by computed x-ray densitometry.

We evaluated bone density in term and preterm infants using computed x-ray densitometry, which permits measurement of bone density with minimal disturbance to the infants in their incubators. Bone density, bone width, and bone length of the right radius were determined in 155 infants of appropriate weights for their gestational ages (23 to 41 weeks). A curve for intrauterine bone growth was extrapolated from these data. The mean coefficients of variations for variabilities for intra- and interobserver error for all measurements were < 3.5%. In 18 infants, measurements of the right forearm were obtained in two positions to confirm the validity of densitometric measurements. The mean coefficients of variation were 3.42% for bone density, 3.48% for bone width, and 0.21% for bone length. Bone density was significantly correlated with gestational age (r = 0.924) and birth weight (r = 0.921). Bone width and length were also correlated with gestational age (r = 0.866 and 0.937) and birth weight (r = 0.878 and 0.954). Our results suggest that computed x-ray densitometry is a useful method for evaluation of bone density in preterm infants, including those in an intensive care environment.

Absorptiometry, Photon↗
PubMed1993

Bone-derived serum enzymes and bone density in perimenopausal Caucasian women.

Serum levels of bone-origin alkaline phosphatase and of tartrate-resistant acid phosphatase were measured in Caucasian women aged 41-69 years who had volunteered for bone densitometry. Bone alkaline phosphatase and tartrate-resistant acid phosphatase were inversely correlated with vertebral bone density and with femoral neck bone density. Bone alkaline phosphatase and acid phosphatase were also significantly correlated, consistent with the concept of 'coupling' between osteoblast and osteoclast activity.

Acid Phosphatase↗
PubMed2002

Impact of degenerative radiographic abnormalities and vertebral fractures on spinal bone density of women with osteoporosis.

CONTEXT: Measurements of bone density taken by dual-energy x-ray absorptiometry are the most accurate procedure for the diagnosis of osteoporosis. This procedure has the disadvantage of measuring the density of all mineral components, including osteophytes, vascular and extra vertebral calcifications. These alterations can influence bone density results and densitometry interpretation. OBJECTIVE: To correlate radiography and densitometry findings from women with osteoporosis, analyzing the influence of degenerative processes and vertebral fractures on the evaluation of bone density. DESIGN: Retrospective study. SETTING: Osteoporosis outpatients' clinic at Hospital das Clínicas, Universidade Estadual de Campinas. PARTICIPANTS: Ninety-six postmenopausal women presenting osteoporosis diagnosed by bone density. MAIN MEASUREMENTS: Bone mineral density of the lumbar spine and femoral neck were measured by the technique of dual-energy x-ray absorptiometry, using a LUNAR-DPX densitometer. Fractures, osteophytes and aortic calcifications were evaluated by simple x-rays of the thoracic and lumbar spine. RESULTS: The x-rays confirmed vertebral fractures in 41.6%, osteophytes in 33.3% and calcifications of the aorta in 30.2%. The prevalence of fractures and aortic calcifications increased with age. The mean bone mineral density was 0.783g/cm2 and the mean T-score was - 3.47 DP. Neither fractures nor aortic calcifications had significant influence on bone mineral density (P = 0.36 and P = 0.09, respectively), despite the fractured vertebrae having greater bone mineral density (P < 0.02). Patients with lumbar spine osteophytes showed greater bone mineral density (P = 0.04). Osteophytosis was associated with lumbar spine bone mineral density after adjustment for fractures and aortic calcifications by multiple regression (P = 0.01). CONCLUSION: Osteophytes and lumbar spine fractures can overestimate bone density interpretation. The interpretation of densitometry results should be carried out together with the interpretation of a simple lumbar spine x-ray in elderly women.

Absorptiometry, Photon↗
PubMed1988

Effects of natural menopause, hysterectomy, and oophorectomy on lumbar spine and femoral neck bone densities.

Lumbar spine and femoral neck bone densities of women, aged 35-65, were measured by dual photon bone densitometry. After exclusion of women with spinal and other abnormalities, this study included 233 subjects: 60 menstruant, 91 who underwent natural menopause (56 more than 2 years post-menopause), 45 bilaterally oophorectomized, and 37 hysterectomized without bilateral oophorectomy. No significant differences were found between the age-normalized average bone densities of the menstruant, early postmenopausal, and late postmenopausal women; nor was there a difference between the rates of their bone loss. The bone densities of the hysterectomized women were significantly lower than those of the normals. The bone densities of the oophorectomized women were significantly lower than those of the hysterectomized patients. The rates of bone loss, however, were comparable in all groups studied. The use of estrogen without progestin was associated with significantly higher lumbar spine densities in the oophorectomized women, but showed no significant effect in any of the other groups.

Adult↗
PubMed2003

Effects of a herbal extract on the bone density, strength and markers of bone turnover of mature ovariectomized rats.

For many decades, the Chinese have been using herbal medications to treat bone diseases. To examine effects of an extract of ten medicinal herbs on estrogen deficiency bone loss, ten-month-old female rats were randomly divided into three groups: ovariectomized (OVX), OVX treated with herbs (OVX-M) 4 ml/day by gavage, and OVX treated with estrogen (OVX-E) 10 mg subcutaneously (s.c.) twice per week. The bone mineral density (BMD) of the left femur (fBMD), spine (sBMD) and global body (gBMD) were measured at baseline and at 4, 8 and 12 weeks using a Hologic QDR 2000 dual-energy X-ray densitometer. Tibial strength was tested using the Instron Model 5566 electro-mechanical testing machine. The urinary pyridinoline creatinine ratio (Pyd/Cr), deoxypyridinoline creatinine ratio (Dpd/Cr), plasma alkaline phosphatase (ALP), calcium (CA), phosphorus (P) and albumin (ALB) were also determined. Uterine weight was determined at 12 weeks. The results showed that percent changes of fBMD in the OVX (n = 9), OVX-E (n = 8) and OVX-M (n = 8) rats at the 12-week time point were -11.8 +/- 4.6(c), 1.8 +/- 3.1(a), -7.6 +/- 1.9(abc) (p < 0.05-0.001, a: vs. OVX, b: vs. OVX-E, c: vs. baseline); sBMD were -10.7 +/- 4.6(c), -0.3 +/- 5.5(a), -5.9 +/- 3.5(abc); and gBMD were -4.8 +/- 2.3(c), 0.1 +/- 2.4(a), -2.7 +/- 2.6(abc), respectively. Further, the tibia maximum breaking stress and flexural modulus of elasticity in OVX-M rats (295 +/- 33(a), 18,194 +/- 3,264(a)) were significantly higher (p < 0.005-0.001) than that in OVX rats (189 +/- 83, 10,309 +/- 4,930), and similar to OVX-E rats (298 +/- 35(a), 18,766 +/- 2,620(a)). Additionally, the herbal extract reduced the urinary Pyd/Cr, Dpd/Cr and plasma ALP increment followed OVX and was not associated with a rise in uterine weight. In conclusion, the herbal extract demonstrated a therapeutic effect to inhibit bone resorption and to reduce estrogen-dependent bone loss without uterine stimulation. It may have potential as a new approach in treating and preventing postmenopausal osteoporosis (PMOP).

Alkaline Phosphatase↗
PubMed1991

Aging of bone density in the second metacarpal.

Bone weight, bone and cortical areas, and apparent and true bone densities (W/BV and W/CV) were measured on the second metacarpals of 114 male and 114 female Japanese, aged 30 to 98 years. Measurements were taken from midshaft cross-sections 2 mm thick, using an electron balance and an image analyzing system. The mean values of these variables were greater in men than in women at all ages. Bone area stayed almost unchanged regardless of age. Bone weight and cortical area decreased linearly with advancing age. The respective rates of decrease per decade observed for the these variables were 3.1% and 2.9% in men and 5.5% and 4.8% in women. Apparent bone density decreased gradually with age after the fourth decade in women. While, in men, it stayed almost unchanged or increased slightly until the fifth decade and then, decreased gradually with age. The rate of decrease per decade was accelerated after the fifth decade in women and after the sixth in men, being 10.3% and 8.1% in each gender, respectively. The mean loss of bone was about twice as great in women as in men. In women, significant differences (p less than 0.01) were found in these variables after the seventh decade compared with the preceding age group. However, true bone density (W/CV) stayed almost unchanged regardless of age, being about 2.0 in men and about 1.9 in women. Osteoporosis could be primarily a manifestation of normal aging, including the postmenopausal estrogen deficiency in women, regardless of gender or race.

Adult↗