Bone mineral density-independent association of quantitative ultrasound measurements and fracture risk in women

Osteoporotic fracture is considered to result from reduced bone strength and to be related to decreased bone mass and impaired bone architecture. Quantitative ultrasound measurements (QUS) of bone, that may reflect certain architectural aspects of bone, have been shown to be associated with fracture, but it is not clear whether the association is independent of bone mineral density (BMD). This study was designed to examine the contributions of cortical QUS and BMD measurements to the prediction of fracture risk in postmenopausal Caucasian women. Speed of sound (SOS) at the distal radius, tibia, and phalanx (Sunlight Omnisense) and BMD at the lumbar spine and femoral neck (GE Lunar) were measured in 549 women, aged 63.2 ± 12.3 years (mean ± SD; range, 49–88 years), including 77 fracture cases. Lower SOS at the distal radius, tibia, and phalanx, which were correlated with each other, were associated with increased risk of fracture. Independent predictors of fracture risk (in multivariate analysis) were distal radius SOS (OR per SD = 1.8; 95% CI, 1.3–2.4), femoral neck BMD (OR per SD = 1.9; 95% CI, 1.4–2.4), and age (OR per 5 years = 1.2; 95% CI, 1.0–1.5). Approximately 30% of the women had distal radius SOS T-scores <–2.5; however, only 6.6% of women had both BMD and SOS T-scores <–2.5. Among the 77 fracture cases, only 14 (18.2%) had both BMD and QUS T-scores below –2.5. These data in postmenopausal women suggest that speed of sound at the distal radius was associated with fracture risk, independent of BMD and age. The combination of QUS and BMD measurements may improve the accuracy of identification of women who will sustain a fracture.     

Bone density of the radius,spine, and hip in relation to percent of ideal body weight in postmenopausal women

Summary Bone mineral content (BMC) and bone mineral density (BMD) of the spine (L2–L4) and hip (at femoral neck, Ward's triangle, and greater trochanter sites) were determined by dual-photon absorptiometry (DPA), and of the radius by single-photon absorptiometry (SPA) in healthy postmenopausal women aged 40–70 years. The relationships of BMC and BMD to years since menopause were examined separately in 97 women who were above 115% of ideal body weight (IBW) and in 128 women below. The heavier women had significantly greater mean BMC and BMD at each site than did the normal-weight women. In the normal-weight women, there was a significant negative correlation between BMD and years since menopause at each measurement site except the greater trochanter. In the obese women, BMD decreased with increasing years since menopause at the radius site only and BMC declined with increasing years after menopause at the hip (femoral neck and Ward's triangle region) as well as the radius. Thus, body size is a significant determinant of BMD in this population. The pattern of loss of BMD from Ward's triangle and femoral neck regions of hip are similar to that of the spine. The BMC and BMD findings in the hip suggest that remodeling occurs at this weight-bearing site which has a favorable effect on bone strength.     

High parity is associated with increased bone size and strength

Some, but not all, studies report an association between decreased hip fracture risk and high parity despite similar bone mineral density (BMD). Our hypothesis was that bone size, a major determinant of bone strength, is greater in women with high parity compared with low parity or nulliparous women. A cross-sectional study of 168 Hutterite women aged 40–80 years was conducted. BMD, bone mineral content (BMC) and bone area of the total body (TB), hip, femoral neck (FN), and lumbar spine (LS) were measured, as well as bone geometry at the 4% and 20% distal radius and bending strength at 20% radius. Diet and activity recall and strength measurements were obtained. Of the 168 women, 42 (25%) were nulliparous while the remaining women reported 1 to 16 births (median=6). Of the 126 parous women, 122 (97%) breast-fed their infants (range 1.5–24 months). Hip, FN and LS BMD were not associated with either parity or months of breast-feeding. TB BMC and bone area (both, p <0.05) and FN bone area ( p <0.01) were associated with parity. FN bone area was 4% greater in women with 7+ vs 1–4 children. Torsional bending strength, which includes structural and material bone properties, at the 20% distal radius was greater with higher parity ( p =0.01). No bone measure was associated with average months of breast-feeding. High parity is associated with increased radial torsional bending strength and femoral neck size. The greater femoral neck size, without higher BMD, may explain the reduced hip fracture risk among women with high parity previously reported in some studies.     

Effects of high-impact exercise on bone mineral density: a randomized controlled trial in premenopausal women

Introduction: The purpose of this randomized controlled study was to assess the effects of high-impact exercise on the bone mineral density (BMD) of premenopausal women at the population level. Materials and methods: The study population consisted of a random population-based sample of 120 women from a cohort of 5,161 women, aged 35 to 40 years. They were randomly assigned to either an exercise or control group. The exercise regimen consisted of supervised, progressive high-impact exercises three times per week and an additional home program for 12 months. BMD was measured on the lumbar spine (L1–L4), proximal femur, and distal forearm, by dual-energy X-ray absorptiometry at baseline and after 12 months. Calcaneal bone was measured using quantitative ultrasound. Results: Thirty-nine women (65%) in the exercise group and 41 women (68%) in the control group completed the study. The exercise group demonstrated significant change compared with the control group in femoral neck BMD (1.1% vs –0.4%; p=0.003), intertrochanteric BMD (0.8% vs –0.2%; p=0.029), and total femoral BMD (0.1% vs –0.3%; p=0.006). No exercise-induced effects were found in the total lumbar BMD or in the lumbar vertebrae L2–L4. Instead, L1 BMD (2.2% vs –0.4%; p=0.002) increased significantly more in the exercise group than in the control group. Calcaneal broadband ultrasound attenuation showed also a significant change in the exercise group compared with the control group (7.3% vs –0.6%; p=0.015). The changes were also significant within the exercise group, but not within the control group. There were no significant differences between or within the groups in the distal forearm. Conclusions: This study indicates that high-impact exercise is effective in improving bone mineral density in the lumbar spine and upper femur in premenopausal women, and the results of the study may be generalized at the population level. This type of training may be an efficient, safe, and inexpensive way to prevent osteoporosis later in life.     

The peak bone mass of Hawaiian,Filipino, Japanese,and white women living in Hawaii

Our study compares the bone mass of Hawaiian, Filipino, Japanese, and white women living in Oahu, Hawaii. Eligible women ranged in age from 25 to 34; all had bone mass measurements at the spine, calcaneus, and proximal and distal radius. Their average bone mineral density (BMD) remained stable with age at all four bone sites, indicating that the age range 25–34 may represent the peak bone mass. Bone mass varied, however, between ethnicities; differences in BMD up to 11% were observed. The Hawaiian women had the greatest BMD, and whites had the second greatest BMD at the spine and calcaneus. The Japanese most frequently had the lowest BMD. Differences in body size partly explained the differences; most ethnic differences were reduced or eliminated after adjusting for height and weight. At the spine, the ethnic differences for BMD were also apparent with BMC and with vertebral area. Hawaiian and white women had greater values than Japanese or Filipino women. Differences at the proximal radius resembled the spine, except that whites had the widest proximal widths. The results were more complex for the distal radius. At the distal radius whites had the lowest BMD of the four ethic groups. The difference between whites and Hawaiians derived from the greater bone mineral content (BMC) of the Hawaiian women. By contrast, the difference between whites and the Japanese and Filipinos derived from the wider distal widths of the white women. Compared with the Japanese and Filipino women, the white women appeared to disperse their BMC at the distal radius across a wider bone width. Such differences in bone distributions might lead to an altered risk of distal radius (wrist) fractures. Within ethnicities there was marked variation among individuals in bone mass. At the extremes, women differed by 50–100% or more within all four ethnic groups.     

When should bone density measurements be repeated?

We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement.     

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.     

Two-year changes in bone and body composition in young children with a history of prolonged milk avoidance

No previous longitudinal studies of calcium intake, anthropometry and bone health in young children with a history of avoiding cows milk have been undertaken. We report the 2-year changes of a group of 46 Caucasian children (28 girls, l8 boys) aged 8.1±2.0 years (mean ± SD) who had low calcium intakes at baseline and were short in stature, with elevated body mass index, poor skeletons and lower Z scores for both areal bone mineral density (BMD, in grams per square centimeter) and volumetric density (bone mineral apparent density, BMAD, in grams per cubic centimeter), compared with a reference population of milk drinkers. At follow-up, adverse symptoms to milk had diminished and modest increases in milk consumption and calcium intake had occurred. Total body bone mineral content (BMC) and bone area assessed by dual energy X-ray absorptiometry had increased (P<0.05), and calcium intake from all sources was associated with both these measures (P<0.05). However, although some catch-up in height had taken place, the group remained significantly shorter than the reference population (Z scores –0.39±1.14), with elevated body mass index (Z scores 0.46±1.0). The ultradistal radius BMC Z scores remained low (–0.31±0.98). The Z scores for BMD had improved to lie within the normal range at predominantly cortical sites (33% radius, neck of femur and hip trochanter) but had worsened at predominantly trabecular sites (ultradistal radius and lumbar spine), where values lay below those of the reference group (P<0.05). Similarly, although volumetric BMAD Z scores at the 33% radius had normalized, BMAD Z scores at the lumbar spine remained below the reference population at follow-up (–0.67±1.12, P<0.001). Our results demonstrate persisting height reduction, overweight and osteopenia at the ultradistal radius and lumbar spine in young milk avoiders over 2 years of follow-up.     

Familial aggregation of bone mineral density and bone mineral content in a Chinese population

Familial aggregation of bone mineral density (BMD) and bone mineral content (BMC) has been shown in twin and familial studies, but most sample sizes were small. We here report a large familial aggregation study in a Chinese population. A total of 13,973 siblings aged 25–64 years from 3,882 families were enrolled from Anhui, China. We assessed the whole-body, hip and lumbar spine BMD and BMC by dual-energy X-ray absorptiometry (DXA). Intra-class correlation coefficients of BMD and BMC between siblings varied among different skeletal sites and between different age groups of male sib-pairs and premenopausal and postmenopausal female sib-pairs, with a range of 0.228 to 0.397. The sibling recurrence risk ratio (s) of osteoporosis was 2.6 in our population. We also evaluated the joint association of the BMD values of the first siblings and the second siblings with the risk of low BMD (defined as less than the 10th percentile of the same group population) of their younger siblings. If both the first and second siblings BMDs were in the lowest tertile, the odd ratios (ORs) of low BMD in their subsequent siblings were 8.32 [95% confidence interval (CI) 5.59–12.39)], 8.71 (95% CI 5.74–13.22) and 5.90 (95% CI 3.57–9.76) for total body, total hip and lumbar spine, respectively. This study demonstrates a significant familial aggregation of BMD and BMC in a large sample of rural Chinese adults.     

Exercise frequency and calcium intake predict 4-year bone changes in postmenopausal women

The aim of this study was to examine the association of exercise frequency and calcium intake (CI) with change in regional and total bone mineral density (BMD) in a group of postmenopausal women completing 4 years of progressive strength training. One hundred sixty-seven calcium-supplemented (800 mg/day) sedentary women (56.1±4.5 years) randomized to a progressive strength training exercise program or to control were followed for 4 years. Fifty-four percent of the women were using hormone therapy (HT) at baseline. At 1 year, controls were permitted to begin the exercise program (crossovers). The final sample included 23 controls, 55 crossovers, and 89 randomized exercisers. Exercisers were instructed to complete two sets of six to eight repetitions of exercises at 70–80% of one repetition maximum, three times weekly. BMD was measured at baseline and thereafter annually using dual-energy X-ray absorptiometry. Four-year percentage exercise frequency (ExFreq) averaged 26.8%±20.1% for crossovers (including the first year at 0%), and 50.4%±26.7% for exercisers. Four-year total CI averaged 1,635±367 mg/day and supplemental calcium intake, 711±174 mg/day. In adjusted multiple linear regression models, ExFreq was positively and significantly related to changes in femur trochanter (FT) and neck (FN), lumbar spine (LS), and total body (TB) BMD. Among HT users, FT BMD increased 1.5%, and FN and LS BMD, 1.2% ( p <0.01) for each standard deviation (SD) of percentage ExFreq (29.5% or 0.9 days/week). HT non-users gained 1.9% and 2.3% BMD at FT and FN, respectively, ( p <0.05) for every SD of CI. The significant, positive, association between BMD change and ExFreq supports the long-term usefulness of strength training exercise for the prevention of osteoporosis in postmenopausal women, especially HT users. The positive relationship of CI to change in BMD among postmenopausal women not using HT has clinical implications in light of recent evidence of an increased health risk associated with HT.     

Overweight postmenopausal women lose bone with moderate weight reduction and 1 g/day calcium intake.

Overweight postmenopausal women may be more susceptible to bone loss with weight reduction than previously studied obese women. The influence of energy restriction and Ca intake on BMD was assessed in 66 individuals. Weight reduction resulted in bone loss at several sites in women consuming 1 g Ca/day and was mitigated with higher calcium intake at 1.7 g/day. INTRODUCTION: Bone loss is associated with weight loss in obese postmenopausal women and can be prevented with calcium (Ca) supplementation. However, because bone loss caused by weight loss may be greater in overweight than obese women, it is not clear whether Ca supplementation is also beneficial in overweight women. MATERIALS AND METHODS: We assessed the influence of caloric restriction at two levels of Ca intake on BMD and BMC in 66 overweight postmenopausal women (age, 61 +/- 6 years; body mass index, 27.0 +/- 1.8 kg/m2). Subjects completed either a 6-month energy-restricted diet (WL, n = 47) and lost 9.3 +/- 3.9 % weight or maintained weight (WM; 1 g Ca/day, n = 19). Participants in the WL group were randomly assigned to either normal (1 g/day; WL NL-Ca) or high (1.7 g/day; WL Hi-Ca) Ca intake. Regional BMD and BMC were measured at baseline and after 6 months. RESULTS: During normal Ca intake, trochanter BMD and BMC and total spine BMD were decreased more in WL than WM women (p < 0.05). The WL NL-Ca group lost more trochanter BMD (-4.2 +/- 4.1%) and BMC (-4.8 +/- 7.1%) than the WL Hi-Ca group (-1.4 +/- 5.6% and -1.1 +/- 8.1%, respectively; p < 0.05). There were no significant changes in BMD or BMC at the femoral neck in any group. Weight loss correlated with trochanter BMD loss (r = 0.687, p < 0.001) in the WL NL-Ca group. CONCLUSION: Despite an intake of 1 g Ca/day, bone loss occurred at some sites because of weight loss. Calcium intake of 1.7 g/day will minimize bone loss during weight loss in postmenopausal overweight women.     

Home-based resistance training improves femoral bone mineral density in women on hormone therapy

This study tested whether moderate resistance training would improve femoral bone mineral density (BMD) in long-term users of hormone therapy with low BMD. The study was a 2-year randomized, controlled, trial (RCT) of moderate resistance training of either the lower extremity or the upper extremity. Eighty-five women participated in a 6-month observation period. The setting was center-based and home-based training. The participants were 189 women aged 59–78 years, with total femur T-scores from –0.8 to –2.8 and on hormone therapy (HT) for a minimum of 2 years (mean 11.8 years); 153 completed the trial. Lower extremity training used weight belts (mean 7.8 kg) in step-ups and chair rises; upper extremity training used elastic bands and dumbbells. Measurements were BMD and body composition [dual-energy X-ray absorptiometry (DXA)], bone turnover markers. Total femoral BMD showed a downward trend during the observation period: 0.35%±0.18% (P=0.14). The response to training was similar in the upper and lower groups in the primary outcomes. At 2 years, total femoral BMD increased 1.5% (95% CI 0.8%–2.2%) in the lower group and 1.8% (95% CI 1.1%–2.5%) in the upper group. Trochanter BMD increased 2.4% (95% CI 1.3%–3.5%) in the lower group and 2.5% (95% CI 1.4%–3.6%) in the upper group (for both analyses time effect P<0.001). At 1 year, a bone resorption marker (C-telopeptide) decreased 9% (P=0.04). Bone formation markers, bone-specific alkaline phosphatase, decreased 5% (P<0.001), and N-terminal type I procollagen peptide decreased 7% (P=0.01). Body composition (percent lean and percent body fat) was maintained in both groups. We concluded that long-term moderate resistance training reversed bone loss, decreased bone turnover, increased femur BMD, and maintained body composition. The similarity of response in upper and lower groups supports a systemic response rather than a site-specific response to moderate resistance training.     

Reproductive, Menstrual and Menopausal Factors: Which Are Associated with Bone Mineral Density in Early Postmenopausal Women?

The associations between a number of reproductive and menopausal factors and bone mineral density (BMD) were studied in a sample of early postmenopausal women. The study included 580 women aged 45–61 years who completed a risk factor questionnaire containing sections on obstetric and menstrual history. BMD measurements were taken at the anteroposterior (AP) spine, greater trochanter, femoral neck, total radius and whole body, along with whole body bone mineral content (BMC). In analyses adjusting for key confounders, number of pregnancies was more strongly associated with increased BMD than number of live births at all sites (p<0.05 at femoral neck and total radius), and menstrual years was more strongly associated with increased BMD than years since menopause (p<0.05 at all sites). Hysterectomized women had a significantly higher adjusted mean BMD than non-hysterectomized women at all sites (AP spine: 0.999 g/cm² vs 0.941 g/cm², p<0.001), although there were no significant differences in BMD between hysterectomized women who had a bilateral oophorectomy and those whose ovaries were preserved. Negative associations between the duration of hot flushes and BMD were statistically significant (p<0.05) at the three non-hip sites. In multiple regression analyses containing all reproductive terms, duration of hormone replacement therapy (HRT) use, menstrual years and hysterectomy status were significantly associated with BMD at all five sites, whilst oral contraceptive use before the age of 23 years was significantly associated with increased BMD at all sites except the total radius. Breastfeeding duration, the duration of oral contraceptive use and premenopausal amenorrhea were found to have no association with BMD. Results for whole body BMC were consistent with those for the five BMD sites, across all the variables considered here. These findings confirm the importance of HRT use and duration of menses as predictors of BMD, whilst the results for hysterectomy status and early oral contraceptive use require further consideration. Received: 26 July 2000 / Accepted: 5 April 2001     

Association between weight cycling history and bone mineral density in premenopausal women

The hypothesis that a history of one or more weight reductions and regains (weight cycling) is associated with lower site-specific bone mineral density (BMD) was examined in 169 premenopausal women, aged 29–46 years. Data on the previous 10-years' weight cycling history, present weight-bearing physical exercise, number of deliveries, present use of contraceptive pills or hormone-releasing coils, age at menarche and present menstrual status were collected by a self-administered questionnaire. Dietary intake was calculated from food records. The areal BMD (g/cm²) was measured with dual-energy X-ray absorptiometry (norland XR-26). The lumbar spine (L2–4) BMD, adjusted to weight and age at menarche (ANCOVA), was 0.062 g/cm² (95% confidence interval: 0.015 to 0.011 g/cm²;p=0.01) higher in the non-cyclers (n=68) than in subjects with reported weight-cycling history (n=101). The corresponding difference for femoral neck BMD was 0.019 g/cm² (–0.018 to 0.056;p=0.30), for trochanter BMD 0.013 g/cm² (–0.025 to 0.05 g/cm²;p=0.50) and for distal radius BMD 0.022 g/cm² (0.006 to 0.397 g/cm²;p=0.008). A pairwise comparison of 34 weight-matched subjects (non-cycler vs cycler) gave similar BMD differences as found in the above (ANCOVA) analyses. The results suggest that weight cycling might be associated with lower spine and distal radius BMD.     

High bone mineral density among perimenopausal women

Studies regarding high bone mineral density (HBMD) are few. In the population-based Kuopio Osteoporosis Risk Factor and Prevention Study, BMDs of women were measured from 1990–1991 and 1995–1997. The mean age of the 1,873 women studied was 53.5 years at baseline (range 48.0–59.6). In all, 248 women were excluded because of BMD measurement errors or artifacts: 41 from the HBMD group (20.6%) and 207 (12.4%) from the control group. The final study group consisted of 1,551 women, 168 in the HBMD group (baseline lumbar BMD >1.23 g/cm²; femoral BMD >1.01 g/cm², and 5-year follow-up lumbar BMD >1.21 g/cm²; femoral BMD >0.98 g/cm², respectively) and 1,383 in the control group. The predictors for HBMD in the multivariate regression analysis were as follows: hormone therapy (HT) during the follow-up from 0.5 to 2 years and for over 2 years (OR 2.06, CI: 1.11–3.81 and OR 2.16, CI 1.43–3.26) and being overweight (BMI from 25 kg/m² to 30 kg/m², and BMI >30 kg/m²) at baseline (OR 2.84, CI: 1.82–4.42; OR 5.94, CI: 3.47–10.16, respectively). High physical activity while 11–18 years of age was associated with HBMD (OR 1.69, CI: 1.17–2.45). Parity predicted HBMD so that after one to two births the OR was 2.66 (CI: 1.03–6.88) and 3.03 (CI: 1.16–7.90) after three or more births. Menopause was negatively associated with HBMD (OR 0.57, CI 0.38–0.85). There were more premenopausal women in the HBMD group (53.9 vs. 34.6%, P <0.001). The HBMD group showed fewer fractures. In conclusion, being overweight, parity, HT use, premenopause and high physical activity in adolescence seemed to be predictors for persistently high BMD in early postmenopausal women. We suggest that the fracture risk is low in these women, and thus they are neither primary candidates for BMD screening nor for osteoporosis medication.     

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 Wards 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 Wards 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 Wards 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 Wards 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 Wards triangle might be caused by the intrinsic differences from the different measuring instruments.     

Prevention of Bone Loss by Clodronate in Early Postmenopausal Women with Vertebral Osteopenia: A Dose-Finding Study

This double-masked, placebo-controlled study was undertaken to determine the efficacy and safety of oral clodronate in the prevention of bone loss in early postmenopausal women with vertebral osteopenia. Altogether 610 women with a mean age of 53 years were recruited for the study. They were 1–5 years postmenopausal and their lumbar spine bone mineral density (BMD) was at least 1 standard deviation below the mean of premenopausal women (T-score ≤−1). The subjects were randomized into five study groups to receive either placebo, clodronate 65 mg, 400 mg or 800 mg daily, or intermittent clodronate in 3 month cycles with 400 mg daily for 15 days followed with no treatment for 75 days for 3 years. One hundred and eighty-seven of 509 women who completed the primary study continued in the extension study of 2 years in which previous placebo users were switched to clodronate 800 mg daily, while previous users of 400 mg or 800 mg of clodronate used either placebo or 800 mg of clodronate daily. In the primary study clodronate was administered in the evening, and in the extension 1 h before breakfast on an empty stomach. In the primary study mean changes in lumbar spine BMD were −3.4% in the placebo group and +0.4% in 800 mg clodronate group [difference between groups at 3 years 3.8% (95% CI 2.7% to 4.9%, p<0.0001)], and in the trochanter area BMD −1.1% in the placebo group, and + 0.4% in the 800 mg clodronate group [difference between groups at 3 years 1.5% (95% CI 0.05% to 2.9%)]. During the extension study mean changes in lumbar spine BMD were +1.5% in the clodronate group and −0.2 % in the placebo group [difference between groups 1.7% (CI 0.4% to 3.0%, p = 0.010)] and in trochanter BMD were +2.5% in the clodronate group and no change in the placebo group [difference between groups 2.1% (CI 0.3% to 3.9%, p = 0.007)]. No statistically significant differences between the placebo and 800 mg clodronate groups were found in the femoral neck BMD. In the primary study the urinary excretion of type I collagen aminoterminal telopeptide (NTX) decreased by 44% (p<0.0001 compared with placebo) and that of deoxypyridinoline by 18% (p<0.0001) in the clodronate 800 mg group. In the extension study urinary NTX decreased by 51% (p<0.0001) in those who were switched to 800 mg of clodronate and increased by 67% (p<0.0001) in those who stopped using that dose. There was no difference in the frequency of gastrointestinal complaints between clodronate- and placebo-treated patients in the primary study, but they were more common among women who received clodronate in the extension phase. Clodronate in daily doses of 400–800 mg caused a slight elevation of aminotransferase levels, usually within the reference range. In bone biopsies no defect in mineralization was found. In conclusion, clodronate in a daily dose of 800 mg prevents early postmenopausal bone loss at the sites of the skeleton in which cancellous bone predominates. It effectively reduces bone resorption and bone turnover rate. Antifracture efficacy of clodronate remains to be established by prospective, placebo-controlled trials. Received: 4 March 2002 / Accepted: 9 July 2002     

Effects of High‐Impact Training on Bone and Articular Cartilage: 12‐Month Randomized Controlled Quantitative MRI Study

Osteoarthritis and osteoporosis often coexist in postmenopausal women. The simultaneous effect of bone‐favorable high‐impact training on these diseases is not well understood and is a topic of controversy. We evaluated the effects of high‐impact exercise on bone mineral content (BMC) and the estimated biochemical composition of knee cartilage in postmenopausal women with mild knee osteoarthritis. Eighty women aged 50 to 66 years with mild knee osteoarthritis were randomly assigned to undergo supervised progressive exercise three times a week for 12 months (n = 40) or to a nonintervention control group (n = 40). BMC of the femoral neck, trochanter, and lumbar spine was measured by dual‐energy X‐ray absorptiometry (DXA). The biochemical composition of cartilage was estimated using delayed gadolinium‐enhanced magnetic resonance imaging (MRI) cartilage (dGEMRIC), sensitive to cartilage glycosaminoglycan content, and transverse relaxation time (T2) mapping that is sensitive to the properties of the collagen network. In addition, we evaluated clinically important symptoms and physical performance–related risk factors of falling: cardiorespiratory fitness, dynamic balance, maximal isometric knee extension and flexion forces, and leg power. Thirty‐six trainees and 40 controls completed the study. The mean gain in femoral neck BMC in the exercise group was 0.6% (95% CI, –0.2% to 1.4%) and the mean loss in the control group was –1.2% (95% CI, –2.1% to –0.4%). The change in baseline, body mass, and adjusted body mass change in BMC between the groups was significant (p = 0.005), whereas no changes occurred in the biochemical composition of the cartilage, as investigated by MRI. Balance, muscle force, and cardiorespiratory fitness improved significantly more (3% to 11%) in the exercise group than in the control group. Progressively implemented high‐impact training, which increased bone mass, did not affect the biochemical composition of cartilage and may be feasible in the prevention of osteoporosis and physical performance–related risk factors of falling in postmenopausal women. © 2014 American Society for Bone and Mineral Research.     

Bone mineral density in Norwegian premenopausal women

The aims of this study were: 1) to determine bone mineral density (BMD) in different age groups, 2) to determine the prevalence of low BMD, and 3) to determine the possible association between BMD and a number of risk factors in Norwegian premenopausal women. BMD of the lumbar spine (L₂–L₄), total body, and the hip (total femur, femur neck, and trochanter) were measured using dual-energy X-ray absorptiometry (Prodigy, Lunar) in 145 randomly selected women aged 13–39 years. Information on other factors thought to influence BMD was obtained through questionnaire and a clinical interview. The group aged 25–29 years had the highest mean BMD in the total body, lumbar spine, and total femur while the group aged 13–19 years had the highest mean BMD in the femur neck and the trochanter. The mean BMD values of Norwegian premenopausal women were 3.4–5.1% higher than US/European reference data (P<0.05). Five percent of the study sample aged 20–39 years were defined with low BMD (Z-score <–2) using the standard values from this study. Weight-bearing physical activity, body weight, body height, and age were positively associated with BMD, whilst menstrual dysfunction and previous pregnancy were associated with lower BMD in some of the measurement sites. The results show that the factors associated with BMD are extensive, and the strategies to prevent low BMD have to be multifactorial. A follow-up study should be conducted on the study sample to investigate actual mean BMD values and BMD changes through time.     

Differential action of pamidronate on trabecular and cortical bone in women with involutional osteoporosis

Since osteoporotic fractures are mainly related to the diminution of the bone mineral density (BMD), the effect of pamidronate (3-amino-1-hydroxy-propylidene) 1,1-bisphosphonate on the BMD of the spine, proximal femur and radius shaft was evaluated in an initial cohort of 35 postmenopausal women with at least one vertebral fracture due to involutional osteoporosis.Pamidronate was given continuously during 18 months in a daily oral dose of 4.8 to 6.0 mg/kg supplemented with calcium (1 g/day).BMD — measured by dual photon absorptiometry — increased after one year 5.3±1.0% (P<0.001) in lumbar spine and 5.3±1.5% (P<0.001) over trochanter. However no significant changes were observed in the BMD of the femoral neck, Ward's triangle or in the cortical bone of the radius shaft measured by single photon absorptiometry.Pamidronate also decreased significantly urinary hydroxyproline-creatinine excretion after 6 months and thereafter maintained a plateau. After 18 months of treatment the diminution was 42.6±4.9% (P<0.001).The differing effects of pamidronate on the BMD of lumbar spine and proximal femur might be ascribed to dissimilarities between the proportions of trabecular and cortical bone in these. These results suggest that pamidronate may be prescribed to prevent fractures in cases of involutional osteoporosis with a significant decrease of BMD in lumbar spine and/or trochanter.