Metacarpal Bone Mineral Density Research Articles

Accelerated metacarpal bone mineral density loss is associated with radiographic progressive hand osteoarthritis

ObjectiveTo study the association between metacarpal bone mineral density (BMD) loss and progressive hand osteoarthritis (OA) over 2 years.MethodsUsing the Kellgren–Lawrence (KL) grading scale and the Osteoarthritis Research Society International...

ORIGINAL ARTICLE: Physiological values and factors affecting the metacarpal bone density of healthy feedlot beef cattle as measured by dual-energy X-ray absorptiometry

The metacarpal bone mineral density of 136 healthy feedlot beef cattle of four different breeds (Charolaise, Limousine, Irish Crossbreed and Slovakian Crossbreed) raised and fed on standard conditions was measured by means of a dual-energy X-ray absorptiometry technique in an ex vivo study design. The average reference values (mean ± SD) of bone mineral density (BMD) for animals aged between 12 and 22 months and weighing between 236 and 546 kg have been reported and the effects of (i) breed, (ii) gender, (iii) age and (iv) body weight on bone mineral density have been considered. A significant difference (i) among different breeds and (ii) between genders resulted, whereas a high correlation between bone density and (iii) age and (iv) body weight was detected within the same breed and gender, with body weight being the most important factor affecting BMD. A modern new technological insight into the study of bovine bone physio-pathology is proposed.

Quantitative ultrasound and radiographic absorptiometry are associated with vertebral deformity in Japanese Women: the Hizen–Oshima study

We evaluated the ability of heel quantitative ultrasound (QUS) and metacarpal radiographic absorptiometry (RA) to identify subjects with vertebral deformities in Japanese women aged ≥40. Both QUS and RA were associated with vertebral deformities, and the estimated prevalence at each T-score widely varied with age. Heel QUS and metacarpal RA have been used for screening patients to evaluate risk of osteoporotic fractures. The aim of this study was to evaluate the ability of QUS and RA to identify women with vertebral deformities in 570 Japanese women aged ≥40, and to estimate the prevalence of vertebral deformity at each T-score. Calcaneal QUS and metacarpal RA were performed. Radiographic vertebral deformities were assessed by quantitative morphometry, defined as vertebral heights more than 3 SD below the normal mean. The receiver operating characteristic analysis showed that both calcaneal stiffness index (SI) and metacarpal bone mineral density (BMD) were associated with vertebral deformities. Using the T-score of -2.5 as a cutoff value, the specificity and sensitivity for identifying individuals with vertebral deformities was 65% and 83% for calcaneal SI, and 40% and 88% for metacarpal BMD, respectively. The prevalence of vertebral deformity was estimated using age-adjusted logistic regression models. Women with calcaneal SI T-score of -2.5 had a 2% estimated probability of vertebral deformity at age 40, and 22% at age 80. For metacarpal BMD T-score of -2.5, estimated probability was less than 1% at age 40, and 27% at age 80. Both calcaneal SI and metacarpal BMD were associated with prevalence of vertebral deformity. Furthermore, the prevalence widely varied with age at any given bone value.

Factors Affecting Discontinuation of Alendronate Treatment in Postmenopausal Japanese Women With Osteoporosis

The main challenge to the long-term treatment of osteoporosis with bisphosphonates has been patient adherence. The purposes of this cohort study were to investigate the 3-year outcome of alendronate treatment in postmenopausal Japanese women with osteoporosis and to identify factors that contributed to the discontinuation of alendronate treatment. A total of 72 postmenopausal Japanese women with osteoporosis and aged from 58 to 85 years were treated with alendronate in a 3-year trial. Metacarpal bone mineral density, serum alkaline phosphatase, and urinary cross-linked N-terminal telopeptides of type I collagen were monitored, and factors contributing to the discontinuation of alendronate treatment were determined. Fourteen patients dropped out of the trial. The reasons for dropout were side effects (diarrhea [n = 1], gastric symptoms [n = 9], and inflammation of the mouth [n = 1]) or non-compliance (n = 3). Logistic regression analysis showed that the number of prevalent vertebral fractures was a significant factor affecting the discontinuation of alendronate treatment for the reasons listed above. In 58 patients who continued the 3-year treatment, urinary cross-linked N-terminal telopeptides of type I collagen level was reduced by 44.1% at 3 months and serum alkaline phosphatase level was decreased by 11.6%, 11.8%, and 12.5% at 1, 2, and 3 years, respectively. However, metacarpal bone mineral density did not change significantly. Alendronate treatment decreased urinary cross-linked N-terminal telopeptides of type I collagen and serum alkaline phosphatase levels, and maintained metacarpal bone mineral density in postmenopausal Japanese women with osteoporosis. The patients adhered well to alendronate treatment in our clinic. The number of prevalent vertebral fractures was an important factor affecting the discontinuation of alendronate treatment due to side effects and non-compliance.

Long-Term Oral Anticoagulation Therapy and the Risk of Hip Fracture in Patients with Previous Hemispheric Infarction and Nonrheumatic Atrial Fibrillation

Warfarin therapy has been demonstrated to reduce the risk of stroke in nonrheumatic atrial fibrillation (NRAF). We showed that long-term warfarin therapy reduces vitamin K and second metacarpal bone mineral density (BMD) in NRAF patients who had previous hemispheric infarction. To determine whether warfarin is associated with increased hip fracture risk, we compared the incidence of hip fracture between post-stroke patients receiving warfarin therapy and post-stroke patients without such therapy. Eighty-four post-stroke patients with NRAF who had been treated with warfarin and 93 post-stroke patients without warfarin were followed for 5 years and their incidence of hip fracture was compared. At baseline and 3 and 5 years later, sera were collected from both groups. Sera were assayed for undercarboxylated osteocalcin (ucOC), bone Gla protein and 25-hydroxyvitamin D (25-OHD). BMD was determined in second metacarpals. During 5 years, 8 hip fractures in the treated group and 9 hip fracture in the untreated group occurred (p = 0.92). After 5 years, serum ucOC concentrations were higher in treated patients (9.1 +/- 1.5 ng/ml) than in untreated patients (6.0 +/- 1.2 ng/ml). ucOC was significantly related to BMD in treated but not in untreated patients. Concentrations of 25-OHD were lower in both patient groups. Percent change of BMD from baseline was lower in treated patients than in untreated patients (p < 0.01). Long-term treatment with warfarin in stroke patients seems not to be associated with an increased risk of hip fracture.

Five-year alendronate treatment outcome in older postmenopausal Japanese women with osteoporosis or osteopenia and clinical risk factors for fractures.

A retrospective study was conducted to evaluate the outcome of treatment with alendronate (ALN) for 5 years in postmenopausal Japanese women with an increased risk of fractures. Forty postmenopausal Japanese women with osteoporosis or osteopenia and clinical risk factors for fractures (mean age: 75.4 years) were analyzed; 33 patients were treated with alendronate and 7 were treated with alfacalcidol (ALF, controls) in an outpatient clinic run by general practitioners. The metacarpal bone mineral density (BMD) measured using a computed X-ray densitometer, urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX), and serum levels of alkaline phosphatase (ALP) were monitored during the 5-year treatment period. The urinary NTX and serum ALP levels decreased significantly in the ALN group, compared with the ALF group. The metacarpal BMD was sustained in the ALN group but decreased significantly in the ALF group; the difference between these two groups was also significant. The present study evaluated the outcome of treatment with ALN for 5 years in postmenopausal Japanese women with osteoporosis or osteopenia and clinical risk factors for fractures. ALN successfully suppressed bone turnover and sustained the metacarpal BMD over the 5-year period of treatment in postmenopausal Japanese women with an increased risk of fractures.

RETRACTED ARTICLE: Prevention of hip fractures by exposure to sunlight and pharmacotherapy in patients with Alzheimer’s disease

Hypovitaminosis D and K due to malnutrition or sunlight deprivation, compensatory hyperparathyroidism, increased bone resorption, low bone mineral density (BMD), and an increased risk of falls may contribute to an increased risk of hip fractures in patients with Alzheimer's disease. The purpose of the present study was to clarify the efficacy of interventions against hip fractures in patients with Alzheimer's disease. With respect to randomized controlled trials (RCTs) regarding Alzheimer's disease and hip fractures, the literature was searched with PubMed. Three RCTs were identified, and the relative risk (RR) and 95% confidence interval (CI) were calculated for individual RCTs. Exposure to sunlight with calcium supplementation, menatetrenone (vitamin K2) plus calcium and vitamin D supplementation, and risedronate plus calcium and vitamin D supplementation improved hypovitaminosis D and hyperparathyroidism, contributing to a reduction in bone resorption. Risedronate itself strongly decreased bone resorption. Menatetrenone also decreased the serum level of undercarboxylated osteocalcin. The three interventions increased metacarpal BMD and reduced the incidence of hip fractures. The respective RRs (95% CI) were 0.22 (0.049-0.999), 0.13 (0.031-0.554), and 0.26 (0.100- 0.690). The present study clarified the efficacy of three interventions, including exposure to sunlight, menatetrenone, and risedronate with calcium and/or vitamin D supplementation against hip fractures in patients with Alzheimer's disease.

Measuring metacarpal cortical bone by digital x-ray radiogrammetry: a step forward?

Changes in metacarpal cortical bone mineral density (BMD) using digital x-ray radiogrammetry were studied in patients with early rheumatoid arthritis. After 1, 2, and 5 years, large BMD losses were found: -1.7%, -2.8%, and -5.6%, respectively. Elevated erythrocyte sedimentation rate and anti-cyclic citrullinated peptide levels were independent predictors of bone loss, indicating that the largest amount of bone loss was found in patients with severe inflammation and high production of auto-antibodies, who are known to be at the highest risk of developing radiological bone damage. Studies are needed about the spatial and time relationship between erosions and juxta-articular and metacarpal bone loss.

Metacarpal Index Estimated by Digital X-ray Radiogrammetry as a Tool for Differentiating Rheumatoid Arthritis Related Periarticular Osteopenia

To investigate Metacarpal Index (MCI) and Bone Mineral Density (BMD) estimated by Digital X-ray Radiogrammetry (DXR) with respect to its ability to quantify severity-dependent variations of bone mineralisation in patients with early rheumatoid arthritis compared to Dual Energy X-ray Absorptiometry (DXA), 122 patients underwent a prospective analysis of BMD and MCI by DXR, whereas both DXR-parameters were estimated from plain radiographs of the non-dominant hand. In comparison DXA measured BMD on total femur and lumbar spine (L2-L4). Additionally Steinbrocker Stage was assessed to differentiate the severity of rheumatoid arthritis (RA). Disease activity of RA was estimated by C-reactive Protein (CRP; in mg/l), Erythrocyte Sedimentation Rate (ESR in mm/1st hour) and by the disease activity score with 28-joint count (DAS 28). In consequence, The DXR-parameters, in particular DXR-MCI, revealed significant associations to age, Body Mass Index, CRP, DAS 28 and Steinbrocker graduation; no significant associations could be verified between DXA-parameters and all characteristics of disease activity and severity of RA. The highest correlation was found between DXR-MCI and DXR-BMD with R= 0.89 (independent from severity of RA). In all patients DXR-MCI significantly decreased (-14.3%) from 0.42 ± 0.09 (stage 1) to 0.36 ± 0.07 (stage 2) dependent on severity of RA. The comparable relative reduction of DXR-BMD was -11.1%. The group of patients with minor disease activity (DAS 28 &gt; 5.1) showed a significant flattened reduction (-11.4%) for DXR-MCI from 0.44 ± 0.08 (stage 1) to 0.39 ± 0.08 (stage 2). For accentuated disease activity (DAS 28 &gt; 5.1) the DXR-MCI revealed a pronounced reduction (-23.1 %). No significant declines were observed for DXA-BMD of the lumbar spine and total femur in all patients as well as dependent on disease activity. Conclusion: DXR can exactly quantify cortical thinning of the metacarpal bones and can identify cortical demineralisation in patients suffering from early rheumatoid arthritis surpassing DXA-measurements at axial bone sites. In this context DXR-MCI seems to be the most sensitive parameter for differentiation of patients with minor or accentuated disease activity following severity-dependent cortical bone loss. Keywords: digital X–ray radiogrammetry; dual energy X-ray absorptiometry; metacarpal index; bone mineral density; rheumatoid arthritis; steinbrocker stage

The Correlation between Metacarpal Bone Mineral Content and Bone Mineral Density of the Jawbone in Implant Patients

The Correlation between Metacarpal Bone Mineral Content and Bone Mineral Density of the Jawbone in Implant Patients

Walking duration and habitual exercise related to bone mineral density using computer‐assisted X‐ray densitometry in Japanese women

Background: We conducted a survey to examine the difference in metacarpal bone mineral density (BMD) associated with the duration of walking and participation in habitual exercise in order to assess the benefits of walking for the prevention of bone loss in Japanese women.Methods: The subjects were 1873 healthy women (premenopausal, n = 1502; postmenopausal, n = 371), aged 18–72 years, who were screened for osteoporosis at health‐care centers. They were classified into pre‐ (n = 1502), early post‐ (0–5 years since menopause, n = 195) and late post‐menopausal (6–20 years since menopause, n = 176) phases. The metacarpal BMD was measured by computer‐assisted X‐ray densitometry. Subjects completed a questionnaire on lifestyle factors that included habitual exercise and daily walking time. To consider the factors of aging and physical characteristics, the BMD of all subjects was adjusted for age and height using a multiple non‐linear model based on the data for premenopausal women.Results: anova indicated significant differences in adjusted BMD (BMDadj) in all menopausal phases according to walking duration and whether or not habitual exercise was engaged in. Premenopausal and early postmenopausal women who walked for over 30 min a day had a significantly greater BMDadj than those walking for less than 30 min (2.743 vs 2.684 mm thickness of an aluminum equivalent [mm Al]; and 2.711 vs 2.597 mm Al, respectively). Late postmenopausal women who walked for over 120 min had a significantly greater BMDadj than those walking under 30 min per day (2.746 vs 2.539 mm Al).Conclusion: These findings suggest that daily walks of more than 30 min also affect the metacarpal BMD, which is a non‐weight bearing site, although walking over 120 min seems required to benefit late postmenopausal women. We conclude that such daily walks appeared to be beneficial in maintaining BMD in Japanese women.

Efficacy of Periodontal Disease and Tooth Loss to Screen for Low Bone Mineral Density in Japanese Women

The relationship between oral indicators and bone mineral density (BMD) has been studied by many investigators, with mixed and complex results. The purpose of the present cross-sectional study was to evaluate the associations of periodontal conditions and tooth loss with metacarpal BMD (m-BMD) in a community-based cohort and the usefulness of tooth count as a potential screening tool to detect low BMD. Subjects were 356 Japanese women (171 premenopausal, mean age 37.9+/-8.0 years; 185 postmenopausal, mean age 63.3+/-7.7 years). Periodontal status was evaluated by the Community Periodontal Index of Treatment Needs (CPITN). m-BMD was measured by computerized X-ray densitometry. The proportion of subjects with periodontitis (CPITN 3 or 4) increased as m-BMD decreased. The odds ratio (OR) of osteopenia or osteoporosis in relation to periodontitis was 3.2 (95% confidence interval [CI], 2.0--5.3). After adjustment for age and menopausal status, the OR was 2.0 (95% CI, 1.1--3.7). Among postmenopausal women, those having fewer than 20 teeth were 1.6 times more likely to have low m-BMD than those having more than 20 teeth (chi-square for trend in postmenopausal group, 4.27; P<0.05). Receiver-operating curve (ROC) analysis indicated that number of teeth remaining or CPITN score had a greater than 50/50 chance to correctly identify women with osteoporosis or osteopenia, but the areas under the curve (0.72 and 0.67, respectively) are considered less than highly accurate screening tools. These results indicate that periodontitis and tooth loss after menopause may be useful indicators of m-BMD loss in Japanese women.

Metacarpal index and bone mineral density in healthy African-American women

Bone mineral density (BMD) reference data of non-Caucasian women is scarce but greatly needed for African-American women. The objective of this study was to establish a metacarpal normative reference database for African-American women using digital X-ray radiogrammetry (DXR) and hand radiographs and compare these values to existing Caucasian data. Two hundred and fifty healthy African-American women between the ages of 20 and 79 years old, 14 of whom were excluded, were recruited to participate from four different clinical sites. The study population was recruited in approximately equal number into the following groups: 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years of age. A radiograph was acquired of each subject's non-dominant hand. The radiographs were scanned and analyzed using radiogrammetric techniques, and the BMD, MCI (Metacarpal Index), bone width and cortical thickness were calculated. The regression curve that best fit the data was a second order polynomial. The BMD and MCI of young adult women (20-40 years of age) were used to calculate T-score parameters. The young reference BMD and MCI with their associated standard deviations were found to be 0.6045 g/cm2+/-0.0529 g/cm2 and 0.5096 and 0.0792, respectively. However, the MCI was found to be approximately 2.5% lower (-0.0118) compared to Caucasian women. The African-American metacarpal BMD was found to be 3.5% (0.0207 g/cm2) higher across all ages when compared to existing Caucasian reference data acquired in a similar way. The differences were found to be entirely due to larger bone size, cortical diameter and bone width in the African-American women.

Changes in metacarpal bone mineral density with age and menopause using computed X-ray densitometry in Japanese women: Cross-sectional and longitudinal study

Bone mineral density (BMD) loss with age and menopause is widely accepted in elderly women. However, only a few studies have utilized a multiple regression model that includes physical characteristics to assess comprehensive lifetime changes in BMD. A prospective study was conducted to characterize the normal patterns in metacarpal BMD changes in Japanese women, and to assess the applicability of a fitting model using cross-sectional data compared with longitudinal variability. The study consisted of 5422 healthy women in cross-sectional data and a 1-year follow-up of 359 women. The metacarpal BMD was measured by computed X-ray densitometry. Multiple linear and nonlinear regression analyses were performed in cross-sectional subjects. Nonparametric analysis was used to compare percentage rates of BMD changes between actual and estimated values. The cross-sectional data showed that the best-fit equation was a nonlinear change model using the variables of age and height in premenopausal women, and years since menopause (YSM), age and height in postmenopausal women. The results of longitudinal data indicated the following. In premenopausal women, the actual BMD changes were greater in the 30-39 age group than the 20-29 age group and were less in the 50-59 group than the 40-49 group. The rates of annual change in BMD between the actual value and estimated value by change model were very similar. In postmenopausal women, the actual changes in BMD indicated that the rapid rate of reduction observed was over 3% at 0-5 YSM and 1.5% at 6-10 YSM, and thereafter showed a slower rate of decline at 11 YSM. The change model represented the trend of actual change in BMD for postmenopausal women, whereas the rates of estimated BMD loss underestimated the actual changes at 1-10 YSM. The change model for premenopausal women using cross-sectional data is beneficial in evaluating the actual metacarpal BMD variability, whereas that for postmenopausal women is insufficient in estimating the longitudinal BMD variability.

Efficacy of oral etidronate for skeletal diseases in Japan.

Etidronate is an oral bisphosphonate compound that is known to reduce bone resorption through the inhibition of osteoclastic activity. The efficacy of etidronate for involutional (postmenopausal and senile) and glucocorticoid-induced osteoporosis, as well as that for other skeletal diseases, was reviewed in Japanese patients. Cyclical etidronate treatment (200 mg or 400 mg/day for 2 weeks about every 3 months) increases the lumbar bone mineral density (BMD) in patients with involutional osteoporosis and prevents incident vertebral fractures in patients with glucocorticoid-induced osteoporosis. The losses of the lumbar BMD in patients with liver cirrhosis and the metacarpal BMD in hemiplegic patients after stroke are prevented, and the lumbar BMD is possibly increased, preventing fragile fractures in adult patients with osteogenesis imperfecta type I. Furthermore, proximal bone resorption around the femoral stem is reduced and some complications may be prevented in patients who undergo cementless total hip arthroplasty. Oral etidronate treatment may also help to transiently relieve metastatic cancer bone pain followed by a decrease in abnormally raised bone resorption in patients with painful bone metastases from primary cancer sites, such as the lung, breast and prostate. Thus, oral etidronate treatment is suggested to be efficacious for osteoporosis, as well as other skeletal diseases associated with increased bone resorption, in Japanese patients. Randomized controlled trials needed to be conducted on a large number of patients to confirm these effects.

Third metacarpal bone mineral density assessment in the standing horse by dual X-ray absorptiometry

Bone mineral density (BMD) is correlated to mechanical properties of bone. In the horse, dual energy X-ray absorptiometry (DXA) has yet only been performed ex-vivo, but a new portable DXA device would be ideal for in-vivo BMD measurement. We explored field suitability, precision and accuracy of this device for in-vivo third metacarpal density assessment. Precision was analysed by calculating measurement variation under repeated measurement tests with (reproducibility) and without (repeatability) limb repositioning. Repeatability and reproducibility were tested ex-vivo, at the same time that intra- and inter-operator reproducibility were assessed in-vivo. In order to test accuracy, bone mineral content (BMC) of several bone samples determined by DXA and ashing were compared. Repeatability was 1.47% and reproducibility 1.69% ex-vivo. In-vivo reproducibility varied between 2.91 and 4.06% for intra-operator test and between 3.13 and 5.53% for inter-operator test. BMC measured by DXA and ash weight were highly correlated (R2>0.99). In conclusion, under described conditions this DXA device is usable, accurate and precise. Its sensitiveness reaches 8.23% in an individual longitudinal monitoring. Using the third metacarpal bone as an example, we have shown that this device is suitable for experimental or clinical monitoring.

Retracted: Effects of Vitamin K2 on Osteoporosis

1. Iwamoto J, Takeda T, Ichimura S. Combined treatment with vitamin K2 and bisphosphonate in postmenopausal women with osteoporosis. Yonsei Med J 2003; 44: 751-6. Available at: https://eymj.org/DOIx.php?id=10.3349/ymj.2019.60.1.115. It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

RETRACTED: Abnormal calcium homeostasis in disabled stroke patients with low 25-hydroxyvitamin D

Disabled elderly stroke patients occasionally have very low serum 25-hydroxyvitamin D (25-OHD), which may be due to sunlight deprivation and malnutrition. Many of such patients have very low level of serum 1, 25-dihydroxyvitamin D (1, 25-[OH]2D; calcitriol), and immobilization-induced hypercalcemia may be responsible for inhibition of renal synthesis of calcitriol. To elucidate determinants of serum 1, 25-[OH]2D levels in elderly poststroke patients, we measured serum indices of bone and calcium metabolism and metacarpal bone mineral density (BMD). Patients whose serum 1, 25-[OH]2D concentration was below the mean-3 SD of normal control subjects were defined as the low 1, 25-[OH]2D group and the rest of the patients were designated as the normal group. Mean illness duration was 59 months in the normal group and 20 months in the low group. The Barthel index (BI), which predicts the degree of immobilization, was significantly lower in the low group than in the normal group. Mean serum 1, 25-[OH]2D and 25-OHD concentrations in the normal group were 36.7 pg/ml and 4.4 ng/ml, respectively; and those in the low group were 14.2 pg/ml and 1.8 ng/ml, respectively. Multiple regression analysis identified illness duration and calcium level as independent determinants of 1, 25-[OH]2D in both groups, and PTH in the normal group and 25-OHD in the low group were additional independent determinants. BMD in stroke patients was significantly lower than that in controls, and BMD in the normal group was lower as compared to the low group. BMD correlated negatively with 1, 25-[OH]2D and PTH in the normal group, and hyperparathyroidism may contribute to reduced BMD. These results suggest that treatment of decreased bone mass in stroke patients has to be individualized according to vitamin D status and calcium homeostasis.

Patients with Van Buchem disease, an osteosclerotic genetic disease, have elevated bone formation markers, higher bone density, and greater derived polar moment of inertia than normal.

Van Buchem disease is an autosomal recessive disease characterized by overgrowth of the skeleton. In a group of Dutch patients the disease is thought to be due to a 52-kb deletion that results in decreased expression of the SOST gene. To further characterize the disease, the morphology of the metacarpals of six adult subjects and two juveniles with Van Buchem disease were measured on hand x-rays along with nine normal adults and nine adult carriers of the disease. Serum bone formation markers, alkaline phosphatase, type I procollagen peptide, and osteocalcin, and the urinary bone resorption marker, cross-linked N-telopeptide, were determined. Van Buchem patients had increased metacarpal outer diameter, inner diameter, cortical thickness, and bone mineral density. Calculated bone volume and derived polar moment of inertia were markedly elevated (elevations of 158 +/- 33% and 497 +/- 95%, respectively) consistent with increased bone strength. Serum procollagen peptide and osteocalcin were significantly higher in Van Buchem patients. Urinary cross-linked N-telopeptide was significantly elevated in Van Buchem patients. None of these changes was found in Van Buchem carriers. These observations indicate that decreased expression of the SOST gene can lead to increased bone formation and to stronger bones.

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

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