Low Bone Mineral Density in Middle-Aged Breast Cancer Survivors: Prevalence and Associated Factors

BACKGROUND: The aim of this study was to investigate the prevalence of low bone mineral density (BMD) and associated factors in middle-aged breast cancer survivors (BCS). PATIENTS AND METHODS: A cross-sectional study was conducted with 70 BCS of 45-65 years of age undergoing complete oncology treatment. Logistic regression models were used to identify factors associated with low BMD (osteopenia and osteoporosis taken together as a single group). RESULTS: The mean age of participants was 53.2 ± 5.9 years. BMD was low at the femoral neck in 28.6% of patients and at the lumbar spine in 45.7%. Body mass index ≤ 30 kg/m(2) (adjusted odds ratio (OR) 3.43; 95% confidence interval (CI) 1.0-11.3) and postmenopausal status (OR adjusted 20.42; 95% CI 2.0-201.2) were associated with low BMD at the lumbar spine. Femoral neck measurements, age > 50 years (OR 3.41; 95% CI 1.0-11.6), and time since diagnosis > 50 months (OR adjusted 3.34; 95% CI 1.0-11.3) increased the likelihood of low BMD. CONCLUSION: These findings show that low BMD is common in middle-aged BCS. Factors were identified that may affect BMD in BCS and should be considered when implementing strategies to minimize bone loss in middle-aged women with breast cancer.     

Prevalence of Bone Mineral Density Abnormalities and Related Risk Factors in an Ambulatory HIV Clinic Population

Bone mineral density (BMD) abnormalities are observed frequently among human immunodeficiency virus (HIV)-infected patients. Risk factors for reduced BMD in the setting of HIV have been previously studied, but detailed antiretroviral treatment history is often not available. A cross-sectional observational study was conducted between 2005 and 2007 among unselected HIV-infected adults attending an ambulatory urban HIV clinic. Dual-energy X-ray absorptiometry (DXA) scans of lumbar spine and femoral neck, full laboratory profile, detailed questionnaire, and antiretroviral history were obtained. Univariate and multivariate logistic regression analyses were performed to investigate factors associated with BMD below the expected range for age. Two hundred ninety patients completed the study: 80% Caucasians, 89% males, with median age of 49 yr. Low BMD as assessed by Z-score was present in 19.7% of the patients. By multivariate analysis, only lower body mass index (BMI) was an independent risk factor for low BMD. Cumulative exposure to protease inhibitors, non-nucleosides, and individual nucleoside and nucleotide analogs were not independently associated with low BMD. In conclusion, a 19.7% prevalence of abnormal BMD by DXA scan was identified in an unselected group of HIV-infected adults. Lower BMI was independently associated with low BMD. No correlation was found between abnormal BMD and cumulative exposure to any antiretroviral agents.     

Sarcopenia is Related to Increased Risk for Low Bone Mineral Density

Lean body mass is positively correlated with bone mineral density (BMD). The association between sarcopenia and BMD is less studied. The aim of the study is to investigate the association between sarcopenia and abnormal BMD. A total of 600 community residents aged 40–85 yr (mean = 63.63 ± 10.12) from Taipei, Taiwan were included. Abnormal and normal BMD groups were categorized by T-score of femoral neck and lumbar spine (L2–L4) measured by dual-energy X-ray absorptiometry. Skeletal muscle mass (SM) index (SMI) was obtained from SM divided by height squared using bioelectrical impedance analysis (BIA) method. Sarcopenia was defined as SMI less than 8.87 kg/m² in men and 6.42 kg/m² in women according to previous Taiwanese sarcopenia study. The association between BMD groups and sarcopenia was examined using binary logistic regression analyses after controlling potential confounders. Subjects with sarcopenia were at higher risk for low BMD (odds ratio (OR) = 1.59, 95% confidence interval (CI) = 1.06–2.39 for femoral neck BMD and OR = 1.72, 95% CI = 1.09–2.72 for lumbar BMD) compared with the nonsarcopenia group. Even in different gender groups with age categorized, sarcopenia was still an important independent factor in female group. The least square (LS) means of BMD of femoral neck and lumbar spine were significantly lower in sarcopenia group. The risk of low BMD increased significantly with sarcopenia.     

Low Bone Mineral Density in Rotating-Shift Workers

Shift workers have been reported to have an increased bone resorption. However, no existing evidence indicates lower bone mineral density (BMD) in this group. The objective of this study was to test the hypothesis that a rotating-shift work schedule is associated with low BMD and osteoporosis. We evaluated 70 postmenopausal nurses from the Naval Hospital in Concepcion, Chile. The participants were categorized according to the type of work schedule: 39 had a rotating shift and 31 were daytime workers. Medical history, a health examination, a questionnaire on health-related behaviors and biochemical determinations, and BMD examination were obtained for all participants. When comparing the 2 groups, the rotating-shift workers had lower BMD in the lumbar spine (L1–L4: 0.957 ± 0.15 vs 1.104 ± 0.13; p < 0.05) and lower bone density in both femoral neck bones (right: 0.936 ± 0.17 vs 1.06 ± 0.12; p < 0.05 and left: 0.956 ± 0.19 vs 1.05 ± 0.12; p < 0.05). Additionally, the T-scores for 10 (25.6%) of the rotating-shift workers indicated osteoporosis at lumbar spine (T-score > ?2.5). No evidence of osteoporosis was found for daytime workers. When comparing the 2 groups, the rotating-shift workers had a higher prevalence of osteopenia (T-score = ?1.0 to ?2.5) than the daytime workers: 46.2% vs 35.5%, respectively. We found significant evidence that rotating-shift workers have lower BMD in the trabecular and cortical bones, thus suggesting that this type of work may be a risk factor for osteoporosis. Because this is the first time that this osteoporosis risk factor has been reported, the association needs to be replicated and confirmed in other settings.     

Changes in Bone Density in Patients with Ankylosing Spondylitis: A Two-Year Follow-Up Study

The objectives of the study were to determine the 2 year rate of bone changes in patients with ankylosing spondylitis (AS) and, whether bone loss is related to physical impairment, systemic inflammation, and therapy. Consecutive outpatients fulfilling the modified New York criteria for AS were included. Baseline assessment included age, disease duration, treatment, clinical, radiologic and laboratory data. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were determined every 6 months. Persistent systemic inflammation was defined as mean ESR ≥ 28 mm/h or mean CRP ≥ 15 mg/l. Bone mineral density (BMD) at the lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry, at baseline and year 2. Statistical analysis compared the baseline and 24 month follow-up BMD data, and determined whether baseline data, and persistent systemic inflammation during the 2 years, were related to the 24 month percentage changes in BMD. Fifty-four patients (35 men, 19 women; mean age 37.3 ± 11.3 years, mean disease duration 12.4 ± 8.6 years) were included. After 2 years, BMD did not change at the lumbar spine (+0.75%± 3.5, p= 0.23), and decreased at the femoral neck (–1.6%± 4, p= 0.006). The 24 month percentage change in femoral neck BMD was related to persistent systemic inflammation, defined using ESR (mean percentage change –4.1%± 5.7 and –1.2%± 3.9 in patients with and without persistent inflammation; respectively; p= 0.007). These results suggest that persistent inflammation might be an etiologic factor of bone loss in AS. Received: 15 November 2000 / Accepted: 15 February 2001     

Bone Mineral Density Around the Knee Joint: Correlation With Central Bone Mineral Density and Associated Factors

Introduction: The aims of this study were to (1) assess the bone mineral density (BMD) around the knee joint, (2) determine the correlation between central and knee BMDs, and (3) investigate the factors associated with BMD around the knee joint in patients with knee osteoarthritis (OA). Methodology: This cross-sectional study included 122 patients who underwent total knee arthroplasty. Central and knee dual-energy X-ray absorptiometry was performed preoperatively. BMD at 6 regions of interest (ROIs) around the knee joint were measured, and their correlations with central BMD were determined using Spearman's correlation analysis. Lower limb alignment, severity of OA, body mass index (BMI), preoperative functional and pain scores were assessed to elucidate the factors associated with knee BMD using linear regression analysis. Results: Around the knee joint, BMD was the lowest at the distal femoral metaphysis and lateral tibial condyle. Knee BMD was significantly correlated with central BMD. However, the correlation coefficients varied by the ROI. Additionally, multivariate analysis revealed different associations with respect to the regions around the knee joint. Varus alignment of the lower limb was associated with increased BMD of the medial condyles and decreased BMD of lateral condyles. High grade OA was a protective factor; it was associated with increased BMD at the lateral condyles of the femur and tibia. Higher BMI was an independent protective factor in all ROIs around the knee joint except the lateral femoral condyles. Lower functional level was not associated with decreased BMD, whereas a higher pain score was significantly associated with lower BMD at the proximal tibial metaphysis. Conclusions: Knee BMD was significantly correlated with central BMD. However, the correlations varied with the regions around the knee joint probably due to their independent association with the alignment of the lower limb, severity of OA, BMI, and preoperative pain level.     

Perspective on Fracture Risk and Phalangeal Bone Mineral Density

Current bone mineral density (BMD) represents the composite, cumulative effect of many past and present risk factors, including both genetic and lifestyle influences. Reduced BMD, increasing age, and the presence of pre-existing fractures independently increase the risk of osteoporotic fracture. BMD is the most clinically useful of these indicators. Assessment of phalangeal BMD by dual-energy X-ray absorptiometry (DXA) or radiographic absorptiometry (RA) has been shown to provide long-term value in predicting the risk of both hip and spine fracture. Data from phalangeal BMD measurements may be most valuable to the patient if they are used to compute the patient's remaining lifetime fracture probability (RLFP).     

The Prevalence of Low Bone Mineral Density in Dutch Perimenopausal Women: The Eindhoven Perimenopausal Osteoporosis Study

The aim of this study was to estimate the prevalence of osteopenia and osteoporosis in perimenopausal women, and to assess determinants of low bone mineral density (BMD). All women born between 1941 and 1947 (aged between 46 and 54 years) living in the city of Eindhoven were invited to participate in the study; 5896 white Dutch women, representing 73% of the total number of Dutch women in this age group, were studied. Of these, 24% were using estrogen preparations and 19% had undergone hysterectomy, with or without oophorectomy. All women were interviewed and bone mineral density (BMD) of the lumbar spine was measured by dual-energy X-ray absorptiometry (DXA). Osteopenia and osteoporosis were defined according to the criteria proposed by a WHO working group. In the population studied the prevalence of osteopenia and osteoporosis was 27.3% and 4.1%, respectively. With progression from premenopause to menopause, the prevalence of osteoporosis increased from 0.4% to 12.7%, and that of osteopenia from 14.5% to 42.8%. An increased risk for low BMD (osteopenia and osteoporosis) was associated with age, menopausal status and smoking, while alcohol consumption, high body mass index (BMI) and use of estrogens had a protective effect. This study of a large population-based cohort of perimenopausal women revealed a high prevalence of low bone mass and, therefore, a higher risk for osteoporotic fractures. The data further suggest that, when issues on the long-term efficacy and safety of preventive treatments are resolved, it may be possible to identify women at higher risk who are most likely to benefit from screening strategies. Received: 2 June 1997 / Accepted: 21 January 1998     

Intramuscular Neridronate in Postmenopausal Women with Low Bone Mineral Density

Compliance to osteoporosis treatment with oral bisphosphonates is very poor. Intermittent intravenous bisphosphonate is a useful alternative, but this route is not readily available. Neridronate, a nitrogen-containing bisphosphonate that can be given intramuscularly (IM), was tested in a phase 2 clinical trial in 188 postmenopausal osteoporotic women randomized to IM treatment with 25 mg neridronate every 2 weeks, neridronate 12.5 or 25 mg every 4 weeks, or placebo. All patients received calcium and vitamin D supplements. The patients were treated over 12 months with 2-year posttreatment follow-up. After 12-month treatment, all three doses were associated with significant bone mineral density (BMD) increases at both the total hip and spine. A significant dose–response relationship over the three doses was observed for the BMD changes at the total hip but not at the spine. Bone alkaline phosphatase decreased significantly by 40–55% in neridronate-treated patients, with an insignificant dose–response relationship. Serum type I collagen C-telopeptide decreased by 58–79%, with a significant dose–response relationship (P < 0.05). Two years after treatment discontinuation, BMD declined by 1–2% in each dose group, with values still significantly higher than baseline at both the spine and the total hip. Bone turnover markers progressively increased after treatment discontinuation, and on the second year of follow-up the values were significantly higher than pretreatment baseline. The results of this study indicate that IM neridronate might be of value for patients intolerant to oral bisphosphonates and unwilling or unable to undergo intravenous infusion of bisphosphonates.     

Bone Mineral Density in Children and Adolescents with Diabetes Mellitus Type 1 of Recent Onset

There is still controversy over the impact of diabetes control and duration on bone mass and growth parameters in children and adolescents with insulin-dependent diabetes mellitus (IDDM). The aim of this study was to assess bone mineral density (BMD) at axial and appendicular sites, in children with noncomplicated IDDM of recent onset, and its relation to metabolic control and auxological parameters (weight, height, and puberal stage). Fifty-five young Spanish IDDM, otherwise healthy patients (26 males, aged (SD 9.7 ± 4.3 years) and 29 females, aged (SD 11.2 ± 3.8 years) were studied. Duration of diabetes was 1–13.8 years. Two hundred eighty-two age-matched, healthy, Spanish children served as controls. HbA₁ was assayed by high pressure liquid chromatography (HPLC) and BMD was measured using dual X-ray absorptiometry (DXA) densitometry at the spine and forearm. Results showed a Gaussian BMD distribution of patients according to sex and age, without sexual-stage differences. There was no correlation between BMD and glycated hemoglobin (average life disease or last HbA₁ values) or duration of the disease; moreover, no differences in bone mass were found between <3 and ≥3 years of disease duration. Diabetes impact index (mean HbA₁× duration of disease in months) showed no significant influence of diabetes control on BMD. We could not demonstrate any impact of diabetes on BMD and growth parameters in children with IDDM of short duration. Received: 7 November 1996 / Accepted: 26 June 1997     

Fracture Burden in Relation to Low Bone Mineral Density and FRAX Probability

Although the risk of fracture increases exponentially with declining bone mineral density, most fragility fractures have been shown to occur in individuals who do not meet the conventional densitometric definition for osteoporosis. The World Health Organization fracture risk assessment tool (FRAX^®) estimates individual 10-yr major osteoporotic and hip fracture probabilities. Intervention criteria based on risk assessment have been proposed by several groups, including the National Osteoporosis Foundation (NOF). We determined the relationship between 10-yr fracture probability and subsequent fracture burden in 36,730 women and 2873 men aged 50 yr and older. Using a major fracture probability cutoff of 20%, 29.4% of major osteoporotic fractures were identified in women and 4.9% in men. Based on a hip fracture probability cutoff of 3%, 54.1% of major osteoporotic fractures were detected in women and 53.4% in men. Using all NOF criteria, 65.9% of major osteoporotic fractures were detected in women and 69.3% in men. We conclude that men and women with FRAX probabilities below the high-risk NOF cutoffs have a high burden of major osteoporotic fractures. Strategies to enhance risk stratification in this group should be developed through international collaborations.     

Low Bone Mineral Density and Fragility Fractures in Permanent Vegetative State Patients

Disuse of the musculoskeletal system causes bone loss. Whether patients in vegetative state, a dramatic example of immobilization after severe brain injury, suffer from bone loss and fractures is currently unknown. Serum markers of bone turnover, bone mineral density (BMD) measurements, and clinical data were cross‐sectionally analyzed in 30 consecutive vegetative state patients of a dedicated apallic care unit between 2003 and 2007 and compared with age‐ and sex‐matched healthy individuals. Vegetative state patients showed low calcium levels and vitamin D deficiency compared with healthy controls. Serum bone turnover markers revealed high turnover as evidenced by markedly elevated carboxy‐terminal telopeptide of type I collagen (β‐crosslaps) and increased levels of alkaline phosphatase. BMD measured by dual‐energy X‐ray absorptiometry (DXA) scanning showed strongly decreased T‐ and Z‐scores for hip and spine. Over a period of 5 years, 8 fragility fractures occurred at peripheral sites in 6 of 30 patients (n = 3 femur, n = 2 tibia, n = 2 fibula, n = 1 humerus). In conclusion, high bone turnover and low BMD is highly prevalent in vegetative state patients, translating into a clinically relevant problem as shown by fragility fractures in 20% of patients over a time period of 5 years. © 2014 American Society for Bone and Mineral Research.     

Amino Acid Intakes Are Associated With Bone Mineral Density and Prevalence of Low Bone Mass in Women: Evidence From Discordant Monozygotic Twins

Although a higher protein intake, particularly from vegetable sources, has been shown to be associated with higher bone mineral density (BMD) the relative impact of specific amino acids on BMD and risk of osteoporosis remains to be determined. Mechanistic research suggests that a number of specific amino acids, including five nonessential amino acids—alanine, arginine, glutamic acid, glycine, and proline—may play a role in bone health, principally through improved production of insulin and insulin‐like growth factor 1 and the synthesis of collagen and muscle protein. However to date, no previous studies have examined the associations between habitual intake of amino acids and direct measures of BMD and prevalence of osteoporosis or osteopenia, and no studies have examined this relationship in discordant identical twin‐pairs. In these analyses of female monozygotic twin‐pairs discordant for amino acid intake (n = 135), twins with higher intakes of alanine and glycine had significantly higher BMD at the spine than their co‐twins with within‐pair differences in spine‐BMD of 0.012 g/cm² (SE 0.01; p = 0.039) and 0.014 g/cm² (SE 0.01; p = 0.026), respectively. Furthermore, in cross‐sectional multivariable analyses of 3160 females aged 18 to 79 years, a higher intake of total protein was significantly associated with higher DXA‐measured BMD at the spine (quartile Q4 to quartile Q1: 0.017 g/cm², SE 0.01, p = 0.035) and forearm (Q4 to Q1: 0.010 g/cm², SE 0.003, p = 0.002). Intake of six amino acids (alanine, arginine, glutamic acid, leucine, lysine, and proline) were associated with higher BMD at the spine and forearm with the strongest association observed for leucine (Q4 to Q1: 0.024 g/cm², SE 0.01, p = 0.007). When intakes were stratified by protein source, vegetable or animal, prevalence of osteoporosis or osteopenia was 13% to 19% lower comparing extreme quartiles of vegetable intake for five amino acids (not glutamic acid or proline). These data provide evidence to suggest that intake of protein and several amino acids, including alanine and glycine, may be beneficial for bone health, independent of genetic background. © 2015 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.     

Use of Clinical Risk Factors in Elderly Women with Low Bone Mineral Density to Identify Women at Higher Risk of Hip Fracture: The EPIDOS Prospective Study

Elderly women with very low bone mineral density (BMD) (T-score ≤−3.5) have a risk of hip fracture more than two times higher than the average risk of women of the same age. Using data from the EPIDOS prospective study, we have shown that by measuring BMD on the 50% of women who have the lowest weight, it is possible to identify the majority of these women at higher risk. In the present analysis, we assessed whether the use of clinical risk factors, in the subset of women selected for osteodensitometry and with moderately low BMD (T-score between −3.5 and −2.5), allows the identification of another subgroup of women with a risk 2 times higher than average and, thereby, increases the efficiency of selective BMD screening. We then assessed the discriminant value for hip fracture of the overall screening strategy (i.e., use of weight to select women for osteodensitometry, then use of clinical risk factors to enhance the predictive value of BMD), and compared it with the value of BMD used as a population screening tool. In total, 6933 EPIDOS participants, aged 75 years or above, were included in this analysis. Using Cox regression models, we first determined which baseline factors were most predictive of hip fracture among the 1588 women with weight below median (selection criteria for osteodensitometry in the proposed strategy) and T-score between −3.5 and −2.5. Based on the relative risk (RR) estimates from the final risk function, we calculated an individual risk score for hip fracture. We assessed the incidence of hip fracture for each value of the score, and determined the cutoff to identify women with a risk about 2 times higher than the average risk in this elderly cohort. The overall screening strategy (i.e., selective BMD measurement based on weight, followed by clinical fracture risk assessment) identifies two subgroups of higher risk women: a group with very low BMD (T-score ≤–3.5), and another group with moderately low BMD (T-score between –3.5 and –2.5) but a high fracture risk score. We calculated the total number of women classified as being at high risk, and assessed the overall sensitivity and specificity of this strategy to identify elderly women who will suffer a hip fracture. Among women with weight below median and T-score between −3.5 and −2.5, the factors most predictive of the risk of hip fracture were age, history of fall, ability to do the tandem walk (test of dynamic balance), gait speed and visual acuity. A simple additive score based on these factors (except visual acuity) allows a high-risk group (risk about 2 times higher than average) to be clearly distinguished from a low-risk group (risk below average). Overall, the proposed strategy identifies approximately 15% of the women in the cohort as being at high risk, i.e., 543 women with T-score ≤−3.5 and 503 women with −3.5 <T-score ≤−2.5 and a high fracture risk score. The sensitivity for hip fracture is equal to 37% and the specificity to 85%, which is equivalent to the discriminant value of BMD as a population screening tool. In elderly women, the use of a simple clinical risk score, in women with previous BMD values, allows the number of high-risk women identified to be increased. Overall, the proposed screening strategy (use of weight to select women for osteodensitometry, and then use of clinical risk factors to enhance the predictive value of BMD) has the same discriminant value for hip fracture as BMD used as a population screening tool. Received: 20 November 2001 / Accepted: 11 February 2002     

Effect of Bone Mineral Density and Parathyroidectomy on Fracture Risk in Primary Hyperparathyroidism

Background  Bone mineral density is one parameter used to decide whether patients with primary hyperparathyroidism (PHPT) should undergo parathyroidectomy. However, the influence of bone mineral density and parathyroidectomy on subsequent fracture risk is unclear. Methods  The authors conducted a retrospective cohort study of patients with PHPT based on administrative discharge abstract data. The dual energy x-ray absorptiometry (DEXA) scan T-scores at the femur were collected by chart review, and 10-year fracture-free survival (FFS) was the main outcome measured. Results  A total of 533 patients were identified, most of them ≥ 50 years old (89%) and female (87%). Seventeen percent of the patients were black. Mean initial calcium, parathormone, and creatinine levels were 11.1 mg/dl, 116 pg/ml, and 0.9 mg/dl, respectively. Parathyroidectomy was performed in 159 (30%) patients, and 374 (70%) were observed. The 10-year FFS after PHPT diagnosis was 94% in patients treated with parathyroidectomy and 81% in those observed (p = 0.006). Compared to observation, parathyroidectomy improved the 10-year FFS by 9.1% (p = 0.99), 12% (p = 0.92), and 12% (p = 0.02) in patients with normal bones (T-score ≥ −1.0), osteopenia (T-score ≤ −1.0, ≥ −2.5), and osteoporosis (T-score < −2.5), respectively. On multivariate analysis, parathyroidectomy was independently associated with decreased fracture risk (HR = 0.41; 95%CI 0.18, 0.93), whereas non-black race (HR = 2.94; 95%CI 1.04, 8.30) and T-score < −2.5 (HR = 2.29; 95%CI 1.08, 4.88) remained independently associated with increased fracture risk. Conclusions  Parathyroidectomy decreases the risk of fracture in patients with normal, osteopenic, and osteoporotic bones. The largest impact from parathyroidectomy is in patients with osteoporosis. The highest risk of fracture is in non-blacks and in patients with osteoporosis.     

Dual Energy X-Ray Absorptiometry in Small Rats with Low Bone Mineral Density

The feasibility of dual energy X-ray absorptiometry (DXA) using the Norland XR-26 Mark II bone densitometer for measurements of bone mineral content (BMC) and bone mineral density (BMD) in small rats was evaluated. Thirty-two young, isogenic, Lewis rats (weights from 119 g to 227 g) were used; normal rats (n = 7) and rats with low BMD obtained from three different vitamin D-depleted models (n = 25). DXA measurements were performed using the special software for small animals. Duplicate scans of excised femurs performed at 2 mm/second (pixel size of 0.5 mm × 0.5 mm) were very precise measurements with a coefficient of variation (CV) below 1.6% in animals with normal BMD; in rats with low BMD, the CV was significantly higher (P= 0.02–0.04), 7.8% and 4.4% for BMC and BMD, respectively. Regression analysis demonstrated that these measurements were related to the ash weight (R² > 98.6%). The CV for measurements of the lumbar spine at 10 mm/second (pixel size 0.5 mm × 0.5 mm) was 2.6% and 2.2% for BMC and BMD, respectively in rats with normal BMD, and again higher (P= 0.03–0.14) in rats with low BMD, 7.3% and 4.7%, respectively, for BMC and BMD. Even though low CVs were obtained for total body duplicate scans (scan speed of 20 mm/second and a pixel size of 1.5 mm × 1.5 mm), the measurements were problematic for accuracy because of an overestimation of both BMC and the area of bone. Using these scan parameters the measurements of total body bone mineral could not be recommended in small rats with low BMD. Received: 21 May 1999 / Accepted: 3 August 2000 / Online publication: 22 December 2000