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PubMed2001

A polymorphic variant at the Werner helicase (WRN) gene is associated with bone density, but not spondylosis, in postmenopausal women.

Werner syndrome (WS) is a rare autosomal recessive progeroid syndrome characterized by the premature onset of multiple age-related disorders. The gene responsible for WS has been identified as WRN, a member of the RecQ family of helicase genes. Based on the fact that patients with WS exhibit osteoporosis and osteoarthritis, the present study was undertaken to clarify the contribution of the WRN gene to the etiology of these two common age-related disorders in normal postmenopausal women. We investigated the association of a WRN gene polymorphism, namely c.4330 T --> C leading to an amino acid substitution from Cys to Arg, with bone density and lumbar spondylosis score in unrelated Japanese postmenopausal women (n = 377). Genotypic frequencies of T/T, T/C, and C/C were 87.5%, 12.2%, and 0.3%, respectively. Bone density of the lumbar spine (L2-4) was significantly lower in women carrying the minor C allele than in non-carriers (P = 0.037). When bone density was expressed by the Z score after being adjusted by age and weight, carriers of the C allele showed lower values not only in the lumbar spine, but also in the total body (P = 0.015 and 0.042, respectively). The association study with spondylosis in postmenopausal women (n = 221) revealed that this polymorphism was not related to the severity of spondylosis expressed by the Kellgren-Lawrence score at any disk level of the lumbar spine (L2/3-L5/S1). These findings indicate that the WRN gene may be a candidate for the genetic regulation of osteoporosis, but not spondylosis, in normal Japanese postmenopausal women.

Aged↗

PubMed2002

Summary of meta-analyses of therapies for postmenopausal osteoporosis and the relationship between bone density and fractures.

We review the methodologic quality of the individual randomized trials and summarize the impact of different treatments on the risk of fractures and bone density. We present an estimate of the expected impact of anti-osteoporosis interventions on fracture incidence in prevention and treatment populations using numbers needed to treat. We also examine the relationship between changes in bone density and the relative risk reduction for vertebral and nonvertebral fractures using regression analyses drawn from the results of the systematic reviews. We also outline other important facets of the decision-making process regarding osteoporosis therapy, including attitudes toward uncertainty, circumstances, and patients' and societal preferences.

Bone Density↗

PubMed1990

Somatomedin-C, physical fitness, and bone density.

Somatomedin-C (Sm-C) or insulin-like growth factor-I, GH and physical fitness decline with age. Physical fitness and muscle strength are important determinants of bone density, and the age-related decline in bone density may be related in part to a decline in fitness and muscle strength. Also, Sm-C has been shown to stimulate osteoblasts in vitro and may effect skeletal muscle mass. We postulated that the age-related decline in GH and Sm-C levels may be related to an age-related decline in physical fitness and/or muscle strength, and the effect of physical fitness and muscle strength on bone may be mediated by Sm-C. We, therefore, examined the relationship between circulating GH and Sm-C levels and physical fitness, as determined by predicted maximal oxygen uptake (VO2max) in 134 normal women, 34 of whom were postmenopausal. In a subgroup of 62 women overall muscle strength was estimated as the sum of the Z-sores for biceps, quadriceps, and grip strength. Overall muscle strength correlated with GH levels (r = 0.28; P less than 0.02), but not with Sm-C levels. There was a significant positive relationship between plasma Sm-C levels and VO2max in all women (r = 0.47; P less than 0.001) and in the postmenopausal group alone (r = 0.05; P less than 0.01). Although there was a significant negative relationship between Sm-C and age (r = -0.36; P = 0.001), VO2max was a better independent predictor than age (r = 0.47; P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

[Instrumentation and techniques in bone density measurement].

Manifold methods for bone mineral density analyses are introduced in this paper, and the characteristics of precision, accuracy, position, convenience, sensitivity and the radiation hazards of these methods are also discussed here.

Absorptiometry, Photon↗

PubMed1994

Bone density in osteogenesis imperfecta may well be normal.

Osteogenesis imperfecta (OI) is often regarded as a form of osteoporosis. However, the bone fragility is the result of defective collagen and earlier work has demonstrated that cortical thickness, in bones not previously fractured, is usually normal. We have now measured the bone mineral content of the distal forearm in 61 adult patients with well characterized OI. Three patients with the Silence type III disorder had bone mass values well below the reference interval. For the 47 type I patients and 11 type IV patients, the bone mass was significantly lower than normal (P < 0.001). However 70% of patients had values within the reference interval. One cannot therefore exclude the diagnosis of OI by finding normal values with densitometry. Diagnostic difficulties do not occur in type III patients and our main objective was to recruit as many individuals as possible with OI types I and IV. In the type IV disease, the diagnosis can be particularly difficult without a positive family history. Since the evaluation of bone density by subjective examination of radiographs is a much less precise procedure, most patients with type I and IV OI would be expected to have 'normal' appearances with this assessment. Osteogenesis imperfecta cannot be excluded on the basis of apparently normal bone density or cortical thickness with routine radiographs.

Absorptiometry, Photon↗

PubMed2002

Bone density and metabolism in children and adolescents with moderate to severe cerebral palsy.

OBJECTIVES: Diminished bone density and a propensity to fracture with minimal trauma are common in children and adolescents with moderate to severe cerebral palsy (CP). The purpose of this study was to provide a detailed evaluation of bone mineral density (BMD) and metabolism in this population and to assess the relationship of these measures to multiple other clinical, growth, and nutrition variables. METHODS: The study group consisted of 117 subjects ages 2 to 19 years (mean: 9.7 years) with moderate to severe CP as defined by the Gross Motor Functional Classification scale. Population-based sampling was used to recruit 62 of the participants, which allows for estimations of prevalence. The remaining 55 subjects were a convenience sampling from both hospital- and school-based sources. The evaluation included measures of BMD, a detailed anthropometric assessment of growth and nutritional status, medical and surgical history, the Child Health Status Questionnaire, and multiple serum analyses. BMD was measured in the distal femur, a site specifically developed for use in this contracted population, and the lumbar spine. BMD measures were converted to age and gender normalized z scores based on our own previously published control series (n > 250). RESULTS: Osteopenia (BMD z score <-2.0) was found in the femur of 77% of the population-based cohort and in 97% of all study participants who were unable to stand and were older than 9 years. BMD was not as low in the lumbar spine (population-based cohort mean +/- standard error z score: -1.8 +/- 0.1) as in the distal femur (mean z score: -3.1 +/- 0.2). Fractures had occurred in 26% of the children who were older than 10 years. Multiple clinical and nutritional variables correlated with BMD z scores, but interpretation of these findings is complicated by covariance among variables. In stepwise regression analyses, it was found that severity of neurologic impairment as graded by Gross Motor Functional Classification level, increasing difficulty feeding the child, use of anticonvulsants, and lower triceps skinfold z scores (in decreasing order of importance) all independently contribute to lower BMD z scores in the femur. CONCLUSIONS: Low BMD is prevalent in children with moderate to severe CP and is associated with significant fracture risk. The underlying pathophysiology is complex, with multiple factors contributing to the problem and significant variation between different regions of the skeleton.

Adolescent↗

PubMed1995

Forearm bone density and grip strength in women after menopause, with and without estrogen replacement therapy.

Peaking in young adulthood, both bone mass and muscle strength decrease with ageing, but bone loss may accelerate after the menopause and can be delayed by estrogen replacement therapy (ERT). This study was designed to evaluate whether, like bone density, the muscle strength was affected by the onset of menopause and/or ERT. First grip strength (GS) of young female adults (group III; n = 18; age (+/- S.E.M.) 21.8 +/- 0.4 years) was compared to that of postmenopausal women, who were divided into two groups. Group I (n = 22; age 59.6 +/- 1.6 years) was 12.5 +/- 1.7 years after the menopause and received no ERT, and group II (n = 21; age 59.5 +/- 1.1 years) was 8.3 +/- 1.2 years after the menopause and had received ERT for 3.9 +/- 2.3 years at the time of the study. GS of the postmenopausal women was significantly (P < 0.005) lower than that of the young female adults. GS did not differ significantly between both postmenopausal groups. Further analysis revealed a weak negative correlation of years since menopause with forearm bone density (r = -0.37, P < or = 0.023 for group II and III together), but not with GS. It is concluded that the later onset of menopause and estrogen replacement therapy do not seem to have a noticeable influence on muscle strength.

Adult↗

PubMed1996

Measurement of periprosthetic bone density in hip arthroplasty using dual-energy x-ray absorptiometry. Reproducibility of measurements.

To define the precision (reproducibility) of measurement of periprosthetic bone mineral density and bone mineral content, dual-energy x-ray absorptiometry scans were obtained on 45 randomly selected patients who had had a unilateral total hip arthroplasty within the previous 3 years. The coefficients of variation of the bone mineral density in the proximal Gruen zones were 5.0 and 5.3%, corresponding to errors of 0.07 and 0.11 g/cm2. The coefficients of variation of the bone mineral density for the distal zones averaged 2.8%, with an error of 0.08 g/cm2. The coefficients of variation of the bone mineral content were 4.8 and 2.9% for the proximal and distal zones. The contralateral femur was also scanned in 32 of the patients. For the contralateral femur bone mineral density, the coefficients of variation were 5.0% for the proximal zones and 4.8% for the distal zones. The bone mineral content was 6.0% for the contralateral regions. These results imply that differences in bone mineral density greater than 0.16 g/cm2 (2 standard errors) can be reliably measured. Dual-energy x-ray absorptiometry therefore provides a highly reproducible technique for quantitatively monitoring the changes in bone density that occur after total hip arthroplasty.

Absorptiometry, Photon↗

PubMed1996

Bone density studies in pregnant women receiving heparin.

Lumbar spine bone density falls during pregnancy in both women who are treated with heparin and those who are not. Breast feeding delays recovery to baseline values until suckling stops.

Anticoagulants↗

PubMed1988

Menstrual status in female athletes: correlation with reproductive hormones and bone density.

To determine whether the changes induced in serum hormone levels by strenuous exercise are accompanied by changes in bone density, we obtained medical, sports, and dietary histories, trabecular bone density, percentage body fat, and serum hormone concentrations in collegiate athletes for comparison with those of college students not involved in organized strenuous exercise. Several important observations emerged from this study of collegiate athletes. First, the eumenorrheic athletes began sports training earlier than the oligomenorrheic athletes. Second, oligomenorrheic athletes displayed significantly lower serum estradiol concentrations during cycle weeks 2 and 3 but had a rise in this hormone concentration during cycle week 4. Significant differences in serum gonadotropin concentrations during week 4 were found in the oligomenorrheic athletes. Finally, no significant difference in spinal mineral density values was found in the three groups.

Adolescent↗

PubMed1993

Femoral neck bone density. Direct measurement and histomorphometric validation.

The purpose of this study was to develop a method for directly measuring bone density of femoral neck sections. Three types of density were measured. Real density equals wet weight divided by the actual volume of bone tissue (real volume). Apparent density equals wet weight divided by the total volume occupied by the bone plus the pore spaces (total sample volume). Ash density equals the ash weight divided by the real volume. Corticocancellous cross-sections of the femoral neck were analyzed for density at two levels: level 1, proximal neck and level 3, distal neck. Density measurements were compared with histomorphometric measurements performed on cross-sections at the midportion of the femoral neck (level 2) and with a clinical radiographic measure of bone density (cortical index 3 cm below the lesser trochanter). No correlation was found between apparent density and either real (r = .12, P = .62) or ash density (r = -.09, P = .72) within a given femoral neck section. There was, however, a strong correlation between real and ash density (r = .93, P = .0001). This was expected because real and ash densities are both reflections of bone mineralization. Apparent density showed better correlation, when comparing level 1 with level 3 sections (r = .76, P = .0001), than did ash (r = .57, P = .01) or real density (r = .55, P = .01). There was no correlation between either real or ash density with any histomorphometric parameter. Apparent density was moderately correlated with total bone area expressed as a percentage of cross-sectional area (r = .66, P = .008). This finding tends to validate the direct measurement of apparent density in that both apparent density and total bone area are measurements of the concentration of bone in space. No significant correlation was found between any of the density measurements and the cortical index at 3 cm. This underscores the necessity for precisely qualifying any definition or discussion of bone quality. The success or failure of hip implants may be at least partially determined by the ability of the bone to withstand the insult of implantation of the prosthesis and to adapt successfully to the new mechanical environment. This study represents an early phase of defining parameters that may have prognostic value in long-term implant fixation.

Adult↗

PubMed2003

Bone density in sheep: genetic variation and quantitative trait loci localisation.

Bone density (BD) is an important factor in osteoporotic fracture risk in humans. However, BD is a complex trait confounded by environmental influences and polygenic inheritance. Sheep provide a potentially useful model for studying differences in BD, as they provide a means of circumventing complex environmental factors and are a similar weight to humans. The aims of this study were to establish whether there is genetic variation in BD in sheep and then to localise quantitative trait loci (QTLs) associated with this variation. We also aimed to evaluate the relationship between fat and muscle body components and BD in sheep. Results showed that there was significant (P < 0.01) genetic variation among Coopworth sheep sires for BD. This genetic difference was correlated (P < 0.01) with body weight and muscle mass. A number of QTLs exceeding the suggestive threshold were identified (nine in total). Of these, two (chromosomes 1, P < 0.05; chromosome 24, P < 0.01) were significant using genome-wide permutation significance thresholds (2000 iterations). The position of the QTL on chromosome 24 coincided with a number of other body composition QTLs, indicating possible pleiotropic effects or the presence of multiple genes affecting body composition at that site. This study shows that sheep are potentially a useful model for studying the genetics of BD.

Animals↗

PubMed2003

Three-dimensional distribution of bone density in the proximal humerus.

Bone quality of the proximal humerus is important for the surgical treatment of proximal humeral fractures and rotator cuff tears. However, very few studies have evaluated the areal bone mineral density (BMD) of the proximal humerus. The aim of this study was to analyze the volumetric BMD (vBMD) using peripheral-quantitative-computed-tomography. Total, trabecular and cortical vBMD were determined separately for the proximal and distal half of the humeral head, the surgical neck and seven specific regions of interest. The greater tuberosity (GT) was divided into three regions, and the lesser tuberosity (LT) and articular surface (AS) were each divided into two regions. The proximal head showed a significantly higher trabecular (+ 46%) and cortical vBMD (+ 15%) than the distal one. The mean trabecular vBMD of AS was significantly higher (+ 80%), and the cortical vBMD was significantly lower (- 11%) than that of the tuberosities. In the proximal half of GT, trabecular vBMD was higher in the posterior than in the middle and anterior regions. Cortical vBMD was higher in middle region than in the anterior and posterior ones. In the distal half of GT, trabecular vBMD was significantly higher in the posterior than in the middle region, and cortical vBMD was significantly higher in the anterior than in the middle region. In one. These results point to bone sites that may provide stronger fixation for implants, reduce the risk of implant loosening, and therefore improve patient outcome.

Absorptiometry, Photon↗

PubMed1999

A randomized, double-blind study comparing the effects of beclomethasone and fluticasone on bone density over two years.

Cross-sectional studies have suggested that asthmatic patients receiving high dose inhaled corticosteroids and intermittent courses of oral corticosteroids have reduced bone mass. This prospective 2-yr study was undertaken to evaluate changes in bone density of patients receiving high doses of inhaled corticosteroids. Patients (n = 33) (males aged 18-50 yrs, females aged 18-40 yrs) on inhaled corticosteroids 1,000-2,000 microg x day(-1), were randomized in a double-blind fashion to either fluticasone propionate (FP) 1,000 microg x day(-1) or beclomethasone dipropionate (BDP) 2,000 microg x day(-1). In parallel, three open control groups of the same age range were studied: asthmatics (n = 8) receiving low dose inhaled corticosteroids (< or =400 microg x day(-1)) (group A); chronic, severe asthmatics (n = 8) receiving oral corticosteroids (> or =10 mg x day(-1) (group B); and healthy untreated volunteers (n = 7) (group C). Bone densitometry scans (quantitative computed tomography (QCT) of spine; dual X-ray absorptiometry of spine, femoral neck, and single photon absorptiometry of forearm) were performed at baseline and after 6, 12 and 24 months of treatment. Biochemical bone marker measurements (serum osteocalcin, bone alkaline phosphatase, pro-collagen type 1 carboxy terminal propeptide, deoxypyridinoline and C-telopeptide of type 1 collagen) were collected every 3 months. Fifteen FP (mean age 36 yrs, six male) and 9 BDP patients (mean age 33 yrs, five male); completed the study. At 0 months, mean bone mineral density (BMD) was lower in patients receiving inhaled corticosteroids (both low dose and high dose) than in normal volunteers. In the FP-treated group, mean vertebral trabecular BMD quantitative computed tomography remained stable with no evidence of decline, whereas there was some decline in the BDP-treated group. The treatment difference between FP and BDP was statistically significant in favour of FP for quantitative computed tomography measurements after 12 months (p = 0.006) and 24 months (p = 0.004). This study suggests that over 24 months, changes in bone density are minimal in patients on high-dose inhaled corticosteroids.

Absorptiometry, Photon↗

PubMed2004

Influence of type of mechanical loading, menstrual status, and training season on bone density in young women athletes.

Bone mineral density (BMD) variables were compared in 2 groups of women Division I collegiate athletes-gymnasts (GYM) and cross-country runners (CC)-during the preseason and during the competitive season. An osteogenic advantage may exist in women athletes involved in impact loading (gymnastics) over those women in active loading sports like long-distance running. The effects of menstrual status and the time of the training season on BMD also were examined. Dietary intake, menstrual status, BMD, and serum estradiol levels were measured during the preseason and during the competitive season in 26 women athletes (18-22 years of age). GYM had significantly higher BMD (p < 0.05) at all sites for both the pre- and posttests compared to CC. Neither group experienced a significant change (p > 0.05) in BMD between trials for any site; however, CC showed slight decreases at all BMD sites from baseline to the posttest. GYM had a higher prevalence of self-reported menstrual cycle disturbances than CC. No significant difference (p > 0.05) in BMD was found between the eumenorrheic and menstrual dysfunction groups (oligo/amenorrheic). In conclusion, the gymnasts had significantly higher (p < 0.05) BMD than the runners, suggesting BMD is influenced by the type of mechanical loading. Menstrual status did not significantly affect BMD in these women athletes. Cross-country runners were determined to be at greater risk than the gymnasts for low bone mass; thus, it is recommended that these athletes include more high-impact activities in their training regimen to optimize their bone health.

Adolescent↗

PubMedDate not supplied

Photon scattering measurement of calcaneal bone density: result of in vivo cross-sectional studies.

The density of trabecular bone in the os calcis has been measured in 321 subjects using a gamma ray scattering technique. In normal subjects it was shown that density could be predicted from body weight and age with a standard error of 5.6%. It was also shown that the dependence of density upon weight and age was the same for both sexes. When the os calcis had been subjected to a greater than normal mechanical stress by either increased physical activity or excessive body weight, trabecular bone density was increased. Density was measured in 128 patients in whom the incidence of skeletal demineralization was expected to be greater than that in control subjects. Some significant reductions in density were observed. It is projected that density measurements might be of value in those situations where, in response to metabolic stress, the rate of loss of mineral from trabecular bone is greater than that from cortical bone.

Adult↗

PubMed2002

Seasonal interaction of serum vitamin D concentration and bone density in alpacas.

OBJECTIVE: To evaluate temporal changes in bone mineral density associated with seasonal variation in serum vitamin D, calcium, and phosphorus concentrations in alpacas. ANIMALS: 5 healthy mature neutered male alpacas. PROCEDURE: Metacarpal bone mineral density was measured at 4 times during a year. Each time alpacas were weighed, blood was collected for determination of serum calcium, phosphorus, and vitamin D concentrations, and samples of feed were analyzed for nutrient content. Vitamin D status was determined by use of an assay that measured serum 25-hydroxycalciferol concentration. Effects of changes in serum vitamin D, calcium, and phosphorus concentration and body weight with season on bone mineral density were determined. RESULTS: Bone mineral density, body weight, and serum vitamin D and phosphorus concentrations varied with season. Bone mineral density, serum vitamin D concentration, and body weight also varied among individual alpacas. Serum vitamin D concentration was lower in January than the previous October and increased from May to the following September. The decrease in bone mineral density lagged behind the decrease in serum vitamin D concentration and was lower in May, compared with the previous October. Body weight was lower in May than the previous October or following September. Solar radiation was highest in July and lowest in December. CONCLUSIONS AND CLINICAL RELEVANCE: Seasonal changes in bone mineral density are associated with changes in serum vitamin D concentrations in alpacas. Changes in bone mineral density associated with a decline in serum vitamin D concentration may predispose some alpacas to developing fractures minimal trauma.

Animals↗

PubMed1990

[Assessment of lumbar trabecular bone density by means of single energy quantitative CT in hospital control children and bone metabolic disorders. 1].

We studied the 3rd lumbar vertebral trabecular bone mineral density in 59 cross-sectional pictures of quantitative computed tomography (QCT) with CaCO3 phantom for 28 hospital control children and 30 cases of suspected bone metabolic disorders. The QCT value of bone mineral density of control children showed neither age dependency nor sexual difference before puberty: for males was 221.8 +/- 30.2 mg CaCO3/cm3 (Mean +/- SD) under 4 years, 218.1 +/- 39.7 at 5-9 years and 217.2 +/- 30.9 at 10-15 years; and for females 220.9 +/- 18.3 under 4 years and 240.0 +/- 29.4 at 5-9 years. The QCT values of bone mineral density in bed-ridden patients, children receiving glucocorticoids and children receiving anticonvulsants were significantly lower than that in control children (p less than 0.005). The QCT value of bone mineral density of bed-ridden patients was significantly lower than that of children receiving glucocorticoids and of children receiving anticonvulsants (p less than 0.05, p less than 0.005 respectively). Our study confirmed that single energy quantitative CT was very useful in pediatric clinical application.

Adolescent↗