Effect of bone area on spine density in Chinese men and women in Taiwan

Cyclic pamidronate infusion for neonatal-onset osteogenesis imperfecta

BACKGROUND

Patients with severe osteogenesis imperfecta (OI; MIM number 259420) suffer from low bone mass, fractures, and bone pain since birth, and have poor prognosis. This study assessed the outcome of patients with severe OI who were treated with cyclic pamidronate prior to the age of 1 year.

METHODS

The six patients, who had bone fractures either in utero or in their 1st month of life, were treated with cyclic pamidronate from a mean age of 2.8 months.

RESULTS

All the patients tolerated the infusion, except for having transient hypocalcemia at the first infusion. Decreases in irritability and improvements in feeding were observed 2-3 months after the first infusion. All patients showed a rapid increase in bone mineral density over the first 2 years. Fractures occurred at a rate of 0.6/year. At a mean age of 6.4 years, five patients with no interruption in treatment had normal ambulatory function, but they were short in height.

CONCLUSION

Patients with neonatal OI can have a favorable outcome when treated with cyclic pamidronate infusions early in life.

Epidemiology and structural basis of racial differences in fragility fractures in Chinese and Caucasians

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.

Divergent Significance of Bone Mineral Density Changes in Aging Depending on Sites and Sex Revealed through Separate Analyses of Bone Mineral Content and Area

Bone mineral density (aBMD) is equivalent to bone mineral content (BMC) divided by area. We rechecked the significance of aBMD changes in aging by examining BMC and area separately. Subjects were 1167 community-dwelling Japanese men and women, aged 40-79 years. ABMDs of femoral neck and lumbar spine were assessed by DXA twice, at 6-year intervals. The change rates of BMC and area, as well as aBMD, were calculated and described separately by the age stratum and by sex. In the femoral neck region, aBMDs were significantly decreased in all age strata by an increase in area as well as BMC loss in the same pattern in both sexes. In the lumbar spine region, aBMDs decreased until the age of 60 in women, caused by the significant BMC decrease accompanying the small area change. Very differently in men, aBMDs increased after their 50s due to BMC increase, accompanied by an area increase. Separate analyses of BMC and area change revealed that the significance of aBMD changes in aging was very divergent among sites and between sexes. This may explain in part the dissociation of aBMD change and bone strength, suggesting that we should be more cautious when interpreting the meaning of aBMD change.

Bone mineral density discordance and exploration of one of its causes

Discordances between hip and spine areal density T-score values are common and incompletely understood. In a cohort of 1157 postmenopausal women, discordances of greater than 10% occurred in 91%, with spine bone mineral density (BMD) T-scores significantly less negative than femoral neck (FN) T-scores (p<0.001). However, when T-scores based on bone mineral content (BMC) rather than BMD were used, the mean discordance was not significantly different from 0. This was largely because BMC at the FN had seemingly declined with age less rapidly than had BMD at that site. This can be explained by age-related areal expansion at the hip, which would be missed in the reported BMD output. One consequence is that if BMC-based T-scores are used to classify patients, substantially fewer individuals would have been judged osteoporotic in this cohort (two-thirds fewer for spine and three-fourths fewer for hip).

One-year soy isoflavone supplementation prevents early postmenopausal bone loss but without a dose-dependent effect

It is believed that soy isoflavone has much potential effectiveness on the postmenopausal status; however, the optimal dose for preventing postmenopausal bone loss still remains unclear. This open-labeled, self-controlled pilot study was undertaken to determine the effect of 1-year supplementation of different high dosages of soy isoflavone in postmenopausal Taiwanese women. Forty-three women aged 45-67 years were enrolled and randomly assigned into a control (C), 100 mg/day isoflavone (IF100) and 200 mg/day isoflavone (IF200) groups for 1 year. Dual-energy X-ray absorptiometry and other related biochemical markers of bone metabolism were measured. Results indicated that the decrease in bone mineral density (BMD) was significant for lumbar vertebrae L1-3, L1-4 and the femur neck in the C group; surprisingly, the BMD of L1-3 was significantly elevated in the IF100 group; however, there were no consistent responses in the IF200 group. No significant change except loss of the bone mineral content of Ward's triangle (P=.003) was found in the IF200 group after treatment. The percentage change at L1-3 was less (P=.04) in the IF200 group when compared to the IF100 group. A relatively uniform direction of bone formation in expanding the weight and area with different rates of change resulted in different BMD changes. Both indicated a change of bone formation patterns with the higher-dose supplement. A protective effect of IF100 on estrogen-related bone loss was observed. A lack of a benefit such as high safety in the IF200 group for 1-year administration was ensured and lacked undesirable side effects.

Home-based trunk-strengthening exercise for osteoporotic and osteopenic postmenopausal women without fracture--a pilot study

OBJECTIVES

To investigate whether a 12-week home-based programme of trunk-strengthening exercise could benefit spinal mobility, function and quality of life for osteoporotic and osteopenic postmenopausal women without fracture.

DESIGNS

Randomized controlled clinical trial.

SETTING

Department of Physical Therapy in National Taiwan University Hospital.

SUBJECTS

Twenty-eight postmenopausal women (mean age 60.3+/-9.3 years) diagnosed with osteoporosis or osteopenia without fracture history were recruited for this study. Subjects were randomly assigned into exercise or control groups, each consisting of 14 subjects.

INTERVENTIONS

The 12-week exercise programme included strengthening routines for the trunk extensor and flexor muscles. The subjects performed three sets of 10 repetitions for each of the exercises, with programmes carried out three times per day at home.

MAIN OUTCOME MEASUREMENTS

Muscular strength, spinal range of motion (ROM) and motion velocity, Oswestry Disability Questionnaire (ODQ) and quality of life (QOL) were measured before the start and after completion of the exercise programme.

RESULTS

Statistically significant improvements were demonstrated in spinal ROM and motion velocity in the sagittal and frontal planes for the exercise group (p<0.05). Further, the strength of the trunk flexors and extensors increased after exercise training (p<0.05). ODQ measure was significantly reduced in the exercise group (p<0.05), while the controls showed no significant change. Subjects in the exercise group showed better satisfaction in some domains of the Short-Form-36 Health Survey quality of life questionnaire (p<0.05).

CONCLUSIONS

This 12-week home-based trunk-strengthening exercise programme could improve trunk mobility and strength, and enhance QOL in osteoporotic and osteopenic postmenopausal women without vertebral fracture. Future study should recruit more cases or more severe subjects to verify the results.

Race and sex differences and contribution of height: A study on bone size in healthy Caucasians and Chinese

Osteoporosis is characterized by a loss of bone strength, of which bone size (BS) is an important determinant. However, studies on the factors determining BS are relatively few. The present study evaluated the independent effects of height, age, weight, sex, and race on areal BS at the hip and spine, measured by dual-energy X-ray absorptiometry, while focusing on the differential contributions of height to BS across sex, race, and skeletal site. The subjects were aged 40 years or older, including 763 Chinese (384 males and 379 females) from Shanghai, People's Republic of China, and 424 Caucasians (188 males and 236 females) from Omaha, Nebraska. Basically, Caucasians had significantly larger BS than Chinese. After adjusting for height, age, and weight, the Chinese had similar spine BS, but significantly larger intertrochanter BS in both sexes and larger total hip BS in females compared with Caucasians. Males had significantly larger BS than females before and after adjustment in both ethnic groups. The effects of age, weight, and race varied, depending on skeletal site. As expected, height had major effects on BS variation in both sexes and races. Height tended to account for larger BS variation at the spine than at the hip (except for Chinese females), and larger BS variation in Caucasians than in Chinese of the same sex (except for the trochanter in females). We conclude that height is a major predictor for BS, and its contributions vary across sex, race, and skeletal site.

Apparent bone mineral density estimated from DXA in healthy men and women

The aim of this study was to measure bone mineral density (BMD) in healthy people and examine the influence of age, anthropometry, and postmenopause on calculated bone mineral apparent density (BMAD). The study included 541 healthy subjects (249 men and 292 women), aged 20 to 79 years. Anthropometric measurements included height, weight, and body mass index (BMI). Bone mineral content (BMC) and areal BMD were measured at the lumbar spine and proximal femur, using dual-energy X-ray absorptiometry (DXA). The calculation of volumetric density relied on the formula BMAD=BMD/ square root BA (where BA = bone area). Association between densitometric parameters and age, height, weight, and postmenopause was analyzed with multiple regression. BMC and BMD decreased with age, especially in postmenopausal women. The average annual bone loss in spine was 0.2% in both sexes, whereas femur loss was 0.5% in men and 0.3% in women. Bone area slightly increased with age in both sexes, and BMD loss after the age of 50 could be attributed to bone area increase. To minimize the effect of bone size on bone density, volumetric density and areal density were regressed to age, anthropometry, and postmenopause. Age and postmenopause were significantly associated with BMD and BMAD in the spine and femur. Furthermore, BMD showed a stronger association with height and weight than BMAD, in both regions. Weaker association of body height and weight with BMAD than with BMD suggests that BMD depends on the bone size and body size and that the different BMDs could be the consequence of the difference in those parameters.

Severe bone disease and low bone mineral density after juvenile renal failure

BACKGROUND

Little is known about the late effects of juvenile end-stage renal disease (ESRD) on bone integrity. To establish clinical manifestations of metabolic bone disease and bone mineral density (BMD) in young adult patients with juvenile ESRD, we performed a long-term outcome study.

METHODS

A cohort was formed of all Dutch patients with onset of ESRD between 1972 and 1992 at age 0 to 14 years, born before 1979. Data were collected by review of medical charts, current history, physical examination, and performing dual energy x-ray absorptiometry (DEXA) of the lumbar spine and the femoral neck.

RESULTS

Clinical information was retrieved in 247 out of 249 patients. Of all of these patients, 61.4% had severe growth retardation (<-2 SD), 36.8% had clinical symptoms of bone disease, and 17.8% were disabled by bone disease. Growth retardation and clinical bone disease were associated with a long duration of dialysis. DEXA was performed in 140 out of 187 living patients. Mean BMD +/- SD corrected for gender and age (Z score) of the lumbar spine was -2.12 +/- 1.4 and of the femoral neck was -1.77 +/- 1.4. A low lean body mass was associated with a low lumbar spine and a low femoral neck BMD; male gender, physical inactivity and aseptic bone necrosis were associated with a low lumbar spine BMD.

CONCLUSION

Bone disease is a major clinical problem in young adults with pediatric ESRD. Further follow-up is needed to establish the impact of the low bone mineral densities found in these patients.

Additive effect of alfacalcidol on bone mineral density of the lumbar spine in Taiwanese postmenopausal women treated with hormone replacement therapy and calcium supplementation: a randomized 2-year study

OBJECTIVE

To evaluate the effect of 1alpha-hydroxyvitamin D3 on bone mineral density of the lumbar spine in postmenopausal women receiving hormone replacement therapy and calcium supplement.

DESIGN

A randomized, prospective 2-year clinical trial.

PATIENTS AND MEASUREMENTS

A total of 240 postmenopausal women were enrolled with randomized assignment of 120 patients to each treatment group (the D + E group of 1alpha-hydroxyvitamin D3 + sequential combined HRT + calcium supplement; the E group: sequential combined HRT + calcium supplement). None of the patients had received HRT for menopausal syndrome or osteoporosis before being enrolled in our study. Serum biochemical assays, electrolytes and calcitonin were performed at baseline and after 6 and 12 months of treatment. Bone mineral density (BMD) of L2-L4 was measured by dual energy X-ray absorptiometry (DXA) at the initial assessment and after 12 and 24 months of treatment.

RESULTS

One hundred and five patients (87.5%) in the D + E group and 92 patients (76.7%) in the E group completed the first 1-year study. Ninety-six patients (80%) in the D + E group and 80 patients (66.7%) in the E group completed the 2-year trial. Renal function, liver function, electrolytes and calcitonin showed no significant changes during the first year of follow-up. In the D + E group, the BMD of L2-4 increased 3.24 +/- 0.32% from baseline after 1 year (P < 0.05) and 5.32 +/- 0.23% after 2 years of treatment (P < 0.05). On the other hand, the changes of BMD in the E group were 1.12 +/- 0.34% after 1 year (P < 0.05) and 2.42 +/- 0.26% after 2 years of treatment (P < 0.05). The changes of BMD of L2-L4 of the D + E group were higher than the changes of the E group after both 1 and 2 years of treatment (P < 0.05).

CONCLUSIONS

Our study demonstrated that combination of 1alpha-hydroxyvitamin D3 with HRT is superior to HRT alone for the preservation of bone mineral density in postmenopausal women under calcium supplementation.

Effects of gender and age differences on the distribution of bone content in the third lumbar vertebra

STUDY DESIGN

A cross-sectional study on the distribution of bone mineral content in the third lumbar vertebrae.

OBJECTIVES

To evaluate the effects of age and gender on the distribution of bone mineral content in the third lumbar vertebrae.

SUMMARY OF BACKGROUND DATA

Compression fractures occur mainly at the vertebral body. Variations in the distribution of bone mass in a vertebra, if undefined, may bias the ability of the acquired bone mineral density values, which was usually measured posteroanteriorly, to predict the risk of fractures.

METHODS

The bone mineral content of the whole L3, including the L3 vertebral body and the posterior segment, was measured using a lateral approach with a dual energy radiograph absorptiometer on 177 healthy Taiwanese adults including 65 men and 55 premenopausal and 57 postmenopausal women.

RESULTS

The proportion of bone mineral content in the vertebral body was significantly lower in premenopausal women than in age-matched men (39.1 +/- 0.9% vs. 50.0 +/- 1.7%, P < 0.0001). Furthermore, whereas postmenopausal women showed a decreased proportion of bone mineral content in the vertebral body with increased age (about -0.0022 per year, P = 0.0001), premenopausal women and men showed a sustained proportion.

CONCLUSIONS

The proportion of bone mineral content distributed in the body of L3 vertebrae was lower in women than in men. The discrepancy of this parameter between the genders was even larger with increased ages.

Effects of alendronate on osteopenic postmenopausal Chinese women

To evaluate the effects of alendronate on postmenopausal Chinese women with osteopenia, we treated 46 subjects daily with either 10 mg alendronate (N = 24) or placebo plus 500 mg calcium supplement (N = 22), and measured their bone mineral density (BMD) at the lumbar spine and hip, and urinary bone resorption markers before, during, and after the 1 year treatment period. The bone markers included N-telopeptide of type I collagen (NTx) and deoxypyridinoline (Dpd); both were corrected by the concentration of creatinine in the same sample (NTx/Cr and Dpd/Cr). Both NTx/Cr and Dpd/Cr decreased significantly by 44% and 28%, respectively (p < 0.05 for both), in 1 month in the active treatment group but did not change in the placebo group. BMD at the spine, femoral neck, trochanter, and Ward's triangle increased significantly by 6 months and showed a further increase through month 12 at the spine in the alendronate-treated group. Relative to the placebo group, BMD changes at various sites in the alendronate-treated group were higher at 12 months by 6%-11%. Thus, our data suggest that 10 mg alendronate daily resulted in significant increases in spine and hip BMD, and decreases of urinary resorption markers in the osteopenic postmenopausal Chinese women studied. The amplitude of responses was higher than in previous reports in the USA and Europe.