Resistive Training Maintains Bone Mineral Density in Postmenopausal Women

We examined the effects of a total body resistive training program (RT) on total and regional bone mineral density (BMD) in older women. Twenty-seven healthy postmenopausal women (mean age 62 ± 1 years) participated in a strength training program three times/week for 16 weeks. Strength was assessed before and after training by either one or three repetition maximum (1RM and 3RM) tests. Both upper and lower body strength significantly increased by 36–65% and 32–98%, respectively, after training. There was a small but significant decrease in body weight and body mass index after training (P < 0.05), with no change in the waist-to-hip ratio. BMD, assessed by dual-energy X-ray absorptiometry, did not change over the duration of the training period in the anterioposterior spine (L₂–L₄), femoral neck, Ward's triangle, and greater trochanter. BMD of the total body, lateral spine (B₂–B₄), and the regions of the radius (1/3 radius and ultradistal radius) also did not fall in subsets of these women. Muscular strength of both the leg and chest press were significantly associated with L₂–L₄, femoral neck, Ward's triangle, and greater trochanter BMD (range r = 0.57–0.84, all P < 0.005). Markers of bone turnover, namely, bone-specific alkaline phosphatase, osteocalcin, and urinary aminoterminal cross-linked telopeptide of type I collagen did not change significantly. In conclusion, a resistive training program maintains BMD and improves muscular strength in healthy, older women. This may be important in preventing the negative health outcomes associated with the age-related loss of bone density. Received 5 June 1996 / Accepted: 26 June 1997     

脊髓损伤对大鼠骨转换及骨密度的影响

目的：探讨脊髓损伤（spinal cord injury,SCI）对大鼠骨转换及骨密度的影响。方法：60只3月龄SD大鼠均分为SCI组与对照组。SCI组于T10处完全横断脊髓;对照组仅行椎板切除术。术后1、3、6周时处死动物测血清钙（Ca）、磷（P）、碱性磷酸酶（ALP）、尿钙、磷、肌酊（Cr）以及股骨、股骨骨密度（bone mineral density,BMD）。:桂花 血钙、尿钙、尿钙／肌酝在伤后不同时间段均升高;血ALP在伤后1周时显著下降,3、6周时恢复正常。胫骨近端,股骨远、近端的BMD在6周时较对照组下降且差异显著。结论：SCI大鼠可见明显的骨转换增高以及破骨活性增强,其生化、骨密度的改变与人体有较好的相关性。SD大鼠可用于评价SCI后骨代谢改变,具可以作为SCI后骨质疏松的模型。     

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     

Relationship of Spinal Fracture to Bone Density,Textural, and Anthropometric Parameters

To investigate risk factors for spinal fracture, we studied the relationship between the prevalence of asymptomatic spinal fracture and various morphological measures including spinal bone mineral density (BMD) in women. A total of 122 women ranging in age from 55 to 79 years were studied. The group consisted of 46 women aged 55–59 years (18 with fracture), 51 women aged 60–69 years (26 with fracture), and 26 women aged 70–79 years (14 with fracture). BMD of cortical and trabecular bone from L1 to L3 was measured using quantitative computed tomography (QCT). Run-length analysis was applied to evaluate the spinal trabecular textural features using CT images; the texture indices which represent the mean width of trabeculae (the T-texture) and that of intertrabecular spaces (the I-texture) were obtained. Anthropometric factors including body weight and height, psoas muscle area, and vertebral bone volume were measured using CT images. Among the various factors, trabecular BMD in women aged 55–69 years showed the highest odds ratio for the presence of fracture per standard deviation (SD) decrease in bone density. However, in women aged 70–79 years, the highest odds ratio was observed for trabecular texture index but not for trabecular BMD. The I-texture in women aged 55–59 years, the muscle area in women aged 60–69 years, and cortical BMD and muscle area in women aged 70–79 years were also considered significantly related to the risk of fracture. Received: 31 December 1995 / Accepted: 24 July 1996     

Bone Mineral Density in Flatwater Sprint Kayakers

To elucidate the possible skeletal benefits of the muscular contractions and the nonweight-bearing loading pattern associated with kayaking, we investigated the bone mineral density (BMD, g/cm²) of 10 elite kayakers, six males and four females, with a median age of 19 years. Each subject was compared with the mean value of two matched controls. BMD of the total body, head, ribs, humerus, legs, proximal femur (neck, wards, trochanter), spine, lumbar spine, and bone mineral content (BMC, g), of the arms was obtained using a dual energy X-ray absorptiometer (DXA). Body composition was also assessed. The kayakers had a significantly (P < 0.05–0.01) greater BMD in most upper body sites: left and right humerus (10.4% and 11.7%), respectively, ribs (6.4%), spine (10.9%), and a greater BMC of the left and right arm (15.7% and 10.6%, respectively). No significant differences in the BMD of the total body, head, or any of the lower body sites were found, except for the pelvis, which was significantly greater in kayakers (5.1%). The controls had a significantly lesser lean body mass (10.4%) and greater percentage of body fat (19.5%) than the kayakers. Bivariate correlation analysis in the controls demonstrated significant and strong relationships between BMD in upper body sites and lean body mass, weight, and fat; the effects of training seem to outweigh most such relationships in kayakers. In conclusion, it seems that the loading pattern and muscular contractions associated with kayaking may result in site-specific adaptations of the skeleton. Received: 21 April 1998 / Accepted: 1 October 1998     

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     

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 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     

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     

Rates of Change in Spinal Bone Density Among Japanese Women

To determine the rates of change in bone mineral density (BMD) at the spine in healthy Japanese women, longitudinal measurements of spinal BMD using dual X-ray absorptiometry were collected from 984 women over 17 years of age (mean age 51.6) at eight medical research centers. They were followed up for 20.9 months on average without any treatment influencing bone and calcium metabolism. Measurements of BMD obtained by two different scanners were converted into standardized BMD (sBMD) values. The multiple linear regression model predicts that spinal sBMD increases up to about 23 years of age: the estimated average rates of increases were 0.13%/year for women aged 20 years. After the age of 23, the sBMD began decreasing: the rates of loss increased by 0.045%/year for each year increase in age among premenopausal women. In perimenopausal women, the rate of loss was 2.1%/year. In postnatural menopausal women, the rates of loss decreased exponentially with increasing years since menopause. The rates of loss increased by 0.04%/year for 1 kg decrease in body weight or by 0.1%/year for 1 kg/m² decrease in body mass index. No significant differences in changes in sBMD were found between scanners and between centers after multiple adjustment. We conclude that the rates of change in spinal sBMD are associated with age in premenopausal women, and with years since menopause and weight or BMI in postmenopausal women. Caution is needed, however, when using data from different densitometers to evaluate rates in bone loss in multicenter trials. Received: 13 March 1997 / Accepted: 27 January 1998     

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     

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     

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     

Increased Osteoclast-Like Cells Formation in Long-Term Bone Marrow Cultures from Patients with a Spinal Cord Injury

Patients with a spinal cord section loose a significant amount of bone. After paraplegia, bone loss occurs below the lesional level and is the more dramatic in iliac bones and in the metaphyseal area of long bones. A peak of urinary calcium and hydroxyprolinuria is observed approximately 6 weeks after their lesion. To further understand the mechanisms underlying the bone damage, we used long-term bone marrow cultures to compare osteoclast-like (OCL-like) cell formation above and below the lesional level. Seven paraplegic, one quadriparetic, one quadriplegic patients and five normal subjects were investigated. Six weeks after their spinal cord section, the number of OCL-like cells formed in iliac bone marrow cultures was significantly greater than those formed in sternal bone marrow cultures for all paraplegic patients tested. No significant differences were seen between iliac and sternal bone marrow cultures for the quadriparetic, the quadriplegic patient, or for the five normal subjects. Conditioned media (CM) from iliac marrow of paraplegic patients increased OCL-like cell formation in normal bone marrow cultures. IL-1, TNF-alpha, IL-6, and PGE₂ were measured in the CM after 3 weeks of culture. IL-6 was found to be significantly higher in iliac CM compared with sternal CM in six out of seven paraplegic patients. In two patients, addition of an anti-IL-6 monoclonal antibody to the marrow cultures significantly decreased the number of OCL-like cells formed at 3 weeks. We conclude that paraplegia caused by a cord section locally induces an increase in the capacity of progenitors to form OCL-like cells in long-term bone marrow cultures. A locally increased IL-6 production in the marrow below the lesional level could be partly responsible for this observation. Received: 25 July 1997 / Accepted: 5 March 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     

Evaluation of Bone Mineral Density in Patients With Spinal Cord Injury

Abstract

Background/Objective: This study was performed to evaluate the bone mineral density (BMD) values in patients with spinal cord injury (SCI) and determine the effects of the level, severity, and duration of the neurological lesion and spasticity on BMD values.

Methods: A total of 75 patients with traumatic SCI and a healthy control group of 39 people were included in the study. The BMD values of the lumbar spine and 4 different regions of the hip (femoral neck, Ward's triangle, trochanter, and femoral shaft) of all cases were measured using dual energy x-ray absorptiometry. The biochemical markers were also analyzed.

Results: The BMD values in all measured regions were found to be decreased in patients compared with that of controls. The level and seventy of the lesion and the spasticity did not significantly affect BMD values in the regions analyzed. The BMD values of the hip decreased as the duration of SCI increased. The levels of plasma phosphorus and alkaline phosphatase, calcium in 24-hour urine samples, and the calcium/creatinine ratio in spot urines were found to be significantly higher in the patient group.

Conclusion: All patients with SCI had lower BMD values than controls. The level and severity of SCI and spasticity did not significantly affect BMD values. The BMD values of the hip decreased as the duration of SCI increased.     

Bone Mineral Density and Biochemical Markers of Bone Turnover in Peri- and Postmenopausal Women

Bone mineral density (BMD) measured by densitometry is the elective parameter for the diagnosis of osteopenia and osteoporosis. Biochemical markers have been proposed as sensitive indicators of high bone turnover and for monitoring response to antiresorptive treatment. We conducted a retrospective study to investigate the values of biochemical markers of bone metabolism with a view to early diagnosis of osteoporosis and monitoring of hormone replacement and calcitonin therapy. The subjects were 415 women, mean age 51 ± 8 years (43–62 years) in peri- and postmenopause, recruited at the Menopause Center of Obstetrics and Gynecology Department of Siena University and divided in five groups. Bone densitometry was performed in all subjects and blood samples were taken for assayed biochemical markers, that is, [osteocalcin (OC), parathyroid hormone (PTH), type 1 procollagen (PICP), and calcitonin (CT)]. Three groups of women were divided into two subgroups: those with normal and those with low BMD (<1 SD). Basal concentrations of PCP1, OC, PTH, and CT were compared in the various groups. Two groups of postmenopausal women with BMD below the normal were treated with estrogen replacement therapy and unmodified eel calcitonin. We evaluated whether some of these biochemical markers of bone turnover could help identify women with low BMD and whether they could be useful for monitoring the results of antiresorptive therapies. Markers of bone formation (PICP and OC) make it possible to distinguish women with high turnover who are at risk for osteoporosis from women with low turnover in menopause. A good correlation was also found between changes in levels of these markers and changes in BMD during treatments, which suggests that the PICP and OC would be useful for monitoring response to antiresorptive therapy. Received: 29 March 1998 / Accepted: 2 November 1999     

Effect of Long-Term Growth-Hormone Substitution Therapy on Bone Mineral Density and Parameters of Bone Metabolism in Adult Patients with Growth Hormone Deficiency

Reduced bone mineral density (BMD) and the prevalence for osteoporotic vertebral fractures are symptoms of growth hormone deficiency (GHD) syndrome, and GH replacement therapy is now available for GH-deficient adults. We investigated the long-term effects of GH replacement therapy on bone mineral density (BMD) and bone metabolism in 19 adult patients with GHD over a period of 18 months. In response to GH treatment, the initially decreased IGF-I concentrations rose significantly during 18 months of therapy to levels within the normal range (matched for sex and age) (mean change 158.1 ± 50.8 ng/ml, P < 0.001). Parameters of bone formation such as osteocalcin (OC) and procollagen I-C-Peptide (PICP) showed a significant increase in the first 6 months of therapy, followed by a slight decrease in the next months. Markers of bone resorption (Crosslaps^R and deoxypyridinoline (D-Pyr) also increased significantly with a peak value after 6 months and all parameters except PICP remained above baseline values after 18 months. BMD of the femoral neck (FN) showed an increase after 18 months of therapy (mean change 0.01 ± 0.03 g/cm² after 18 months, n.s.). However, the increase in BMD was significant only in the lumbar spine (LS) (mean change 0.03 ± 0.04 g/cm², P < 0.05 after 18 months). We conclude that GH replacement therapy in adult patients with GHD over a period of 18 months causes a pronounced increase in bone turnover mainly during the first 12 months of therapy and increases BMD of the lumbar spine and the femoral neck after 18 months. Received: 13 March 1997 / Accepted: 7 August 1997     

Decreased Bone Mineral Density in Neurofibromatosis-1 Patients with Spinal Deformities

A cross-sectional study was carried out to obtain data on the bone mineral density status of a group of neurofibromatosis-1 patients with spinal deformities, and to search for possible accompanying changes in the bone mineral turnover. Neurofibromatosis-1 is a heredofamiliar disorder that is associated with a variety of skeletal anomalies (mostly spinal deformities) in 10–50% of patients. Intraoperatively, a poor vertebral bone quality has been observed. Efforts have been made to identify factors preventing curve progression, to optimize operational planning and to explain the pathomechanism. As part of the preoperative evaluation, dual-energy X-ray absorptiometry was used to assess the bone mineral density of the lumbar spine in 12 patients with neurofibromatosis-1, supplemented by laboratory blood/urine investigations. A significant decrease in bone mineral density of the lumbar spine was measured. An inverse relation was suggested between the severity of scoliosis and the lumbar spine Z-scores. No pivotal alterations were identified in the laboratory measurements. The bony tissue abnormality observed intraoperatively in neurofibromatosis-1 patients may be described as a diminution of the axial bone mineral density. The biochemical parameters do not support the presence of hyperparathyroidism, renal disorders or other associated diseases influencing the bone mineral turnover. The evaluation of bone mineral density in the course of the preoperative planning is proposed in neurofibromatosis-1; the exact background and the role of a possible osteoporosis in the prognosis remain to be elucidated. Received: 12 January 2001 / Accepted: 21 March 2001