Serum zinc and its relation to bone mineral density in β-thalassemic adolescents

Trace elements have been considered to play critical roles in bone metabolism. This study aims at determining the serum zinc profile and its association with bone mineral density (BMD) abnormalities in thalassemic patients. In 131 transfusion-dependent β-thalassemic patients, aged 10–20 yr, serum levels of zinc were measured by flame atomic absorption spectrophotometry (F-AAS). BMD values at the lumbar (L1–L4) and femoral neck were determined by dual X-ray absorptiometry (DXA). Dietary zinc intake and daily consumption of calcium were evaluated by a food-frequency questionnaire. Low serum zinc was found in 84.8% (in 44.7% severely low). Below −2 BMD Z-scores were observed in 68.7% and 17.6% of the patients at the lumbar and femoral regions, respectively. Female patients with severe zinc deficiency had lower lumbar BMD Z-scores in comparison to the other females (−3.26 vs −2.54). Serum zinc in females with femoral BMD Z-scores <−2 was significantly lower by 16.4 μg/dL than other females. Our study suggests that serum levels of zinc can be lowered in the thalassemic patients and partly affect the BMD.     

Splenectomy changes the pattern of cytokine production in beta-thalassemic patients

A major cause of morbidity and mortality in beta-thalassemic patients is infections, assumed to be the result of immunological changes. To determine the possible defect, we investigated the cytokine productions by blood cells of beta-thalassemic patients using in-vivo and in-vitro methods. Heparinized blood samples collected aseptically from 22 beta-thalassemic children aged 10-12yrs (half of them were splenectomized). Samples from 10 healthy children served as control group. Part of samples was used for evaluation of plasma IL-2, IL-10 and TGF-beta1. Other part were stimulated with a mixture of LPS and PHA (1 and 10 microg/ml final concentration), for different time period (4, 24, 48 and 72h). Results showed circulating TGF-beta1 of splenectomized patients was significantly higher (p<0.01) than the control group. In-vitro results showed IL-2 production of patients' groups were significantly (p<0.01) lower than corresponding value obtained for the control group. In addition, IL-10 production by splenectomized group were less than other two group (p<0.01), while their TGF-beta1 were higher (p<0.001) at all time points treated. In conclusion, multi-transfusions could be responsible for a change in the subset of circulating lymphocytes that could contribute to a state of partial immune deficiency in beta-thalassemic patients, which is more prominence among the splenectomized patient.     

Function of reticuloendothelial system in splenectomised thalassemics

The activity of reticuloendothelial system (RES) was estimated in 19 patients with beta-thalassemia major, 20 +/- 4 years old, who had undergone successful splenectomy 6 +/- 5 years previously. The kinetics of 125I denatured human serum albumin in low and large doses was applied for this purpose and the parameters derived (effective RES blood flow-ERBF- and maximum phagocytic capacity-PCmax) were compared to those of nonsplenectomized thalassemics, detected in previous works, as well as to those of 13 healthy controls. In splenectomised thalassemics both parameters of RES activity were found significantly lower than those of nonsplenectomized patients (p less than 0.001). Compared to those of healthy controls, PCmax of splenectomised thalassemics was found not to be significantly different, while ERBF was significantly lower (p less than 0.001). No correlation was noted between the above parameters of RES function and the age of the patients, the age at which splenectomy was performed, the time lapsed since the operation, the amount of blood transfused to the patients after splenectomy or their serum ferritin levels. A pilot study performed in 6 out of the 19 splenectomised patients did not reveal any effect of blood transfusion on RES function parameters, by contrast to observations in nonsplenectomized thalassemics. The results of this study suggest that in splenectomised thalassemics the remaining RES reacts to the continuing hemolytic stimulus in a manner different than that of splenic RES of nonsplenectomized patients and account for, at least in part, the predisposition of the former group to infections.     

N-acetylcysteine amide (AD4) attenuates oxidative stress in beta-thalassemia blood cells

Many aspects of the pathology in beta-hemoglobinopathies (beta-thalassemia and sickle cell anemia) are mediated by oxidative stress. In the present study we tested a novel thiol compound, N-acetylcysteine amide (AD4), the amide form of N-acetyl cysteine (NAC) for its antioxidant effects. Using flow-cytometry, we showed that in vitro treatment of blood cells from beta-thalassemic patients with AD4 elevated the reduced glutathione (GSH) content of red blood cells (RBC), platelets and polymorphonuclear (PMN) leukocytes, and reduced their ROS. These effects resulted in a significant reduced sensitivity of thalassemic RBC to hemolysis and phagocytosis by macrophages. Intra-peritoneal injection of AD4 to beta-thalassemic mice (150 mg/kg) reduced the parameters of oxidative stress (p<0.001). Our results show the superiority of AD4, compared to NAC, in reducing oxidative stress markers in thalassemic cells both in vitro and in vivo.     

Osteoprotegerin--does it play a protective role in the pathogenesis of bone loss in obese perimenopausal women?

INTRODUCTION: Assessment of serum osteoprotegerin (OPG) concentrations in obese patients in comparison to healthy controls and evaluation of a possible correlation between OPG and other markers of bone turnover or calcitropic hormones. MATERIAL AND METHODS: 50 obese perimenopausal women without concomitant diseases (BMI 36.7 +/- 4.1 kg/m(2), mean age 50.4 +/- 4.9 yrs). The control group consisted of 19 healthy women (BMI 24.2 +/- 2.1 kg/m(2); mean age 53.8 +/- 5.1 yrs). In all patients serum concentration of OPG, C telopeptide of type I collagen containing the crosslinking site (CTX), osteocalcin, parathormone (PTH) and vitamin D (25-OH-D(3)) was assessed. Dual energy x-ray absorptiometry (the DXA method) of the lumbar spine and femoral neck was performed using a Lunar DPXL to measure bone marrow density (BMD). RESULTS: In obese perimenopausal women serum OPG, osteocalcin and 25-OH-D(3) levels were significantly lower, and the serum PTH level was significantly higher in comparison to healthy controls. A significantly positive correlation was found between serum OPG level and age in both obese and control subjects. CONCLUSION: The serum OPG level in obese perimenopausal women is significantly lower in comparison to healthy controls and does not correlate significantly with biochemical markers of bone turnover, calcitropic hormones and BMD. It probably cannot play a protective role in the pathogenesis of bone loss in obese perimenopausal women.     

Effects of physical training on bone mineral density and bone metabolism

The purpose of this study was to examine the influences of long-term walking training and walking and jumping training on bone mineral density (BMD) and bone metabolism. Data from 28 healthy premenopausal women was assessed. The subjects were divided into the walking group (WG; 17 women mean+/-SE age 35+/-2 years), and the walking and jumping group (WJG; 11 women mean+/-SE age 39+/-1 years). BMD was measured in the lumbar spine and proximal femur using dual energy X-ray absorptiometry (DXA). As markers of bone metabolism, this study was to measure bone formation markers, bone-alkaline phosphatase (B-ALP: measured by enzyme immunoassay/EIA) and osteocalcin (BGP: by radioimmunoassay/RI) as well as bone resorption markers, parathyroid hormone (PTH: measured by/RI) and type I collagen cross-linked N-telopeptides (NTx: by EIA). Despite the significant decrease in body weight (p<0.05), no corresponding decrease in BMD was observed. Moreover, no significant difference in bone markers BGP, PTH, and NTx was observed. B-ALP was significantly increased (p<0.05) after one year, and the rate of this increase was greater in the WJG than in the WG. It is thus concluded that walking training for one year is beneficial for the promotion of bone formation, and that jumping stimulus maintain BMD effectively.     

Bone Mineral Density of the Spine in 11,898 Chinese Infants and Young Children: A Cross-Sectional Study

Background

Bone mineral density (BMD) increases progressively during childhood and adolescence and is affected by various genetic and environmental factors. The aim of this study was to establish reference values for lumbar BMD in healthy Chinese infants and young children and investigate its influencing factors.

Methods and Findings

Healthy children aged 0 to 3 years who underwent regular physical examinations at the Child Health Care Clinic of Hubei Maternal and Child Health Hospital (N = 11,898) were recruited for this study. We also chose 379 preterm infants aged 0 to 1 years to preliminarily explore the development of BMD in this special population. BMD (g/cm²) measurements of the lumbar spine (L2–L4) were carried out with dual-energy X-ray absorptiometry and a questionnaire was administered to full-term children''s parents to gather information on various nutritional and lifestyle factors as well as mothers'' nutritional supplement use during pregnancy. Lumbar BMD significantly increased with age among both boys and girls (p<0.05), with fastest growth observed during the first postnatal year. There was no significant difference in lumbar BMD between boys and girls of similar age (p>0.05), either among healthy reference children or preterm infants. However, BMD values in preterm infants were significantly lower than those in term infants 3 to 8 months old (p<0.05) after adjustment for gestational age. Multivariable linear regression analysis indicated significant positive associations between lumbar BMD of healthy children and the child''s age and current weight, mother''s weight gain during pregnancy, birth weight, children''s outdoor activity duration and children''s physical activity duration.

Conclusion

Our study provides reference values of lumbar BMD for healthy Chinese children aged 0 to 3 years and identifies several influencing factors.     

Relationship between Body Mass Composition,Bone Mineral Density,Skin Fibrosis and 25(OH) Vitamin D Serum Levels in Systemic Sclerosis

A reduced bone mineral density (BMD) is observed in several rheumatic autoimmune diseases, including Systemic Sclerosis (SSc); nevertheless, data concerning the possible determinants of bone loss in this disease are not fully investigated. The aim of this study is to evaluate the relationship between BMD, body mass composition, skin sclerosis and serum Vitamin D levels in two subsets of SSc patients. 64 post-menopausal SSc patients, classified as limited cutaneous (lcSSc) or diffuse cutaneous (dcSSc) SSc, were studied. As control, 35 healthy post-menopausal women were recruited. Clinical parameters were evaluated, including the extent of skin involvement. BMD at lumbar spine, hip, femoral neck and body mass composition were determined by dual-energy X-ray absorptiometry. Serum calcium, phosphorus, alkaline phosphatase, urine pyridinium cross-links, intact parathyroid hormone and 25-hydroxyvitamin D (25OHD) were measured. BMD at spine, femoral neck and total hip was significantly lower in SSc patients compared to controls. In dcSSc subset, BMD at spine, femoral neck and total hip was significantly lower compared to lcSSc. No differences in both fat and lean mass were found in the three study groups even if patients with dcSSc showed a slightly lower total body mass compared to healthy controls. Total mineral content was significantly reduced in dSSc compared to both healthy subjects and lcSSc group. Hypovitaminosis D was observed both in healthy post-menopausal women and in SSc patients, but 25OHD levels were significantly lower in dcSSc compared to lcSSc and inversely correlated with the extent of skin thickness. These results support the hypothesis that the extent of skin involvement in SSc patients could be an important factor in determining low circulating levels of 25OHD, which in turn could play a significant role in the reduction of BMD and total mineral content.     

Radial bone mineral content of normal Japanese infants and prepubertal children: influence of age,sex and body size

The present study was performed to measure appendicular bone mass of Japanese infants and children, and to assess the influence of age, sex and body size on bone mass during the period of bone growth. The bone mineral content (BMC) and bone width (BW) at the distal third of the radius were measured by single photon absorptiometry (SPA) in 229 healthy Japanese infants and children aged 0–12 years, and the BMC/BW ratio was calculated to give the bone mineral density (BMD). BMC and BW increased with age until 2 years, while BMD did not obviously change until 2 years. After 2 years of age, the overall effect of aging appeared more prominent in BMC and BMD than in BW. There were no significant differences in BMC, BW and BMD between males and females aged 0–12 years. Age, body height, and body weight were strongly correlated with three parameters of bone mass (BMC, BW, and BMD). Among the three parameters of bone mass, BMC showed the highest Pearson coefficient of correlation with age (r = 0.955), body height (r = 0.957) and body weight (r = 0.966), as compared with BW and BMD. The present cross-sectional study provides normative data of the appendicular bone mass in healthy Japanese children, which may serve as a standard for assessment of bone mineralization in Japanese infants and children with medical problems.     

Bone remodelling is reduced by recovery from iron-deficiency anaemia in premenopausal women

Iron-deficiency anaemia (IDA), one of the most common and widespread health disorders worldwide, affects fundamental metabolic functions and has been associated with deleterious effects on bone. Our aim was to know whether there are differences in bone remodelling between a group of premenopausal IDA women and a healthy group, and whether recovery of iron status has an effect on bone turnover markers. Thirty-five IDA women and 38 healthy women (control group) were recruited throughout the year. IDA women received pharmacological iron treatment. Iron biomarkers, aminoterminal telopeptide of collagen I (NTx), procollagen type 1 N-terminal propeptide (P1NP), 25-hydroxyvitamin D, and parathormone (PTH) were determined at baseline for both groups and after treatment with pharmacological iron for the IDA group. IDA subjects were classified as recovered (R) or non-recovered (nR) from IDA after treatment. NTx levels were significantly higher (p <0.001), and P1NP levels tended to be lower in IDA women than controls after adjusting for age and body mass index (BMI), with no differences in 25-hydroxyvitamin D or PTH. After treatment, the R group had significantly lower NTx and P1NP levels compared to baseline (p <0.05 and p <0.001 respectively), whilst no significant changes were seen in the nR group. No changes were seen in 25-hydroxyvitamin D or PTH for either group. IDA is related to higher bone resorption independent of age and BMI. Recovery from IDA has a concomitant beneficial effect on bone remodelling in premenopausal women, decreasing both bone resorption and formation.     

Bone mineral density and body composition in men with multiple sclerosis chronically treated with low-dose glucocorticoids

The aim of the study was to compare the bone mineral density (BMD) and body composition between ambulatory male MS patients and control subjects and to evaluate the relationships among body composition, motor disability, glucocorticoids (GC) use, and bone health. Body composition and BMD were measured by dual-energy X-ray absorptiometry in 104 ambulatory men with MS (mean age: 45.2 years) chronically treated with low-dose GC and in 54 healthy age-matched men. Compared to age-matched controls, MS patients had a significantly lower total body bone mineral content (TBBMC) and BMD at all measured sites except for the radius. Sixty five male MS patients (62.5 %) met the criteria for osteopenia and twenty six of them (25 %) for osteoporosis. The multivariate analysis showed a consistent dependence of bone measures (except whole body BMD) on BMI. The total leg lean mass % was as an independent predictor of TBBMC. The Expanded Disability Status Scale (EDSS), cumulative GC dose and age were independent determinants for BMD of the proximal femur. We conclude that decreasing mobility in male MS patients is associated with an increasing degree of osteoporosis and muscle wasting in the lower extremities. The chronic low-dose GC treatment further contributes to bone loss.     

Cross-sex pattern of bone mineral density in early onset gender identity disorder

Hormonally controlled differences in bone mineral density (BMD) between males and females are well studied. The effects of cross-sex hormones on bone metabolism in patients with early onset gender identity disorder (EO-GID), however, are unclear. We examined BMD, total body fat (TBF) and total lean body mass (TLBM) in patients prior to initiation of sex hormone treatment and during treatment at months 3 and 12. The study included 33 EO-GID patients who were approved for sex reassignment and a control group of 122 healthy Norwegians (males, n=77; females, n=45). Male patients (n=12) received an oral dose of 50 mug ethinylestradiol daily for the first 3 months and 100 mug daily thereafter. Female patients (n=21) received 250 mg testosterone enantate intramuscularly every third week. BMD, TBF and TLBM were estimated using dual energy X-ray absorptiometry (DXA). In male patients, the DXA measurements except TBF were significantly lower compared to their same-sex control group at baseline and did not change during treatment. In female patients, the DXA measurements were slightly higher than in same-sex controls at baseline and also remained unchanged during treatment. In conclusion, this study reports that body composition and bone density of EO-GID patients show less pronounced sex differences compared to controls and that bone density was unaffected by cross-sex hormone treatment.     

Calcium supplementation increases bone mass in GH-deficient prepubertal children during GH replacement

BACKGROUND/AIMS: Since GH plays an important role in bone mineralization, and several studies demonstrated the positive influence of a higher calcium intake on bone mass, we studied the effect of calcium supplementation in GHD children during GH therapy. METHODS: 28 prepubertal GHD children, 5.0-9.9 years old, were assigned to two groups: group A (n = 14; 7 females) treated with GH, and group B (n = 14; 7 females) treated with GH + calcium gluconolactate and carbonate (1 g calcium/day per os). Auxological parameters, total bone mineral content (TBMC) and density (TBMD), leg BMC and BMD, lumbar BMD, fat mass (FM) and lean tissue mass (LTM), blood 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), osteocalcin (OC) and urinary N-terminal telopeptide of type I collagen (NTx) were determined at the start of therapy and after 1 and 2 years of treatment. RESULTS: During the 2 years of the study, TBMC, TBMD, leg BMC and BMD (but not lumbar BMD) increased in both groups of patients, however after 2 years of treatment they were significantly higher in the calcium-supplemented group B than in group A (p < 0.05, for all parameters). At the start of therapy, in both groups of patients percentage FM was higher and total and leg LTM lower than in controls (p < 0.05 for each parameter). Thereafter, FM decreased and LTM increased and after 2 years they were both different from baseline (p < 0.05). After 2 years of treatment, leg BMC and BMD were more positively correlated with regional leg LTM in patients of group B (r = 0.834 and r = 0.827, respectively; p < 0.001) than in patients of group A (r = 0.617 and r = 0.637, respectively; p < 0.05). 25-OHD and PTH levels were in the normal range in all patients at the start and during treatment. OC levels were lower and urinary NTx levels higher in patients than in controls (p < 0.05 for both parameters), either at the start and after 1 year of treatment. After 2 years of treatment, OC levels were significantly higher than at the start of the study (p < 0.05) in both groups of patients, but they were higher in group B than in group A (p < 0.05); on the contrary, urinary Ntx levels were lower in group B than in group A (p < 0.05). CONCLUSION: In GHD children, treated with GH, calcium supplementation improved bone mass; it may aid in reaching better peak bone mass and in protecting weight-bearing bones, usually completed in childhood to maximum levels, from risk of osteoporosis and fractures later in life.     

血清25-羟维生素D水平与儿童骨密度的相关性研究

目的:研究血清25-羟维生素D[25-(OH)D]水平与儿童骨密度(BMD)的相关性。方法:选择2017年1月到2017年12月在亳州市人民医院接受健康体检的儿童100例作为研究对象。根据血清25-(OH)D水平对维生素D(Vit D)营养状况进行分组,其中严重缺乏组9例,缺乏组28例,不足组42例和充足组21例。对比不同年龄段和不同性别儿童血清25-(OH)D、BMD水平以及不同Vit D营养状况儿童对应的BMD水平,并采用Spearman相关性分析法分析血清25-(OH)D水平与儿童BMD、年龄的相关性。结果:5-9岁和10-14岁儿童的血清25-(OH)D及BMD水平均分别低于1-4岁儿童,而10-14岁儿童又低于5-9岁儿童(P0.05)。男童的血清25-(OH)D及BMD水平均分别高于女童,差异有统计学意义(P0.05)。不足组、缺乏组、严重缺乏组儿童的BMD水平均分别低于充足组,且缺乏组和严重缺乏组低于不足组,严重缺乏组又低于缺乏组(P0.05)。根据Spearman相关性分析结果显示,血清25-(OH)D水平与儿童BMD呈正相关,而与年龄呈负相关(P0.05),年龄与儿童BMD呈负相关(P0.05)。结论:血清25-(OH)D水平与儿童BMD呈正相关,但与年龄则呈负相关,及时补充适量的Vit D以满足儿童的机体所需,有利于儿童健康成长。     

Gut peptide hormones and pediatric type 1 diabetes mellitus

The aims of our study were to evaluate plasma levels of gut hormones in children with Type 1 diabetes mellitus (T1DM) in comparison with healthy controls and to correlate plasma concentrations of gut hormones with blood biochemistry, markers of metabolic control and with anthropometric parameters. We measured postprandial levels of specific gut peptide hormones in T1DM children. Amylin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1), ghrelin, leptin, pancreatic polypeptide (PP), and polypeptide YY (PYY) were assessed in 19 T1DM children and 21 healthy reference controls. Multiplex assay kit (LINCOplex(?)) was used for determination of the defined plasma hormone levels. T1DM subjects had significantly reduced amylin (p<0.001) and ghrelin (p<0.05) levels, whereas GIP (p<0.05) was elevated when compared with healthy controls. Plasma levels of other measured hormones did not differ statistically between the studied groups. Further analysis of T1DM patients demonstrated an association between body mass index and GLP-1 (r=0.4642; p<0.05), leptin (r=0.5151; p<0.05), and amylin (r=0.5193; p<0.05). Ghrelin levels positively correlated with serum HDL cholesterol (r=0.4760; p<0.05). An inverse correlation was demonstrated with triglycerides (TG) (r= -0.5674; p<0.01), insulin dosage (r= -0.5366; p<0.05), and HbA1c% (r= -0.6864; p<0.01). Leptin was inversely correlated with TG (r= -0.6351; p<0.01). Stepwise regression analysis was performed to enlighten the predictive variables. Our study demonstrated an altered secretion pattern of gut peptide hormones in T1DM children. A close correlation was revealed between these peptides as well as with blood biochemistry, markers of metabolic control and with anthropometric parameters. Further studies are essential to explore this issue in T1DM children.     

Estimation of bone mineral density and architectural parameters of the distal radius in hemodialysis patients using peripheral quantitative computed tomography

We analyzed bone changes in a series of hemodialysis patients followed up for a maximum of 299 months by assessing bone mineral density (BMD) and architectural parameters of the distal radius using peripheral quantitative computed tomography (pQCT), and determined the predictors of skeletal changes in these patients. No significant differences in trabecular BMD (BMD(T)) were found compared with BMD(T) of the normal control. In contrast, cortical BMD (BMD(C)) was significantly decreased compared with BMD(C) of the normal controls. Hemodialysis patients had significantly lower values for cortical bone area, cortical thickness, moment of inertia, and polar moment of inertia than the age-matched controls. From single and multiple regression analysis, the most significant predictor of metabolic bone disease in these cases was found to be duration of hemodialysis. In addition, increases in serum alkaline phosphatase and intact parathyroid hormone in secondary hyperparathyroidism were found to correlate with a decrease in pQCT values in cortical bone; as such, these increases were also found to be a predictive. The present study confirms that the reduction in both BMD(C) and architectural parameters in hemodialysis patients occurs partly because of prolonged hemodialysis and secondary hyperparathyroidism. In addition, immobilization, dietary factors, daily intake of calcium or vitamin D, and so on must be taken into account when clarifying the causes of skeletal complications resulting from hemodialysis.     

Reasons given by general practitioners for non-treatment decisions in younger and older patients with newly diagnosed type 2 diabetes mellitus in the United Kingdom: a survey study

Background

Hyperthyroidism is accompanied by osteoporosis with higher incidence of fracture rates. The present work aimed to study bone status in hyperthyroidism and to elucidate the impact of severity, duration, and etiology of hyperthyroidism on biochemical markers of bone turnover and bone mineral density (BMD).

Methods

Fifty-two male patients with hyperthyroidism, 31 with Graves' disease (GD) and 21 with toxic multinodular goiter (TNG), with an age ranging from 23 to 65 years were included, together with 25 healthy euthyroid men with matched age as a control group. In addition to full clinical examination, patients and controls were subjected to measurement of BMD using dual-energy X-ray absorptiometery scanning of the lower half of the left radius. Also, some biochemical markers of bone turnover were done for all patients and controls.

Results

Biochemical markers of bone turnover: included serum bone specific alkaline phosphatase, osteocalcin, carboxy terminal telopeptide of type l collagen also, urinary deoxypyridinoline cross-links (DXP), urinary DXP/urinary creatinine ratio and urinary calcium/urinary creatinine ratio were significantly higher in patients with GD and TNG compared to controls (P < 0.01). However, there was non-significant difference in these parameters between GD and TNG patients (P > 0.05). BMD was significantly lower in GD and TNG compared to controls, but the Z-score of BMD at the lower half of the left radius in patients with GD (-1.7 ± 0.5 SD) was not significantly different from those with TNG (-1.6 ± 0.6 SD) (>0.05). There was significant positive correlation between free T3 and free T4 with biochemical markers of bone turnover, but negative correlation between TSH and those biochemical markers of bone turnover. The duration of the thyrotoxic state positively correlated with the assessed bone turnover markers, but it is negatively correlated with the Z-score of BMD in the studied hyperthyroid patients (r = -0.68, P < 0.0001).

Conclusion

Men with hyperthyroidism have significant bone loss with higher biochemical markers of bone turnover. The severity and the duration of the thyrotoxic state are directly related to the derangement of biochemical markers of bone turnover and bone loss.     

Associations between physical activity and bone mass in black and white South African children at age 9 yr.

We investigated differences in physical activity (PA) levels between black and white South African 9-yr-old children and their association with bone mineral content (BMC) and density (BMD) by using dual-energy X-ray absorptiometry. PA was analyzed in terms of a metabolic (METPA; weighted metabolic score of intensity, frequency, and duration) and a mechanical (MECHPA; sum of all ground reaction forces multiplied by duration) component. There were significant ethnic differences in patterns of activity. White children expended a significantly greater energy score (METPA of 21.7 +/- 2.9) than black children (METPA of 9.5 +/- 0.5) (P < 0.001). When children were divided into quartiles according to the amount and intensity of sport played, the most active white children (using METPA scores) had significantly higher whole body BMD and higher hip and spine BMC and BMD than less active children. White children in the highest MECHPA quartile also showed significantly higher whole body, hip, and spine BMC and BMD than those children in the lowest quartile. No association between exercise and bone mass of black children was found. In this population, PA has an osteogenic association with white children, but not black children, which may be explained by the lower levels of PA in the black children. Despite this, black children had significantly greater bone mass at the hip and spine (girls only) (P < 0.001) even after adjustment for body size. The role of exercise in increasing bone mass may become increasingly critical as a protective mechanism against osteoporosis in both ethnic groups, especially because the genetic benefit exhibited by black children to higher bone mass may be weakened with time, as environmental influences become stronger.     

不同强度有氧跑有助于改善IGR老年人的症状

为了探讨不同强度持续跑步干预对糖调节受损(impaired glucose regulation,IGR)人群胰岛素敏感性、骨密度、糖调节、激素分泌的影响效果差异,为研发促进IGR人群糖调节能力恢复的运动处方提供实证参考,本研究选定90名糖调节受损老年人为本研究实验对象,进行随机分组,随机分为Fatmax强度跑步组(F组,n=30);AT强度跑步组(A组,n=30);对照组(C组,n=30)。在干预开始前1周内对受试者进行前测(BMD,骨代谢,FPG,OGTT-2h,HOMA-IR,IGF-1,生长激素分泌指标)。干预前3天,F组进行FATMAX强度测试、A组进行AT强度测试,各组按照运动计划进行为期24周的干预,运动干预结束后测。通过24周干预,F组和A组受试者的BMI、体脂率后测结果显著低于前测结果(p<0.05),而C组BMI和体脂率前后测结果对比没有显著性差异(p>0.05);F组、A组的FPG和OGTT-2h后测结果显著低于前测,且显著低于C组后测结果(p<0.05);F组和A组受试者的血清GH、IGF-1以及BGP的后测结果明显高于其前测结果和C组后测结果(p<0.05),而C组GH、IGF-1和BGP前后测结果对比没有显著性差异(p>0.05)。F组和A组受试者股骨颈BMD、大转子骨BMD、Ward’s三角区BMD后测结果显著高于前测结果和C组后测结果(p<0.05)。IGR老年人长期进行以Fatmax和AT强度进行长时间有氧跑步,不仅能够增加其下肢骨密度、促进骨生产和改善骨代谢,而且降低FPG、缓解胰岛素抵抗、促进GH、IGF-1分泌。其机制可能是IGR老年人长期进行中低强度有氧跑会提升血清GH、IGF-1浓度,而GH和IGF-1能够促进胰岛素的分泌合成以及促进成骨细胞工作,从而缓解IGR老年人的胰岛素抵抗和增加下肢BMD。     

Altered osteoprotegerin/RANKL ratio and low bone mineral density in celiac patients on long-term treatment with gluten-free diet.

Skeletal demineralization and mineral metabolism derangement are well-recognized features of untreated celiac disease (CD). Although treatment with a gluten-free diet appears to prevent bone loss while correcting skeletal demineralization in childhood, there is evidence that bone mineral density does not return to normal in celiacs diagnosed in adulthood. Osteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, and ligand of receptor activator of NFkB (RANKL) are involved in the process of bone turnover and have been implicated in the pathogenesis of osteoporosis and other metabolic bone diseases. We measured OPG, RANKL, bone mineral density (BMD), and biochemical markers of bone turnover in 32 adult female premenopausal celiac patients on a gluten-free diet, and thirty age-matched healthy women. We correlated the OPG/RANKL ratio with the severity of bone loss. Celiac patients had a mean BMD lower than controls in lumbar spine and in the femoral neck. Serum levels of bone alkaline phosphatase (BAP, marker of bone formation), and urinary excretion of telopeptides of type I collagen (a marker of bone resorption) were significantly higher than in controls. Serum OPG and RANKL levels were significantly higher in CD patients than in controls, while the OPG/RANKL ratio was significantly lower in CD patients than in controls and was positively correlated with BMD at the spine. The role of elevated OPG in CD patients is unclear, but it might represent a compensatory mechanism against other factors that promote bone damage. Further studies are required to assess a possible therapeutic potential of osteoprotegerin in optimally treated celiacs with persistent osteopenia.