骨康对骨质疏松性大鼠骨中微量元素的影响

目的 探讨中药骨康对骨质疏松性大鼠骨中微量元素的影响。方法 切除卵巢后引起大鼠骨质疏松的雌性大鼠进行了雌激素尼尔雌醇和中药骨康口服液的治疗。观察了4组(空白对照组、模型组、中药骨康组、尼尔雌醇组)大鼠股骨中Cu、Mn、Zn、Sr、B、V、F等微量元素的变化。结果 统计学结果显示与骨质疏松模型组比较，尼尔雌醇和中药骨康能提高去势大鼠骨质中Zn、Sr、F、Ca、P等元素的含量，尼尔雌醇组中Cu、Mn、B、V的含量提高，中药骨康组中的含量反而下降；尼尔雌醇组与中药骨康组比较，B、Cu、Mn、V、Zn、Ca、P含量提高明显，而F、Sr含量无明显差异。结论 骨康的治疗作用并不是单一的，可以认为中药骨康是通过发挥对人体整体的调节作用来调节骨骼中微量元素的变化，改变骨质的代谢情况，促进骨密度的提高。     

Concentration of bone elements in osteoporosis

In aging and in osteoporosis, decreased bone density is associated with decreased bone mass. However, changes in the bone mineral phase remain a matter for investigation. In particular, it is unknown whether bone mineral loss is directly related to reduction in bone mass or associated with changes in the concentration of mineral elements in mineralized bone tissue. In this study, the cortical bone concentration of elements was determined in biopsies of the ilium from 33 subjects (12 controls and 21 individuals with untreated severe osteoporosis). Calcium and phosphorus concentrations were evaluated in cortical and trabecular bone using energy-dispersive x-ray (EDX) microanalysis and inductively coupled plasma optical emission spectrometry (ICPOES). Bone concentrations of Na, K, Mg, Cu, Zn, Fe, Sr, Al, B, and Si were also determined in cortical bone using ICPOES. Additionally, the concentration of F in cortical bone was measured with a specific ion electrode and the concentration of Pb was determined by atomic absorption spectrometry. In mineralized bone tissue there was no significant age-dependent variation in the concentration of Ca, P, or other elements either in controls or in osteoporotic subjects. Moreover, the concentration of elements in bone tissue did not differ in the two groups. These results suggest that the decrease in bone density in osteoporosis is directly related to evolution of the bone mass, without detectable changes in the concentration of elements in bone.     

胸椎黄韧带骨化与腰椎黄韧带退变的病理及基本代谢元素的比较研究

目的：探讨胸椎黄韧带骨化的病因。方法：对１４例胸椎黄韧带骨化（包括５例氟骨症）及１４例腰椎管狭窄症患者手术切除的黄韧带标本作病理研究；对患者血清及黄韧带采用雾化原子吸收法等方法测定钙、磷、镁、锌、铜、锰、钼、氟含量，取急性外伤性截瘫患者为对照。结果：（１）骨化黄韧带初期的病理改变与黄韧带退变性质类似；（２）除氟元素外，７种基本代谢元素在骨化与退变患者血清及黄韧带中含量均呈基本一致的变化规律；（３）非氟骨症骨化患者黄韧带中氟含量显著增高（Ｐ＜０．０１）。结论：本文证实胸椎黄韧带骨化发生于黄韧带退变的基础之上，但退变不直接导致骨化，元素氟是诱导退变黄韧带进一步骨化的重要诱因。     

The distribution of trace metal ions in bone and tendon

The natural trace metal compositions of human bone mineral and demineralized bone were measured by emission spectroscopy and compared with those of the original whole bone and human tendon. Cu, Fe and Zn remained in the collagenous matrix of bone and were found in similar quantities in tendon. It is suggested, therefore, that these ions are chemically bound to the collagen matrix in these tissuesin vivo, and that the binding has a part in their activity. Most of the Pb, Si, Sr, and V in bone remained with the mineral portion, probably as substituted or interstitial ions. Zn is divided between the organic and mineral phases.This work was supported in part by Grant No. AMO 7626, National Institutes of Health, United States Public Health Service and by the Veterans Administration Research Service.     

不育症患者和正常人精液八种元素含量的测定及锌镉比值的分析

我们对长沙地区不育症患者和正常人的精液中锌、铜、镁、钙、锰、铅、镉、镍８种元素进行了测定。其数据经统计学处理发现：不育症组精液的锌、钙、镁３种元素含量显著低于正常对照组（Ｐ＜００ｌ）；前者镉的含量高于后者（Ｐ＜０．０５），锌／镉比值低于后者；而铜、锰、铅、镍等４种元素含量在两组间均无差异。我们认为，精液中锌／镉比值可作为诊断和治疗男性不育症的参考。     

Copper deficit as a potential pathogenic factor of reduced bone mineral density and severe tooth wear

Summary

The study evaluated if men and women with severe tooth wear were at increased risk of general bone loss. Enamel biopsies obtained from 50 subjects aged 47.5?±?5 years showed decreased copper content, which was associated with reduced spine bone mineral density, suggesting deficits of this trace element contributing to bone demineralization, enamel attrition, and deteriorated quality of mineralized tissues.

Introduction

The objective of this cross-sectional study was to assess associations between enamel trace minerals and bone mineral density (BMD) in severe tooth wear. We hypothesized that similar factors contributed to both the excessive abrasion of dental enamel and reduced BMD in subjects with tooth wear.

Methods

Fifty patients aged 47.5?±?5 years with severe tooth wear and 20 age-, sex-, and body mass index (BMI)-matched healthy volunteers with normal dental status were studied regarding dietary intakes of trace elements, serum and salivary copper (Cu), zinc (Zn), and calcium (Ca) concentrations, and serum PTH, osteocalcin, and hydroxyvitamin D levels. Tooth wear was determined using clinical examination based on standard protocol according to Smith and Knight. In all subjects, acid biopsies of the maxillary central incisors were carried out to assess mineral composition of the enamel. Atomic absorption spectroscopy with an air/acetylene flame was used to measure Ca and Zn, and graphite furnace atomic absorption spectroscopy was used to analyze Cu content. BMD was examined using dual energy X-ray absorptiometry.

Results

Tooth wear patients had reduced lumbar spine, but not femoral, BMD relative to controls (p?<?0.001). No differences were found in enamel Ca concentration and Zn content was slightly higher in tooth wear patients than in controls whereas Cu content was significantly decreased in the patients: 19.59?±?16.4 vs 36.86?±?26.1 μg/l (p?=?0.01) despite similar levels of Cu in serum and saliva. The differences were independent of serum 25-OH-D, osteocalcin concentrations or PTH either.

Conclusion

Severe tooth wear is associated with reduced spinal BMD. Enamel in adult individuals with severe tooth wear is low in copper content. Therefore, further work is needed to determine whether copper plays a role in bone pathophysiology in these patients.     

Determination of multiple chemical elements in CSF in Parkinson disease after intracerebral autotransplantation of the adrenal medulla]

The contents of indispensable major elements sodium (Na), phosphorus (P), calcium (Ca), magnesium (Mg), trace elements iron (Fe), copper (Cu), nickel (Ni), zinc (Zn), strontium (Sr), vanadium (V), chromium (Cr), manganese (Mn), molybdenum (Mo), and other elements lead (Pb), silicon (Si), aluminium (Al), titanium (Ti), barium (Ba), lanthanum (La), cadmium (Yb), cerium (Ce), scandium (Sc), silver (Ag), in cerebrospinal fluid (CSF) were measured in 13 patients suffering from Parkinson disease before and after autotransplantation of adrenal medulla. It was found that while the patients' objective symptoms were relieved and the contents of monoamine transmitters were changed, the contents of P, V, Co, Cr, in CSF increased significantly (P less than 0.05 or 0.01) at the first, 2nd, 4th, 6th, and 8th week, the contents of Mn in CSF also increased significantly at the first 4th week (P less than 0.05) but decreased significantly at the 8th week the contents of Zn in CSF increased significantly (P less than 0.05) at the 2nd week; Mo increased significantly (P less than 0.05 or 0.01) at the 4th and 8th week B increased significantly (P less than 0.05) at the first week; the contents of Ca, Na, Sr, Ba, Al, Ti, La, Ce, Yb, Sc, Ag in CSF increased significantly (P less than 0.05 or 0.01) at the 8th week, Mg, Fe, Cu Ni, Pb, Si, Cd remained unchanged after operation. The results suggest that the contents of these chemical elements can be affected by this kind of operation, indicating that these elements are involved in the pathogenesis of Parkinsonism.     

The importance of calcium ions forin vitro malignant hyperthermia testing

Intracellular Ca++ levels in skeletal muscle are elevated during the in vitro contracture response of muscle from subjects with malignant hyperthermia. The role of Ca++ in the bathing medium and the consequences of substitution of Sr++ for Ca++ in the response to agents associated with malignant hyperthermia were examined. When Ca++ was omitted from the bathing medium the contractures induced in human vastus lateralis by halothane (three per cent) or succinylcholine (50 mM) were reduced by 80 and 100 per cent, respectively, while contractures induced by caffeine (8 mM) were only reduced by 50 per cent. Substitution of Ca++ by another divalent cation, Sr++, completely restored contractures induced by caffeine, but only partially restored contractures induced by halothane or succinylcholine (to 50 and 30 per cent of Ca(++)-containing medium, respectively). Mepacrine (10 microM) was effective in antagonizing contractures by caffeine, whereas verapamil and nifedipine (10 microM) were not. These results support an essential role for extracellular Ca++ not fulfilled by Sr++ in contracture induction by halothane and succinylcholine, but not by caffeine.     

去卵巢大鼠骨组成成分的改变

目的观察切除双侧卵巢后大鼠骨组成成分的改变。方法将27只健康4月龄雌性SD大鼠随机分成3组：正常对照组，假去卵巢组和去卵巢组；于切除卵巢后80d，同时将各组动物处死，测其骨矿盐含量，用ICP测其骨元素含量。结果切除双侧卵巢的大鼠骨无机质含量、无机质/cm^3、无机质占骨干重％等均显著减少（P〈0．01），而有机质占骨干重％、有机质，无机质的比值显著升高（P〈0．01）；骨元素Ca、S、Mg、Mn显著减少（P〈0．01）；Zn减少（P〈0．05），C0有减少趋势（P〉0．05）。骨磷显著增加（P〈0．05）。结论切除卵巢后引起骨组成成分特征性的改变。     

Impaired zinc and copper status in children with burn injuries: need to reassess nutritional requirements

Major burns are associated with impaired Zn and Cu status. These micronutrients are essential for bone matrix formation, linear growth, and wound healing. This study evaluated the status of Zn and Cu in burned children and assessed adequacy of supplementation. Six children, mean total body surface area (TBSA), 54+/-9% (S.D.), were recruited. Nutrient intakes, plasma, wound exudate, and 24h urine samples were collected and analyzed for Zn and Cu. Bone mineral content was assessed by dual energy X-ray absorptiometry. Dietary Zn and Cu were three times the dietary reference, and mean plasma concentrations of Zn and Cu were low at admission and discharge. Urinary Zn was elevated at admission, whereas Cu was elevated at both times. Wound Zn and Cu concentrations exceeded plasma concentrations, suggesting that inflammatory wound exudate was a primary route of loss. We demonstrate that burn injury in children results in low plasma levels of Zn and Cu that are inadequately compensated during hospitalization.     

Influence of Strontium on Bone Mineral Density and Bone Mineral Content Measurements by Dual X-Ray Absorptiometry

The presence of Sr in bone influences bone mineral density (BMD) and content (BMC) measurements by dual-energy X-ray absorptiometry (DXA). This interaction is of interest, since strontium ranelate (S12911) demonstrated positive effects on bone metabolism in various animal models of osteoporosis, and is currently being evaluated for treatment of postmenopausal osteoporosis. The present in vitro study aimed to determine adjustment factors for DXA measurements of BMC and BMD at different Sr concentrations in order to estimate the corresponding values that would have been measured without Sr. A series of mixtures of Ca and Sr hydroxyapatites were prepared, with biologically relevant Sr/Ca ratios ranging from 0 to 3.5 mol/mol%, and a constant total concentration of divalent cations (145 mmol). The mixtures were conditioned in plastic dishes 4.5 cm in diameter, to obtain an areal density close to the human vertebral mineral density of 0.7-1.1 g/cm(2). DXA measurements of the mixtures were made with a wide range of different instruments and various acquisition modes. A direct linear relationship (r(2) > 0.99) was found between strontium content and overestimation of BMD and BMC. There were no significant differences in adjustment factors for BMC or BMD between the different machines or acquisition modes, and the presence of Sr in the water bath used to mimic soft tissues did not affect the accuracy and precision of the method. This demonstrates that reliable DXA determinations of BMD may be carried out in the presence of Sr, and may be interpreted in terms of calcium hydroxyapatite equivalent if the bone Sr content of the measured bone is known. The same adjustment factor (10% overestimation for 1 mol/mol% Sr) can be used for all presently available types of instrument and acquisition modes.     

Beneficial Effect of Copper Supplementation on Deposition of Fluoride in Bone in Fluoride- and Molybdenum-Fed Rabbits

Fluorosis is a major public health problem in the world, including India. The present study was undertaken to investigate the role of molybdenum (Mo) in the deposition of fluoride (F) in bone and whether copper (Cu) supplementation has any alleviating role when F and Mo are ingested together. For this purpose, four groups of rabbits were used [control (C), fluoride (F), fluoride + molybdenum (F + Mo), and fluoride + molybdenum + copper (F + Mo + Cu)] to find out the effect of these treatments on various bone-related parameters like intact parathyroid hormone (iPTH), alkaline phosphatase and Cu in serum, hydroxyproline and calcium (Ca) in urine, and minerals (F, Cu, manganese, and zinc) in femur bone ash. Bone mineral content (BMC), bone mineral density (BMD) [by dual energy X-ray absorptiometry (DXA)], and strength of femur bones were also assessed. F content in the femur was significantly higher (P < 0.01) in all experimental groups compared to control group. Mo supplementation increased F deposition in femur bone in the F + Mo group, whereas supplementation of Cu reduced F deposition in the F + Mo + Cu group compared to the F + Mo and F groups. Levels of Cu in femurs of the F + Mo and F + Mo + Cu groups were significantly higher (P < 0.05, P < 0.01, respectively) than in the C group, although serum Cu was significantly lower in the F and F + Mo than the C and F + Mo + Cu groups. Magnesium levels in the F + Mo group were significantly higher (P < 0.05) than in the F and F + Mo + Cu groups. Cu supplementation in the F + Mo + Cu group increased deposition of zinc significantly (P < 0.05) compared to the F and F + Mo groups. Serum iPTH, alkaline phosphatase, and urinary hydroxyproline and Ca were significantly higher (P < 0.01) in the F and F + Mo than in the C and F + Mo + Cu groups. However, serum iPTH and urinary hydroxyproline were higher in the F + Mo group than the F group. Alkaline phosphatase was significantly higher in the F + Mo group than the F and F + Mo + Cu groups. Levels of serum Cu in the F and F + Mo groups were lower than in the C group, though serum Cu was significantly higher in the F + Mo + Cu than in all other groups. DXA analysis of femur bone indicated that BMD in the F + Mo group was significantly higher than in the F (P < 0.05), C (P < 0.01), and F + Mo + Cu (P < 0.05) groups. However, there was no significant difference in BMC among the groups. Bone strength was significantly higher (P < 0.05) in the F + Mo group than in the C group. Results of the present study show that ingestion of Mo with F does not create secondary Cu deficiency (due to increased excretion of Cu through urine). However, Cu concentration was decreased in serum in this group (F + Mo) compared to the C and F + Mo + Cu groups. Deposition of F in femur bone was more (22%) when it was given along with Mo compared to F alone, while F deposition in femur bone was less in the F + Mo + Cu group by 80% compared to the F group. Also, deposition of F in the F + Mo + Cu group was 120% less compared to the F + Mo group. The increase in F level due to Mo addition appears to be offset by supplementation with Cu. Supplementation with Cu showed a beneficial effect on bone resorption as well as bone formation.     

Cutaneous copper and zinc losses in burns.

To measure the exudative cutaneous copper (Cu) and zinc (Zn) losses in burns, 10 patients, aged 36 +/- 9 years (mean +/- s.d.) with burns covering 33 +/- 10 per cent of the total body surface area, were studied from the first postburn day (D1) until D7. All intakes and losses were analysed for Cu, Zn and nitrogen (N) content. Cutaneous losses were extracted from textiles surrounding the patients. Urinary excretions were 0.12 +/- 0.06mg/24h for Cu, 0.9 +/- 0.6mg/24h for Zn, and 14.1 +/- 4.4g/24h for N. Mean daily exudative losses through wound seepage from D1 to D7 were 4.7 +/- 2.1mg/24h for Cu, 27.1 +/- 14.4mg/24h for Zn, and 8.7 +/- 3.8g/24h for N. The cumulated mean losses over 7 days were 37mg for Cu, and 212mg for Zn, representing respectively 20-40 per cent and 5-10 per cent of normal body content. Serum Cu and Zn levels were strongly depressed. The urinary Cu/N ratios correlated with clinical improvement. We conclude that the exudative Cu and Zn losses during the first week postburn contribute significantly to the increased nutrient requirements in burns.     

Changes in basic metabolic elements associated with the degeneration and ossification of ligamenta flava

OBJECTIVE: To determine the association between levels of basic metabolic elements and degeneration and ossification of the ligamentum flavum (LF). SUBJECTS: Fourteen consecutive patients with degenerative lumbar stenosis, 11 with ossification of the thoracic ligamenta flava, and 11 control subjects. METHODS: The basic elements of calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), molybdenum (Mo), and fluoride (F) in the specimens were measured using atomic absorption spectrometry, the phosphomolybdic blue method, and a fluoride-selected electrode. RESULTS: Ca content and the ratio of Ca/Mg in the LF specimens increased significantly in the sequence of control, degeneration, and ossification groups. Compared with values for the control group, the Zn, Mn, and Mo contents in the ossification and degeneration groups were significantly lower (P < 0.01); in contrast, Cu content was significantly higher (P < 0.01). As to F, its content in the specimens of the ossification group was much higher than those in the degeneration and control groups (P < 0.01); the F content in the ligamenta flava and sera from patients with fluorosis was also significantly higher than in those from patients without fluorosis (P < 0.01). Compared with the control group, there were no differences in the F content in serum from patients without fluorosis; however, the F content in ligamenta flava specimens from patients without fluorosis was significantly higher (P < 0.01). CONCLUSIONS: There are trends in the contents of basic metabolic elements in the degeneration and ossification of ligamenta flava. These basic metabolic elements may play an important role in this process.     

Body weight, early growth and antler size influence antler bone mineral composition of Iberian red deer (Cervus elaphus hispanicus)

Researchers have devoted little attention to the possibility that the chemical composition of bone might be variable under normal nutrition conditions. This study assessed antler bone composition of 25 one-year old deer (spikes). Antler content of ash, Ca, P, K, Na, Mg, Fe and Zn was assessed in base and tine, and the mean composition or the difference in composition between tine and base was used to explain variability in antler length, weight and perimeter. In turn, mean composition and difference in concentration of each mineral were related to body measures at 1 year of age, weight at birth, weight at 1 year of age and weight gains during lactation, or between weaning and year of age. Chemical composition differed between base and tine in ash, Ca, P, K, Zn and Fe, but not in Na or Mg. Composition explained a mean variability of 77% in antler length and weight. Body weight and size, in turn, influenced mineral composition. The greatest body effect was that of gains during lactation on principal components analysis factor related to Ca, P and other major minerals such as Na, K or Mg. Antler bone composition is variable in normal conditions and such variability may play a role in biomechanical properties of the antler, but it is also likely to show the nutritional status or physiological effort to grow antlers. Assessing bone composition may emerge as a new useful tool to obtain information regarding bone biology and its bearer in other species including ours.     

Changes in Basic Metabolic Elements Associated With the Degeneration and Ossification of Ligamenta Flava

Abstract

Objective: To determine the association between levels of basic metabolic elements and degeneration and ossification of the ligamentum flavum (LF).

Subjects: Fourteen consecutive patients with degenerative lumbar stenosis, 11 with ossification of the thoracic ligamenta flava, and 11 control subjects.

Methods: The basic elements of calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), molybdenum (Mo), and fluoride (F) in the specimens were measured using atomic absorption spectrometry, the phosphomolybdic blue method, and a fluoride-selected electrode.

Results: Ca content and the ratio of Ca/Mg in the LF specimens increased significantly in the sequence of control, degeneration, and ossification groups. Compared with values for the control group, the Zn, Mn, and Mo contents in the ossification and degeneration groups were significantly lower (P < 0.01 ); in contrast, Cu content was significantly higher (P < 0.01 ). As to F, its content in the specimens of the ossification group was much higher than those in the degeneration and control groups (P < 0.01); the F content in the ligamenta flava and sera from patients with fluorosis was also significantly higher than in those from patients without fluorosis (P < 0.01). Compared with the control group, there were no differences in the F content in serum from patients without fluorosis; however, the F content in ligamenta flava specimens from patients without fluorosis was significantly higher (P < 0.01).

Conclusions: There are trends in the contents of basic metabolic elements in the degeneration and ossification of ligamenta flava. These basic metabolic elements may play an important role in this process.     

Lead accumulation in tidemark of articular cartilage

OBJECTIVE: Determination of the spatial distribution of the toxic element lead (Pb) and other trace elements in normal articular cartilage and subchondral bone from adult humans with no history of work-related exposure to Pb. METHODS: Four macroscopically normal femoral heads and three patellas were harvested from randomly selected forensic autopsies. All subjects died of acute illnesses, had no history of work-related exposure to Pb and had no metabolic bone disease. The elemental distribution of lead (Pb) together with zinc (Zn), strontium (Sr) and calcium (Ca) in the chondral and subchondral region was detected using high resolution synchrotron radiation induced micro X-ray fluorescence (SR mu-XRF) analysis. SR mu-XRF line scans in conventional and SR mu-XRF area scans in confocal geometry were correlated to backscattered electron (BE) images visualizing the mineralized tissue. RESULTS: In all samples, we found a highly specific accumulation of Pb in the tidemark, the transition zone between calcified and non-calcified articular cartilage. Pb fluorescence intensities in the tidemark, which is thought to be a metabolically active mineralization front, were 13-fold higher when compared to subchondral bone. Pb intensities in the subchondral region were strongly correlated with Zn, but were distinctly different from Ca and Sr. CONCLUSIONS: The finding of the highly specific accumulation of lead in the tidemark of human articular cartilage is novel. However at this point, the exact mechanisms of the local Pb accumulation as well as its clinical implications are unknown.     

胃癌周围淋巴结微量元素变化的研究

目的 研究胃癌组织和癌旁淋巴结微量元素的变化及与胃癌淋巴结转移的关系。方法对40例胃癌患者的胃癌组织、癌转移及无癌转移淋巴结组织进行铁（Fe）、镁（Mg）、锰（Mn）、钙（Ca）、铜（Cu）、锌（Zn）、硒（Se）7种微量元素的测定并进行分析比较。结果胃癌组织、癌转移与无癌转移淋巴结组织中Fe、Mg、Mn、Ca含量比较，差异无统计学意义（P=0．372-0．741，均P〉0．0S）；胃癌组织与癌转移淋巴结的7种微量元素相比，差异无统计学意义（P=0．15—0．59，均P〉0．0S）；癌转移淋巴结与无癌转移淋巴结的微量元素比较，Zn、Se明显下降，Cu及Cu／Zn上升，差异有统计学意义（P=0．001-0．009，均P〈0．01）；癌转移淋巴结中N2站的Zn含量低于N1站Zn，差异有统计学意义（P=0．027）；肠型胃癌中癌转移淋巴结7种微量元素与弥漫型胃癌中癌转移淋巴结比较，差异均无统计学意义（P=0．149-0．758，均P〉0．05）。结论胃癌淋巴结转移过程中伴有体内微量元素的变化；Zn、Cu、Se含量的变化可能与胃癌淋巴结转移机制有关。     

Whole-Body Bone Mineral Measurements in 15-Year-Old Swedish Adolescents

Bone mineral area (BA), total bone mineral content (TBMC) and total bone mineral density (TBMD) were assessed by dual-energy X-ray absorptiometry (DXA) in 396 randomly selected, healthy 15-year-old Swedish boys and girls. The influence of body size, pubertal development, physical activity level (PAL), total energy expenditure (TEE), dietary intake of energy, calcium and vitamin D, and alcohol and smoking habits on TBMC and TBMD were examined in bi- and multivariate analyses. In bivariate analyses BA, TBMC and TBMD showed strong correlations with weight, height and TEE in both sexes. In boys but not in girls these bone variables were significantly correlated with dietary intakes of energy, calcium and vitamin D. No significant correlations were found between PAL and the three bone variables. In multivariate analyses with TBMC as dependent variable BA, height, weight and Tanner stages explained 88% and 87% of the variance in boys and girls respectively. In similar analyses with TBMD as dependent variable the corresponding figures were 50% and 54%. The major part of the variance in all these models was explained by BA, and only a few percent by all the other independent variables. No significant reduction was found when TEE or daily intakes of calcium or vitamin D were introduced into the models. These results illustrate the importance of including BA, weight and height as independent variables in regression models of TBMC to avoid spurious associations with other variables in the analyses. The results may also indicate that in normal Swedish adolescents environmental factors such as dietary intake of nutrients play a minor role as determinants of bone mineralization. High levels of physical activity and bone mineral measures possibly explain the lack of significant correlations between these variables and do not imply a lack of association. Received: 16 December 1997 / Accepted: 19 May 1998