Bone Mineral Density Is a Predictor of Survival

The purpose of this study was to examine the relationship between bone mineral density (BMD) and survival in both sexes and to compare BMD with other established risk factors such as blood pressure and cholesterol. A population-based prospective study of 1924 individuals (850 men, 1074 women) was performed in G?teborg from 1980 to 1983. Measurements of BMD were obtained in 1468 (76%) of the participants (653 men, 815 women). This selection of individuals generated 10,965 person years, and death was registered for 289 men and 197 women in the 7-year period (2661 days) after bone mineral measurement. Later information on date of death was obtained from the official population register. This information covers 7 years from the time of survey of the last examined participant (in Dec. 1983). At the beginning of the study, BMD was measured in the calcaneus by dual photon absorptiometry (DPA), and blood pressure, serum cholesterol, serum triglycerides, and body mass index (BMI) were also recorded. The study was coordinated with the National Register of Causes of Death and the National Cancer Register. A modified version of the Cox proportional hazards model was used to calculate and determine the age-adjusted relations between nontrauma mortality and BMD. When the various quartiles of BMD were compared prospectively from 70, 75, and 79 years of age with survival figures during the 2661-day follow-up period, the first and the second quartiles with the lowest BMD at entry showed the lowest survival rate in both men (P= 0.01) and women (P= 0.01). A decrease of 1 SD of BMD in a univariate analysis was associated with a 1.39-fold increase in mortality in both men (95% confidence interval 1.25–1.56, P < 0.001) and women (95% confidence interval 1.22–1.58, P < 0.001), and a multivariate analysis demonstrated a relative risk of 1.23 (95% confidence interval 1.10–1.41, P < 0.001) in men and 1.19 (95% confidence interval 1.02 to 1.39, P= 0.019) in women. All relations were adjusted for sex, age, and follow-up. This study indicates that BMD is a predictor of survival, especially for subjects over 70. Bone mineral density was found to be a better predictor of death than blood pressure and cholesterol. This study indicates that, after adjustments have been made for diseases, low bone mass is an independent predictor of mortality and might be a marker of general health or functional aging. Its measurement might therefore be a valuable tool in general health investigations. Received: 26 December 1996 / Accepted: 27 January 1998     

Bone Mineral Density and Bone Size in Men With Primary Osteoporosis and Vertebral Fractures

The bone mineral density (BMD) at the lumbar spine, proximal femur, and total skeleton was evaluated in 38 men with primary osteoporosis and vertebral fractures. BMD of the patients was significantly reduced over all skeletal areas compared with controls. The Z-score of the lumbar spine (−2.8 ± 0.9) was less than that of the other areas (P < 0.001) except the legs (−2.5 ± 1.1) (p.n.s.) showing that bone loss had a tendency to be greater over the axial skeleton. Vertebral dimensions compared with age-matched controls were as follows: projected L2–L4 area (cm 2): 45.7 ± 5.6 versus 53.7 ± 3.6 (P < 0.001); vertebral width (cm): 4.37 ± 0.44 versus 4.90 ± 0.36 (P < 0.001). Serum biochemical parameters and testosterone levels were similar between osteoporotic and control men. We conclude that men with vertebral osteoporotic fractures have reduced vertebral BMD and vertebral dimensions compared with age-matched controls. Thus, these findings indicate that the achievement of a reduced bone size at the end of the growth period or a failure of periosteal increase during adult life is likely to contribute to the pathogenesis of the vertebral fractures observed in older men. Received: 31 January 1997 / Accepted: 2 July 1997     

Bone Mineral Density and Androgen Levels in Elderly Males

To clarify the relationship of sex male hormones and bone in men, we studied in 140 healthy elderly men (aged 55–90 years) the relation between serum levels of androgens and related sex hormones, bone mineral density (BMD) at different sites, and other parameters related to bone metabolism. Our results show a slight decrease of serum-free testosterone with age, with an increase of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in a third of the elderly subjects studied. BMD decreased significantly with age in all regions studied, except in the lumbar spine. We found a positive correlation between body mass index (BMI) and BMD at the lumbar spine and femoral neck (P < 0.001). No relationship was found (uni- and multivariate regression analysis) between serum androgens or sex hormone-binding globulin (SHBG) and BMD. We found a positive correlation of vitamin D binding protein (DBP) and osteocalcin with lumbar spine BMD and with BMI, DBP, IGF-1, and PTH with femoral neck BMD. In conclusion, there is a slight decline in free testosterone and BMD in the healthy elderly males. However, sex male hormones are not correlated to the decrease in hip BMD. Other age-related factors must be associated with bone loss in elderly males. Received: 29 April 1997 / Accepted: 9 November 1997     

A Prospective Study of Bone Mineral Density Change in Taiwan

In 1989, a cross-sectional study was carried out in Lin-Kou Township, Taiwan, to determine the distribution of bone mineral density (BMD) in the lumbar spine of Chinese people. Lumbar spine BMD was measured using dual-photon absorptiometry in 404 healthy volunteers (266 women and 138 men, aged 15 to 83 years). In 1994–1995, 318 of the same volunteers were reexamined for the present study. Except for there being fewer males and smokers present, there were no significant differences between the second survey respondents and nonrespondents. Spine BMD decreased at over 1% per year in Chinese women over age 50, which was somewhat higher than reported for caucasian women. Since there was a loss of BMD in Chinese women after their 20s, a case can be made for starting preventive activities for female adolescents. There were no differences in the mean BMD change rates among the different age groups of Chinese men. Baseline BMD, menopause, and weight change were associated with the lumbar spine BMD change rates in Chinese women. Body mass index was the only variable significantly associated with BMD change in Chinese men. The rate of BMD change was not associated with diet. Received: 18 February 1997 / Accepted: 5 June 1997     

Bone Mineral Density in the Chronic Patellofemoral Pain Syndrome

Bone mineral density (BMD) and clinical status of 40 patients with a chronic, unilateral patellofemoral pain syndrome (PFPS) were determinated. The mean duration of the disease at the time of the follow-up was 7.6 ± 1.8 (SD) years. The BMD was measured at the spine (L2–L4), and the femoral neck, trochanter area of the femur, distal femur, patella, proximal tibia, and calcaneus of both lower extremities using a dual-energy X-ray absorptiometric (DXA) scanner. The mean BMD of the affected limb (compared with the unaffected side) was significantly lower in the distal femur (−3.3%; P= 0.002), patella (−2.5%; P= 0.016), and proximal tibia (−1.9%; P= 0.008). The femoral neck, trochanter area of the femur, and calcaneus showed no significant side-to-side differences, and the spinal BMDs of men and women with the PFPS were comparable with the manufacturer's age-adjusted reference values for Western European men and women. The relative BMDs of the affected knee showed strongest correlation with the muscle strength of the same knee: the better the muscle strength compared with the healthy knee, the higher the relative BMD (r = 0.56–0.58 with P < 0.001 in each anatomic site of the knee). In the stepwise regression analysis, low body weight or low body mass index, high level of physical activity, the patient's good subjective overall assessment of his/her affected knee, and short duration of the symptoms were also independent predictors of the high relative BMD in the affected knee so that along with the muscle strength these variables could account for 51% of the variation seen in the relative BMD of the femur, 61% in the patella, and 54% in the proximal tibia. In conclusion, chronic patellofemoral pain syndrome results in a significantly decreased BMD in the knee region of the affected limb. The spine, proximal femur, and calcaneus are not affected. Recovery of normal muscle strength and knee function seems to be of great importance for good BMD. Received: 30 May 1997 / Accepted: 8 January 1998     

Long-Term Vegetarian Diet and Bone Mineral Density in Postmenopausal Taiwanese Women

This study examined bone density among postmenopausal Buddhist nuns and female religious followers of Buddhism in southern Taiwan and related the measurements to subject characteristics including age, body mass, physical activity, nutrient intake, and vegetarian practice. A total of 258 postmenopausal Taiwanese vegetarian women participated in the study. Lumbar spine and femoral neck bone mineral density (BMD) were measured using dual-photon absorptimetry. BMD measurements were analyzed first as quantitative outcomes in multiple regression analyses and next as indicators of osteopenia status in logistic regression analyses. Among the independent variables examined, age inversely and body mass index positively correlated with both the spine and femoral neck BMD measurements. They were also significant predictors of the osteopenia status. Energy intake from protein was a significant correlate of lumbar spine BMD only. Other nutrients, including calcium and energy intake from nonprotein sources, did not correlate significantly with the two bone density parameters. Long-term practitioners of vegan vegetarian were found to be at a higher risk of exceeding lumbar spine fracture threshold (adjusted odds ratio = 2.48, 95% confidence interval = 1.03–5.96) and of being classified as having osteopenia of the femoral neck (3.94, 1.21–12.82). Identification of effective nutrition supplements may be necessary to improve BMD levels and to reduce the risk of osteoporosis among long-term female vegetarians. Received: 10 May 1996 / Accepted: 9 August 1996     

Bone Mineral Density and Turnover Following Forelimb Immobilization and Recovery in Young Adult Dogs

The purpose of this experiment was to study changes in bone mass, structure, and turnover in the canine forelimb after unilateral immobilization and recovery. The right forelimbs of 14 adult mongrel dogs were immobilized for 16 weeks. Six dogs served as controls. Seven immobilized and three control dogs were euthanized at the end of the immobilization period. Recovery consisted of 16 weeks of kennel confinement followed by 16 weeks of treadmill exercise. Seven once-immobilized and three control dogs were euthanized at the end of the recovery period. Bone mineral density of both the proximal (PBMD) and central (CBMD) radius was determined by dual X-ray absorptiometry. Standard histomorphometric endpoints for bone mass and turnover were determined in the cancellous bone of the proximal radius. After immobilization, PBMD, CBMD, and trabecular thickness were lower in the immobilized limb than in either the contralateral or control limbs (P < 0.05). Only CBMD remained significantly lower (P < 0.05) after recovery. At the end of immobilization, bone formation endpoints were significantly higher in the immobilized limb than both the contralateral and control limbs. Bone turnover was also significantly lower in the contralateral limb than in the immobilized and control limbs. After recovery, all differences in bone turnover had resolved. Immobilization of 16 weeks duration caused an elevation in cancellous bone formation rate and reduced bone density in both cortical and cancellous bone. After 32 weeks of recovery, turnover abnormalities disappeared, cancellous bone normalized, but cortical bone mass remained low. Recovery of cortical bone from immobilization takes longer than recovery of cancellous bone. Received: 28 January 1996 / Accepted: 3 May 1996     

Loss of Bone Mineral Density in Women Athletes During Aging

Total and regional bone mineral density (BMD) by dual-energy-X-ray absorptiometry (DXA) and bone turnover were tested in 50 highly trained women athletes and 21 sedentary control women (18–69 years; BMI < 25 kg/m²). VO_2max (ml · kg⁻¹· min⁻¹) and lean tissue mass (DXA) were significantly higher in the athletes versus controls (both P < 0.0001). Total body BMD did not decline significantly with age in the athletes whereas lumbar spine (L₂–L₄) BMD approached statistical significance (r =−0.26; P= 0.07). Significant losses of the femoral neck (r =− 0.42), Ward's triangle (r =−0.53), and greater trochanter BMD (r =−0.33; all P < 0.05) occurred with age in the athletes. In the athletes, total body BMD, L₂–L₄ BMD, and BMD of all sites of the femur were associated with lean tissue mass (r = 0.32 to r = 0.57, all P < 0.05) and VO_2max (r = 0.29 to r = 0.48, all P < 0.05). Femoral neck and greater trochanter BMD were higher in the athletes than in controls (both P < 0.05) and lumbar spine and Ward's triangle BMD approached statistical significance (both P= 0.07). Bone turnover was assessed by serum bone-specific alkaline phosphatase (B-ALP), urinary deoxypyridinoline cross-links (Dpd), and urinary aminoterminal cross-linked telopeptides (NTX). There were no relationships between B-ALP or Dpd with age whereas NTX increased with age (r = 0.46, P < 0.05) in the entire group. Levels of B-ALP and NTX were negatively associated with total body, L₂–L₄, femoral neck, Ward's triangle, and greater trochanter BMD (P < 0.05). B-ALP and Dpd were not significantly different between athletes and controls whereas NTX was lower in the athletes than in controls (P < 0.001). The high levels of physical activity observed in women athletes increase aerobic capacity and improve muscle mass but are not sufficient to prevent the loss of bone with aging. Received: 28 November 1997 / Accepted: 8 April 1998     

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     

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     

Bone Mineral Density of Patients with Thalassemia Major: Four-Year Follow-Up

The purpose of this study was to evaluate the bone mineral density (BMD) of 50 patients aged 9–28 years, with thalassemia major and to assess the alterations of bone density in a 4-year follow-up study. They were measured with a DPX densitometer at the lumbar spine and femur area and divided into three groups: preadolescents, adolescents, and adults. All patients received calcium and vitamin D supplements, and 8 of the 50 received hormone replacement therapy (HRT). All patients had a significantly lower BMD compared with healthy subjects. Mean values of lumbar BMD of the three groups were 1.3, 2, and 3 standard deviations (SDs) lower than those of healthy subjects of the same age. All adolescent patients with normal gonadal function and those who received HRT showed an increase in BMD during the period of the study. Adult patients also showed an increase in bone density as long as the treatment lasted. However, adolescent and adult patients who had hypogonadotropic hypogonadism but could not get therapy showed a decrease in bone density. BMD of patients with thalassemia major shows a good index of bone status which should be evaluated, especially for the determination and follow-up of therapy. Received: 31 March 1997 / Accepted: 1 November 1998     

Effect of Tobacco Consumption on Bone Mineral Density in Healthy Young Males

Smoking is related to a decreased bone mass and increased risk of osteoporotic fractures. Nevertheless, the effect of smoking in males is poorly understood. The purpose of this study was to assess the repercussion of smoking on bone mass in otherwise healthy male smokers and its relationship with markers of mineral metabolism and hormone profile. We measured bone mineral density (BMD) in 57 healthy males (26 nonsmokers, 31 smokers; aged 20–45 years) by dual X-ray absorptiometry (DXA, Hologic QDR₁₀₀₀) in the lumbar spine and proximal femur. In a subset we measured biochemical markers of bone metabolism and hormonal profile. We found significant differences in BMD between heavy smokers (more than 20 cigarettes/day) and nonsmokers in all skeletal sites. Serum levels of dehydroepiandrosterone sulfate (S-DHEAS) were lower in smokers and correlated with femoral BMD measurements. No significant differences in bone turnover markers were found. Our findings show that smoking by healthy young males is associated with decreased bone mass. Received: 30 July 1996 / Accepted: 31 December 1996     

Differences in Bone Resorption after Menopause in Japanese Women with Normal or Low Bone Mineral Density: Quantitation of Urinary Cross-Linked N-Telopeptides

The objective of this study was to examine the value of NTx, a urinary cross-linked N-telopeptides of type I collagen, as a marker of bone resorption. We assessed changes in pre- and postmenopausal bone resorption by evaluating the correlation of NTx with L2–4 bone mineral density (BMD) in a total of 1100 Japanese women, aged 19–80 years [272 premenopausal (45.2 ± 6.2 years) and 828 postmenopausal (59.5 ± 6.2 years)]. Postmenopausal women were divided into three groups based on the range of BMD (normal, osteopenic, and osteoporotic). Within each group, subjects were further segregated according to years since menopause (YSM). NTx values were then evaluated for each group. Our results showed that BMD was significantly decreased (P < 0.05) and NTx was significantly increased (P < 0.01) after menopause in age-matched analysis. Consistent with a previous report, NTx was inversely correlated with BMD for the entire cohort of study subjects (r =−0.299), although NTx correlated better with premenopausal than postmenopausal BMD (r =−0.240 versus r =−0.086). This may have been due to the fact that elevated values of NTx were exhibited over the entire range of BMD present in the postmenopausal women, suggesting that NTx might respond faster to the estrogen withdrawal than BMD. In all postmenopausal women, regardless of the range of BMD, the increase in NTx reached a peak within 5 YSM. After 11 YSM, however, NTx remained elevated in the osteoporotic group but it decreased in the osteopenic group, and showed no significant change in the group of postmenopausal women with normal BMD. These findings suggest that bone resorption is dramatically increased within 5 years after menopause but remains increased only in osteoporotic women. Received: 29 April 1997 / Accepted: 12 August 1997     

Interfemur Variation of Bone Mineral Density in Patients Receiving High-dose Thyroxin Therapy

In order to evaluate the interfemoral variability of bone mineral density (BMD) in patients receiving thyroxin (T4) replacement therapy, dual-energy X-ray absorptiometry (DXA) was performed on both hips and the lumbar spine of 114 individuals. BMD was measured in 47 patients under T4 therapy in suppressive doses because of histologically proven thyroid cancer and 67 age-matched controls free of any known local or generalized disorder that would affect the bones and joints. Variation in BMD between both hips was determined for four different regions of interest, i.e., Ward's triangle, intertrochanteric region, trochanter, and femoral neck. No significant difference in hip BMD was found between patients and controls. Even though some individuals had large interfemoral BMD variation, no significant difference in hip BMD variability between the groups was observed. In patients under suppressive T4 replacement therapy, BMD measurement in one hip is suitable to predict BMD of the other hip and therefore unilateral hip measurement may be adequate. Received: 7 June 1997 / Accepted: 27 January 1998     

Bone Mineral Density in Patients Taking H2-Receptor Antagonist

Osteoporosis after gastrectomy is a common clinical disorder. In gastrectomized patients, decreased gastric acidity may be associated with impaired calcium absorption. This study was undertaken to determine whether patients with chronic use of H₂-receptor antagonists (HRA) had demonstrable decreases in bone mineral density (BMD). Thirty-three patients taking cimetidine, ranitidine, or famotidine for more than 2 years were analyzed. We measured BMD of L2–L4 using dual energy X-ray absorptiometry (DXA). Osteoporosis (BMD less than 0.70 g/cm²) was found only in three patients (9%). As compared with healthy controls, age- and sex-matched BMD ranged from 74.4% to 132.9%, with a mean of 97.0%, and was not influenced by the period of HRA use (<5 years versus >5 years or more). Although the age- and sex-matched BMD was different among the kinds of HRA (98.6% for cimetidine, 101.3% for ranitidine, and 85.5% for famotidine), the relationship between the BMD and type of drug was not significant by multivariate analysis. These results indicate that chronic use of HRA has little influence on the degree of BMD, and suggest that decreased gastric acidity is not always associated with osteoporosis after gastrectomy. Received: 18 February 1977 / Accepted: 7 August 1997     

Bone Mineral Density of the Skull in Premenopausal Women

Dual-energy X-ray absorptiometry (DXA) of the head has received little attention. We used DXA to measure bone mineral density (BMD) of the entire skull including the mandible (BMD_Head) and BMD of the cranial vault (BMD_Vault) in 91 normal young women. We also measured BMD of the total body (BMD_{Total body}), proximal femur (``total femur'), and lumbar vertebrae (L1–L4). BMD (g/cm²; mean ± SE) was 1.032 ± 0.011 for L1–L4, 0.995 ± 0.011 for total femur, and 2.283 ± 0.028 for BMD_Vault (cranial vault) and the mean body weight of all subjects was 59.8 kg. Correlation between BMD_Vault and BMD_Head was 0.991 and this was not different from 1.0 (P= 0.473). The average difference between BMD_Vault and BMD_Head was −0.004 g/cm² suggesting that these two measurements of bone mass of the skull were similar. To determine the correlation between the different variables after accounting for external sources of variation, partial correlation derived from multiple regression was determined. Correlations between BMD at the various locations and with BMD_{Total body} were moderate to strong. Although small in magnitude, the partial correlations of body weight with BMD_{Total body}, total femur, and L1–L4 were significantly different from zero (P < 0.02). The results show that BMD_Vault, total femur, and L1–L4 were of equal value in predicting BMD_{Total body} and further, BMD_Vault was not influenced by body weight. Including body weight in multiple regression in addition to total femur or L1–L4 removed the extraneous variation due to body weight, and predictions of BMD_{Total body} were as reliable as when BMD_Vault was based on goodness of fit tests (P= 0.314). The technique used to measure BMD of the cranial vault is a relatively new variation of DXA technology. The precision was as good as other measurements of bone mass of the entire skull (including the mandible). Because the cranial vault is less sensitive to mechanical influences, it may be a region where response to therapy could be evaluated. The cranial vault may be a useful area to study certain heritable diseases that affect the skeleton, skeletal artifact, or evaluation of oral bone loss. Received: 22 December 1995 / Accepted: 24 September 1996     

Effects of High-Intensity Resistance Training on Bone Mineral Density in Young Male Powerlifters

The effects of high-intensity resistance training on bone mineral density (BMD) and its relationship to strength were investigated. Lumbar spine (L2-L4), proximal femur, and whole body BMD were measured in 10 male powerlifters and 11 controls using dual-energy X-ray absorptiometry (DXA). There were significant differences in lumbar spine and whole body BMD between powerlifters and controls, but not in proximal femur BMD. A significant correlation was found between lumbar spine BMD and powerlifting performance. These results suggest that high-intensity resistance training is effective in increasing the lumbar spine and whole body BMD. Received: 27 February 1997 / Accepted: 23 March 1998     

Androgen-Receptor Blockade Does Not Impair Bone Mineral Density in Adolescent Females

The effect of peripheral androgen hypersensitivity on bone mineral density (BMD) was investigated in a group of adolescent women with idiopathic hirsutism (n= 17; mean age 17.0 ± 1.7 years). The effect of long-term androgen-receptor blockade with flutamide (500 mg daily in two divided doses for 12 months) on BMD was assessed too. BMD was measured at lumbar spine (L2–L4) by a dual energy X-ray densitometer. Before flutamide treatment, patient BMD (1.14 ± 0.07 g/cm²) was not significantly different from that of the control group (1.16 ± 0.12 g/cm², n= 22), and was normal for age and sex (BMD 0.14 ± 0.69 SDS, P= NS vs. 0). After 12 months of treatment, absolute BMD in patients increased (1.18 ± 0.08 g/cm², P < 0.002), but SDS BMD did not change (0.21 ± 0.72, P= NS vs. baseline). Flutamide treatment determined a clinical, marked improvement of androgen hypersensitivity (Ferriman–Gallwey score: before 22.0 ± 6.2; 6 months: 13.2 ± 6.4, P < 0.003; 12 months; 7.6 ± 4.1, P < 0.001; acne score: before 3.8 ± 0.8; 3 months 0.8 ± 0.5, P < 0.001; later disappeared). The serum levels of 3α-androstenediol-glucoronide decreased (before: 8.6 ± 1.1 μg/liter; 12 months: 7.2 ± 1.0 μg/liter, P < 0.02), whereas the other endocrinological parameters did not change. No relationship was found between BMD and clinical or biochemical parameters of hyperandrogenism. We concluded that in adolescent women, peripheral hyperandrogenism is not associated with abnormal BMD; long-term treatment with flutamide, which blocks the androgen receptor, does not alter their BMD. Received: 19 February 96 / Accepted: 31 December 96     

The Relation Between Trabecular Bone Strength and Bone Mineral Density Assessed by Dual Photon and Dual Energy X-Ray Absorptiometry in the Proximal Tibia

The feasibility of two noninvasive methods [dual photon absorptiometry (DPA) and dual energy X-ray absorptiometry (DXA)] for prediction in vivo of local variations of trabecular bone strength within the proximal tibia was evaluated in 14 cadaveric knees. Trabecular bone strength was measured using an osteopenetrometer and from destructive compression tests performed on bone cylinders, thus measuring the penetration strength and ultimate strength in the medial, lateral, and central part of the tibial bone specimens. Linear regression analysis showed significant relations between BMD measured by DPA (r²= 72%) or DXA (r²= 73%) and ultimate strength. Even closer relations between BMD (DPA: r²= 80%, DXA r²= 81%) and penetration strength of trabecular bone were found. We conclude that DPA and DXA are suitable methods for evaluation in vivo of local variations in trabecular bone strength within the proximal tibia, and could easily be performed preoperatively before insertion of total knee arthroplasty. Received: 7 September 1995 / Accepted: 16 February 1996