Isokinetic Resistance Training Increases Tibial Bending Stiffness in Young Women

Bone mineral content (BMC) and bone mineral density (BMD) are common but imperfect surrogate measures of bone strength. The mechanical response tissue analyzer is a device that measures long bone bending stiffness (EI), which strongly predicts bone breaking strength. We hypothesized that isokinetic resistance training of the knee flexor and extensor muscles would increase tibial EI, BMC, and BMD in young women. Fifty-two women, aged 18–26 years, performed concentric (CON, n = 30) or eccentric (ECC, n = 22) isokinetic resistance training with the nondominant leg three times per week for 20 weeks. Before and after the training period, subjects were tested for CON and ECC peak torque of the knee flexor and extensor muscles with isokinetic dynamometry, tibial BMC and BMD using dual-energy X-ray absorptiometry, and tibial EI using mechanical response tissue analysis. Both training groups increased CON (15–21%) and ECC (17–31%) peak torque vs. the untrained leg. Tibial EI increased in the entire cohort (26%) and in each training group (CON 34%, ECC 16%) vs. the untrained tibia. Tibial BMC and BMD increased in the trained and untrained tibiae, with no significant differences between limbs. No differential tibial EI or bone mineral outcomes were observed between the CON and ECC training groups. In summary, CON and ECC isokinetic resistance training increased tibial EI, but not BMC or BMD, in young women.     

Effect of menatetrenone on bone mineral density and incidence of vertebral fractures in postmenopausal women with osteoporosis: a comparison with the effect of etidronate

The purpose of the present study was to compare the effects of etidronate and menatetrenone on bone mineral density (BMD) and the incidence of vertebral fractures in postmenopausal women with osteoporosis. Seventy-two osteoporotic women, more than 5 years after menopause, 53–78 years of age, were randomly divided into three administration groups: E group; intermittent cyclical etidronate (200 mg/day, 14 days per 3 months; n = 25); M group; menatetrenone (45 mg/day, daily; n = 23); and C group (control); calcium lactate (2 g/day, daily; n = 24). Forearm BMD was measured by dual-energy X-ray absorptiometry at 0, 6, 12, 18, and 24 months after the treatment started. There were no significant differences in age, body mass index, years since menopause, and initial BMD among the three groups. One-way analysis of variance (ANOVA) with repeated measurements showed a significant decrease in BMD in the C group (P < 0.0001). Two-way ANOVA with repeated measurements showed a significant increase in BMD in the M group compared with that in the C group (P < 0.0001), and a significant increase in BMD in the E group compared with that in the C and M groups (P < 0.0001 and P < 0.01, respectively). The indices of new vertebral fractures/1000 patient-years in the E and M groups were significantly higher than that in the C group (χ² = 47.7; P < 0.0001 and χ² = 42.4; P < 0.0001, respectively), and did not differ significantly between the E and M groups. The present preliminary study provides evidence to suggest that, despite the lower increase in BMD produced by me-natetrenone, this agent, as well as etidronate, may have the potential to reduce osteoporotic vertebral fractures in postmenopausal women with osteoporosis. Received: January 9, 2001 / Accepted: June 8, 2001     

Nail calcium and magnesium content in relation to age and bone mineral density

In view of the importance of calcium (Ca) and magnesium (Mg) as major bone components and nutrients controlling bone metabolism, and the ready availability of nail samples for analysis, clippings of fingernails and toenails were analyzed for Ca and Mg. The clippings were dissolved in nitric acid and analysis was done, using atomic absorption spectrophotometry, in 169 women and 115 men between 20 and 80 years of age. Fingernail Ca concentration in men decreased from 927 ± 50 ppm (mean ± SEM) in their twenties to 464 ± 50 ppm in their eighties, with a significant negative correlation with age (r = −0.322; P < 0.0001) and such a negative correlation was also shown in the women (r = −0.269; P = 0.0004). Toenail Ca concentrations also decreased significantly with age in men (r = −0.534; P < 0.0001) and women (r = −0.224; P = 0.0016). Fingernail Mg concentration, in contrast, increased significantly with age in both men (r = 0.209; P = 0.0145) and women (r = 0.280; P < 0.0001), but toenail Mg failed to show significant changes with age in either men or women. Multiple stepwise regression analysis of age and lumbar bone mineral density (LBMD) on fingernail Ca concentration eliminated age before LBMD. In a separate group of 33 women in their sixties, a significant positive correlation was noted between fingernail Ca and LBMD (r = 0.544; P = 0.0016) and between toenail Ca and LBMD (r = 0.399; P = 0.0215). A negative correlation was also noted between fingernail Mg concentration and LBMD (r = −0.389; P = 0.0252). Nail mineral content may be utilized as one of the indicators of bone mineral metabolism.     

An effective regimen of intranasal salmon calcitonin in early postmenopausal bone loss

Summary In order to devise a convenient and effective therapeutic regimen of intranasal salmon calcitonin (sCT) for the treatment of early postmenopausal bone loss, we studied the effects of a 1-year course of sCT nasal spray on vertebral mineral content (VMC), assessed by dual photon densitometry, and bone turnover in 21 early postmenopausal osteoporotic women. Subjects enrolled in the study had a value above the normal average of at least one index of bone turnover: whole body retention (WBR) of ^99mTc-methylenedichloro-bisphosphonate (^99mTc-MDP), serum bone gla protein (BGP), urinary hydroxyproline/creatinine excretion (HOP/Cr). After baseline evaluation, patients were randomized for treatment with either sCT (200 IU every other day) or plabebo. Treatment with sCT significantly increased VMC by 2.7±0.9% at 6 months, and 3.3±0.8% at 1 year, whereas a progressive decline was observed in the placebo group (-2.6±0.5%, and -3.5±0.5% after 6 and 12 months, respectively). These changes were associated with a progressive and significant reduction of all parameters of bone turnover in the sCT-treated patients, whereas no changes were detected in the control group during the study period. The differences between the two groups were significant after 1 year for VMC, BGP, and WBR (P<0.05, one-way analysis of variance). Thus, 200 IU intranasal sCT administered on alternate days is adequate to stop the fast bone loss occurring early after the menopause in women with high bone turnover rates. This therapeutical modality represents an important addition to the available pharmacologic spectrum for the prevention and treatment of postmenopausal osteoporosis.     

Tooth loss and skeletal bone density in healthy postmenopausal women

Associations between dental status and skeletal bone density were investigated in a group of 329 healthy postmenopausal women with normal bone density. Bone mineral density (BMD) of the lumbar spine, femoral neck and distal radius were measured by dual-or single-photon absorptiometry. Number of teeth remaining were counted and presence of complete dentures noted by a nurse practitioner. Forty-eight women (15%) wore a complete maxillary and/or mandibular denture: 22 (7%) were completely edentulous and an additional 26 (8%) had one edentulous ridge. Among women without complete dentures (n=281), significant positive linear relationships were observed between number of teeth and BMD at the spine (p<0.05) and radius (p<0.01), controlling for years since menopause, pack-years of smoking, education and body mass index. BMD did not differ between the groups with and without dentures. However, women who acquired dentures after the age of 40 years had significantly lower mean spinal and radial BMD than women who acquired dentures at age 40 years or earlier (at the radius, 0.584±0.015 v 0.630±0.017 g/cm²,p<0.05; at the spine, 1.043±0.031 v 1.124±0.029 g/cm²,p=0.05). In linear regression analysis, significant independent correlations were found among all women (n=329) between number of teeth and age (partialr=–0.19,p<0.001), pack-years of cigarette use (partialr=–0.23,p<0.001) and years of education (partialr=+0.11,p<0.05). These associations between dental status and BMD support the hypothesis that systemic bone loss may contribute to tooth loss.     

Interpretation of lumbar spine densitometry in women with fractures

Identification of postmenopausal women at risk of developing osteoporotic fractures is a major clinical problem. In this study the use of projected planar lumbar bone density values for individual fracture risk assessment was questioned. Osteodensitometry (DXA) results from 415 normal women, 62 women with previous vertebral compressions, and 76 women with previous low-energy fractures were analyzed, together with their body size and lumbar vertebral body size variables. The following were found: (1) Lumbar vertebral projected bone mineral areal density (BMD) and bone mineral content (BMC) of normal women correlated with body size variables (p<0.001). (2) Lumbar vertebral body size variables also correlated with body size variables (p<0.001). Logistic regression analysis of measured and derived physical variables from women without and with vertebral compression fractures (n=477) showed: (3) The best compression fracture discriminator, significantly better than BMD, was BMC divided by (H_max/165 cm)¹⁵×(D/4.35 cm)^1.5, where H_max is the body height (cm) at the menopause, and D the mean lumbar vertebral diameter of the three mid-lumbar vertebral bodies (cm). This parameter was termed BMC_corr.. ROC analysis showed: (4) At a BMC_coor. true positive ratio of 80% the corresponding uncorrected BMC or BMD true positive ratio was only 60%. The corresponding false positive ratio was 6%. Lumbar osteodensitometry could not be used to identify women with a history of peripheral low-energy fractures. (5) BMC_coor. did not, unlike BMC and BMD, correlate with body size and vertebral size variables. (6) Likewise, an observed correlation between BMC and lean body mass in a subpopulation of 116 normal women was abolished when BMC_corr. replaced BMC. We suggest that vertebral compression fracture risk limits based on BMC, corrected for individual differences in body size and vertebral body size, replace the commonly used BMD fracture risk limits. The discriminatory ability of BMC_corr. for low-energy fractures needs to be tested in a different population.This investigation was carried out as part of a collaborative study by the Danish Osteoporosis Study Group (DOPS: O. Helmer Sørensen, L. Mosekilde, P. Charles, H. Beck-Nielsen and S. Pors Nielsen).     

Changes in the RANK ligand/osteoprotegerin system are correlated to changes in bone mineral density in bisphosphonate-treated osteoporotic patients

Introduction Since the soluble receptor activator of the NF-κB ligand (sRANKL) as well as the endogenous anti-resorptive cytokine osteoprotegerin (OPG) are produced by osteoblasts and given that these cells undergo significant changes during antiresorptive treatment, we hypothesized that treatment with bisphosphonates (BP) would be accompanied by changes in serum OPG and sRANKL levels. Methods In a prospective, randomized controlled trial of previously untreated postmenopausal women with osteoporosis, oral BP therapy (daily doses of either 10 mg alendronate or 5 mg risedronate) in combination with calcium/vitamin D was compared to calcium/vitamin D treatment alone (control group). Follow-up at 2, 6 and 12 months was completed for 56 patients. Standardized spinal X-rays were performed at baseline, and DEXA measurements at the femoral neck and trochanter were made at baseline and after 1 year. Serum OPG and sRANKL levels were measured with a polyclonal antibody-based ELISA system. Results After 1 year, there was a non-significant loss in neck and trochanteric bone mineral density (BMD) in the CTR group and a mean increase of 3.3% and 4.6% in the combined BP group (both p<0.0001), respectively. Serum levels of C-terminal telopeptides of type I collagen (sCTX) and osteocalcin decreased by 12% and 10% at 12 months in the CTR group and by 43% and 23% in the combined BP group, respectively (all significant). OPG serum levels in the CTR group decreased significantly by 9% at 2 months (p<0.005) and remained below pre-treatment levels at later time points. Both the alendronate- and risedronate-treated patient groups showed unaltered OPG levels after 2 months, but they had significantly increased serum levels at 6 and 12 months. Levels of sRANKL were unchanged throughout the treatment period. Univariate regression analysis demonstrated that changes in serum OPG levels after 12 months of BP treatment were positively and better correlated to BMD changes (trochanter: r= 0.59, p<0.0001; neck: r= 0.50, p<0.001) than those of sCTX, which showed the expected negative correlation to BMD change (trochanter: r= –0.35, p=0.03; neck: r= –0.23, p=0.16). With multiple regression analyses at 12 months, R² values for 1-year changes in trochanteric BMD of 0.33 (OPG alone) and 0.23 (sCTX alone) were significantly improved to the 0.57 when OPG and sCTX changes were combined (p<0.001). Results for the femoral neck were also statistically significant R²=0.35, p<0.001). BMD and OPG changes in the CTR group were not correlated with each other. Conclusions We conclude that with BP treatment, changes in serum OPG levels, unlike changes in sCTX levels, are positively correlated to changes in BMD response. The BP-related changes in serum OPG levels during treatment could result from effects on osteoclastogenesis and osteoclast apoptosis as well as from a direct stimulatory effect on osteoblastic OPG production. These changes in OPG levels may be used to predict the individual response of patients to BP treatment.     

Does high-intensity resistance training maintain bone mass during moderate weight loss in older overweight adults with type 2 diabetes?

The aim was to investigate whether the addition of supervised high intensity progressive resistance training to a moderate weight loss program (RT+WLoss) could maintain bone mineral density (BMD) and lean mass compared to moderate weight loss (WLoss) alone in older overweight adults with type 2 diabetes. We also investigated whether any benefits derived from a supervised RT program could be sustained through an additional home-based program. This was a 12-month trial in which 36 sedentary, overweight adults aged 60 to 80 years with type 2 diabetes were randomized to either a supervised gymnasium-based RT+WLoss or WLoss program for 6 months (phase 1). Thereafter, all participants completed an additional 6-month home-based training without further dietary modification (phase 2). Total body and regional BMD and bone mineral content (BMC), fat mass (FM) and lean mass (LM) were assessed by DXA every 6 months. Diet, muscle strength (1-RM) and serum total testosterone, estradiol, SHBG, insulin and IGF-1 were measured every 3 months. No between group differences were detected for changes in any of the hormonal parameters at any measurement point. In phase 1, after 6 months of gymnasium-based training, weight and FM decreased similarly in both groups (P<0.01), but LM tended to increase in the RT+WLoss (n=16) relative to the WLoss (n=13) group [net difference (95% CI), 1.8% (0.2, 3.5), P<0.05]. Total body BMD and BMC remained unchanged in the RT+WLoss group, but decreased by 0.9 and 1.5%, respectively, in the WLoss group (interaction, P<0.05). Similar, though non-significant, changes were detected at the femoral neck and lumbar spine (L2-L4). In phase 2, after a further 6 months of home-based training, weight and FM increased significantly in both the RT+WLoss (n=14) and WLoss (n=12) group, but there were no significant changes in LM or total body or regional BMD or BMC in either group from 6 to 12 months. These results indicate that in older, overweight adults with type 2 diabetes, dietary modification should be combined with progressive resistance training to optimize the effects on body composition without having a negative effect on bone health.     

Association of Grip Strength Change with Menopausal Bone Loss and Related Fractures: A Population-Based Follow-Up Study

The aim of the present study was to investigate the association between grip strength change and bone health according to menopausal status. A random sample of 971 pre- to postmenopausal women from the Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort was measured with dual X-ray absorptiometry in the lumbar spine (LS) and femoral neck (FN) and grip strength with pneumatic squeeze dynamometer at baseline (1989–1991), 5 years (1994–1997), and 10 years (1999–2001). Fractures were recorded based on self-reports and validated from medical records. Women were divided into two groups according to change in grip strength quartile from baseline to 5-year follow-up: not improved (n = 735) and improved (n = 236). In the total population, the greatest bone loss was observed in perimenopausal (beginning of menopause during follow-up, n = 311) women [P < 0.001 vs. premenopausal women (n = 139)], and it declined in postmenopausal (n = 521) women [P < 0.001 by analysis of covariance (ANCOVA)]. The perimenopausal bone loss rate was significantly lower in women in the improved group in comparison to the not improved group (P < 0.01) in contrast to the pre- and postmenopausal groups (P > 0.05). Accordingly, there was a greater decline in perimenopausal LS and FN T-scores in the improved group vs. the not improved group over the first 5-year follow-up interval (P < 0.05 by ANCOVA) and remained unchanged over the 10-year follow-up. In perimenopausal women, there was a trend toward higher fracture-free survival rate in the improved group (82%) vs. the not improved group (88%) after 10 years. Adjustments did not change the results. In conclusion, maintenance of grip strength is associated with menopausal bone loss and future fractures.     

Influence of maternal genetic and lifestyle factors on bone mineral density in adolescent daughters: a cohort study in 387 Japanese daughter-mother pairs

We conducted a cross-sectional study in a cohort of Japanese adolescent schoolgirls (12–18 years of age) and their mothers (387 pairs). Age, lumbar bone mineral density (BMD), birth and menarche-related status, height, body weight and lifestyles were surveyed in the participants. The values of BMD, height and body weight were converted to standard deviation (SD) by age. There were 49 (12.7%) pre-menarche and 338 (87.3%) post-menarche daughters. BMD-SD, height-SD, vitamin D intake and vitamin K intake were significantly correlated between the pre-menarche daughters and mothers (P < 0.05), while BMD-SD, birth weight, age at menarche and all lifestyle-related factors were significantly correlated between the post-menarche daughters and mothers (P < 0.05). BMD-SD in the pre-menarche daughters was affected by BMD-SD in mothers (R ² = 0.069, P = 0.033) and their own height-SD (R ² = 0.199, P = 0.001) (model R ² = 0.340), independently. BMD-SD in the post-menarche daughters was affected by BMD-SD in mothers (R ² = 0.073, P < 0.001) as well as by their own age at menarche (R ² = 0.020, P = 0.001), height-SD (R ² = 0.022, P < 0.001), body weight-SD (R ² = 0.081, P < 0.001) and intensity of exercise (R ² = 0.015, P = 0.045) (model R ² = 0.372), independently. The results suggest that BMD is strongly correlated between daughters and mothers and that a greater age at menarche leads to lower peak bone mass. It was also suggested that maintaining high-intensity physical activity and adequate body weight is important in achieving maximum BMD as factors amenable to intervention in post-menarche daughters.     

Association between height loss and bone loss, cumulative incidence of vertebral fractures and future quality of life: the Miyama study

Introduction The study aimed to clarify associations between height loss, bone loss and the quality of life (QOL) score among general inhabitants of Miyama, a rural Japanese community. This population-based epidemiological study was conducted in Miyama, a village located in a mountain area in Wakayama Prefecture, Japan. Methods A list of all inhabitants comprising 1,543 inhabitants (716 men, 827 women) born in this village between 1910–1949 was compiled. From the above whole cohort, a subcohort to measure bone mineral density (BMD) was recruited, consisting of 400 participants, divided into four groups of 50 men and 50 women each, and stratified into age decades by decade of birth-year (1910–1919, 1920–1929, 1930–1939 or 1940–1949). BMD measurement, physical measurements of height (cm) and body weight (kg) were taken, and body mass index (BMI; kg/m²) were calculated. BMD and anthropometric measurements were repeated on the same participants at 3, 7 and 10 years after baseline measurement (1993, 1997 and 2000). Results and discussion Among 299 of 400 participants, changes in height over 10 years for men in their 40s, 50s, 60s and 70s were −0.7 cm, −0.5 cm, −1.2 cm and −1.5 cm, respectively, compared with −0.7 cm, −1.4 cm, −2.1 cm and −3.7 cm in women, respectively. No significant relationships between change in height and rate of change in BMD at the lumbar spine and femoral neck after adjustment for age in men (lumbar spine, β = 0.058, standard error of the mean (SE) = 0.031, P = 0.501, R² = 0.038; femoral neck, β = 0.100, SE = 0.038, P = 0.228, R² = 0.121) were identified. By contrast, among women, a significant positive association was identified between height change and change rate of BMD at the lumbar spine after adjusting for age (β = 0.221, SE = 0.039, P = 0.012, R² = 0.069), while no significant relationship was found between height change and change rate at the femoral neck (β = 0.107, SE = 0.039, P = 0.229, R² = 0.048). No significant relationship was noted between vertebral fractures (VFx) and height at baseline in men and women (men: odds ratio (OR) 0.93, 95% confidence interval (CI) 0.81–1.05, P = 0.24; women: OR 0.97, 95% CI 0.87–1.08, P = 0.58) or between VFx and height loss (men: OR 1.31, 95% CI 1.00–1.71, P = 0.051; women: OR 1.20, 95% CI 0.94–1.53, P = 0.14). In both men and women, no significant relationship was identified between utility of the EuroQol EQ5D questionnaire and height at baseline (men: β = −0.148, SE = 0.003, P = 0.202, R² = 0.076; women: β = 0.127, SE = 0.004, P = 0.235, R² = 0.048), and height change (men: β = −0.078, SE = 0.008, P = 0.452, R² = 0.065; women: β = 0.053, SE = 0.010, P = 0.608, R² = 0.038).     

Bone mineral density and prevalent vertebral fractures in men and women

To test the hypothesis that the association between bone mineral density (BMD) and estimated volumetric BMD and prevalent vertebral fractures differs in men and women, we studied 317 Caucasian men and 2,067 Caucasian women (average age 73 years). A total of 43 (14%) men and 386 (19%) women had a vertebral fracture identified on lateral spine radiographs using vertebral morphometry. Hip and spine areal BMD was about 1/3 standard deviation lower among men and women with a vertebral fracture. A 0.10 g/cm² decrease in areal BMD was associated with 30–40% increased odds of having a fracture in men and 60–70% increased likelihood in women. Low bone mineral apparent density (BMAD) was also associated with 40–50% increased odds of a vertebral fracture in both genders. The probability of a man having a fracture was observed at higher absolute areal BMD values than observed for women (P=values for interaction of BMD × gender: trochanter, P=0.05; femoral neck, P=0.10; total hip, P=0.09). In contrast, the probability of fracture was similar in men and women across the range of estimated volumetric BMD (BMAD). In conclusion, low BMD and low BMAD are associated with increased odds of vertebral fracture in both men and women. Measures of bone mass that partially correct for gender differences in bone size may yield universal estimates of fracture risk. Prospective studies are needed to confirm this observation.     

Increased bone fracture prevalence in postmenopausal women suffering from pollen-allergy

Introduction Our aim was to investigate whether pollen-allergy can affect bone mass and fractures in postmenopausal women. Methods A total of 125 postmenopausal pollen-allergic women (mean age: 61.26 yr) were split into four groups: (1) treated with neither H1 histamine receptor (H1R) antagonist nor inhaled corticosteroid (n=43); (2) treated only with H1R antagonist (n=53); (3) treated with both H1R antagonist and inhaled corticosteroid (n=17); (4) treated with only inhaled corticosteroid (n=12). Treatment, in the appropriate groups, had occurred for at least 5 years, seasonally. One-hundred non-allergic postmenopausal subjects matched for age, body mass index (BMI), and age at menopause served as controls. Results Overweight and obesity (25 kg/m²≤BMI) were common among the allergic women (76%). Allergic patients without treatment had a slightly lower bone density than their non-allergic counterparts. The rate (34.9%) of prevalent low-energy fractures (distal forearm, hip, and clinical vertebral fractures) in untreated allergic patients was almost triple that observed in non-allergic women (13%, chi² p=0.003). Bone fracture occurred more often in H1R-only treated patients (30.19%) than in controls (chi² p=0.01); however, clinical vertebral or hip fractures developed neither in those treated only with H1R antagonist nor in those who received both H1R antagonist and inhaled corticosteroid. Bone fractures were more frequent among patients with inhaled steroid treatment than among patients with a combined treatment of inhaled steroid and antihistamine (50 versus 29.4%). BMI predicted prevalent fractures at 1.278 (95% CI: 1.047–1.559, p=0.016) for a 1 kg/m² increase among untreated allergic patients. Conclusion In conclusion, we found a high prevalence of low-energy fractures among pollen-allergic postmenopausal women which was associated with obesity. It is possible that the H1R antagonists compensate for both the negative effect of pollen-allergy and the adverse effect of inhaled corticosteroid treatment on bone fracture risk.     

Bone Biomechanical Property Deterioration Due to Tobacco Smoke Exposure

Tobacco smoking has been implicated in the development of osteoporosis and early onset of menopause in women smokers. We measured various biomechanical properties of femurs and tibiae obtained from smoke-exposed and control mice to determine cigarette smoke influences on bone mass, structure, and strength. Growing female C57BL mice were exposed to sidestream cigarette smoke in a whole-body exposure chamber, set at 30 ± 2 mg smoke particulates/m³ for 4 hours/day and 5 days/week for 12 consecutive weeks. Elevated levels of urinary cotinine and pulmonary ethoxyresorufin deethylase activity in smoke-exposed mice confirmed their effective exposure to cigarette smoke. There were no differences in body weight and physical size (length, medial-lateral and anterior-posterior widths, midshaft cortical area and thickness) of femurs and tibiae between smoke-exposed and control mice. The femoral mid-shaft yield load, stiffness, yield stress, and modulus were, respectively 8%, 13%, 10%, and 14% lower (P < 0.05) in smoke-exposed compared to control mice. The ultimate load and stress in mid-shaft femurs showed decreasing trends (P < 0.1) in smoke-exposed mice. In the femoral neck, the ultimate load and stiffness were 9% and 12% lower (P < 0.05) in smoke-exposed mice, respectively. Further, the ash-to-dry bone weight ratio was smaller (∼6%, P < 0.05), and micro-computed tomographic scanning of distal femoral bone volume/total volume (%) and trabecular thickness showed decreasing trends in smoke-exposed mice compared to the control group. We conclude that exposure to tobacco smoke deteriorates some of the biomechanical properties of bone in growing female mice.     

The development of femoral osteopenia in ovariectomized rats is not reduced by high intensity treadmill training: A mechanical and densitometric study

The effect of treadmill running on the development of osteopenia was investigated in adult ovariectomized (OVX) rats compared with sedentary OVX and sedentary sham-operated rats. The rats were 3 months old with a mean weight of 214 g. OVX rats were fed a low calcium diet (0.01%), and the sham rats received the normal diet (1.1% calcium). The training consisted of treadmill running at a speed of 27 m/minute for 1 hour 5 out of 7 days during a period of 8^1/2 weeks. The weight gain was higher in the sedentary OVX (108 g) than in the training OVX (62 g) and sham-operated rats (61 g) (P<0.001). Comparing the two OVX groups, training had no significant effects on the development of femoral osteopenia as assessed by mechanical testing of the femoral shaft and neck, and by bone mass measurements by dual energy X-ray absorptiometry (DXA) or by ashing. Comparing all three groups bone mineral content (BMC) and bone mineral density (BMD) were reduced by more than 40% in both the OVX groups compared with the sham-operated rats (P<0.001). Ash weight and calcium content were reduced by approximately 40% in both OVX groups. Femoral volume and length were 10% higher in the sedentary OVX animals compared with the trained (P<0.05), indicating that the training had had a negative effect on the growth changes induced by ovariectomy. The fracture strength of the femoral shaft was reduced by 26% and 22% in the trained and sedentary OVX rats, respectively compared with the sham-operated group (P<0.001). The fracture strength of the femoral neck was reduced by 18% and 15% but due to one very weak neck in the sham group, this difference was not significant. The accuracy of BMC measured by DXA was high when compared with calcium content (r=0.98, P<0.001) and ash weight (r=0.96, P<0.001). DXA underestimated the BMC of the femur by 27% as compared with ash weight. BMC was also highly correlated to fracture strength of the shaft (r=0.85, P<0.001), but not to fracture strength of the neck. This study shows that high intensity training had no positive effect on the development of osteopenia in rats, and we have also validated and found DXA to be a precise and useful tool for experimental studies on osteoporosis in the rat.     

A new biochemical marker of bone resorption for follow-up on treatment with nasal salmon calcitonin

In a double-blind, placebo-controlled, randomized group comparison, new and specific biochemical markers for bone resorption as follow-up parameters on the therapeutic response to nasal salmon calcitonin (sCT) were evaluated. Evaluation took place at an outpatient clinic where osteoporosis was being researched. The subjects included 208 women aged 68–72 treated for 2 years with either 50 IU, 100 IU, or 200 IU of nasal sCT or placebo; all groups received a daily calcium supplementation of 500 mg. Only 164 women fulfilled the study as valid completers. Markers were applied to frozen urine samples of a previously published intervention study of a new fasting urinary (fU) biochemical marker for bone resorption (CrossLaps^TM, ELISA) and the urinary excretion of cross-links (pyridinoline and deoxypyridinoline) was measured, all corrected for creatinine. Bone mineral density of the lumbar spine and rates of vertebral and peripheral fractures were measured after 2 years of treatment. The creatinine corrected urinary pyridinoline, deoxypyridinoline, and CrossLaps showed maximum decreases of 10–43% (95% confidence interval-29.5% to 9.6% and -75.1% to 9.3%;P < 0.01-0.001) after 6–9 months, after which the response leveled off. A significant difference among the four treatment groups was seen in fU CrossLaps(P < 0.01). The changes in spinal bone mass were significantly related to the decreases in fU CrossLaps: women with the highest response in spinal bone mass had decreases in fU CrossLaps of 44% (-83.5% to 7.4%) and women without response of 5% (-57.6% to 99.9%)P 0.001). In women who fractured during the 2-year period, fU CrossLaps remained unchanged, whereas decreases of 30% (-75.1% to 44.7%) were seen in women who did not fracture(P = 0.002). The results suggest that biochemical markers can be used to determine the optimum treatment regimen of nasal sCT. The response of the new marker, fU CrossLaps, significantly reflects the responses in bone mass of the spine and fracture rates.     

The BPAQ: a bone-specific physical activity assessment instrument

Summary  A newly developed bone-specific physical activity questionnaire (BPAQ) was compared with other common measures of physical activity for its ability to predict parameters of bone strength in healthy, young adults. The BPAQ predicted indices of bone strength at clinically relevant sites in both men and women, while other measures did not. Introduction  Only certain types of physical activity (PA) are notably osteogenic. Most methods to quantify levels of PA fail to account for bone relevant loading. Our aim was to examine the ability of several methods of PA assessment and a new bone-specific measure to predict parameters of bone strength in healthy adults. Methods  We recruited 40 men and women (mean age 24.5). Subjects completed the modifiable activity questionnaire, Bouchard 3-day activity record, a recently published bone loading history questionnaire (BLHQ), and wore a pedometer for 14 days. We also administered our bone-specific physical activity questionnaire (BPAQ). Calcaneal broadband ultrasound attenuation (BUA) (QUS-2, Quidel) and densitometric measures (XR-36, Norland) were examined. Multiple regression and correlation analyses were performed on the data. Results  The current activity component of BPAQ was a significant predictor of variance in femoral neck bone mineral density (BMD), lumbar spine BMD, and whole body BMD (R² = 0.36–0.68, p < 0.01) for men, while the past activity component of BPAQ predicted calcaneal BUA (R² = 0.48, p = 0.001) for women. Conclusions  The BPAQ predicted indices of bone strength at skeletal sites at risk of osteoporotic fracture while other PA measurement tools did not.     

The relationships among bone health, insulin-like growth factor-1 and sex hormones in adolescent female athletes

The aim of this study was to determine the relationships of bone mineral density (BMD) and content (BMC) with insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3) and estradiol in pubertal female athletes. The participants were 170 healthy adolescent girls (13–15 years) who participated in competitive extramural athletic programs, i.e., sports games (n = 49), track sprinting (n = 24), rhythmic gymnastics (n = 23), swimming (n = 24) and cross-country skiing (n = 17). The control group (n = 33) consisted of girls who took part only in compulsory physical education classes at school. The whole-body BMD and femoral neck and lumbar spine BMD and BMC were measured using DXA, and the volumetric BMD was calculated. Venous blood samples to determine the concentration of IGF-1, IGFBP-3 and estradiol were drawn after an overnight fasting. After adjusting for age, body height and body mass, the relationships among BMD variables, IGF-1 and the IGF-1/IGFBP-3 molar ratio remained significant only in the rhythmic gymnast group. BMDs at the femoral neck and lumbar spine were also related to estradiol levels (r = 0.45–0.60; p < 0.05) only in the rhythmic gymnast group. No relationships were found among the measured BMD, IGF axis and estradiol in other athletic groups. Only BMC at the femoral neck remained associated with the IGF-1/IGFBP-3 molar ratio in the rhythmic gymnast group after adjusting for age, body height and body mass. Stepwise multiple regression analysis indicated that IGF-1 and estradiol together explained 42.6% (R ² × 100) of total variance in the femoral neck BMD and IGF-1 alone 35.4% (R ² × 100) of the total variance in the femoral neck BMC only in the rhythmic gymnast group. We conclude that femoral neck and lumbar spine BMD correlated with IGF-1, IGF-1/IGFBP-3 molar ratio and estradiol in rhythmic gymnasts. No relationships were found between bone parameters and the hormones used in other athletic groups.     

Effect of combined administration of vitamin D3 and vitamin K2 on bone mineral density of the lumbar spine in postmenopausal women with osteoporosis

The effect of the combined administration of vitamin D₃ and vitamin K₂ on bone mineral density (BMD) of the lumbar spine was examined in postmenopausal women with osteoporosis. Ninety-two osteoporotic women who were more than 5 years after menopause, aged 55–81 years, were randomly divided into four administration groups: vitamin D₃ (1α hydroxyvitamin D₃, 0.75 μg/day) (D group; n = 29), vitamin K₂ (menatetrenone, 45 mg/day) (K group; n = 22), vitamin D₃ plus vitamin K₂ (DK group, n = 21), and calcium (calcium lactate, 2 g/day) (C group; n = 20). BMD of the lumbar spine (L2–L4) was measured by dual energy X-ray absorptiometry at 0, 1, and 2 years after the treatment started. There were no significant differences in age, body mass index, years since menopause, and initial BMD among the four groups. One-way analysis of variance (ANOVA) with repeated measurements showed a significant decrease in BMD in the C group (P < 0.001). Two-way ANOVA with repeated measurements showed a significant increase in BMD in the D and K groups compared with that in the C group (P < 0.05 and P < 0.001, respectively), and a significant increase in BMD in the DK group compared with that in the C, D, and K groups (P < 0.0001, P < 0.05 and P < 0.01, respectively). These findings indicate that combined administration of vitamin D₃ and vitamin K₂, compared with calcium administration, appears to be useful in increasing the BMD of the lumbar spine in postmenopausal women with osteoporosis. Received: January 13, 2000 / Accepted: June 5, 2000     

Relationships Between Body Composition, Muscular Strength, and Bone Mineral Density in Estrogen-Deficient Postmenopausal Women

The purpose of this study was to examine relationships between muscular strength, body composition, and bone mineral density (BMD) in untrained postmenopausal women who are not on hormone replacement therapy (HRT). Fifty-five women (age: 63.3 ± 0.6 yr) completed menstrual history, physical activity, and calcium intake questionnaires. Total and regional body composition and total body, anteroposterior lumbar spine, nondominant forearm, and right proximal femur BMD were measured using dual-energy X-ray absorptiometry (DXA) (GE Lunar Prodigy, Prodigy enCORE software version 10.50.086, Madison, WI). Participants performed strength tests for 3 upper body and 5 lower body resistance exercises. Women with a relative skeletal muscle mass index (RSMI) value less than 5.45 kg/m² were defined as a sarcopenia group (SAR). SAR had significantly (p < 0.05) lower total body and forearm BMD compared with those who were not sarcopenic. BMD sites were significantly correlated with upper body strength (UBS) and lower body strength (LBS) (r = 0.28–0.50, p < 0.01), with the strength of relationship being site specific. Strength and fat mass (FM) significantly predicted total body BMD (R² = 0.232–0.241, p < 0.05), FM variables predicted spine BMD (R² = 0.109–0.140, p < 0.05), and LBS and RSMI predicted hip BMD sites (R² = 0.073–0.237, p < 0.05). Body composition variables failed to significantly predict LBS. In conclusion, the contribution of body composition and strength variables to BMD varied by site as FM was more important for total body, forearm and spine BMD, and LBS exerted greater influence on the hip sites.