Bone mineral density of the spine and femur in healthy Saudis

The reference values of bone mineral density (BMD) were determined in healthy Saudis of both sexes and compared with US / northern European and other reference data. BMD was determined by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and femur including subregions: trochanter, Wards triangle, and neck, in 1,980 randomly selected Saudis (age range 20–79 years; 915 males and 1,065 females) living in the Jeddah area. Age-related changes in BMD were similar to those described in US / northern European and Lebanese reference data. Decreases in BMD of males were evident (% per year): 0.3–0.8 (lumbar spine), 0.2–0.4 (femoral trochanter), 0.2–1.4 (Wards triangle), and 0.2–0.7 (femoral neck). Also, decreases in BMD of females were observed (% per year): 0.8–0.9 (lumbar spine), 0.7–0.9 (Wards triangle), and 0.3–0.7 (femoral neck). Using stepwise multiple regressions that included both body weight and height, the former had 2–4 times greater effect on BMD than the latter. Using the mean BMD of the <35-year-old group the T-score values were calculated for Saudis. The prevalence of osteoporosis in Saudis (50–79 years) at the lumbar spine using the manufacturers vs Saudi reference data was 38.3–47.7% vs 30.5–49.6 (P<0.000), respectively. Similarly, based on BMD of total femur, the prevalence of osteoporosis using the manufacturers vs Saudi reference data was 6.3–7.8% vs 1.2–4.7% (P<0.000), respectively. Saudis (50 years) in the lowest quartile of body weight exhibited higher prevalence of osteoporosis (25.6% in females and 15.5% in males) as compared to that of the highest quartiles (0.0% in females and 0.8% in males). The present study underscores the importance of using population-specific reference values for BMD measurements to avoid overdiagnosis and/or underdiagnosis of osteoporosis.     

A Comparison Study of the Reference Curves of Bone Mineral Density at Different Skeletal Sites in Native Chinese,Japanese, and American Caucasian Women

To understand the differences among reference curves for bone mineral density (BMD) for Chinese, Japanese, and American Caucasian women, we measured the BMD at the anteroposterior (AP) lumbar spine (L1–L4), lateral lumbar spine (L2–L4), hip (including the femoral neck, trochanter, intertrochanter, Wards triangle, and total hip), and ultradistal forearm by the dual-energy X-ray absorptiometry (DXA) in a total of 2728 healthy Chinese women, aged 5–96 years. Documented BMD data for Japanese women and device manufacturers BMD new reference databases (including the NHANES III dataset) for American Caucasian women were also used in this study. The cubic regression model was found to fit best in analyzing the age-associated variations of BMD at various sites in Chinese women, i.e., the equations had the largest coefficient of determination (R ²). At the AP/Lat spine, trochanter, intertrochanter, and Wards triangle, BMD reference curves for Chinese women were lower than those for Japanese or Caucasian women, while at the femoral neck, total hip, and ultradistal forearm, the reference curves for Chinese women were higher than those for Japanese women, with overlaps and crossing of the curves for some age spans in comparing the Chinese and Caucasian women. There were significant differences in the peak BMD (PBMD) at various sites among the Chinese, Japanese, and Caucasian women (P = 0.000). The PBMDs for Chinese women at the lumbar spine and various sites of the hip were 5.7% ± 2.1% (mean ± SD, range, 2.7–7.9%) lower than those for Japanese women and 5.1% ± 2.7% (range, 0.5–7.2%) lower than those for Caucasian women; however, the PBMDs for Chinese women were 26.2% higher than those for Japanese women and 10% higher than those for Caucasian women at the ultradistal forearm. After the PBMD, average T-scores of Chinese women for losses at the AP lumbar spine with increasing age were nearly identical to those for Japanese women, but both were greater than those for Caucasian women. The average T-scores for BMD loss at various sites in Chinese women were higher than those for both Japanese and Caucasian women except at the femoral neck, where the T-scores of Chinese women were exceeded by those of both Japanese and Caucasian women. Estimated from the T-score curve of BMD loss, the age of osteoporosis occurrence at the femoral neck in Chinese women was about 10 years later than that in Japanese or Caucasian women; at the AP spine, Chinese women were similar to Japanese women; at the other sites, the age for occurrence of osteoporosis in Chinese women was about 5–15 years earlier than that in either Japanese or Caucasian women. There are differences in prevalence or odds ratio (OR) of osteoporosis at the same skeletal region for Chinese, Japanese, and Caucasian women aged 50 years or at different skeletal regions in women of the same race. The prevalences of osteoporosis at various regions of the hip in Chinese women are 10.1–19.8% and ORs are 22.0–32.3, of which prevalence at the femoral neck is the lowest (10.1%); the prevalences of osteoporosis in Japanese women are 11.6–16.8% and ORs are 21.1–26.3, of which prevalence at the femoral neck is the lowest (11.6%); and the prevalences of osteoporosis in Caucasian women are 13.0–20.0% and ORs are 19.4–48.9, of which prevalence at the femoral neck is the highest (20%). In conclusion, racial differences in BMD reference curves, prevalences, and risks of osteoporosis at various skeletal sites exist among native Chinese, Japanese, and American Caucasian women.     

Establishment of BMD reference curves at different skeletal sites in women, using a Cartesian coordinate numeration system

The BMD reference curve is the reference value used for diagnosing osteoporosis and assessing bone mass changes. Its accuracy would affect the correctness of T -score and Z -score values and thus the reliability of diagnostic results. In this paper, we report the use of a new method, a Cartesian coordinate numeration system, to establish BMD reference curves at different skeletal sites in women. In a reference population of 3,919 women ranging in age from 5–85 years, we used the dual X-ray absorptiometry (DXA) bone densitometer to measure BMD at the posteroanterior spine (PA; vertebrae L1–L4), followed by a paired PA/lateral spine scan of the vertebral bodies of L2–L4, expressed in g/cm² and g/cm³, and of the hip and forearm. We chose the cubic regression model to best fit BMD curves that varied with age at different skeletal sites. We then referred the BMD of the fitting curves established by the method of the coordinate numeration system as reference curves, compared them to BMD reference curves derived from the fitting curve equation or age cross-section, and calculated the deflection degrees of the BMD reference curves acquired from the fitting curve equation. At the PA spine, lateral spine (expressed in g/cm³), femoral neck, Wards triangle and radius + ulna ultradistal, the reference curves calculated from the equation were significantly lower than those confirmed by the method of the coordinate numeration system; whereas, at the lateral spine (expressed in g/cm²), total hip, and radius + ulna 1/3 sites, the reference curves derived from the equation were markedly higher than those acquired from the coordinate numeration system. The differences in the two kinds of reference curves calculated by these two different methods gradually increased along with the increment in ages of the women. At the peak value of the reference curves, the BMD calculated from the equation deflected from 2.02% to –10.0% from the BMD acquired from the coordinate numeration system at different skeletal sites, and from 21.5% to –121.8% until the age of 85 years. The highest positive deflection of 65.2% existed at the lateral spine (expressed in g/cm²) and the lowest positive deflection of 21.5% at the total hip. The maximum negative deflection of –121.8% was at the radius + ulna ultradistal, and the minimum negative deflection of –32.6% at the PA spine. The BMD curve acquired from age cross-section was highly positive compared with the one derived from the coordinate numeration system ( r =0.955–0.985 p =0.000) with no significant difference between them. Various analysts used such a method to obtain the coefficient of variance (CV) in BMD precision on each curve that was from 0.05–0.19%. Our study shows that the Cartesian coordinate numeration system is an accurate, precise and reliable method and can serve to reveal the serious drawbacks of using the fitting curve equation to calculate BMD. The BMD reference curves established by this coordinate numeration system maintained the authenticity of the fitting curve, whereas, using the fitting curve equation to obtain BMD reference curves at different skeletal sites led to distortion, and resulted in false increases or decreases in T -score and Z -score values.     

Bone Mineral Density of the Spine and Femur in Early Postmenopausal Turkish Women with Endemic Skeletal Fluorosis

The aim of this prospective, comparative study was to investigate the bone mineral density (BMD) changes in a group of early postmenopausal Turkish women with endemic skeletal fluorosis and to study effects of endemic fluorosis on BMD. Bone mineral density of L₂–L₄ vertebra, femur neck, femur trochanter, and Wards triangle were measured in 45 female patients with endemic skeletal fluorosis and 41 age-matched controls by dual X-ray absorbtiometry (DXA). The BMD of L₂–L₄ vertebra and Wards triangle were higher in the endemic fluorosis group than in the control group (P < 0.001). Patients with endemic fluorosis had higher femur neck and femur trochanter BMDs than did controls (P < 0.01 and P < 0.05, respectively). There was a positive correlation between serum fluoride content and BMD at the spine (r = 0.345, P = 0.001), femoral neck (r = 0.274, P = 0.011), Wards triangle (r = 0.295, P = 0.006), and trochanter (r = 0.217, P = 0.045). In conclusion, higher bone mineral density levels were seen in early postmenopausal women with endemic skeletal fluorosis. BMD measurement is a tool in the diagnosis and management of this preventable crippling disease.     

Association between bone mineral densities and serum lipid profiles of pre- and post-menopausal rural women in South Korea

The objectives of this population-based study were to investigate the potential association between bone mineral density (BMD) and serum lipid profiles and to compare the effects of serum lipids on BMD at various skeletal sites in pre- and post-menopausal women. In July and August of 2004, BMD was measured at a variety of skeletal sites [lumbar spine (L_1–4), femoral neck, trochanter, Wards triangle, shaft and proximal total hip] using the GE/Bravo Lunar DPX dual-energy X-ray absorptiometer in a South Korean population-based sample of 375 pre-menopausal and 355 post-menopausal rural women aged 19–80 years. The levels of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were inversely associated with BMD in both pre- and post-menopausal women. In the pre-menopausal women, correlations were shown only for lumbar 1–4 (TC: r =–0.12, P <0.05; LDL-C: r =–0.12, P <0.05), whereas in the post-menopausal women, no correlation was evident for the lumbar sites. In the post-menopausal subjects, the TC levels showed significant correlations with the BMD values at the trochanter ( r =–0.15, P <0.01), shaft ( r =–0.16, P <0.001) and proximal total hip ( r =–0.15, P <0.01) sites, while the LDL-C levels showed significant correlations with the BMD values at the neck ( r =–0.13, P <0.05), trochanter ( r =–0.21, P <0.001), shaft ( r =–0.20, P <0.001) and proximal total hip ( r =–0.20, P <0.001) sites. The levels of triglyceride (TG) were shown to have a significant positive correlation with BMD values at the trochanter site ( r =0.11, P =0.05) in the post-menopausal women; by contrast, subjects in a higher quartile of TG levels show lower lumbar BMD values in the pre-menopausal women. The levels of high-density lipoprotein cholesterol (HDL-C) were not associated with BMD values at any of the sites in the pre- and post-menopausal subjects. Our data indicate a relationship between BMD values and serum lipid levels and suggest differences between pre- and post-menopausal women in terms of the effects of serum lipids on BMD at various skeletal sites.     

A longitudinal study of supine lateral DXA of the lumbar spine: A comparison with posteroanterior spine,hip and total-body DXA

We report a study to assess whether supine lateral dual-energy X-ray absorptiometry (DXA) scans of the lumbar spine provide better data for monitoring response to treatment than alternative measurement sites such as the posteroanterior (PA) spine, hip and total body. The study population was 152 women enrolled in a placebo-controlled clinical trial of cyclical etidronate therapy. All subjects were 1–10 years after the menopause with bone mineral density (BMD) between 0 and –2 SD of age-matched normal women. Paired PA and lateral spine, left hip and total-body DXA scans were performed at baseline, 1 year and 2 years on a Hologic QDR-2000. One hundred and thirty-one subjects completed the study. Mean percentage change from baseline at 2 years in the treated (n=61) and control (n=70) groups was calculated for vertebral body, width-adjusted (WA) vertebral body, mid-vertebral body and WA mid-vertebral body BMD measurements on the lateral scans and compared with the percentage changes in PA spine, femoral neck, trochanter, Ward's triangle and total-body BMD. The long-term precision for each BMD measurement site was obtained by linear regression analysis in subjects taking placebo. Overall treatment effect, defined as the difference in the percentage change in BMD in the two treatment groups at 2 years, was divided by long-term precision to give an index of the ability of each site to monitor response to treatment. Results (and standard errors) normalized to the ratio of treatment effect/precision for PA spine BMD were as follows: PA spine, 1.00; vertebral body, 0.89 (0.14); WA vertebral body, 0.78 (0.14); mid-vertebral body, 0.65 (0.14); WA mid-vertebral body, 0.60 (0.13); femoral neck, 0.35 (0.15); trochanter, 0.45 (0.15); Ward's triangle, 0.59 (0.22); total body, 0.52 (0.19). Although treatment effect was larger for lateral than for PA spine BMD, this advantage was offset by the greater precision errors. PA spine BMD remains the optimum measurement for longitudinal studies in recently postmenopausal women.     

Association of estrogen receptor-α gene polymorphisms with bone mineral density in postmenopausal Korean women

We examined the potential associations between PvuII and XbaI polymorphisms in the first intron of the estrogen receptor alpha (ER-) gene and bone mineral density (BMD) in a population-based study of 174 postmenopausal Korean women. BMD was measured at the lumbar spine (L₂–L₄), right femoral neck, right trochanter, and right Wards triangle. ER- gene polymorphisms were detected by PvuII and XbaI restriction endonuclease digestion of polymerase chain reaction products. Differences in BMD values between the ER- genotypes were analyzed in a general linear model, with adjustments for age, height, weight, and smoking status. The following genotype frequencies were noted: PP, 14.9%; Pp, 46.0%; pp, 39.1%; XX, 3.5%; Xx, 29.3%; and xx, 67.2%. Both the femoral neck and Wards triangle BMD values in women with the Pp genotype were significantly (P < 0.05) higher than those in women with the pp genotype. No significant effect of the XbaI genotype on BMD was found at any site. Carriers of the pX haplotype were more likely to have lower BMD values at the trochanter than noncarriers, after adjustment for potentially confounding factors. Women with the pp genotype had more previous hip or spine fractures than those with other genotypes (P = 0.05). These results suggest that the PvuII polymorphism and the ER- haplotype may be associated with the BMD at several femur sites in postmenopausal Korean women.     

Impact of Detraining on Bone Loss in Former Collegiate Female Gymnasts

Undesirable changes in health-related parameters are thought to occur in retiring female athletes, but this has not been examined in longitudinal studies. The purpose of this study was to examine longitudinal changes in bone mineral density (BMD), body composition, and dietary intake in gymnasts and controls. Nonathletic, college-age women (n = 9) were selected as a control group for comparison to the gymnasts (n = 10). Initial BMDs for the gymnasts were determined by using dual energy X-ray absorptiometry (Lunar, DPX) at the beginning of their final competitive year. Initial BMDs for the controls were measured during a similar time-frame. Follow-up measurements were made at least 1-year after the initial measurement. Gymnasts had significantly greater BMD of the femoral neck (1.262 versus 1.058 g/cm², respectively), Wards triangle (1.230 versus 1.008 g/cm²), greater trochanter (1002 versus 0.822 g/cm²), and total body (1.232 versus 1.145 g/cm²) than controls while still competing (P < .05). Following retirement from competition, (mean years of retirement, 4 years), BMD of the gymnasts remained significantly greater than controls at total body, femoral neck, trochanter, and Wards triangle (P < .05). Significant declines in femoral neck, Wards triangle, and greater trochanter BMD were found in both gymnasts and controls (0.72% to 1.9% per year), but only gymnasts had a significant decline at the lumbar spine (0.87% per year). In conclusion, BMD changes in former gymnasts appear to be site-specific, and gymnasts continue to have greater proximal femur BMD than controls, despite their decreased exercise, which may help postpone or prevent osteoporosis later in life.     

Beneficial effects of regular Tai Chi exercise on musculoskeletal system

This study was performed to evaluate the potential benefits of regular Tai Chi Chun (TCC) exercise on bone mineral density (BMD) and neuromuscular function in postmenopausal women. In this cross-sectional study, 99 healthy postmenopausal women, with a mean age of 55.9 ± 3.1 years and within 10 years after the menopause, were recruited; including 48 subjects who had been regularly practicing TCC exercise for more than 3h/week and 51 age- and sex-matched sedentary controls (CON). BMD was measured in the lumbar spine and proximal femur of the non-dominant leg (femoral neck, greater trochanter, and Wards triangle), using dual-energy X-ray absorptiometry (DXA). Neuromuscular function was evaluated, including magnitude of trunk bend-and-reach, quadriceps muscle strength, and single-stance time on the nondominant leg. The TCC group showed overall higher BMD at all measurement sites, with a significant difference found at the spine (7.1%), greater trochanter (7.2%), and Wards triangle (7.1%) of the proximal femur (all; P < 0.05). Functional tests revealed an average 43.3% significantly greater quadriceps strength (P < 0.01), and 67.8% significantly longer single-stance time in the TCC group as compared with the CON group (P < 0.05), as well as a greater magnitude of trunk bend-and-reach in the TCC group (P = 0.08). Bivariate linear correlation analysis showed that quadriceps muscle strength was significantly correlated with the single-stance time (r = 0.41; P < 0.01). This study revealed that regular TCC exercise may have an association with higher BMD and better neuromuscular function in early postmenopausal women.     

Spine and femur densitometry at the menopause: Are both sites necessary in the assessment of the risk of osteoporosis?

Summary The aim of our study was to compare the results provided by the measurement of vertebral and femoral bone mineral density (BMD) for assessing the individual risk of osteoporosis as defined by either low BMD and/or rapid bone loss. Vertebral and femoral BMD were measured twice at a mean interval of 21 months in 85 normal, early post-menopausal women who had passed a natural menopause 6 months to 3 years previously. According to the measurement site, 36% (spine), 29% (femoral neck), 35% (Ward's triangle), and 25% (trochanter) fall in the at risk category, defined by a BMD value of 1 SD or more below the normal values for premenopausal women. Based on vertebral BMD, 39–48% of the women at risk had a normal femoral BMD. On the other hand, 24–37% of the women classified at risk based on femoral BMD maintained a low risk at the vertebral level. The annual rate of bone loss was significantly greater for the Ward's triangle (-2.7±3.8%) and femoral neck (-2.1±2.5%) than for the spine (-1.5±2.1%) and trochanter (-1.5±3.4%). There was a significant relationship between the rate of loss measured at the spine and femoral levels (r=0.34–0.58). Among the 21 women with a rapid vertebral bone loss, 48–67% had a low bone loss at the femoral level and vice versa. The ratio between mean rate of loss and the precision of the measurement sites was greater for the spine (1.6) compared with the femur (1.1–0.71). Our results indicate that vertebral and femoral BMD measurements produce discordant results in assessing the individual risk for osteoporosis.     

Femoral and whole-body bone mineral density in middle-aged and older Norwegian men and women: suitability of the reference values

The aim of this study was to compare bone mineral density (BMD) in a population-based sample of middle-aged and older Norwegians, with reference values provided by the manufacturer of the densitometer (Lunar) in order to evaluate whether these reference values are suitable for Norwegians. Additional aims were to estimate the prevalence of osteoporosis. Bone mineral density of the hip and total body was measured by dual-energy X-ray absorptiometry in 2303 men and 3105 women 47–50 and 71–75 years old, respectively, in western Norway, as part of the Hordaland Health Study (HUSK). Of these, 3403 white individuals were free of medications or diseases known to influence bone metabolism (reference group). Compared with the Lunar reference population, men and older women had a slightly but significantly lower BMD of trochanter and total femur and middle aged women had significantly higher total body BMD. Except for the higher mean BMD of total body among middle-aged women and the uniformly lower BMD values of Wards triangle, the deviations from the reference values of the manufacturer were less than 4%. Approximately 2.6% of middle-aged men vs 0.9% of middle-aged women were classified as osteoporotic on the basis of BMD of femoral neck. While the BMD values for femoral neck in this healthy Norwegian population are similar to the reference population of Lunar, the values of trochanter and total femur are lower in all groups except middle-aged women; however, the discrepancies are not of sufficient magnitude to warrant rejection of this commonly used database among Norwegians. Use of the young adult means from the Lunar reference database classified a higher proportion of middle-aged men than women as osteoporotic and osteopenic.     

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. However, the limited variability in both BW and BMD changes among premenopausal women in this study may explain the poor association between change in BW and change in BMD in the premenopausal group. As individual differences in each group is considerably large, annual measurements of BMD may be necessary to find possible candidates for early intervention.     

Total lymphocyte count and femoral bone mineral density in postmenopausal women

In vitro studies showed that several cytokines produced by the immune system can play a relevant role in modulating bone turnover, thus affecting the health of bone tissue. Our aim was to evaluate the association between total lymphocyte count (TLC) and femoral bone mineral density (BMD) in a sample of postmenopausal women. We studied 114 out of 124 consecutive, caucasian, home-dwelling, apparently healthy postmenopausal women referred for osteodensitometry by general practitioners. Femoral BMD was measured by dual-energy X-ray absorptiometry at five sites. A significant positive correlation (p 0.001) was observed between TLC and BMD (T score) measured the five sites: total proximal femur (r = 0.45), trochanter (r = 0.43), intertrochanteric region (r = 0.38), femoral neck (r = 0.49), and Wards triangle (r = 0.42). With a linear multiple regression model, TLC adjusted for age, weight, height, body mass index, and erythrocyte sedimentation rate showed a significant association with femoral BMD assessed at each of the five sites. The R² values ranged from 0.33 with BMD measured at Wards triangle to 0.51 with BMD measured at the trochanter. The significance of the association between TLC and BMD ranged from P 0.001 with BMD measured at the femoral neck to P 0.05 with BMD measured at the intertrochanteric area. The results were similar when BMD was expressed as either a Z score (in the 110 of the 114 women aged 84 years or younger) or as absolute values. Our data show a positive association between TLC and femoral BMD in a sample of apparently healthy, postmenopausal women, supporting the view of a close connection between the immune system and bone tissue.     

A Randomized Trial Comparing Hormone Replacement Therapy (HRT) and HRT Plus Calcitriol in the Treatment of Postmenopausal Osteoporosis with Vertebral Fractures: Benefit of the Combination on Total Body and Hip Density

We report a prospective, randomized, multicenter, open-label 2-year trial of 81 postmenopausal women aged 53-79 years with at least one minimal-trauma vertebral fracture (VF) and low (T-score below - 2) lumbar bone mineral density (BMD). Group HRT received piperazine estrone sulfate (PES) 0.625 – 1.25 mg/d ± medroxyprogesterone acetate (MPA) 2.5 – 5 mg/d; group HRT/D received HRT plus calcitriol 0.25 µg bd. All with a baseline dietary calcium (Ca) of <1 g/d received Ca carbonate 0.6 g nocte. Final data were on 66 – 70 patients. On HRT/D, significant (P < 0.001) BMD increases from baseline by DXA were at total body – head, trochanter, Wards, total hip, intertrochanter and femoral shaft (% group mean 4.2, 6.1, 9.3, 3.7, 3.3 and 3.3%, respectively). On HRT, at these 6 sites, significant s were restricted to the trochanter and Wards. Significant advantages of HRT/D over HRT were in BMD of total body (- head), total hip and trochanter (all P = 0.01). The differences in mean at these sites were 1.3, 2.6 and 3.9%. At the following, both groups improved significantly -lumbar spine (AP and lateral), forearm shaft and ultradistal tibia/fibula. The weightbearing, site — specific benefits of the combination associated with significant suppression of parathyroid hormone—suggest a beneficial effect on cortical bone. Suppression of bone turnover was significantly greater on HRT/D (serum osteocalcin P = 0.024 and urinary hydroxyproline/creatinine ratio P = 0.035). There was no significant difference in the number of patients who developed fresh VFs during the trial (HRT 8/36, 22%; HRT/D 4/34, 12% - intention to treat); likewise in the number who developed incident nonvertebral fractures. This is the first study comparing the 2 treatments in a fracture population. The results indicate a significant benefit of calcitriol combined with HRT on total body BMD and on BMD at the hip, the major site of osteoporotic fracture. Present address of K.J.: Department of Primary Health Care, Imperial College, London, UK     

Dual X-ray Absorptiometry

The DMS Lexxos is the first cone-beam dual X-ray absorptiometry (DXA) system capable of performing bone mineral density (BMD) measurements of the spine and hip. By using a two-dimensional (2-D) detector array rather than the linear array used with conventional fan-beam DXA systems, image acquisition time on Lexxos is only 1.5 s. However, the need to correct for the large signal from scattered radiation reaching the detector is a potential source of error in cone-beam DXA. The aim of this clinical evaluation of the Lexxos bone densitometer was to investigate the relative accuracy of cone-beam BMD measurements compared with conventional DXA by performing an in vivo cross-calibration study with an established fan-beam system, the Hologic QDR-4500. Spine (L1–L4) and hip BMD measurements were performed in 135 patients (111 women, 24 men) referred for a bone densitometry examination. Duplicate Lexxos measurements were performed in 27 female patients to evaluate precision. On average, Lexxos spine and femoral neck BMD measurements were 2% lower than those on the QDR-4500, whereas total hip BMD was 5% higher. Larger differences were found for the trochanter and Wards triangle regions. For all sites, Lexxos BMD measurements showed a strong linear relationship with those measured on the QDR-4500 with correlation coefficients in the range r = 0.95 to 0.97 for the clinically important spine, femoral neck, and total hip regions. The root mean standard error (RMSE) between Lexxos and QDR-4500 BMDs ranged from 0.037 g/cm² for the femoral neck to 0.060 g/cm² for the spine, whereas Lexxos precision was 1.3% for total hip, 2.0% for femoral neck, and 2.3% for spine BMD. Although for the hip BMD sites the RMSE and precision of Lexxos measurements were similar to studies of pencil-beam and fan-beam DXA systems, the results for the spine were poorer than expected. The findings of this study suggest that Lexxos corrects accurately for the effects of scattered radiation at the detector, but that the precision of spine BMD measurements may be limited by involuntary patient movement between the high and low energy X-ray exposures.     

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.     

Bone mineral density in elderly Chinese: effects of age,sex, weight,height, and body mass index

To enhance our understanding of the relationship between bone mineral density (BMD) and sex, age, body mass index (BMI), weight, and height in elderly Chinese, we studied 258 males aged 50–80 years (mean ± SD, 62.9 ± 6.2 years) and 193 females aged 46–75 years (59.0 ± 6.2 years). We measured BMD at the lumbar spine (L1–L4), hip (femoral neck, trochanter, and intertrochanter), and Wards triangle. A significant difference of age-adjusted BMD among male-female groups (P 0.0001) was observed. After adjustment for weight, the magnitude of the sex difference in BMD was reduced at all studied skeletal sites; for example, the difference declined from 18.3% to 5.5% at the spine. There were significant differences in BMD among age-stratified groups at all the sites in both sexes (P 0.01), except for spine BMD in males (P = 0.928). Regression analysis suggested that, with aging, greater differences of BMD distribution exist in elderly females than in males. Weight accounted for the greatest proportion of age-adjusted BMD variation (e.g., at femoral neck, R² = 0.17 in males) among four variables: weight, height, BMI, and a principal component formed from weight and height. These results suggested that weight decreased the sex difference in BMD in elderly Chinese. Patterns of age-related BMD distribution and BMD change among different age groups differed between the sexes and between the studied sites. Weight accounted for most of the effect of two correlated variables (weight and height) on BMD in our sample.     

Bone mineral density measured by dual-energy X-ray absorptiometry in healthy finnish women

Summary A cross-sectional study of 351 healthy Finnish women aged 20–76 years was done to establish reference values of bone mineral density (BMD) using dual-energy X-ray absorptiometry (DEXA). The effects of age and of several physical and lifestyle factors on BMD of the lumbar spine and proximal femur (femoral neck, trochanter, and Ward's triangle area) were investigated. Altogether 58 women were excluded from the final analysis due to significant spinal osteoarthritis or other diseases or drugs known to influence calcium or bone metabolism. The precision of the method was 0.9, 1.2, 2.7, and 2.4% in the lumbar, femoral neck, Ward's triangle and trochanter area, respectively. Lumbar BMD was increased by 30% (P<0.001) in 15 patients with osteoarthritis (21% of women 50 years or older), but it was apparently unaffected in 5 cases with aortic calcification. Except for the trochanter area, BMD diminished along with age, and this was significant after the menopause. The peak of mean BMD was observed at the age of 31–35 years in the spine and at the age of 20–25 years in the femoral neck and Ward's triangle. BMD was in a positive relationship to weight both in premenopausal and postmenopausal women and to the use of oral contraceptives in premenopausal women and to that of estrogen replacement therapy in postmenopausal women. Labors and pregnancies had a weak positive effect on BMD in premenopausal women. As compared with nonusers premenopausal women who had used alcohol showed a slightly decreased BMD of Ward's triangle. In postmenopausal women there was a positive correlation between alcohol intake and BMD.     

Dual X-ray Absorptiometry: Cross-Calibration of a New Fan-Beam System

The high precision and stable calibration of dual X-ray absorptiometry (DXA) scanners have led to their widespread use in longitudinal studies for research and the follow-up of individual patients who are receiving treatment for osteoporosis. However, difficulties in maintaining the continuity of the bone mineral density (BMD) calibration scale can arise when an old DXA system is replaced by a newer model. We report the results of an in vivo cross-calibration study performed when a GE-Lunar Prodigy fan-beam system replaced a DPX-L pencil-beam scanner. Lumbar spine and hip DXA scans were performed in 133 patients (104 female, 29 male) attending long-term BMD monitoring. On average, lumbar spine BMD measurements on the two systems agreed closely, with Prodigy values 1% lower than those on the DPX-L. However, after allowing for this difference, the root mean square error (RMSE) of 0.037 g/cm² was larger than in previous cross-calibration studies reported in the literature, and was 3 times the value expected from the precision of the BMD measurements. Mean femoral neck BMD also agreed closely between the two systems, although for Prodigy, the spread of measurements was 10% smaller than that for the DPX-L. For the trochanter and Wards triangle regions, mean BMD was 4% and 6% lower, respectively, on the Prodigy system, and the results were affected by a similar compression of the range of values. RMSE values were 0.037 g/cm², 0.044 g/cm², and 0.044 g/cm², respectively, for the femoral neck, trochanter, and Wards triangle sites. When the high value of the RMSE was investigated, it was found that for lumbar spine BMD, patient body weight and the difference between the two systems in the percentage fat reported in the soft tissue reference region explained 40% of the variance. This enabled equations to be developed that significantly improved the agreement between scans performed on the two systems. Smaller improvements were obtained for the femur BMD measurements.     

Two new regions of interest to evaluate separately cortical and trabecular BMD in the proximal femur using DXA

To differentiate changes in trabecular and cortical bone density at a skeletal site bearing body weight, the main goal of this retrospective study was to develop and characterize two new regions of interest (ROIs) for DXA at the hip, one mainly focusing on trabecular bone and another mainly focusing on cortical bone. Specific aims were to maximize the precision of the ROIs and to characterize their usefulness for monitoring age-related bone loss and discriminating controls from fracture cases in a cross-sectional study population and to compare them with earlier ROIs designed by our group. The study used populations from two different previous studies conducted in our laboratory, with one comprising cohorts of healthy premenopausal women, healthy postmenopausal women, and postmenopausal osteoporotic women with at least one spinal fracture (Spine Fx Study) and the other one comprising two cohorts of age-matched postmenopausal women, in whom cases had sustained a hip fracture (Hip Fx study). The new ROI for trabecular bone (CIRCROI) tries to improve on the earlier custom-designed Central ROI, which was also targeted at trabecular bone. CIRCROI consists of an approximate largest circle that can fit inside the femoral proximal metaphysis without touching the superior and inferior endocortical walls. The new ROI for cortical bone (CORTROI) at a site bearing body weight is defined as a horizontal rectangular box crossing the femoral shaft below the lesser trochanter. CORTROI BMD cohort means were significantly higher than all other ROIs, and CIRCROI BMD cohort means were lower than standard ROIs with the exception of Wards ROI. CIRCROI BMD was highly correlated with total femur BMD (r=0.94) and Central BMD (r=0.93), whereas CORTROI BMD correlations were lower (highest with total femur BMD (r=0.86)). Fracture discrimination odds ratios (ORs) of all ROIs were significant for the Hip Fx Study, with CIRCROI BMD having the highest, and CORTROI BMD the lowest, OR (4.83 and 2.49 per SD, respectively, compared with 3.69 for Wards ROI as the highest OR of standard ROIs). For the Spine Fx Study, only spinal and trochanteric BMD had significant OR. The new trabecular ROI had good short-term precision, comparable to the standard ROIs at the hip, but improving on that of Wards triangle, the only standard ROI only including the anterior and posterior cortical walls and therefore more predominantly consisting of trabecular bone than other standard ROIs. The precision of the new cortical ROI was lower than standard DXA ROIs, except for Wards triangle, but provides unique information on purely cortical bone at a skeletal site bearing body weight.