Comparison of bone mineral content among Japanese, Koreans, and Taiwanese assessed by dual-photon absorptiometry

The Prevalence of Osteopenia and Osteoporosis Among Malaysian Type 2 Diabetic Patients Using Quantitative Ultrasound Densitometer

Background:

Type 2 Diabetes Mellitus (T2DM) and osteoporosis are both chronic conditions and the relationship between them is complex.

Objective:

The aims of this study were to assess the prevalence of Low Bone Mineral density (LBMD, i.e., osteopenia and osteoporosis), as well as, the difference and associations between Quantitative Ultrasound Scan (QUS) parameters with socio-demographic data and clinical related data among T2DM in Penang, Malaysia.

Method:

An observational, cross-sectional study with a convenient sample of 450 T2DM patients were recruited from the outpatient diabetes clinic at Hospital Pulau Pinang (HPP) to measure Bone Mineral Density (BMD) at the heel bone using QUS. In addition, a self-reported structured questionnaire about the socio-demographic data and osteoporosis risk factors were collected. Moreover, the study included the retrospective collection of clinical data from patients’ medical records.

Results:

The mean value of T-score for normal BMD, osteopenic and osteoporotic patients’ were (-0.41±0.44), (-1.65±0.39) and (-2.76±0.27), respectively. According to QUS measurements, more than three quarters of T2DM patients (82%) were at high risk of abnormal BMD. The results showed that QUS scores were significantly associated with age, gender, menopausal duration, educational level and diabetic related data. Moreover, the QUS parameters and T-scores demonstrated significant negative correlation with age, menopausal duration, diabetic duration and glycaemic control, as well as, a positive correlation with body mass index and waist to hip ratio. The current study revealed that none of the cardiovascular disease risk factors appear to influence the prevalence of low BMD among T2DM Malaysian patients.

Conclusion:

The study findings revealed that the assessment of T2DM patients’ bone health and related factor are essential and future educational programs are crucial to improve osteoporosis management.

Association between secreted phosphoprotein-1 (SPP1) polymorphisms and low bone mineral density in women

BACKGROUND

A recent meta-analysis found that secreted phosphoprotein-1 (SPP1) can predict the risk of both osteoporosis and fracture. No study has explored the association of SPP1 haplotype-tagging single nucleotide polymorphisms (htSNPs) and haplotypes with bone mineral density (BMD).

METHODS

This is a cross-sectional study. A total of 1,313 healthy Taiwanese women aged 40 to 55 years were recruited from MJ Health Management Institute from 2009 to 2010. BMD was dichotomized into high and low BMD groups. Three common (allele frequency ≥5%) htSNPs were selected to examine the association between sequence variants of SPP1 and BMD.

RESULTS

Homozygosity for the T allele of rs4754 were protective from low BMD [TT vs. CC: adjusted OR (AOR)  = 0.58, 95% confidence interval (CI)  = 0.83-0.89]. A protective effect was also found for women carrying 2 copies of Hap3 TCT (AOR  = 0.57, 95% CI  = 0.34-0.95). Menopausal status marginally interacted with SPP1 rs6839524 on BMD (p = 0.049). Postmenopausal women carrying variant rs6839524 (GG+GC vs. CC: AOR  = 2.35, 95% CI  = 1.06-5.20) or Hap1 TGC (AOR  = 2.36, 95% CI  = 1.06-5.24) were associated with 2.4-fold risk of low BMD. For women with low BMI (<18.5 kg/m2), variant rs6839524 (AOR  = 7.64) and Hap1 (AOR  = 6.42) were associated with increased risk of low BMD. These findings did not reach statistical significance after correction for multiple tests.

CONCLUSIONS

SPP1 htSNP protected against low BMD in middle-aged women. SPP1 genetic markers may be important for the prediction of osteoporosis at an early age.

Bone mineral density of the femoral neck is increased after successful lumbar spine surgery: a 2-year prospective analysis

STUDY DESIGN

Prospective study.

OBJECTIVE

To determine whether or not lumbar spine surgery increases bone mineral density (BMD) of the vertebral body and/or the femoral neck, and if it is in fact related to an increase of postoperative BMD. This study was further designed to analyze the factors involved in the BMD increase.

SUMMARY OF BACKGROUND DATA

Long-term immobilization results in bone loss. Inactive patients who are bedridden or restricted to wheelchair mobility may have a low BMD due to immobilization. Successful lumbar spine surgery improves the activities of daily living. Thus, it might lead to an increase in BMD of the body.

METHODS

Forty-seven Japanese patients, older than 60 years, who had lumbar spine surgery in the period from January to December 2009 were included. BMD of the vertebral body and the femoral neck was measured by dual-energy x-ray absorptiometry preoperatively and at 1 and 2 years after surgery, respectively. The surgical results and activities of daily living were evaluated by the Japanese Orthopaedic Association score. Walking ability was evaluated using the Nurick scale.

RESULTS

The average preoperative BMD of the lumbar spine and the femoral neck gradually decreased postoperatively. BMD of the femoral neck in the excellent group, according to the postoperative Nurick scale, had increased at the 2-year follow-up period. There were significant differences in the percent change of BMD of both the vertebral body and the femoral neck among the groups that was categorized by the postoperative Nurick scale grades.

CONCLUSION

Successful lumbar spine surgery might increase BMD of the femoral neck. The percent change of BMD of both the vertebral body and the femoral neck was related to postoperative walking ability.

LEVEL OF EVIDENCE

3.

Reference data for quantitative ultrasound values of calcaneus in 2927 healthy Chinese men

Quantitative ultrasound (QUS) is a bone densitometry technique that is rapidly gaining popularity for the assessment of bone status. However, few QUS data are available for men, especially in China. In the present study, a random stratified sample of 2927 Chinese men (10-90 years) was recruited, and bone status was established using measurements by Achilles ultrasonometer. The peak stiffness index (SI) value for Chinese men was 103.0 +/- 20.8, which presented in the age group of 20-24 years. Pearson correlation analysis showed that there was significant correlation between SI and age (P < 0.001), and multivariate regression analysis indicated that weight was also an important factor for SI. In addition, in comparison with the normal data of Italian and Japanese males, the SI value for Chinese males in each age group was lower than those of Italians but higher than Japanese, except for the 20-29 years age group. The descending velocity of curves for Chinese men was lower than that of Italian and Japanese men. In conclusion, QUS values of the calcaneus provided by the present study may be used as normal reference values for Chinese men.

Comparison of spine and femur reference data in native Chinese women from different regions of China

The aim of this study is to explore the differences of BMD reference curves at various skeletal sites among Chinese women from different regions of China and to investigate the feasibility of establishing a unified national BMD reference database for Chinese women. We measured BMD at the posteroanterior (PA) lumbar spine, femoral neck, trochanter and Ward's triangle by dual-energy X-ray absorptiometry bone densitometer in 3,422 Changsha women of South Central China, aged 20-84 years. The documented BMDs of reference populations of women in all other areas included Shanghai ( n =2,111) and Nanjing ( n =3,174) in the East, Shenyang ( n =1,213) in the Northeast, Kunming ( n =523) in the Southwest, Chongqing ( n =811) in the Midwest and Xian ( n =1,320) in the Northwest. We adopted the cubic regression as the fitting model for reference curves of BMD that varied with age, conducted conversions of BMD measured by various bone densitometers from different manufacturers and compared the differences between standardized BMD (sBMD) reference curves and combined ones for women from different areas. Our results revealed that by comparing variances in women from different areas, the average variances of non-standard BMD were 0.8-30.8% at the PA spine, 0.7-24.5% at the femoral neck, 0.6-29.9% at the trochanter and 1.1-54.7% at Ward's triangle, while average variances of sBMD either significantly decreased or disappeared (0.8-3.9% at the PA spine, 0.7-8.6% at the femoral neck, 0.6-8.3% at the trochanter and 1.1-29.9% at Ward's triangle). The sBMD reference curves were highly positive-dependent with combined ones ( r =0.913-0.999, P =0.000). At the PA spine and trochanter, the effect of combined sBMD curves presented well in women from different areas, except for those from Shanghai at the PA spine and Shenyang at the trochanter, indicating that sBMD curves were significantly different from pooled ones; at the femoral neck and Ward's triangle, the effect of combined sBMD reference curves was poor, indicating that sBMD curves demonstrated significant differences from pooled ones in women from a majority of these areas. We conclude that, in high density population areas, sBMD reference curves showed no significant geographic differences in women from various regions. In women from different areas, sBMD reference curves present good pooled results at the PA spine and trochanter. The less ideal combining effect of the sBMD curves at both femoral neck and Ward's triangle might be caused by the intrinsic differences from the different measuring instruments.

Relationship of body surface area with bone density and its risk of osteoporosis at various skeletal regions in women of mainland China

The aim of this study was to investigate the relationship between body surface area (BS) and bone mineral density (BMD) and the associated osteoporosis risk at various skeletal regions in women from mainland China. BMD was measured at the posteroanterior (PA) spine (L1-L4), supine lateral spine (L2-L4) including volumetric BMD (vBMD), hip including femoral neck, trochanter and total hip, and forearm, including radius + ulna ultradistal (R + UUD), 1/3 site (R + U1/3) and total region (R + UT) using a dual-energy X-ray absorptiometry (DXA) fan-beam bone densitometer (Hologic QDR 4500A) in 3418 females aged from 18 to 75 years. Data analysis revealed a positive correlation between BS and BMD at the various skeletal regions (r = 0.114-0.373, all P = 0.000), but no correlation with vBMD (r = 0.000, P = 0.934). Using the stepwise regression model, BMDs at various skeletal regions were dependent variables while height, weight, body mass index (BMI), BS and projective bone area (BA) were independent variables; BS was determined to be the most important variable that affected the PA spine, hip and forearm BMDs. Subjects were divided into three groups according to size: large BS group (LBSG), intermediate BS group (IBSG) and small BS group (SBSG). The BMD at different skeletal regions of subjects between groups exhibited a significant gradient difference, with LBSG > IBSG > SBSG, but this was not seen for vBMD. On the fitting curves where BMD varied with age at the PA spine, femoral neck, total hip and R + UUD, BMDs of LBSG were 6.93-9.29% higher than those of IBSG and 12.1-16.9 % higher than those of SBSG, whereas those of SBSG were 6.12-9.59% lower than those of IBSG at various skeletal regions, respectively. The prevalence rates and risks of osteoporosis of LBSG were significantly lower than those of SBSG and IBSG, whereas those of IBSG were obviously lower than those of SBSG at various skeletal regions, respectively, presenting a gradient difference among the three study groups, LBSG < IBSG < SBSG. Our study shows that the relationship between BS and BMD exceeds that between BMD and height or weight in women in mainland China. When areal BMD is employed, those with a larger BS have higher areal BMD and lower risks of osteoporosis while, conversely, those with a smaller BS have lower areal BMD, and therefore higher risk for osteoporosis. However, when vBMD is used, these differences diminish or even disappear.

Epidemiology worldwide

Osteoporosis is a global problem that will increase in significance with the growing elderly population. The condition affects both sexes and all races, albeit to different degrees. This article reviews the epidemiology of osteoporosis as it relates to age, sex, ethnicity, and other risk factors and makes projections for the future as populations continue to age worldwide.

Reduced bone mineral density in Japanese premenopausal women with systemic lupus erythematosus treated with glucocorticoids

Abstract We evaluated bone mineral density (BMD) in Japanese female patients with systemic lupus erythematosus (SLE) and assessed the influence of the use of glucocorticoids. Lumbar BMD was measured by dual x-ray absorptiometry (DXA) in 60 premenopausal females who previously had been receiving glucocorticoid therapy. Therapeutic- and disease-related variables for SLE were analyzed and bone resorption or formation markers were measured. Osteoporosis was defined as a T-score below 2.5 SD by DXA; 12 patients (20%) showed osteoporosis, and 30 (50%) had osteopenia. Compared with the nonosteoporotic group (n = 48), the osteoporotic group (n = 12) had a significantly longer duration of glucocorticoid treatment (P = 0.01), a cumulative prednisolone dose (P = 0.002), and an SLE damage index (SLICC/ACR). There was no difference in the incidence of osteoporosis either with or without the previous use of methyl-prednisolone pulse or immunosuppressive drugs. There was a significant positive correlation between urinary type I collagen cross-linked N-telopeptides (NTx) and serum bone-specific alkaline phosphatase (BAP) (r = 0.404, P = 0.002), but these bone metabolic markers showed no difference between the osteoporotic and nonosteoporotic groups. A good significant negative correlation was shown between BMD and the cumulative glucocorticoid dose (r = -0.351, P = 0.007). Stepwise logistic regression analysis showed that the cumulative glucocorticoid intake was independently associated with osteoporosis. Glucocorticoid-induced osteoporosis was frequently observed in Japanese SLE patients, as in Caucasian populations. The cumulative glucocorticoid dose was associated with an increased risk for osteoporosis. Bone metabolic markers such as NTx and BAP were not influenced by glucocorticoid treatment and could not predict current osteoporosis in SLE patients.

Evaluation of bone mineral density by quantitative ultrasound of bone in 16,862 subjects during routine health examination

Caucasians and Asians are among those with the highest risk for involutional osteoporosis. To obtain accurate data about the prevalence of osteoporosis or osteopenia in different age groups, a large epidemiological study is necessary. Quantitative ultrasound (QUS) of bone is a promising technique in assessing bone microarchitecture in addition to bone mass. This study had two aims. The first was to establish bone mineral density (BMD) using QUS in subjects with no obvious disease undergoing routine health examination. The second was to determine risk factors for osteoporosis in Taiwan in order that better prevention and treatment measures may be provided for these patients. A prospective study of the risk factors for fracture was conducted in the health examination division of Chang Gung Medical Center in Linkou, Taiwan, from January 1996 to December 1997. Broadband ultrasound attenuation of the right heel was measured with an achilles bone densitometer (Lunar, Nauheim, Germany). A total of 16,862 subjects were examined, including 9,314 women (mean age 51.5+/-11.7 years) and 7,548 men (mean age 51.1+/-12.1 years). The incidence of osteoporosis in all subjects increased from 1.13% in the 21--30-year-old age group to 54.55% in those over 80 years of age. 12.02% of the subjects had osteoporosis and 34.45% had osteopenia. From multivariate analysis, bone density evaluated by QUS showed a relationship with age, gender, body mass index, waist/hip ratio, smoking and frequency of exercise. In conclusion, BMD evaluated by QUS is not found to be higher in Taiwan than elsewhere. The role of QUS in predicting fractures in Taiwan requires further investigation.

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

Areal bone mineral density (BMD), the quotient of bone mineral content (BMC) divided by the projectional bone area (BA), measured with dual-energy X-ray absorptiometers (DXA), is the most common parameter used today to evaluate spinal osteoporosis. To evaluate whether gender, age, weight, and height can determine spinal BA, and to compare BA and analyze its effects on spinal density in the two genders, we measured BA and BMC, and calculated areal BMD, and the bone mineral apparent density (BMAD = BMD/the square root of BA) of the L-2 to L-4 vertebrae of 604 female and 223 male Chinese volunteers from 20 to 70 years of age using a Norland XR-26 DXA. Standardized for height and weight, BA showed a relatively large variation and a significant increase with increasing age in both genders. On the other hand, BMC stayed unchanged in men > 50 years of age and decreased with aging in postmenopausal women. Younger men (< 51 years) had a much larger mean BA (by 15.5%) and larger mean BMC (only 10%) than that of age-matched women. As a result, younger men had a slightly and significantly lower areal BMD (by 7.1%) and a much lower BMAD (by 16%) (p < 0.0001 for both) than premenopausal women of similar age. Men had higher areal BMD and BMAD values than age-matched women only after age 50 years. Although taller body height, heavier weight, and increasing age were associated with a larger BA, these factors could not explain most of the interindividual variations in BA in both genders. Thus anteroposterior BA of lumbar vertebrae measured with DXA seems to affect the areal BMD and BMAD readings in the two genders. The larger BA caused a low BMAD and probably underestimated the true volumetric spine density in men.

Whole body bone, fat and lean mass in children: comparison of three ethnic groups

We measured whole body bone, fat and lean mass, by dual-energy x-ray absorptiometry, of third-grade children in a suburban public school district adjacent to Detroit. Of 1,340 eligible children, 773 participated. Using U.S. Census categories, parents identified their children as black/African-American (57%), white (38%), or one of several other categories (5%). Some of the participants also identified with a relatively large Middle Eastern subgroup (Chaldeans). Of the 773 participants, 734 are included in this report (71 Chaldeans, 226 whites, and 437 black/African-Americans; other categories are omitted). We describe body size, body composition, and physical activity levels in the three groups. The Chaldean and black children have significantly higher average whole body bone mineral content (BMC) than whites (P > 0.05), but are not different from each other. Lean mass and height are significantly greater for Chaldeans and blacks than for whites. The ratio of BMC to height was also significantly greater in Chaldeans and blacks compared with whites. Chaldeans have a significantly higher weight and fat mass than either the black or white children, and report significantly less physical activity than either the white or the black children. The higher bone mass among the Chaldean children may be partially explained by their greater body mass, but there is no readily apparent explanation for the observed ethnic differences in body size. We cannot exclude genetic or environmental factors not evaluated in this observational study. Our unexpected finding that Chaldean children, when analyzed as a separate group, are more similar in body composition to black/African-American than to white children contributes to a growing body of literature indicating that the uncritical use of "race" categories may obscure rather than facilitate the identification of population differences.

Bone densitometry of proximal femur in Chinese subjects: gender differences in bone mass and bone areas

Bone mineral content (BMC), bone areas (BA), and bone mineral density (BMD) of the proximal femur were measured in 202 healthy Chinese men and 507 healthy Chinese women, aged 21-70 years, to investigate gender differences in densitometry of the femur. Densitometric values measured at the femoral neck, trochanter, and Ward's triangle were generally greater in men than women of the same age, except at Ward's triangle. While BMD decreased with aging with similar slopes of -0.2 approximately -1% per year, the actual readings were 10%-15% lower than those of Caucasian subjects of the same age and gender for Chinese men and women. Furthermore, with increasing age, trochanteric BA increased in women but not in men, and femoral neck BA increased in men but not in women. These different trends of change in bone dimensions were independent of weight or height. They may reflect a structural difference at the proximal femur and imply differences in mechanical strength, and thus may have played some roles in the different incidence of hip fractures between the elderly men and women.

Risk of underestimation of the bone mineral density of proximal femur

Decreased bone mineral density (BMD) in the elderly increases the risk of hip fracture. Measurement of proximal femoral BMD can help us predict the risk of hip fracture, especially in the elderly. Since the BMD of proximal femur is usually measured on the unilateral side, we studied the risk of underestimation with measurement of unilateral proximal femur BMD in 266 normal Chinese women. In order to evaluate the effect of age, these subjects were divided into group A (18-59 years, n = 189) and group B (60-88 years, n = 77). BMDs of both proximal femurs were assessed with Norland 2600 dual photon absorptiometry. Using a cutoff T score of -1, the negative predictive value (NPV) in the entire group was 86.9% for femoral neck BMD and 85.7% for trochanter, and 82.2% for Ward's triangle: in group A, the NPV was 88.9% for femoral neck, 88.8% for trochanter, and 97.2% for Ward's triangle, but in group B, the NPV was 60.0% for femoral neck, 71.0% for trochanter, and 24.1% for Ward's triangle. The accuracy in the entire group was 86.1% for femoral neck, 84.2% for trochanter, and 86.3% for Ward's triangle: in group A the accuracy was 84.6% for femoral neck, 84.9% for trochanter, and 92.8% for Ward's triangle, but in group B, the accuracy was 89.6% for femoral neck, 81.7% for trochanter, and 90.0% for Ward's triangle. In general, NPV and accuracy increased at the expense of positive predictive value when the cutoff T score was changed to -2.5. This study suggested that measurement of unilateral proximal femur BMD was sufficient for screening the contralateral hip BMD in group A at a cutoff T score of -1. However, a T score of -2.5 was recommended for group B, and one should be careful in its application to Ward's triangle.

Body mass is the primary determinant of midfemoral bone acquisition during adolescent growth

To study the determinants of bone mass and structure during adolescence, we analyzed the femoral mid-diaphysis of 375 healthy adolescents and young adults, ages 9-26 years, from four ethnic cohorts (African-American, Asian-American, Caucasian, and Hispanic). Whole-body dual-energy X-ray absorptiometry (DXA) scans were used to determine diaphyseal length and mid-diaphyseal diameter of the left femur, as well as linear bone mineral content (BMCL) of a region at the mid-diaphysis. Cross-sectional geometric properties were estimated and used to calculate two structural strength indicators: the section modulus and the whole bone strength index. When the relationships between the bone measurements and age, pubertal group, height, or body mass were evaluated, all cross-sectional femoral measures correlated most strongly with body mass. Multiple regressions accounting for gender and ethnicity provided little additional predictive value over the simple regressions with body mass alone. Furthermore, accounting for all developmental parameters (age, pubertal group, body mass, lean body mass, calcium intake, physical activity level) as well as ethnicity and gender in a single saturated model also did not generally significantly improve the predictive results achieved using only body mass. Our results indicate that increases in midfemoral bone mass and cross-sectional properties during adolescence are primarily related to increases in mechanical loading as reflected by body mass.

The epidemiology of osteoporosis. The oriental perspective in a world context

In the past 3 decades, the incidence of osteoporotic hip fracture increased in Hong Kong Chinese by 2-fold to reach an incidence of approximately 10 per 1000 in women and men who are 70 years of age or older. It has been projected that 50% of all hip fractures in the world will occur in Asia by the next century. The bone mineral density of Asian populations is comparable to that of whites after adjusting for height and weight. Physical inactivity, a low dietary calcium intake, and falls have been found to be major risk factors for hip fractures in Asia. Other risk factors are cigarette smoking, heavy alcohol consumption, and multiparity. Population strategies to increase physical activity and calcium intake and to prevent falls in Oriental populations will be effective in the prevention of osteoporosis and hip fracture because of the high attributable risk for these factors.

Genetic variability in adult bone density among inbred strains of mice

More than 70% of the variability in human bone density has been attributed to genetic factors as a result of studies with twins, osteoporotic families, and individuals with rare heritable bone disorders. We have applied the Stratec XCT 960M pQCT, specifically modified for small skeletal specimens, to analyses of bones from 11 inbred strains (AKR/J, BALB/cByJ, C3H/HeJ, C57BL/6J, C57L/J, DBA/2J, NZB/B1NJ, SM/J, SJL/BmJ, SWR/BmJ, and 129/J) of female mice to determine the extent of heritable differences in peak bone density, pQCT scans were taken of femurs from (a) 12-month-old inbred strain females and (b) a subset of four strains (C3H/HeJ, DBA/2J, BALB/cByJ, C57BL/6J) at 2, 4, and 8 months. In addition, pQCT scans were also obtained from L5-L6 vertebrae and proximal phalanges from the same subset of four inbred strains at 12 months of age. Comparison of bone parameters among inbred strains revealed significant differences at each of the three sites investigated. Femoral and phalangeal bones differed among strains with respect to total and cortical density, mineral, and volume. Only cortical bone parameters were significantly different among strains at the vertebral site. With respect to strain differences, the highest value for any given bone parameter was found in the C3H/HeJ strain, whereas C57BL/6J values were absolutely, or statistically, the lowest. Similarly, with respect to bone sites, cortical bone density was significantly correlated among strains. On the other hand, we found that none of the femur, vertebral, or phalangeal parameters correlated with body weight, even though body weight varied by 86% among those inbred strains. The developmental studies of femurs conducted at 2, 4, and 8 months of age with C3H/HeJ, DBA/2J, BALB/cByJ, and C57BL/6J females showed differences in total density among strains at 2 months and thereafter. Adult peak bone density was typically achieved by 4 months, whereas femurs continued to lengthen for 4 to 8 months thereafter. We conclude that (1) major genetic effects on femoral, vertebral, and phalangeal bone density are detectable among inbred strains of mice; (2) cortical bone density shares common genetic regulation at the three measured sites; and (3) within the femur, genes that regulate length and density are different.

Epidemiology of hip fractures: implications of the exponential increase with age

Of the fractures linked with osteoporosis, hip fractures are most important in terms of death, functional dependence, and social cost. Reduction of these adverse outcomes depends on preventing hip fractures, which are caused by falling on a biomechanically compromised proximal femur. Skeletal strength depends on the amount of bone and its structural arrangement, whereas the traumatic load on the proximal femur is dictated by the orientation of the fall and other factors. One or several of these underlying mechanisms account for the various risk factors that have been identified for hip fracture, including greater incidence rates among women than men and among white than nonwhite populations. However, the exponentially increasing incidence of hip fractures with age indicates that a complex interplay of factors determines the risk of fracture in each person. The multifactorial nature of the problem suggests that hip fractures will be difficult to prevent even as the fractures and their associated costs continue to rise with the increased number of older people. However, the variability of hip fracture rates within high risk populations in Europe and North America reflects the existence of other powerful risk factors that, if identified, might provide the basis for more effective interventions.

Evolution of spinal bone loss and biochemical markers of bone remodeling after menopause in normal women

The main objective of this study was to describe longitudinal patterns of spinal bone loss in normal women who undergo a natural menopause. The second objective was to determine if a proportion of women suffer excessively rapid postmenopausal bone loss from the spine. If this was the case it was the aim to devise a means of predicting the woman at excess risk; but if all women lost bone at similar rates, the aim was to document changing loss rates over the first 5-8 postmenopausal years. Responding women in six suburban general practices recalled for cervical smears who had their last menstrual period 9- 36 months previously were invited to participate in a longitudinal study of bone loss and the biochemical markers plasma osteocalcin and urinary hydroxyproline. Sixty-four subjects agreed to participate, a response rate of 80%. In the ensuing 5 years, six received hormone replacement therapy and are not reported on. The main outcome measures were rates of spinal bone loss over 5 years, measured by dual photon absorptiometry, and radial bone loss over the first 2 years measured to quantitative computed tomography. Spinal bone loss was similar between individuals, with 94% of the variability in the data being accounted for by a statistical model that assumed parallel rates of bone loss. A less restrictive model allowing women to have different rates of spinal bone loss accounted for 12% more of the remaining variance in the data than the previous model. However, rates of radial bone loss were more dissimilar between women than rates of spinal loss. The results of the biochemical data collected serially showed that the plasma osteocalcin rose slowly to a plateau at 5 years postmenopause; in contrast, the hydroxyproline fell progressively with time over the whole period of study. These results were interpreted as being consistent with diminishing rates of bone destruction which gradually reequilibrated with bone formation as time passed after menopause.

Menopause-related changes in bone mineral density in Japanese women: a longitudinal study on lumbar spine and proximal femur

We investigated 2-year longitudinal changes of bone mineral density (BMD) in lumbar spine and proximal femur in 64 Japanese women aged 38-67. Forty subjects were premenopausal (mean age 44.9) and 24 postmenopausal (mean age 54.6) at enrollment of the study. Six subjects experienced menopause during the 2-year study period and were defined as the perimenopausal group. Measurements of BMD were performed using dual-energy X-ray absorptiometry at L2-4, femoral neck, greater trochanter, and Ward's triangle. Paired t test revealed no significant decrease in BMD at any site in the premenopausal group. Significant annual decrease in BMD was observed in the perimenopausal group at L2-4, femoral neck, and greater trochanter. A similar tendency was observed in Ward's triangle, but did not reach statistical significance. In the postmenopausal group, significant decrease in BMD was found at the proximal femur, but not at L2-4. Significant inverse correlation between age and change rate of BMD was found at L2-4, but not at the proximal femur, in premenopausal women. In postmenopausal women, there was a significant association between body weight (BW) change and change rate in BMD at L2-4, femoral neck, or greater trochanter. This association was not found in the premenopausal group. These results suggest that effect of menopause on BMD may be different in individuals and sites of the skeleton. BW change may affect change in BMD in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

Premenopausal and postmenopausal changes in bone mineral density of the proximal femur measured by dual-energy X-ray absorptiometry

Total and regional bone mineral density (BMD) of the proximal femur was measured by DXA in 1238 healthy white women. In the 389 premenopausal women, aged 21-54 years, no bone loss was observed before the menopause, except in the femoral neck and Ward's triangle, in which BMD decreased by 0.3%/year (SEE 0.2-0.9%/year, p < 0.001) and 0.6%/year (SEE 0.4-0.8%/year, p < 0.001), respectively. In the postmenopausal women aged 48-75 years, there was a highly significant exponential decay in BMD with age and years since menopause (YSM) in all regions (-0.58 < r < -0.48, p < 0.001). However, YSM was a better predictor of BMD than age. The decrease in BMD in the first 5 years postmenopause reached values of 9-13%. The estimated bone loss after 20 years was 17-30%, greatest in Ward's triangle and smallest in the intertrochanteric region. BMD correlated highly significantly with BMI (0.26 < r < 0.48, p < 0.001). In conclusion, the present study indicates a stable premenopausal bone mass of the proximal femur and a postmenopausal bone loss, which is influenced mainly by YSM within the first 10-15 years after menopause. BMD correlated with body mass index (BMI) in the postmenopausal years, confirming that low BMI constitutes a potential risk factor for osteoporosis.

Femoral and spinal bone mineral density in Japanese osteoporotics with hip fracture

In the present study, bone mineral density (BMD) of femoral neck and lumbar spine was compared between 38 Japanese female patients with hip fracture (age 63-89 years, mean +/- SD 76 +/- 7 years) and 162 age-matched female controls (age 62-90 years, mean +/- SD 75 +/- 7 years). BMD was measured in the femoral neck and lumbar spine (L2-4) using dual-photon absorptiometry (Norland model 2600). BMD values of femoral neck as well as lumbar spine were significantly lower in patients with hip fracture than in controls (0.504 +/- 0.097 v 0.597 +/- 0.101, p < 0.01, for femoral neck; 0.661 +/- 0.146 v 0.720 +/- 0.128, p < 0.05, for lumbar spine). Patients with hip fracture and controls were stratified according to their BMD levels at two measuring sites, and the ratio of the number of patients and controls at each BMD level was calculated as an indicator of fracture rate. This ratio showed an exponential increase as the femoral neck BMD declined, but only a gradual increase as the lumbar spine BMD declined. Specificity-sensitivity analysis revealed that BMD values of 0.59 and 0.54 g/cm2 at the femoral neck provided a specificity of 52% and 68% with a sensitivity of 90% and 75%, respectively. These findings suggest that Japanese patients with hip fracture are more osteoporotic than age-matched controls and that the selective measurement of femoral neck would be useful for predicting the risk of hip fracture.

Radial bone mineral content of normal Japanese infants and prepubertal children: influence of age, sex and body size

The present study was performed to measure appendicular bone mass of Japanese infants and children, and to assess the influence of age, sex and body size on bone mass during the period of bone growth. The bone mineral content (BMC) and bone width (BW) at the distal third of the radius were measured by single photon absorptiometry (SPA) in 229 healthy Japanese infants and children aged 0-12 years, and the BMC/BW ratio was calculated to give the bone mineral density (BMD). BMC and BW increased with age until 2 years, while BMD did not obviously change until 2 years. After 2 years of age, the overall effect of aging appeared more prominent in BMC and BMD than in BW. There were no significant differences in BMC, BW and BMD between males and females aged 0-12 years. Age, body height, and body weight were strongly correlated with three parameters of bone mass (BMC, BW, and BMD). Among the three parameters of bone mass, BMC showed the highest Pearson coefficient of correlation with age (r = 0.955), body height (r = 0.957) and body weight (r = 0.966), as compared with BW and BMD. The present cross-sectional study provides normative data of the appendicular bone mass in healthy Japanese children, which may serve as a standard for assessment of bone mineralization in Japanese infants and children with medical problems.

Ethnic and genetic differences in susceptibility to osteoporotic fractures

A plethora of investigations in recent years has demonstrated the occurrence of ethnic differences in bone mineral content, bone density and fracture rates. These findings indicate that genetic determinants exist both for bone development during growth and for bone loss during aging. Twin and parent-offspring studies have corroborated the existence of a hereditary component. It is most evident in the greater bone mass and lower fracture rate in blacks than in whites. Differences in bone mass between Asians and whites are less clear than between blacks and whites because of disparities in body size and other confounding factors. Black children and adults excrete less urinary calcium than whites on essentially the same diets and consequently retain more calcium in their skeletons. Better calcium retention is commensurate with the faster rate of bone growth of black children.

Age- and gender-related changes in body composition in Japanese subjects

Age-dependent changes in body composition, namely a decrease in bone mass and lean mass and a reciprocal increase in fat mass, are often observed in normal populations. The recent development of dual-energy x-ray absorptiometry (DXA) made it possible to analyze bone mineral content (BMC), fat mass (fat), and lean body mass (LBM) more precisely and easily. We measured BMC, fat, and LBM in Japanese subjects by DXA to describe the changes in body composition with aging in the Japanese population. A total of 34 female (aged 20-74) and 34 male (aged 18-78) volunteers were divided into three groups according to their age: young (18-22 years), middle-aged (39-48 years), and old (61-78 years). Mean values for body height (BH), body weight (BW), and body mass index (BMI) of the subjects were very similar to Japanese normative values. The BMI of the middle-aged group was the highest of all groups of both sexes. BMC decreased significantly with aging in females but not in males. A decrease in LBM and a reciprocal increase in fat were found between young and middle-aged males but not in females. The correlation between BMC and LBM tends to be greater in males than in females. On the other hand, the correlation between BMC and fat was greater in females than males. These results demonstrate the age- and gender-related difference in body components in Japanese subjects. DXA may be useful for the analysis of body composition in different age and sex groups.

Pre- and postmenopausal bone mineral density of the spine and proximal femur in Japanese women assessed by dual-energy x-ray absorptiometry: a cross-sectional study

To investigate the influence of menopause on bone mineral density (BMD) of Japanese women, BMD of the spine and proximal femur was measured by dual-energy x-ray absorptiometry (DXA) in 220 premenopausal and 166 postmenopausal Japanese women. The peak bone density of the spine in premenopausal women was detected between 35 and 39 years of age, and that of femur before 20. Thereafter spinal and femoral BMD showed a slight decrease, but they did not show a significant decrease until menopause or menstruation became irregular. Duration of substantial bone loss at lumbar spine continued for about 10 years after menopause, but that at the femur was much longer. To investigate the effect of early menopause on bone loss, postmenopausal women were divided into two groups according to the age at onset of menopause. The BMD of postmenopausal women whose menopause occurred before 50 was significantly less over the latter part of life than that of women whose menopause occurred after 50. These results suggest that bone loss is related to menopause or irregular menstruation rather than age per se, and early menopause should be recognized as one of the risk factors for involutional osteoporosis.

Hip fractures: a worldwide problem today and tomorrow

Hip fractures lead to excess deaths and substantial disability. Most are related both to falls and to osteoporosis, which affects one in four post-menopausal white women, but a lesser number of men or women of other races. Consequently, about half of the 1.66 million hip fractures worldwide in 1990 occurred in Europe and North America. Even within these regions, however, there is substantial variation in hip fracture incidence rates, which suggests the existence of important environmental factors that could be manipulated to reduce hip fracture occurrence. This is important because in the United States alone, a quarter of a million hip fractures annually cost over $8 billion, mostly for acute medical care and nursing home services. Future costs will be even greater because populations are ageing rapidly around the world and because hip fracture incidence rates are rising in some regions. The number of elderly is increasing most rapidly in Asia, Latin America, the Middle East, and Africa, and these regions will account for over 70% of the 6.26 million hip fractures expected in the year 2050. Because fracture treatment is expensive, and rehabilitation not always successful, effective prophylaxis offers the only hope of alleviating the enormous social burden of hip fractures.