Bone Mineral Changes Research Articles

The Effects Of Taichi On Bone Mineral Density And Lipid Profiles In Postmenopausal Women

0424 Estrogen deficiency accelerates the loss of bone mineral density (BMD) and changes of lipid profiles in postmenopausal women which causing osteoporosis and astherosclerosis. There have not been enough past studies about the effects of Taichi exercise on BMD and lipid profiles. PURPOSE: To investigated the effects of Taichi exercise on BMD and lipid profiles in postmenopausal women. METHODS: One hundred and forty-seven postmenopausal women volunteers were divided into two groups. The Taichi group included seventy-nine regular Taichi practitioners (Taichi; 54.2 ± 5.9yrs) who practiced 42 motions of international Taichi for 30–45min, at least 3 times/wk for average 4.7 ± 3.5yrs. The control group was comprised of sixty-eight age- and gender-matched nonexercise women (Con; 55.0 ± 5.8yrs). The BMD in lumbar spine and femoral neck regions were measured by dual-energy X-ray absorptiometry (DEXA). Fasting blood samples were obtained for measurements of total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL) and Low density lipiprotein-cholesterol (LDL). Differences among the groups were compared by using t-test and one-way ANOVA. Pearson correlations between variables were also calculated. RESULTS: Taichi had a significantly higher BMD (10.5–15.6%, p < .01) than Con in lumbar (P < .05) and neck (P < .05). In addition Taichi showed significantly lower levels of TC (−8.5%, p < .05), TG (−25.4%, p < .01), LDL (−12.9%, p < .01) combined with higher HDL (+8.9%, p < .05) than Con. The Taichi and Con groups were further divided into three subgroups, the first based on age (50–54yrs, 55–60yrs), the second based on body mass index (BMI; ≤20, 21–24, ≥25), the third subgroup based on postmenopausal years (PMY; 1–2yrs, 3–4yrs, ≥5yrs). The BMI≤20 and PMY ≥ 5yrs subgroups, belonging to the main Tachi group, did not show significant differences in lumbar BMD, HDL, TG and LDL when compared to like subgroups in main Control group. Age showed significantly correlated with BMD (P < .01) and all lipid profile (p < .01). BMI showed significantly correlated with TC, HDL, TG (p < .01) but not LDL or BMD. PMY was only correlated with HDL (p < .01) and TG (p < .05). BMD showed a negative correlations with TC (p < .05) in the study. CONCLUSIONS: Older women who practice Taichi regularly may have lower LDL, TC, TG values combined with increased HDL levels and BMD in elders. These results indicate Taichi exercise may be prescribed as age-appropriate and cost-effective aerobic exercise of moderate intensity for both preventing osteoporosis and astherosclerosis in postmenopausal women.

The Effects Of Taichi On Bone Mineral Density And Lipid Profiles In Postmenopausal Women

0424 Estrogen deficiency accelerates the loss of bone mineral density (BMD) and changes of lipid profiles in postmenopausal women which causing osteoporosis and astherosclerosis. There have not been enough past studies about the effects of Taichi exercise on BMD and lipid profiles. PURPOSE: To investigated the effects of Taichi exercise on BMD and lipid profiles in postmenopausal women. METHODS: One hundred and forty-seven postmenopausal women volunteers were divided into two groups. The Taichi group included seventy-nine regular Taichi practitioners (Taichi; 54.2 ± 5.9yrs) who practiced 42 motions of international Taichi for 30–45min, at least 3 times/wk for average 4.7 ± 3.5yrs. The control group was comprised of sixty-eight age- and gender-matched nonexercise women (Con; 55.0 ± 5.8yrs). The BMD in lumbar spine and femoral neck regions were measured by dual-energy X-ray absorptiometry (DEXA). Fasting blood samples were obtained for measurements of total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL) and Low density lipiprotein-cholesterol (LDL). Differences among the groups were compared by using t-test and one-way ANOVA. Pearson correlations between variables were also calculated. RESULTS: Taichi had a significantly higher BMD (10.5–15.6%, p < .01) than Con in lumbar (P < .05) and neck (P < .05). In addition Taichi showed significantly lower levels of TC (−8.5%, p < .05), TG (−25.4%, p < .01), LDL (−12.9%, p < .01) combined with higher HDL (+8.9%, p < .05) than Con. The Taichi and Con groups were further divided into three subgroups, the first based on age (50–54yrs, 55–60yrs), the second based on body mass index (BMI; ≤20, 21–24, ≥25), the third subgroup based on postmenopausal years (PMY; 1–2yrs, 3–4yrs, ≥5yrs). The BMI≤20 and PMY ≥ 5yrs subgroups, belonging to the main Tachi group, did not show significant differences in lumbar BMD, HDL, TG and LDL when compared to like subgroups in main Control group. Age showed significantly correlated with BMD (P < .01) and all lipid profile (p < .01). BMI showed significantly correlated with TC, HDL, TG (p < .01) but not LDL or BMD. PMY was only correlated with HDL (p < .01) and TG (p < .05). BMD showed a negative correlations with TC (p < .05) in the study. CONCLUSIONS: Older women who practice Taichi regularly may have lower LDL, TC, TG values combined with increased HDL levels and BMD in elders. These results indicate Taichi exercise may be prescribed as age-appropriate and cost-effective aerobic exercise of moderate intensity for both preventing osteoporosis and astherosclerosis in postmenopausal women.

Effects of Thyroid Hormone on Bone

It is relatively well established that thyroid hormone has a clinically significant effect on bone. Although some aspects, such as the bone mineral loss associated with overt thyrotoxicosis have been relatively well described, others remain much less clear. A major focus of this review is on the effects of chronic exogenous thyroid hormone administration on bone physiology. When thyroid hormone dosage is supraphysiologic, an iatrogenic clinical model is produced comparable to endogenous “subclinical hyperthyroidism”. Indeed, literature on bone mineral changes in the latter entity may be analyzed as representative of effects of excessive circulating thyroid hormone. At the molecular level, thyroid hormone receptors as well as thyroid-stimulating hormone (TSH) receptors have been identified on osteoblasts and osteoclasts, and have been shown to mediate significant effects on bone physiology. In reviewing the literature extant on this subject, an important clinical distinction has to be made between the effects on bone of thyroid hormone given in “suppressive” dosage vs “replacement” dosage. Some, albeit rare, earlier studies reported or implied a potentially harmful effect of physiologic replacement dosage of thyroid hormone on bone. Retrospective analysis indicates that these studies were plagued with a number of problems. Insensitive TSH assays hampered the ability to accurately determine if the replacement dosage was truly physiological, and other problems were related to patient population selection and the techniques used to assess bone mineral density. Data on fracture risk is particularly scant with most studies failing to identify thyroid hormone therapy as a risk factor for fracture. Rather, it would appear that when bone mineral loss is seen in men or premenopausal women on replacement dosage of thyroid hormone, there will be some other confounding element playing the dominant etiologic role. In postmenopausal women, the most important contributing factor to osteoporosis is estrogen deficiency, and bone loss in estrogen-deficient women will be clearly accelerated by concomitant suppressive dosage of thyroid homone. Availability of sensitive TSH assays allows us to carefully titrate thyroid hormone dosage and avoid excesses. The risks of even slight thyroid hormone excess on the heart have been recognized for the past decade, and those risks taken together with the risk of bone loss should cause us to re-examine the indications for suppressive dosage of thyroid hormone. When suppressive dosage is necessary (e.g., for patients with residual or recurrent thyroid cancer), the bone-resorptive effects of thyroid hormone should be tempered by eliminating all other factors contributing to bone loss and considering the addition of a boneenhancing therapeutic agent such as a bisphosphonate.

Skeletal Calcium/Phosphorus Ratio Measuring Techniques and Results. I. Microscopy and Microtomography

An approach to the problem of bone disorders is the measurement of the skeleton's static and dynamic strength, an estimate of which is bone mineral density. A decrease in the latter may be due to a decrease in either Ca or P, or to dissimilar decreases in both. Consequently, the determination of the Ca/P ratio may provide a sensitive measure of bone mineral changes and may add to our understanding of the changes occurring in bone diseases. This paper reviews techniques such as transmission electron microscopy (TEM) and micro-computed tomography (μu-CT), which have been developed for the in vitro assessment of the Ca,P content and the skeletal Ca/P ratio. Their main aspects are presented, as much as results regarding the referred values. The presentation of other in vitro or in vivo techniques, such as instrumental neutron activation analysis (INAA) or X-ray absorptiometry accordingly, would be the issue of another article. The authors argue that the choice of the best technique relies on its cost ad ease of applicability, its reliability, and precision.

Bone mineral change during experimental heating: an X-ray scattering investigation

The effects of heating and burning on bone mineral have previously been studied using techniques such as X-ray diffraction (XRD) with the aim of discerning a characteristic signature of crystal change. This would enable a better understanding of alteration to bone mineral during heating, which would in turn impact on the preparation and use of natural bone hydroxyapatite as a biomaterial resource. In addition, this knowledge could prove invaluable in the investigation of burned human remains from forensic and archaeological contexts in cremation and funerary practice. Here we describe a complementary method, small-angle X-ray scattering (SAXS), to determine more accurately the changes to bone crystallite size and shape during an experimental heating regimen. Samples were subjected to controlled heating at 500°C, 700°C, or 900°C for 15 or 45 min. Our results show bone crystallites begin to alter in the first 15 min of heating to 500°C or above. They then appear to stabilise to a temperature-specific thickness and shape with prolonged heating. While the samples heated to lower temperatures or for shorter periods produce XRD traces showing little alteration to the apatite, corresponding information obtained from SAXS shows an early, subtle change in crystal parameters.

Pathogenesis of bone loss in heart transplant candidates and recipients

Background Heart transplantation (HTX) is associated with decreased bone mineral density and changes in bone metabolism. We conducted this study to evaluate the pathophysiology of bone metabolism in HTX candidates and recipients. Methods Thirty-six HTX recipients were compared with 36 HTX candidates concerning biochemical parameters of bone metabolism and bone mineral density. Results Osteocalcin, bone-specific alkaline phosphatase, cross-linked-N-telopeptide of type I collagen, estradiol, serum creatinine, and blood urea nitrogen concentrations were significantly higher, whereas the calcium–creatinine ratio, thyrotropin, thyroxine, and bone mineral density were significantly lower in HTX recipients than in HTX candidates. Compared with a control group, HTX candidates had decreased renal function and increased bone resorption, whereas HTX recipients additionally had increased alkaline phosphatase and osteocalcin levels. In HTX recipients, we found positive correlations between creatinine clearance and bone mineral density; daily and cumulative cortisone doses were not associated with bone mineral density. Conclusion In HTX candidates, disturbances in bone metabolism with increased bone resorption may be caused partly by existing low-grade renal insufficiency, regular intake of loop diuretics, and restriction of mobility. In HTX recipients, immunosuppressive therapy—glucocorticoids and cyclosporine—seem to be responsible for changes in bone metabolism.

Hyperthyroidism, bone mineral, and fracture risk--a meta-analysis.

This study examined changes in bone mineral and fracture risk after treatment for hyperthyroidism in a meta-analysis. The PubMed and EMBASE were searched using the MESH terms "hyperthyroidism," "bone mineral density" (BMD), and "fracture," resulting in retrieval of 289 references. Twenty references describing BMD and five describing fracture risk were included in the meta-analysis. BMD was significantly decreased in patients with untreated hyperthyroidism. Upon treatment BMD increased significantly and reversed to normal levels with a temporary increase above normal levels 1-4 years after diagnosis. The risk of hip fractures increased significantly with age at diagnosis of hyperthyroidism. The hip fracture risk after diagnosis predicted from studies on BMD was close to that observed in clinical studies comparing fracture risk in hyperthyroid patients with normal controls. Thus BMD is significantly decreased and fracture risk increased in untreated hyperthyroidism. Upon normalization of the hyperthyroid state BMD return to normal even though no specific antiosteoporotic measures are taken other than normalizing the hyperthyroid state.

A study of mineral phase in immobilized rat femur: structure refinements by Rietveld analysis.

The aim of the present work was to examine whether immobilization of a limb influences the structure of bone mineral. The mineral phase in rat femora immobilized for 2 weeks during growth was investigated. Bone mineral was subjected to powder X-ray diffraction, using a scanning method after ashing the bones at 630 degrees C. Occupancy factors of ion positions in bone hydroxyapatite (HAP) were analyzed using the Rietveld refinement method. Occupancy factors of the positions OH(-), Ca(2+), and P(-) were significantly lower in immobilized than in control bones, although the position of ions in the HAP structure did not change. Mineralization of tissue in the immobilized bones was lower than in the controls, but there was no correlation between mineralization and occupancy factors. HAP lattice constants in immobilized bones were slightly but significantly different from those in controls. We conclude that the structure of HAP synthesized in bone during temporary lack of loading differs from that of HAP growing under physiological conditions. The Rietveld refinement method proved to be useful in the estimation of the changes in bone mineral.

Effect of weight change on bone mass in female adolescents

The purpose of this study was to examine changes in bone mineral density/bone mineral content (BMD/BMC) in obese female adolescents (Tanner stages 2 to 4) pursuing a weight reduction program. This was a prospective pilot clinical investigation involving 92 obese females screened to meet inclusion criteria and required to participate in a 6-month weight loss intervention. Baseline, 6 months, and 12 months measurements were taken for total body/lumbar spine BMD/BMC and percentage body fat. Survey instrumentation included the following: calcium food frequency/24-hour dietary recall, physical activity, and psychological assessments for anxiety/self-esteem. Changes in bone measurements were compared with changes in body weight measurements using multiple linear regression. Other potentially confounding variables analyzed included bone area, calcium intake, baseline Tanner stage, activity level, and height. Total body/lumbar spine BMD/BMC changes were found to be most significantly correlated with weight changes in the subject population. Although mean weight increased, the rate of increase per a given height velocity slowed to an appropriate height for weight ratio. Individuals who lost weight did not lose BMD/BMC; however, the rate of growth declined when compared with all study subjects whose bone growth rate was consistent with normal weight female adolescents. In this study, weight changes were strongly related to bone measurement changes in an obese adolescent female population. Dietitians counseling obese young girls are encouraged to emphasize the importance of a healthy weight loss program with optimal calcium intake and inclusive of weight-bearing exercises. J Am Diet Assoc. 2003;103:369-372.

Effect of weight change on bone mass in female adolescents

<h2>Abstract</h2> The purpose of this study was to examine changes in bone mineral density/bone mineral content (BMD/BMC) in obese female adolescents (Tanner stages 2 to 4) pursuing a weight reduction program. This was a prospective pilot clinical investigation involving 92 obese females screened to meet inclusion criteria and required to participate in a 6-month weight loss intervention. Baseline, 6 months, and 12 months measurements were taken for total body/lumbar spine BMD/BMC and percentage body fat. Survey instrumentation included the following: calcium food frequency/24-hour dietary recall, physical activity, and psychological assessments for anxiety/self-esteem. Changes in bone measurements were compared with changes in body weight measurements using multiple linear regression. Other potentially confounding variables analyzed included bone area, calcium intake, baseline Tanner stage, activity level, and height. Total body/lumbar spine BMD/BMC changes were found to be most significantly correlated with weight changes in the subject population. Although mean weight increased, the rate of increase per a given height velocity slowed to an appropriate height for weight ratio. Individuals who lost weight did not lose BMD/BMC; however, the rate of growth declined when compared with all study subjects whose bone growth rate was consistent with normal weight female adolescents. In this study, weight changes were strongly related to bone measurement changes in an obese adolescent female population. Dietitians counseling obese young girls are encouraged to emphasize the importance of a healthy weight loss program with optimal calcium intake and inclusive of weight-bearing exercises. J Am Diet Assoc. 2003;103:369-372.

The mineralization of bone tissue: a forgotten dimension in osteoporosis research.

Osteoporosis treatment should not only prevent the loss of bone tissue, not interfere with apatite and avoid bone mineral changes at the crystal level, but should also increase the mechanical resistance of bone and thus protect the skeleton against new fractures. Mineral substance is crystallized as nonstoichiometric carbonated apatite ionic crystals of small size and extended specific surface. Consequently, they have a very large interface with extracellular fluids, and numerous interactions between ions from the extracellular fluid and ions constituting apatite crystals are thus possible. It is generally agreed that bone strength depends on the bone matrix volume and the microarchitectural distribution of this volume, while the degree of mineralization of bone tissue is almost never mentioned as a determinant of bone strength. We now have evidence that the degree of mineralization of bone tissue strongly influences not only the mechanical resistance of bones but also the bone mineral density. In adult bone, our model is based on the impact of changes in the bone remodeling rate on the degree of mineralization of bone tissue. The purpose of this paper is to report the main results concerning the interactions of strontium (Sr) with bone mineral in animals and in osteoporotic women treated with strontium ranelate (SR). These studies aimed to evaluate using X-ray microanalysis, X-ray diffraction and computerized quantitative contact microradiography: (1) the relative calcium and Sr bone content, (2) the distribution of Sr in compact and cancellous bone, (3) the dose dependence of the deposition of Sr in bone, (4) the interactions between Sr and mineral at the crystal level (in monkeys), (5) the influence of Sr on the mean degree of mineralization of bone tissue and on the distribution of the degree of mineralization of bone tissue, and (6) the bone clearance of Sr over short periods of time (6 and 10 weeks) after cessation of SR administration (monkeys treated for 13 and 52 weeks, respectively). In monkeys killed at the end of exposure (13 or 52 weeks), Sr was taken up in a dose-dependent manner into compact and cancellous bone, with a higher content in new bone than in old bone. The Sr content greatly decreased (about 2-fold) in animals killed 6 or 10 weeks after the end of treatment but this affected new bone almost exclusively. After SR treatment, there were no significant changes in crystal characteristics. Easily exchangeable in bone mineral, Sr was slightly linked to crystals by ionic substitution (generally 1 calcium ion substituted by 1 Sr ion in each unit cell). The degree of bone mineralization was not significantly different in the various groups of monkeys. Thus, at the end of long-term SR treatment and after a period of withdrawal, Sr was taken up in a dose-dependent manner into new bone without alteration of the degree of bone mineralization and with no major modification of bone mineral at the crystal level. In postmenopausal osteoporotic women treated with SR (0.5, 1 and 2 g/day) for 2 years, Sr was dose-dependently deposited into new bone without changes in the degree of mineralization of bone tissue. These findings could reflect dose-dependent stimulation of bone formation and are of potential value for the use of SR in the treatment of osteoporosis. In conclusion, the different studies performed on bone samples from monkeys and humans treated with various doses of SR showed that Sr was heterogeneously distributed between new and old bone but in a dose-dependent manner without alteration of the crystal characteristics and the degree of mineralization of bone tissue, even after long-term administration of often high doses of SR (the highest therapeutic dose used in humans is 4-fold lower than the lowest experimental dose administered to monkeys). This emphasizes the value, as antiosteoporotic treatment, of SR, which is safe at the bone mineral level.

Quantitative ultrasound of the calcaneus and dual X-ray absorptiometry of the lumbar spine in assessment and follow-up of skeletal status in patients after kidney transplantation.

Bone loss after kidney transplantation is a significant complication of immunosuppressive treatment leading to a high prevalence of bone fracture in these patients. The purpose of this study was to determine the usefulness of quantitative ultrasound (QUS) of the calcaneus in comparison with dual X-ray absorptiometry (DXA) of the lumbar spine in determining bone status and mineral changes in patients in the first 6 months after transplantation. Forty-six patients participated in the study (25 men and 21 women; age range 26-62 years, 102+/-66 months previously on dialysis). They were treated with cyclosporine, methylprednisolone, mycophenolate mofetil, and basiliximab. The 6-month cumulative steroid dose was 24.9+/-3.7 mg/kg body weight. Calcaneal QUS (Sahara, Hologic, Waltham, Mass.) and DXA (Hologic QDR 4500) of the lumbar spine were done in all patients within 3 weeks after transplantation and 6 months thereafter. Bone mineral density (BMD) of the lumbar spine measured by DXA decreased from 0.892+/-0.137 to 0.837+/-0.126 g/cm2 (p<0.0001) and the T score decreased from 1.84+/-1.29 standard deviation (SD) to 2.35+/-1.19 SD (p<0.0001) in the first 6 months after transplantation. The QUS parameters of the calcaneus were broadband ultrasound attenuation (BUA), speed of sound (SOS), and quantitative ultrasound index (QUI). The QUS parameters did not change significantly after the first 6 months. All QUS parameters correlated significantly with DXA BMD of the lumbar spine immediately after transplantation and 6 months thereafter. Significant decrease of the lumbar spine BMD in the first 6 months after transplantation was not accompanied by significant changes of calcaneal QUS parameters. The calcaneal QUS does not reflect bone mineral changes occurring in the lumbar spine and could not be a substitute for a direct-site DXA of the lumbar spine in the early period after kidney transplantation.

Bone Scintigraphy as an Adjunct for the Diagnosis of Oral Diseases

Bone scintigraphy is a very sensitive method for the detection of osteoblastic activity of the skeleton. The technique consists of imaging the uptake of bone-seeking radiopharmaceuticals, particularly technetium-99m labeled diphosphonates, in the mineral component of bone, which consists of hydroxyapatite crystals and calcium phosphate, as well as in the organic matrix such as collagen fibers. Plain radiographs, computed tomography, and magnetic resonance imaging are classified as structural imaging modalities, whereas bone scintigraphy is a functional method. In many cases, radionuclide imaging techniques are the only means by which early physiologic changes that are a direct result of biochemical alteration may be assessed, before significant bone mineral changes can be detected by other means. Since many oral diseases may cause metabolic changes in the oromaxillofacial complex, it would be of great value to use bone scintigraphy to evaluate more completely some conditions involving the bones in the region to formulate more appropriate treatment plans. Based upon the current literature, the authors discuss the possible applications of bone scintigraphy as a diagnostic and treatment planning adjunct for oral diseases. Bone scintigraphy has proven particularly useful in the study of malignant lesions and in the evaluation of vascularized bone grafts used for maxillofacial reconstructions.

Bone mineral changes during pregnancy and lactation.

Significant calcium transfer from the mother to the fetus and infant occurs during pregnancy and lactation, theoretically placing the mother at an increased risk for osteoporosis later in life. During pregnancy, intestinal calcium absorption increases to meet much of the fetal calcium needs. Maternal bone loss also may occur in the last months of pregnancy, a time when the fetal skeleton is rapidly mineralizing. The calcium needed for breast milk production is met through renal calcium conservation and, to a greater extent, by mobilization of calcium from the maternal skeleton. Women experience a transient loss of approx 3-7% of their bone density during lactation, which is rapidly regained after weaning. The rate and extent of recovery are influenced by the duration of lactation and postpartum amenorrhea and differ by skeletal site. Additional calcium intake does not prevent bone loss during lactation or enhance the recovery after weaning. The recovery of bone is complete for most women and occurs even with shortly spaced pregnancies. Epidemiologic studies have found that pregnancy and lactation are not associated with an increased risk of osteoporotic fractures.

Preventive effects of running exercise on bones in heavy ion particle irradiated rats.

We examined the effects of running exercise on preventing decreases in bone mineral and tissue volume after heavy ion particle irradiation in rats. Male Wistar rats experienced whole-body irradiation by heavy ion particle beam (C-290 MeV) at doses of 0.5, 1.0, and 5.0 Gy and were divided into voluntary running groups and control groups. Rats in the running groups ran on the treadmill 15 m/min, 90 min/day for 35 days after exposure. At the end of the experiment, a tibia was obtained from each rat for measurement of bone mineral density (BMD) and cross-sectional area, strength strain index, and bone histomorphometric analysis. The weights of muscles and concentration of serum calcium were measured. Total BMD and trabecular BMD in the metaphysis and cortical BMD of the diaphysis of tibia in the running groups increased. Bone volume and trabecular thickness increased while trabecular separation decreased in the running groups compared to those in the control groups at respective doses. However, the osteoid surface and eroded surface varied in the running groups compared to those of the respective corresponding groups. The dynamic parameters such as mineralizing surface, mineral apposition rate, and bone formation rate in the running groups were varied, probably due to the differences in radiation-induced sensitivities of bones following radiation exposure. The overall results suggest that running exercise might have a beneficial effect on preventing bone mineral loss and changes in bone structure induced by space radiation, but it is necessary to examine the optimal conditions of running exercise response to doses.

Regional and hormone-dependent effects of apolipoprotein E genotype on changes in bone mineral in perimenopausal women.

We studied 479 perimenopausal Danish women aged 45-58 years to examine differences between APOE genotypes with respect to (1) baseline total body bone mineral density (BMD) and densities measured in five different regions (ultradistal forearm, proximal forearm, lumbar spine, femoral neck, and total hip region); (2) serum levels of alkaline phosphatase, bone isoenzyme alkaline phosphatase, osteocalcin, parathyroid hormone (PTH), 25-hydroxyvitamin D, and urine hydroxyproline/creatinine excretion ratio; and (3) changes in bone mineral during 5 years of follow-up. Baseline BMDs were identical, whereas serum levels of alkaline phosphatase and its bone isoenzyme were higher in women with APOE 2-2 and APOE 2-3 than in women with APOE 3-3 and APOE 3-4 and lower in women with APOE 4-4. Among women not receiving hormonal-replacement therapy (HRT; n = 262), those with APOE 2-2 and APOE 2-3 had 30-40% lower rates of femoral neck and total hip bone mineral loss than women with APOE 3-3 and APOE 3-4, whereas the rates of mineral loss in other skeletal regions did not differ between these APOE genotypes. Women with APOE 4-4 appeared to have lower rates of bone mineral loss in all regions. Women treated with hormones throughout the follow-up period (n = 113) gained bone mineral, and women with APOE 3-4 and APOE 4-4 gained relatively more mineral than other women. A comparison of untreated and treated women with APOE 2-3, APOE 3-3, and APOE 3-4 suggests a possible modification of the effect of APOE genotype by HRT. In conclusion, the common APOE polymorphism has a complex effect on bone metabolism in perimenopausal Danish women including possible modification by hormone use: (1) among women not receiving HRT, those with APOE*2 have lower bone mineral losses in the femoral neck and hip region than other women, and (2) among women receiving HRT, those with APOE*4 gain more bone mineral than other women.

Longitudinal change in periprosthetic, peripheral, and axial bone mineral density after total hip arthroplasty

To determine the bone mineral changes after total hip arthroplasty, bone mineral densities (BMD) at the periprosthetic interface, lumbar spine, radius, and calcaneus were measured in a prospective and longitudinal observation. Twenty-four patients (24 joints) who had received a total hip arthroplasty and were followed longitudinally were enrolled in this study. The subjects comprised 2 men and 22 women with a mean age of 69.2 years at the time of surgery. Bone mineral measurements were performed at 1, 3, 6, 12, 18, 24, 30, and 36 months after surgery. The periprosthetic BMD after total hip arthroplasty continued to decrease for 6–12 months after surgery, and then recovered, except in Gruen zone 7 (the calcar region). The calcaneal BMD decreased rapidly for 3 months after surgery before increasing. The lumbar BMD showed a decreasing trend for 12 months after surgery, and then increased gradually. The radial BMD was not affected by surgery. We conclude that changes in the periprosthetic BMD after total hip arthroplasty show an apparent difference between zones, and also differ between the weight-bearing bones and the nonweight-bearing bones.

BONE MINERAL RESPONSE TO LOADING EXERCISE IS RELATED TO MATURITY

Several retrospective studies propose a pediatric “window of opportunity” when loading elicits an optimal osteogenic response. To test this hypothesis prospectively, we conducted an 8-month, randomized, controlled, school-based high impact intervention study in 174 pre-and early pubertal girls. Maturity was assessed by Tanner breast staging. Tanner 1 (at baseline) girls were rated as prepubertal (Pre; n = 43 Intervention (I), n = 25 Control (C)) while Tanner 2 and 3 girls were classified as early pubertal (Early; n = 43 I, n = 63 C). Mean (SD) age was 10(0.6) and 10.5(0.6) years for the Pre and Early girls, respectively. Girls attending intervention schools undertook a 10-minute, high impact, progressive circuit program 3 times per week. We measured total body (TB) bone mineral content and area density (aBMD), and aBMD at the total proximal femur (PF), femoral neck (FN) and trochanteric (TR) subregions (Hologic QDR 4500). Other measures were height, weight (standard techniques); lean mass (LM), fat mass (FM) (DXA); general physical activity and calcium intake (validated questionnaires). There were no differences in anthropometric or lifestyle variables between I and C within Pre and Early groups at baseline. Similar changes in height, weight, LM, and FM were observed for I and C within maturity groups over 8 months. We used ANCOVA to compare change in bone mineral from baseline and controlled for baseline bone and weight values, change in height and weight, and Tanner Stage (for Early only). The increase in TB BMC/aBMD, and PF, FN and TR aBMD were similar between Pre-I and Pre-C, and between Early-I and Early-C. However, FN aBMD increased more in the Early-I as compared to the Early-C (6.4 vs. 5.2%, p < 0.03). Thus, early as compared to pre-puberty may be an effective “window of opportunity” for femoral neck bone mineral to respond favourably to loading in growing girls.

No bone ingrowth into the tibia tunnel in anterior cruciate ligament-reconstructed patients: a 1-year prospective quantified CT study of 10 patients reconstructed with an autologous bone-patellar tendon-bone graft.

10 patients with major instability symptoms due to an acute anterior cruciate ligament injury were operated on with a bone-patellar tendon-bone reconstruction. Tibial condyle bone mineral density (BMD), bone ingrowth and changes in diameter in the tibia bone tunnel were studied with quantified computed tomography (QCT) postoperatively and after 1, 3, 6 and 12 months. We found no sign of bone ingrowth in the form of increased bone mineral density (BMD) in the bone tunnels in any of the patients. The tunnel diameter increased in all patients during the first postoperative months. After 1 year, 5 patients had a smaller diameter than at the first postoperative examination, 2 had the same diameter as immediately after surgery and 2 patients had a larger diameter. A sclerotic zone developed in all patients along the perimeter of the tunnel during the 3-6 months of follow-up. The BMD in the tibial condyle decreased at 3 months; it then increased, but between 6 and 12 months, it levelled out and was slightly lower than postoperatively. In conclusion, we found no growth of bone into the tunnel and tendinous part of the graft during the first postoperative year.

ELECTROLYTES IN FEMUR AND PLASMA OF RATS DURING PROLONGED RESTRICTION OF MOTOR ACTIVITY

Hypokinesia (decreased motor activity) induces insignificant bone mineral changes. The aim of this study was to measure mineralization, density, and also electrolyte content in the femur of rats during prolonged hypokinesia (HK). Studies were done on 144 male Wistar rats (370–390 g) during 15 days period of pre-HK and 90 days period of HK. Rats were equally divided into two groups: hypokinetic rats (HKR) and vivarium control (VCR). The HKR group of rats was kept in small individual cages. Femur mineralization density, ash mineral content, calcium (Ca) and phosphate (P) content, and plasma Ca and P concentration were measured. In the HKR group body weight, femur mineralization, density, ash mineral content, Ca and P concentration decreased significantly ( p⩽0.01) while plasma Ca and P concentration increased significantly ( p⩽0.01) when compared with the VCR group. The measured parameters did not change significantly in the VCR group when compared with the baseline control values. It was concluded that prolonged HK induces a significant reduction in electrolyte concentration accompanied by decreased mineralization, density, and ash mineral content of the femur of rats.