Dietary calcium intake and rates of bone loss in women.

We measured bone mineral density (BMD) at the midradius and lumbar spine in 106 normal women, ages 23-84 yr (61 were postmenopausal). Three to nine measurements (median, four) were made over 2.6 to 6.6 yr (mean, 4.1 yr). The correlation between calcium intake (range, 260-2,035 mg/d) and rate of change in BMD was not significant at the midradius (r = 0.06) or lumbar spine (r = 0.08), even after adjusting for age, menopausal status, and serum estrogen levels by multiple regression analysis. Women in the lower (mean, 501 mg/d) and in the upper (mean, 1,397 mg/d) quartiles of dietary intake had similar rates of change in BMD (%/yr [mean +/- SE], at midradius, -0.78 +/- 0.24 and -0.91 +/- 0.17 for lower and upper quartiles, respectively; at lumbar spine, -1.06 +/- 0.24 and 0.98 +/- 0.24). These data do not support the hypothesis that insufficient dietary calcium is a major cause of bone loss in women.     

Changes in calcanean bone mineral occurring spontaneously and during hormone replacement therapy in early post-menopausal women.

The spontaneous calcanean bone loss occurring in healthy early post-menopausal women and the effect of two hormone replacement therapies (HRT's) were investigated in a longitudinal study. There was no difference between the right and left calcanean BMC or BMD (p > 0.15). The spontaneous bone loss was similar at all the skeletal sites measured, with a mean spontaneous loss in calcanean BMD of 1.6% over one year. Both HRT's significantly (p < 0.01) prevented the bone loss from all skeletal sites irrespective of the weight-bearing or content of trabecular bone, and (for the weight-bearing bones) there was even a gain in calcanean BMC and BMD and spinal BMD (p < 0.01). Bone mineral of the calcaneus and the spine correlated equally to body weight (r approximately 0.4, p < 0.001), whereas bone mineral in the forearm was not correlated to body weight. The correlations between the changes in bone mineral at the sites measured were all significant (r approximately 0.2-0.4).     

Calcium and bone

ObjectiveEvaluate the role of calcium on bone health.MethodsReview of literatures on calcium and bone development during childhood and bone health in adulthood and older age.ResultsCalcium intake influences skeletal calcium retention during growth and thus affects peak bone mass achieved in early adulthood. Increased calcium intake is associated with increased bone mineral accretion rate up to a threshold level in all ethnic groups. The minimum intake to achieve maximal retention is 1140 mg/day for white boys and 1300 mg/day for white girls. Calcium also plays a role in preventing bone loss and osteoporotic fractures in later life. Meta-analyses report that calcium supplementation reduce bone loss by 0.5–1.2% and the risk of fracture of all types by at least 10% in older people. Low calcium intake is a widespread problem across countries and age groups.ConclusionAdequate calcium intake throughout lifetime is important for bone health and the prevention of osteoporosis and related fractures.     

Bone mineral density measured by dual-energy X-ray absorptiometry in normal men

A cross-sectional study of 222 healthy Finnish men aged 20-69 years was performed to establish reference values of bone mineral density (BMD) using dual-energy X-ray absorptiometry (DEXA). The effects of age, and of some physical and lifestyle factors on BMD of the lumbar spine and proximal femur (femoral neck, Ward's triangle and trochanter) were investigated. The maximal mean BMD was observed at the age of 20-29 years in all the measurement sites. Except for the trochanteric area, BMD diminished along with age, the over-all decrements being 4%, 11%, and 23% in the lumbar, femoral neck and Ward's triangle areas, respectively. BMD was in a positive relationship to weight and height in all the measurement sites. The adjusted (for age, height and weight) BMDs were higher (P less than 0.05) in the group of daily dietary calcium intake greater than 1200 mg as compared with the group of lowest calcium intake (less than 800 mg day-1) in the three femoral areas. Cigarette smoking or alcohol drinking had no obvious effect on BMD.     

Effect of soluble corn fiber supplementation for 1 year on bone metabolism in children,the MetA-bone trial: Rationale and design

Calcium intake is critical for adequate bone mineralization in adolescence, but it is usually inadequate in US adolescents. A strategy to maximize bone mineralization is to increase calcium absorption, which could be achieved by soluble corn fiber (SCF). There are no studies determining the long-term effects of SCF on bone mass in children.ObjectivesTo determine the effect of one-year SCF supplementation compared to placebo on bone mass and bone biomarkers in children with low habitual calcium intake. We hypothesize that SCF supplementation will result in a higher bone mineral content and higher levels of bone formation and lower bone resorption biomarkers.Methods240 healthy children (10–13 years), with usual low calcium intake, will be randomized to four experimental groups for 1 year: (1) SCF (12 g/d); (2) SCF (12 g/d) + 600 mg/d of calcium; (3) Placebo (maltodextrin); and (4) Placebo +600 mg/d of calcium. The supplements have been pre-mixed with a flavored powder beverage and participants will only need to dilute it in water and drink this twice per day. Bone will be measured using dual energy x-ray absorptiometry (DXA) at baseline, 6 and 12 months. Serum bone biomarkers will be measured at baseline and at 12 months.ConclusionsIf supplementing diets with SCF lead to higher bone mass during adolescence, this could help achieve the genetic potential for PBM and to start adult life with stronger bones. If successful, SCF can be incorporated into diets for promoting bone health in adolescents.     

Metacarpal bone mineral density,body mass index and lifestyle among postmenopausal Japanese women: relationship of body mass index,physical activity,calcium intake,alcohol and smoking to bone mineral density: the Hizen-Oshima study

The present study was designed to investigate the influence of modifiable risk factors (body weight and lifestyle) for bone loss on bone mineral density (BMD). We examined age-specific changes in metacarpal BMD, and its associations with body mass index and lifestyle among 532 community-dwelling postmenopausal Japanese women. Measurements of the second metacarpal BMD were obtained from the hand radiographs using computer-assisted radiographic absorptiometry. Body height and weight were measured, and body mass index (BMI) was calculated. Physical activity index was calculated using validated questionnaire. Daily calcium intake and amount of ingested alcohol were estimated by semiquantitative food frequency questionnaire. Current smoking status was obtained by questionnaire. Metacarpal BMD decreased significantly with increasing age. Simple correlation analysis indicated that metacarpal BMD correlated significantly with BMI and physical activity index. On the other hand, metacarpal BMD did not correlate with calcium intake and alcohol drinking. Metacarpal BMD in current smokers was not different from that in nonsmokers. Multiple regression analysis showed that increasing age was associated with decreased metacarpal BMD and greater BMI increased metacarpal BMD. However, physical activity, calcium intake, alcohol drinking and current smoking were not significant determinants of metacarpal BMD. Our findings suggest that maintenance of adequate body mass (prevention for leanness) is important for prevention of postmenopausal bone loss.     

双能X线骨密度仪测量双侧前臂骨面积、骨矿含量和骨矿密度的比较

目的比较健康人优势和非优势前臂的骨面积（Ａｒｅａ）、骨矿含量（ＢＭＣ）和骨矿密度（ＢＭＤ）。方法采用双能Ｘ线骨密度仪测量５５例１６～７３岁（平均年龄５２岁）健康志愿者双侧前臂（优势臂均为右臂）的Ａｒｅａ、ＢＭＣ和ＢＭＤ。结果右前臂各部位Ａｒｅａ、ＢＭＣ显著高于左前臂（Ｐ＜０．００１和Ｐ＜０．０５）,除桡骨远端１／３段ＥＭＤ右前臂显著高于左前臂外（Ｐ＜０．０１）,其余部位ＢＭＤ左右侧无差别。结论优势臂的Ａｒｅａ和ＢＭＣ均高于非优势臂,而ＢＭＤ两者差别不大。     

Bone effects of canagliflozin,a sodium glucose co-transporter 2 inhibitor,in patients with type 2 diabetes mellitus

Canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM), lowers blood glucose by inhibiting renal glucose reabsorption and increasing urinary glucose excretion. It has been reported that SGLT2 inhibitors may have potential adverse effects on bone, including increased fracture risk and decreased bone mineral density (BMD). Across clinical studies, canagliflozin was not associated with meaningful changes in serum or urine calcium, vitamin D, or parathyroid hormone. Minimal increases in serum phosphate and magnesium that were within normal limits were seen with canagliflozin versus placebo. Canagliflozin was associated with increases in serum collagen type 1 beta-carboxy telopeptide (beta-CTX), a bone resorption marker, and osteocalcin, a bone formation marker. Decreases in total hip BMD were seen with canagliflozin 100 and 300 mg versus placebo after 2 years (–1.7%, –2.1%, –0.8%; differences of –0.9% and –1.2%), but not at other skeletal sites (normal age-related bone loss, ~0.5-1.0%/year). Changes in beta-CTX and total hip BMD were significantly associated with weight loss, which is known to increase bone resorption markers and decrease BMD. Canagliflozin was associated with a higher fracture incidence in an interim analysis of the CANagliflozin cardioVascular Assessment Study (CANVAS) in patients with a history or high risk of cardiovascular disease (incidence per 100 patient-years of 1.6, 1.6, and 1.1 with canagliflozin 100 and 300 mg and placebo), but not in other clinical studies of patients with T2DM. Fractures tended to occur as early as 12 weeks after initiating treatment and were primarily located in the distal parts of the upper and lower extremities. The reason for increased fracture risk with canagliflozin treatment is unknown, but is likely not related to a direct effect of canagliflozin on bone-related biomarkers. Data from ongoing canagliflozin studies, including CANVAS, will provide additional information on fracture risk in patients with T2DM.     

A comparison of the effect of alendronate and risedronate on bone mineral density in postmenopausal women with osteoporosis: 24-month results from FACTS-International

Objectives: To compare alendronate 70 mg once weekly (OW) with risedronate 35 mg OW with respect to change in bone mineral density (BMD), biochemical markers and upper gastrointestinal (UGI) tolerability over 24 months. Methods: This was a 12‐month extension to the Fosamax^® Actonel^® Comparison Trial international study (FACTS). Postmenopausal women with osteoporosis randomly assigned to either alendronate 70 mg OW or risedronate 35 mg OW for the 12‐month base study continued taking the same double‐blind study medication. Efficacy measurements were BMD at the hip trochanter, lumbar spine, total hip, and femoral neck and levels of four bone turnover markers at 24 months. The primary hypothesis was that alendronate would produce a greater mean per cent increase from baseline in hip trochanter BMD at 24 months. Results: Trochanter BMD increased significantly from baseline to month 24 in both groups, with a significantly larger increase with alendronate: adjusted mean treatment difference of 1.50% (95% confidence interval: 0.74%, 2.26%; p < 0.001). Similar results were seen at all BMD sites. Significant geometric mean per cent decreases (p < 0.001) from baseline were seen for all four bone turnover markers in both groups, with significantly larger decreases (p < 0.001) with alendronate: adjusted mean treatment differences ranged from 8.9% to 25.3%. No significant differences were seen in incidence of UGI or other adverse events. Conclusions: Alendronate 70 mg OW yielded significantly greater BMD gains and larger decreases in bone turnover marker levels than risedronate 35 mg OW over 24 months, with no difference in UGI tolerability.     

Impaired glucose tolerance and bone mineral content in overweight latino children with a family history of type 2 diabetes

OBJECTIVE: Research on the skeletal status of pre-diabetic (type 2 diabetic) children is warranted. We examined the hypothesis that bone mineral content (BMC) and bone mineral density (BMD) will be lower in children with impaired glucose tolerance (IGT) versus normal glucose tolerance (NGT). RESEARCH DESIGN AND METHODS: Total body BMC and BMD of 184 overweight Latino children (106 boys, 78 girls, 11.9 +/- 1.7 years) with a family history of type 2 diabetes were measured using dual-energy X-ray absorptiometry. Glucose tolerance was assessed by 2-h glucose after an oral glucose tolerance test. Area under the insulin curve (AUC) assessed the cumulative insulin response to oral glucose. Acute insulin response to glucose (AIR) was determined by an intravenous glucose tolerance test. RESULTS: Partial correlations revealed an inverse relationship between BMC and AIR (r = -0.29, P = 0.00), AUC (r = -0.28, P = 0.00), fasting insulin (r = -0.16, P = 0.04), and 2-h insulin (r = -0.16, P = 0.04). There was no significant difference in BMC or BMD between children with IGT (n = 46) or NGT (n = 138). Stepwise multiple linear regression revealed that 89% of the variance in BMC is attributed to lean mass (87%), age (1%), and AIR (1%). BMD was explained by lean mass (69%), Tanner stage (3%), and AUC (2%). CONCLUSIONS: The findings of this study suggest that in overweight children, lean mass is the primary predictor of BMC and BMD, whereas age, Tanner stage, and the acute and cumulative insulin responses to oral glucose make subtle independent contributions to the total variances. In addition, poor glycemic control does not seem to be detrimental to bone mass of pre-diabetic children.     

Vitamin D: a growing perspective

Vitamin D deficiency has been widely reported in all age groups in recent years. Rickets has never been eradicated in developed countries, and it most commonly affects children from recent immigrant groups. There is much evidence that current vitamin D guidelines for the neonatal period, 5-10 microg (200-400 IU)/day, prevent rickets at the typical calcium intakes in developed countries. The annual incidence of vitamin D-deficiency rickets in developed countries ranges between 2.9 and 7.5 cases per 100,000 children. The prevalence of vitamin D deficiency in mothers and their neonates is remarkable, and the results of one study suggest that third-trimester 25-hydroxyvitamin D (25(OH)D) is associated with fetal bone mineral accrual that may affect prepubertal bone mass accumulation. Beyond infancy, the evidence indicates that 5 microg (200 IU)/day of vitamin D has little effect on vitamin D status as measured by the serum 25(OH)D concentration. Two randomized clinical trials show that higher vitamin D intake improves one-year gain in bone density in adolescent girls. The functions of vitamin D extend beyond bone to include immune system regulation and anti-proliferative effects on cells. Early life vitamin D inadequacy is implicated in the risk of bone disease, autoimmune disease, and certain cancers later in life; however, long-term interventional studies do not exist to validate the widespread implementation of greater vitamin D consumption. Here we review the available data concerning vitamin D status and health effects of vitamin D in pregnancy through to and including adolescence.     

γ-氨基丁酸B2受体基因rs3750344多态与汉族人骨密度及骨矿量的关系

目的探讨γ-氨基丁酸B2受体(GABABR2)基因第二外显子rs3750344单核苷酸多态性（SNP）与骨密度的关联。方法425名健康志愿者采用双能X线骨密度仪测量全身各个部位的骨密度和骨矿量,用Taqman基因分型平台进行rs3750344基因分型。结果SNP rs3750344位点TT、TC及CC基因型携带者个体的上肢、下肢、躯干、肋骨、骨盆和全身总骨密度、骨矿量均依次显著增加。结论GABABR2基因rs3750344多态的C等位基因增加汉族人骨密度骨及骨矿量的水平。     

Effect of teriparatide on bone mineral density and fracture in postmenopausal osteoporosis: meta-analysis of randomised controlled trials

To determine the efficacy of teriparatide supplementation for improving bone mineral density (BMD) and fracture risk in postmenopausal osteoporosis and if effects vary with factors. We identified eight randomised controlled trials (n = 2388) using electronic databases, supplemented by a hand-search of the reference lists. All trials aimed to evaluate the efficacy of daily subcutaneous teriparatide injection in postmenopausal osteoporosis. The main outcomes were fracture risk and percentage change of BMD from baseline. Data were pooled by employing a random-effect model. In trials that reported BMD as an outcome, treatment was associated with an increase of bone mass of 8.14% [95% confidence interval (CI): 6.72-9.55%; eight trials, n = 2206] in spine and 2.48% (95% CI: 1.67-3.29%; seven trials, n = 1303) at the hip. In trials that reported fracture as an outcome, treatment was associated with a 70% risk reduction in vertebral fractures (risk ratio 0.30, 95% CI: 0.21-0.44; three trials, n = 1452) and 38% risk reduction in non-vertebral fractures (risk ratio 0.62, 95% CI: 0.44-0.87; three trials, n = 1842). The PTH treatment with total calcium intake more than 1500 mg was related to a significant increase in BMD gains at total hip (1.40% vs. 3.72%; p = 0.004). However, long-term duration did not appear to contribute to differences in responsiveness to teriparatide. Evidence supports the use of teriparatide in treatment of women with postmenopausal osteoporosis who are at risk for fracture. Further studies directly comparing concurrent therapy and calcium supplement with long-term duration are warranted.     

Implementing an intervention to improve bone mineral density in survivors of childhood acute lymphoblastic leukemia: BONEII, a prospective placebo-controlled double-blind randomized interventional longitudinal study design

The BONEII study is a large two-phase study. The baseline study (Study 1) aims to estimate the prevalence of diminished bone mineral density (BMD) in patients treated for childhood acute lymphoblastic leukemia (ALL) and identify risk factors for BMD deficits. The interventional phase (Study 2) of BONEII has a placebo-controlled double-blind randomized longitudinal design to evaluate the effects of nutritional counseling and calcium and vitamin D supplementation on changes in BMD and serum and urine markers of bone metabolism. The extensive information being collected through this large study will serve as a repository of relational data about BMD and bone turnover and will support further investigations to assess the association of calcium metabolism, bone turnover, nutritional intake, lifestyle factors (such as exercise and the use of alcohol and tobacco), and the specific agents used in ALL therapy in this rapidly increasing population of childhood cancer survivors.     

Lumbar bone mineral content and density measured using a Lunar DPX densitometer in healthy full-term infants during the first year of life

This cross-sectional study provides values for lumbar spine bone mineral content (BMC) and density (BMD) in 41 healthy full-term born Finnish infants, 19 boys and 22 girls, during the first year of life measured by dual energy X-ray absorptiometry (DXA) using the Lunar DPX densitometer. Lumbar BMC correlated with the weight (r=0.733; P=0.000), length (r=0.677; P=0.000), standardized length (r=0.315; r=0.045) and age at examination (r=0.314; P=0.045), and with the bone area (r=0.736; P=0.000). Infants with < or =-1 SD scores for lengths at examination had significantly lower BMC values [mean (SD); 1.79 (0.66) g] than infants with SD scores above -1 SD [2.27 (0.46) g] (P=0.011). Exclusive breast feeding did not correlate with the lumbar BMC values (r=-0.039; P=0.811). No differences were found in lumbar spine BMC (P=0.097), BMD (P=0.254) and bone area (P=0.094) values between boys and girls. In order to determine the predictive value of the anthropometric measurements on lumbar BMC, stepwise multiple regression analysis were performed, bone area and present weight were the only independent variables which explained 67.6% of the variance in the BMC values. The present cross-sectional data imply that, in healthy term infants, patterns of relative linear growth during the first year of life are related to the lumbar BMC values. In future, careful longitudinal measurements of linear growth are needed to study connections between growth patterns and bone mineral status in infancy.     

Sex steroids, bone mass, and bone loss. A prospective study of pre-, peri-, and postmenopausal women.

Although bone loss around the time of menopause is driven by estrogen deficiency, the roles of estrogens and androgens in the preservation of skeletal mass at other stages of life are less well understood. To address this issue we studied 231 women between the ages of 32 and 77 with multiple measurements of sex steroids and bone mass over a period of 2-8 yr. In all women bone mass was negatively associated with concentrations of sex-hormone binding globulin, and positively associated with weight. Bone loss occurred from all skeletal sites in peri- and postmenopausal women, but premenopausal women lost bone only from the hip (-0.3%/yr) and had positive rates of change in the radius and spine. Bone loss was significantly associated with lower androgen concentrations in premenopausal women, and with lower estrogens and androgens in peri- and postmenopausal women. Sex steroids are important for the maintenance of skeletal integrity before menopause, and for as long as 20-25 yr afterwards.     

Increased cortical bone mineral content but unchanged trabecular bone mineral density in female ERβ–/– mice

Ovariectomy in young, growing rodents results in decreased trabecular bone mineral density (BMD) and increased radial growth of the cortical bone. Both of these effects are reversed by treatment with estrogen. The aim of the present study was to determine the physiological role of estrogen receptor-beta (ERbeta) on bone structure and bone mineral content (BMC). The BMC was increased in adult (11 weeks old), but not prepubertal (4 weeks old), female ERbeta(-/-) mice compared with wild-type (WT) mice. This increase in BMC in females was not due to increased trabecular BMD, but to an increased cross-sectional cortical bone area associated with a radial bone growth. Male ERbeta(-/-) mice displayed no bone abnormalities compared with WT mice. Ovariectomy decreased the trabecular BMD to the same extent in adult female ERbeta(-/-) mice as in WT mice. The expression levels of osteoblast-associated genes - alpha1(I) collagen, alkaline phosphatase, and osteocalcin mRNAs - were elevated in bone from adult ERbeta(-/-) females compared with WT mice. These observations provide a possible explanation for the increased radial bone growth seen in female mutants, suggesting a repressive function for ERbeta in the regulation of bone growth during female adolescence. In summary, ERbeta is essential for the pubertal feminization of the cortical bone in female mice but is not required for the protective effect of estrogens on trabecular BMD.     

COMPARISON OF ALENDRONATE,CALCITONIN AND CALCIUM TREATMENTS IN POSTMENOPAUSAL OSTEOPOROSIS

The present study was planned to assess the safety, tolerability and efficacy on bone mineral density (BMD), pain, quality of life and fracture risk of alendronate, calcitonin and calcium treatments. A total of 151 postmenopausal women with lumbar spine BMD 2 SD or more below the young adult mean were randomly assigned to one of three groups: 51 patients received oral alendronate 10 mg and calcium 1000 mg (alendronate group), 50 patients intranasal salmon calcitonin 100 IU and oral calcium 1000 mg (calcitonin group), and 50 patients oral calcium 1000 mg (calcium group) daily for one year. BMD was assessed by dual energy X-ray absorbtiometry, pain by a visual analogue scale, and quality of life by the Nottingham health profile. Significant increases in BMD at all sites were obtained in the calcitonin and alendronate groups, but not in the calcium group. Pain and quality of life improved significantly in both the calcitonin and alendronate groups, but not in the calcium group. New vertebral fractures were seen in 31.58% of the alendronate, 37.5% of the calcitonin, and 40% of the calcium groups, representing no statistical difference. No serious side-effects were seen in any of the patients during follow-up.     

Teriparatide: a review

BACKGROUND: Traditionally, the management of osteoporosis in men and women has included the use of antiresorptive agents in combination with calcium and vitamin D supplementation. The mechanism of action of teriparatide is unique in that it possesses anabolic properties and therefore builds bone. Since the approval of teriparatide in the United States in 2002, a great deal of interest regarding its use in osteoporosis has developed. OBJECTIVES: This article reviews the information available on the new recombinant human parathyroid hormone teriparatide (hPTH [1-34]), including its clinical pharmacology, mechanism of action, pharmacokinetic properties, clinical efficacy, safety profile, potential drug interactions, contraindications and warnings, dosage and administration, and pharmacoeconomics. METHODS: The articles included in this review were identified through searches of PubMed and MEDLINE (1966-December 2003) and International Pharmaceutical Abstracts (1970-December 2003). Search terms included teriparatide, Forteo, recombinant human parathyroid hormone (1-34), and osteoporosis. The references of the identified articles were reviewed for additional publications. Specific product information was also obtained from the manufacturer of teriparatide. RESULTS: Teriparatide has been studied in postmenopausal women with osteoporosis, drug-induced osteoporosis (specifically, corticosteroid-induced osteoporosis), and men with osteoporosis. The data available from various clinical trials have shown an increase in both bone mineral density (BMD) and bone mineral content (BMC) with the use of teriparatide compared with placebo. One study found that women treated with the 20-microg dose and the 40-microg dose were 35% and 40%, respectively, less likely to have one or more new nonvertebral fractures compared with placebo (P = 0.02). Another study compared the use of daily teriparatide 40-microg injections versus oral daily alendronate. Results showed that the incidence of nonvertebral fractures was significantly lower in the teriparatide group than the alendronate group (P < 0.05). A study using 20- and 40-microg daily injections of teriparatide was performed in men with osteoporosis. There was a statistically significant increase in lumbar spine BMD of 5.9% in the 20-microg group and 9.0% in the 40-microg group (both, P < 0.001). In the femoral neck, a 1.5% increase in BMD occurred in the 20-microg group (P = 0.021) and a 0.9% increase in the 40-microg group (P < 0.001). A limited number of studies are available assessing the combination of antiresorptive medications and teriparatide; however, the available data suggest that the effects of teriperatide do not require prior stimulation of bone resorption. CONCLUSIONS: Teriparatide has been shown clinically to improve BMD and BMC in postmenopausal women and in men. Because of its anabolic capabilities, teriparatide can be used as an alternative to the traditional therapies that are currently available for the treatment of osteoporosis, with scheduled monitoring for adverse effects such as hypercalcemia and urinary calcium excretion. In 1 study, mild hypercalcemia was seen most often 4 to 6 hours after SC injection of teriparatide before returning to normal. Urinary calcium was observed to increase by 30 mg/d (0.75 mmol/d) with teriparatide.     

幼鼠骨骼发育中高脂饮食的影响

背景:高脂饮食能引起肥胖,成年人肥胖能增加骨密度,对健康有一定的正面作用,而高脂饮食对生长快速的儿童骨骼发育的影响并不十分明确.目的:观察高脂饮食对雌性幼鼠骨胳发育的影响.方法:取12只4周龄雌性CD1小鼠,分别给予高脂饮食和正常饮食,喂养10周后用双能X射线骨密度仪扫描全身;用三点弯曲实验检测骨生物力学特征;用酶联免疫分析法检测血清中骨转换标志物;股骨组织切片苏木精-伊红染色观察骨小梁变化和骨髓的脂肪化程度.结果与结论:高脂饮食组小鼠的体质量、体脂含量均显著高于正常饮食组,但全身的骨密度、骨矿物质含量、骨面积和肌肉组织含量与正常饮食组无显著差异,但腰椎的骨密度、骨矿物质含量和骨面积都显著低于正常饮食组,而股骨的骨密度、骨矿物质含量和骨面积都显著高于正常饮食组,经体质量或体脂含量校正后虽然无显著统计学差异,但高脂饮食组全身和股骨的骨密度、骨矿物质含量和骨面积都呈现了低于正常饮食组的趋势;两组在骨生物力学特性方面的比较没有显著差异;高脂饮食组的血清骨转换标志物浓度较正常饮食组低;组织切片可见高脂饮食组的骨髓腔中有大量脂肪浸润和骨小梁宽度和面积减小.提示肥胖对生长旺盛阶段的幼鼠骨骼发育有不良影响,椎骨的骨矿物化程度下降,承重部位骨量的增加不能充分代偿体质量的增加.

Abstract：

BACKGROUND:High fat diet (HFD) can induce overweight and obesity,which have been considered to positively affect bone mineral density (BMD) in adults.However,it is unclear how HFD affects the bone development during childhood.OBJECTIVE:To determine the effect of HFD on bone development in young female mice.METHODS:Twelve female CD1 mice were fed with either HFD or normal fat diet (NFD) starting at 4-week of age for 10 weeks.The bone mineral content (BMC),BMD,fat and lean mass were examined in 14-week old mice using dual-energy X-ray absorptiometry,and bone biomechanical properties were also evaluated using three-point bending test.Serum concentration of bone metabolic markers was measured using enzyme immunoassay.Femora were sectioned in the transverse plane and stained with hematoxylin and eosin for observing the adiposity of bone marrow and changes in trabecular bone area.RESULTS AND CONCLUSION:The body weight and fat mass in HFD-treated mice were increased compared with those in NFD-treated mice,respectively.There were no significant differences between HFD-treated and NFD-treated mice in whole body BMD,BMC,bone area and lean mass.However,the spine BMC and bone area in HFD mice were significantly lower than that in NFD mice,while femoral BMD,BMC and bone area in HFD mice were significantly greater than that in NFD mice.But,there was no statistically different in bone biomechanical values between the two groups.Bone metabolic markers were lower in HFD mice than NFD mice,indicating the less active of bone metabolism in HFD mice.It is suggested that HFD can produce deleterious effect on bone during the active growing phase of young mice.Vertebral bone is more sensitive to this negative effect than cortical bone due to the decreased vertebral mineralization.Weight-bearing bone does not response sufficiently to compensate for the excessive weight gaining.