Vitamin D2 dose required to rapidly increase 25OHD levels in osteoporotic women.

OBJECTIVE: Assessment of the effectiveness and safety of high daily 125 microg (5,000 IU) or 250 microg (10,000IU) doses of vitamin D(2) during 3 months, in rapidly obtaining adequate 25 hydroxyvitamin D (25OHD) levels. DESIGN: Longitudinal study. SUBJECTS: Postmenopausal osteopenic/osteoporotic women (n = 38) were studied during winter and spring. Median age (25-75th percentile) was 61.5 (57.00-66.25) years, and mean bone mineral density (BMD) was 0.902 (0.800-1.042)g/cm(2). Subjects were randomly divided into three groups: control group (n=13): no vitamin D(2), 125 mug/day (n=13) and 250 microg/day (n=12) of vitamin D(2) groups, all receiving 500 mg calcium/day. Serum calcium, phosphate, bone alkaline phosphatase (BAP), C-telopeptide (CTX), 25OHD, mid-molecule parathyroid hormone (mmPTH), daily urinary calcium and creatinine excretion were determined at baseline and monthly. RESULTS: For all subjects (n=38), the median baseline 25 hydroxyvitamin D (25OHD) level was 36.25 (27.5-48.12) nmol/l. After 3 months, 8% of the patients in the control group, 50% in the 125 microg/day group and 75% in the 250 microg/day group had 25OHD values above 85 nmol/l (34 ng/ml). Considering both vitamin D(2) groups together, mmPTH and BAP levels diminished significantly after 3 months (P<0.02), unlike those of CTX. Serum calcium remained within normal range during the follow-up. CONCLUSIONS: The oral dose of vitamin D(2) required to rapidly achieve adequate levels of 25OHD is seemingly much higher than the usual recommended vitamin D(3) dose (20 mug/day). During 3 months, 250 microg/day of vitamin D(2) most effectively raised 25OHD levels to 85 nmol/l in 75% of the postmenopausal osteopenic/osteoporotic women treated.

Ultrasound parameters and markers of bone turnover in hyperthyroidism: a longitudinal study.

Hyperthyroid patients are characterized by accelerated bone turnover leading to bone mass loss. The aim of this study was to assess changes in quantitative ultrasound [QUS] parameters, bone mineral density (BMD), and biochemical markers of bone turnover in patients prior to and after the onset of hyperthyroid treatment. A 2-yr longitudinal study was performed on 10 women recently diagnosed with Grave's disease after starting antithyroid therapy. Six patients were postmenopausal. All patients showed evidence of thyrotoxicosis as indicated by suppressed serum TSH and high levels of total serum thyroxine. They received antithyroid therapy (methimazole and/or 131I radiodine). QUS parameters were measured using an Achilles ultrasound unit and BMD was assessed by dual-energy X-ray absorptiometry (DXA). Thyroid hormones and markers of bone turnover were determined at baseline and 6, 12, and 24 mo after the onset of treatment.Stiffness, broadband ultrasound attenuation (BUA), and speed of sound (SOS) were low at baseline compared to normal values for the same age range and increased after 2 yr of treatment. A significant increase in BMD of the lumbar spine, total skeleton, and skeletal regions (legs) was also observed after treatment. Recovery of stiffness was almost complete at 12 mo. No significant elevation was observed between 12 and 24 mo. Stiffness increased 7.6%, 10.4%, and 10.4% after 6 mo (p < 0.02), after 1 yr (p < 0.02), and after 2 yr, respectively. No significant increase in SOS and BUA was observed between 12 and 24 mo. Furthermore, recovery of total skeleton and lumbar spine BMD continued throughout the study. Successful antithyroid therapy produced a rapid increase in QUS parameters (Stiffness) and spine BMD and femoral neck during the first year of treatment and a slower increment in total skeleton (up to 24 mo). Overall, ad integrum restitution was not observed in QUS or BMD.

High prevalence of vitamin D insufficiency in healthy elderly people living at home in Argentina.

OBJECTIVE: To evaluate the nutritional status of vitamin D in urban populations of healthy elderly people living at home, in different regions of Argentina. DESIGN: Cross-sectional study. SUBJECTS: In total, 386 ambulatory subjects over 65 y of age from seven cities (between latitude 26 degrees S and 55 degrees S) were asked to participate between the end of winter and the beginning of spring. Of these, 369 accepted, 30 were excluded because of medical history or abnormal biochemical determinations. Finally, 339 subjects (226 women and 113 men) (X+/-s.d.) (71.3+/- 5.2 y) were included. RESULTS: Serum 25OHD levels were lowest in the South (latitude range: 41 degrees S-55 degrees S): 14.2+/-5.6 ng/ml (P<0.0001vs North and Mid regions); highest in the North (26 degrees S-27 degrees S): 20.7+/-7.4 ng/ml (P<0.03 vs Mid, P<0.0001vs South); and intermediate in the Mid region (33 degrees S-34 degrees S) 17.9+/-8.2 ng/ml. Serum mid-molecule PTH (mmPTH) and 25OHD were inversely related: (r=-0.24, P<0.001). A cutoff level of 25OHD at which serum mmPTH levels began to increase was established at 27 ng/ml. A high prevalence (87-52%) of subjects with 25OHD levels in the deficiency-insufficiency range (25OHD levels <20 ng/ml) was detected. CONCLUSION: This study shows that vitamin D deficiency/insufficiency in the elderly is a worldwide problem. Correction of this deficit would have a positive impact on bone health of elderly people.

Estimating body fat and lean tissue distribution in hyperthyroidism by dual-energy X-ray absorptiometry.

Body composition (fat mass, lean tissue, and bone mineral content), was determined by dual-energy X-ray absorptiometry (DEXA) at baseline and 6, 12, and 24 mo after treatment of hyperthyroidism. Ten women with Graves' disease were included in this study. Suppressed serum TSH and high total serum thyroxine levels were found in all patients. The patients received antithyroid therapy (methimazol and/or (131) I radioiodine). Lean tissue, bone mass, and body weight increased after 2 yr of euthyroidism. Total body lean mass increased from 32.3+/-3.9 kg to 35.2+/-4.1 kg (p < 0.005). Total lean mass increased from 10.6 +/- 1.8 kg to 11.6 +/- 1.9 kg (p < 0.01) in the legs, from 3.6 +/- 0.8 kg to 4.0 +/- 0.7 kg (p < 0.02) in the arms, and 16.0 +/- 1.6 kg to 17.4+/-1.8 kg (p < 0.005) in the trunk. Total-body fat mass increased from 19.9 +/- 6.6 kg to 21.2 +/- 7.6 kg (ns). At 1-yr, regional analysis disclosed that fat mass had increased in the trunk from 8.9 +/- 2.9 kg to 10.9 +/- 3.9 kg (p < 0.04) and from 2.3 +/- 0.9 kg to 3.2 +/- 1.2 kg in the arms (p < 0.04). After 2 yr of treatment, fat tissue remained unchanged in all of the studied regions. The results obtained herein suggest that, compared to initial values, the treatment of hyperthyroidism restore body weight. This increase is mainly the result of recovery of lean mass, predominantly in the limbs and trunk. This study provides new data on the patterns of change in body composition occurring in hyperthyroid patients during a 24-mo follow-up after attaining euthyroidism.

[Osteoporosis in all young daughters of a mother with multiple osteoporotic fractures. A case of familial osteoporosis]. / Osteoporosis en todas las hijas jóvenes de una madre con múltiples fracturas osteoporóticas. Un caso de osteoporosis familiar.

We herein describe a family whose female members are all osteoporotic: a postmenopausal mother and her three premenopausal daughters. The mother aged 60 presented axial and peripheral fractures, and very low bone mineral density (BMD). She reported that her grandmother had suffered a hip fracture. The eldest daughter aged 30 suffered multiple vertebral fractures during pregnancy and lactation associated with very low BMD. In view of these observations, the other two daughters aged 29 and 27 years respectively were evaluated. BMD was found to be severely diminished according to densitometric values for osteoporosis established by WHO, but they had no history of bone fractures. Probably the strong genetic component in bone mass is responsible for the severely diminished BMD observed in all the women in this family, as well as the occurrence of bone fractures in two of them. To our knowledge, there are no similar reports in the literature. Our results evidence the importance of evaluating bone mass in the offspring of an individual presenting severe osteoporosis, in order to detect family members with low bone mass and at high risk of developing bone fractures.

Bone mineral density response to long-term bisphosphonate therapy in fibrous dysplasia.

Fibrous dysplasia of bone is a rare disease related to a genetic mutation in which bone formation at osseous sites is altered. In the last few years, bisphosphonates have become one of the choice drugs to treat this disease. A 26-yr-old woman presented after 6 wk of spontaneous right leg pain owing to a fissure fracture of the right femoral neck. She reported precocious puberty at the age of 2, with diagnosis of McCune-Albright syndrome. Radioisotope bone scanning, radiographic, biochemical, and densitometric studies were performed. Treatment with bisphosphonates was started because bone turnover biochemical markers were abnormal. Oral olpadronate followed by iv pamidronate substantially decreased bone resorption. Bone mineral density (BMD) of total skeleton and subareas was assessed by dual X-ray absorptiometry (DXA) throughout the 5 yr of treatment. At the end of this period, BMD of the total skeleton had increased 6.2%. However, BMD of the areas most affected by fibrous dysplasia, the legs and pelvis, had increased 12.7 and 11%, respectively. Region of interest analysis of individual bones of the legs performed with the total skeleton scan revealed that BMD of the areas most affected by fibrous dysplasia was lower than that of the less affected contralateral bones. During the first 3 yr, treatment with bisphosphonates substantially increased BMD of the right femur and tibia (22 and 28%, respectively). After that, values seemed to stabilize. DXA evaluation of the total skeleton and its subareas was useful to evaluate the efficacy of bisphosphonate treatment. Moreover, the plateau observed in BMD values after 3 yr of treatment suggests that treatment could have been discontinued when the densitometric values stabilized.

Osteoporosis in Argentina.

In Argentina there are approximately 150 equipments of densitometry (population 35,000,000) :more than 90% of them are DEXA axial densitometers. Most centers performing densitometry inform that the patient has osteoporosis when the T-score of either spine or proximal femur is below 2.5 SD from young normals. This has led to frequent errors in diagnosis such as treating for osteoporosis patients having primary hyperparathyroidism. Epidemiological studies of hip fractures disclosed an annual incidence of 380 fractures (women) and 100 fractures (men) per 100,000 persons above 50 years of age.

European origin of patients with Paget's disease of bone in the Buenos Aires area.

Paget's bone disease is heterogeneously distributed and several foci of high prevalence have been reported in Europe, United States, Argentina and Australia. The aim of the present work was to determine the ethnic origin of the disease in Buenos Aires using a cross sectional epidemiological study. Sample choice was based on a sampling according to grandparents' nationality. Ninety five percent of Paget patients were of European descent and 5% were non-European, while in the control group the proportion of European descendants is lower: 83% (OR: 3.7; p < 0.007; IC 95%: 1.4-9.7). Within the group of patients with Paget's disease the proportion of Italian and Russian descendants was higher than expected according to the 1914 Argentinean census. The prevalence of Paget's disease among European migrants was higher than in the control group of citizens. Regardless of environmental factors, it is likely that the migrants carried a higher risk of developing the disease.

Osteoporosis en todas las hijas jóvenes de una madre con múltiples fracturas osteoporóticas. Un caso de osteoporosis familiar. / [Osteoporosis in all young daughters of a mother with multiple osteoporotic fractures. A case of familial osteoporosis]

We herein describe a family whose female members are all osteoporotic: a postmenopausal mother and her three premenopausal daughters. The mother aged 60 presented axial and peripheral fractures, and very low bone mineral density (BMD). She reported that her grandmother had suffered a hip fracture. The eldest daughter aged 30 suffered multiple vertebral fractures during pregnancy and lactation associated with very low BMD. In view of these observations, the other two daughters aged 29 and 27 years respectively were evaluated. BMD was found to be severely diminished according to densitometric values for osteoporosis established by WHO, but they had no history of bone fractures. Probably the strong genetic component in bone mass is responsible for the severely diminished BMD observed in all the women in this family, as well as the occurrence of bone fractures in two of them. To our knowledge, there are no similar reports in the literature. Our results evidence the importance of evaluating bone mass in the offspring of an individual presenting severe osteoporosis, in order to detect family members with low bone mass and at high risk of developing bone fractures.

Short-term therapy with oral olpadronate in active Paget's disease of bone.

One of the aims of the treatment of Paget's disease with bisphosphonates should be the normalization of the activity of the disease with the shortest possible exposure to the drug. Olpadronate (OPD) is a new bisphosphonate characterized by the dimethylation of the amino group, its potency is near to alendronate, and more soluble in the digestive media than other aminobisphosphonates. We treated 46 patients (28 men and 18 women, mean age 70 years) with active Paget's disease with oral OPD, 200 mg/day for 12 +/- 2 days, except 2 patients who received 400 mg/day. Eight patients had never been treated before, and 38 had previously received antiosteolytic drugs. The period without treatment prior to OPD was (X +/- 1 SD) 14 +/- 12 months. Baseline bone alkaline phosphatase (BALP) (levels fell from (X +/- 1 SD) 54.0 +/- 62.7 IU/ml (range 22-396) to a lowest mean value of 16.2 +/- 6.4 IU/ml (range 8-45) (normal range 5-21 IU/ml). Forty patients normalized BALP values, in most of the cases within the first 3 months after OPD treatment. Two patients showed partial response (> 50% decrease from baseline), three patients presented poor response (< 50% decrease from baseline), and one patient did not respond at all. Two patients complained of gastric discomfort, and one patient had diarrhea, which disappeared after discontinuation of the drug. Follow-up was carried out on 36 patients; 22 patients are still in remission, with an average length of 9.0 +/- 2.6 months. Fourteen patients experienced relapse after 9 +/- 2 months remission. In conclusion, a 12-day treatment with 200 mg/day of OPD proved to be a very effective and well tolerated therapy of Paget's disease and induced biochemical remissions in the vast majority of patients, even in those with very active disease.

Hyperthyroidism influences ultrasound bone measurement on the Os calcis.

The objective of our study was to compare bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) parameters in women with hyperthyroidism and controls. In this cross-sectional study, QUS parameters and BMD values observed in untreated hyperthyroid patients were compared with data obtained from age-matched controls. Twenty-four women with Graves' disease were studied. Eight patients were postmenopausal. All patients had evidence of thyrotoxicosis as indicated by a raised total serum thyroxine and a suppressed serum thyroid stimulating hormone. BMD of the hip, lumbar spine and whole body, and body composition, were measured by DXA. Ultrasound evaluation on the os calcis was performed with an Achilles device. All measurements were performed before antithyroid therapy. The QUS parameters of BUA, SOS and Stiffness were significantly lower in hyperthyroid patients than in controls. Similar results were observed for the BMD of lumbar spine, femoral neck and total skeleton. Lean tissue and fat mass were also significantly decreased in hyperthyroid patients. In conclusion, these findings suggest that hyperthyroidism affects cortical and trabecular bone equally, as well as bone quality. QUS measurements may be helpful for assessing, using a simple and non-irradiating method, the bone effects of thyrotoxicosis.

Professional football (soccer) players have a markedly greater skeletal mineral content, density and size than age- and BMI-matched controls.

The total skeletal bone mineral content (BMC), bone mineral density (BMD), bone size, and body composition were measured by dual-energy x-ray absorptiometry (DXA) in all professional male football players of a 1st division team (n = 24) and age- and BMI-matched (n = 22) controls (less than 3 hours of recreational sport activities per week). Average (+/- 1 SD) age of the athletes was 22.6 +/- 2.5 years. Intensive training is conducted during 48 weeks a year for 20-22 hours/week. The length of the registered playing career before the study was 8.2 +/- 2.7 years. Total skeleton BMC was 18.0% (P < 0.001) greater in the football players. The difference resulted from the sum of 5.2% (P < 0.02) increment of bone size and 12.3% (P < 0.001) increment of BMD. The analysis of skeletal subareas revealed that the difference of the BMC and BMD was greater at the level of the pelvis and legs compared with the arms or trunk. The BMC and BMD of the head was equal for both groups. Also, the bone size of the legs and pelvis was significantly greater for the players compared with controls; there was no difference at the level of the arms or head. Within the group of football players the increment of total skeleton BMD was similar in the young players, with less than 7 years of practice (age 20.6 +/- 0.9 years) compared with relative older players (age 24.6 +/- 1.9) with more than 7 years of practice. Lean body mass was significantly greater in the players (63.3 +/- 4.0 kg) compared with the controls (56.7 +/- 3.6, P < 0.001) whereas fat mass was markedly lower (9.4 +/- 2.9 kg versus 14.9 +/- 6.3 kg), P < 0.002). The BMD of the controls was significantly correlated to total weight, height, and lean mass whereas the BMD of the players was only correlated to muscle mass. The calcium intake from dairy products was similar in both groups. The range of calcium intake was wide among the players (184-2519 mg/day) but it was not significantly correlated to BMD (r = 0.03). In conclusion, male professional football players develop a significant increment of BMC as a result of increased bone size and density. This is already present at the end of the second decade and maintained at least to the end of the third decade in active players. As in other high impact loading sports, the effect on area is specific involving mainly the pelvis and legs. The increment was totally unrelated to the calcium intake from dairy products. The fate of the increased BMC after intensive training is discontinued should be assessed. However, if the findings of the present cross-sectional study are supported by detailed longitudinal investigations, the presently reported observations might be important for the prevention of future osteoporotic fractures.

Clinical utility of bone mass measurements in adults: consensus of an international panel. The Society for Clinical Densitometry.

Low bone mass predicts future fracture risk as well as high cholesterol or high blood pressure can predict the risk of heart disease or stroke. Prevention of the first fracture should be a clinical goal. In patients without fractures, osteopenia and osteoporosis can be diagnosed based on the extent of reduction in bone mass below mean peak bone mass of young healthy individuals. As bone mass decreases, fracture risk increases exponentially. Clinical situations in which an assessment of bone mass and fracture risk affects therapeutic decisions include estrogen deficiency, vertebral abnormalities, radiographic osteopenia, asymptomatic primary hyperparathyroidism, and long-term corticosteroid therapy. Serial measurements can also be used to monitor the effects of osteoporosis treatments. The appropriate technique and skeletal site for bone mass measurements should be chosen based on the patient's circumstances and the precision of measurement. A clinical interpretation can enhance the value of computer-generated bone mass measurement reports and improve decision making.

Are the etiologies of cervical and trochanteric hip fractures different?

Review of results published in the past few years indicates that there are several differences between women sustaining trochanteric fractures of cervical hip fractures. In most series women with trochanteric fractures are older, shorter, and lighter than those with cervical fractures. The bone mineral density was found to be lower in trochanteric fractures, but although in the majority of the studies the diminution was statistically significant at the level of the trochanter and spine--with predominant trabecular bone--the decrease was not uniformly significant at the level of the femoral neck or total skeleton. Previous vertebral fractures were twice as common in patients with trochanteric fractures. Ultrasound exploration of the calcaneus disclosed that the values were significantly lower in women with trochanteric fractures and this finding was independent of the diminution of the bone mineral density. On the other hand, fall biomechanics have not been found to be different in the two types of hip fractures. In summary, women with trochanteric fractures have a more severe and generalized bone loss, especially of the trabecular component. Cervical fractures seem to be more related to pelvic structure-failure of the outer diameter of the femoral neck to expand with age and increased acetabular bone width-added to a focal bone loss. The two main types of fractures should be treated separately in epidemiological or clinical studies to increase the knowledge and the possibilities of preventing hip fractures.

[Proximal femoral fractures: risk factors, bone mineral density, body composition and biochemical changes in and age-matched patients and controls]. / Fracturas del fémur proximal: factores de riesgo, densidad mineral osea, composición corporal y alteraciones bioquímicas en pacientes y controles de similar edad.

During one year (6/93-5/94) we performed a prospective study in patients with hip fracture, treated at the Hospital de Clínicas. A total of 102 women 52 to 94 years of age (Mean +/- 1SD: 79.5 +/- 9.1 years) and 17 men 61 to 98 years of age (79.7 +/- 9.9 years) who had sustained a hip fracture due to mild or moderate trauma were included. The ratio women: men was 6:1. We also studied 55 age-matched control women without diseases that could affect the skeleton or previous hip fracture (77.1 +/- 5.8 years of age). We did not study a control group in men. Women with hip fractures had lower weight (p < 0.01), lower age of onset of the menopause (p < 0.01) and a tendency to have with a greater frequency a mother with hip fracture (p < 0.08) compared with age-matched controls. When vertebral fractures were excluded, 44% of the hip fracture women had sustained previous skeletal fractures, while only 16% of the age-matched controls had suffered previous skeletal fractures (p < 0.001) (Table 2). The most frequent previous skeletal fractures were wrist and humerus. Forty eight percent of hip fracture women had had at least one vertebral fracture. About 17% of the hip fractured men had sustained previous skeletal fractures, while 5/12 men had suffered at least one vertebral fracture. Hip fractured women and men sustained greater history of diseases which provoke postural instability (Table 3). Biochemical determinations showed significantly diminished levels of serum albumin (p < 0.001) and calcium (p < 0.01), and increased serum PTH (p < 0.05) compared to age-matched controls (Table 4). Bone mineral density (determined by dual energy X-ray absorptiometry) was significantly diminished over proximal femur, total skeleton, legs and pelvis (p < 0.001), head and spine (p < 0.05) (Table 5). Body composition measurements showed that hip fracture women had a significantly lower lean mass compared with controls (p < 0.05). Fat mass also was lower in fracture patients compared with controls, but the difference was not statistically significant (Table 5). We conclude that hip fracture in our population is related to several previous factors: earlier onset of menopause, lower nutrition and body weight, previous diseases that increase the likelihood of falling, increased levels of PTH and reduced bone mass. Prevention of hip fractures should take into account all these factors, specially those that could be modified.

Calcium metabolism and its regulating hormones in patients with leprosy.

Calcium metabolism was studied in 47 patients with borderline or lepromatous leprosy. Total and ionized calcium, phosphorus, creatinine, total alkaline phosphatase, parathyroid hormone (PTH), 25-hydroxy vitamin D [25(OH)D], and 1,25-dihydroxy vitamin D [1,25(OH)2D] were measured in serum; calcium and total hydroxyproline were determined in urine. Total subperiosteal diameter and medullar cavity diameter were measured on an X-ray of the hand of all patients. Average values were within normal ranges for all of the biochemical determinations. Total serum calcium was moderately below the normal range in eight patients but ionized calcium levels were within the normal ranges in all of the patients. Four patients, all of them with lepromatous leprosy, had levels of 1,25(OH)2D higher than normal but none of them was hypercalcemic and PTH levels were within normal range. Although all values were within the normal ranges, lepromatous leprosy patients had lower total calcium, higher alkaline phosphatase, and higher urinary hydroxyproline than borderline leprosy patients (9.1 +/- 0.4 vs 9.4 +/- 0.3 mg%, p < 0.001; 10.3 +/- 2.9 vs 7.4 +/- 2.3 King-Armstrong units, p < 0.02 and 27.2 +/- 12 vs 19.4 +/- 5.6 mg/24 hr, p < 0.02, respectively). No differences were found between patients and controls in the average micrometric measurements of the second metacarpal bone but significant osteopenia was found in 19% of the patients. The main finding of the present study in a representative sample of leprosy patients is that the average total serum calcium was in the lowest limit of the normal range, but the ionized serum calcium was in the middle of the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of the menopausal age on the severity of osteoporosis in women with vertebral fractures.

To assess the effect of age at the onset of menopause over the skeleton we have determined the age and cause of menopause and bone mineral density (BMD), by dual and single photon absorptiometry of the lumbar spine, the proximal femur and the radius shaft on 1050 osteoporotic women (suffering with at least one atraumatic vertebral fracture). The mean +/- 1 S.D. menopausal age was 47.1 +/- 7.6 years. The onset of menopause occurred prior to age 45 in 22% (premature), after age 52 in 9% (late), and between 45 and 52 years of age in 69% (normal menopausal age). When the osteoporotic women were categorized into three groups according to the age of menopause, those osteoporotic with premature menopause had a significantly greater frequency of hip fractures, a significantly lower age, weight and BMD over the spine, proximal femur and radius shaft compared with those of normal menopausal age. In turn, patients with late menopause had a significantly increased weight and BMD over the spine. These findings indicate that among patients with vertebral osteoporosis those women with premature menopause had a more severe bone loss and a significantly greater frequency of hip fractures.

Precise measurement of bone mineral density in rats using dual-energy X-ray absorptiometry.

The dual X-ray absorptiometer (DEXA, Hologic ZDR-1000) in a high resolution mode was evaluated for measuring: Area (A), Bone Mineral Content (BMC) and Bone Mineral Density (BMD) in femur and tibia of adults rats at four regions: proximal (L1), diaphysis (L2-L3) and distal (L4). Reproducibility with and without repositioning was evaluated in femur after ten measurements in a water bath at depths between 2.0 and 2.5 cm. The whole coefficient of variation (CV = 100 x SD/mean) of BMD was 0.52% and 0.47% respectively. Accuracy was evaluated by comparing the BMC to bone ash weight. BMC was highly correlated with chemical analysis (r = 0.98, p < 0.001) for femur. The ability to detect changes in BMD was studied by comparing BMD of the right and left femurs and tibias of adult normal males and females rats. No significant differences were found between both sides. Nevertheless, when BMD (X +/- SE) of male and female rats were compared, female rats presented lower BMD at distal femur (0.263 +/- 0.021 vs. 0.315 +/- 0.009, p < 0.05) and proximal tibia (0.259 +/- 0.016 vs. 0.315 +/- 0.013 p < 0.02) than male rats. We also studied the ability to detect BMD changes in abnormal metabolic conditions. SHAM operated rats were compared to ovariectomized (OVX) rats and it was observed that femur of OVX showed a lower distal BMD than SHAM (0.217 +/- 0.005 vs. 0.263 +/- 0.021, p < 0.05). In summary, DEXA is a technique accurate and precise enough to detect changes on BMC and BMD in small animals permitting the experimental study of different metabolic bone conditions.