广州地区1 403例成年女性骨密度测定分析

目的了解本地区成年女性人群腰椎、股骨近端各部位骨密度(Bone mineral density BMD)随年龄、绝经年限、体重、身高的变化规律、各部位骨密度的偏相关分析和多元线性回归分析及骨质疏松患病率情况,为骨质疏松的诊断及预防提供科学依据.方法采用美国NORLAND公司的XR-46系列双能X线骨密度仪测量1 403例成年女性人群腰椎(L2-L4前后位及L3侧位)、非优势(左)股骨近端各部位(股骨颈、大粗隆及Ward's三角)BMD值,按10岁一个年龄组分7组对数据进行统计分析.结果广州地区成年女性腰椎骨峰含量出现在30～39岁组,而股骨近端骨峰含量出现在20～29岁组,腰椎及股骨近端各部位BMD值均随年龄增长而下降,腰椎和Ward's三角部位在50～59岁和60～69岁两年龄组骨量呈快速丢失现象.各部位骨密度的偏相关分析显示各部位的骨密度均呈相关性(P＜0.01).多元线性回归分析显示年龄和体重对绝经前女性股骨颈的骨密度有影响(P＜0.01),而绝经后女性腰3侧位骨密度除了年龄和体重的影响外,身高和绝经年限均对其有影响(P＜0.01).成年女性在达到峰值骨量后随着年龄的增加,各部位骨质疏松的患病率都呈上升趋势.结论女性机体BMD随年龄而变化,年龄、体重、绝经年限及身高等对机体BMD均有一定的影响,保持合适的体重和体型,有利于BMD的增加与维持.对不同年龄段的成年女性人群,预防骨质疏松的发生应以测量不同部位的BMD作为评价手段.     

Muscle strength as a predictor of bone mineral density in young women

It is widely accepted that physical activity is beneficial to bone. However, the specific relationships of muscle strength to bone mineral density (BMD) are poorly understood. We examined strength and BMD in 59 women aged 18-31 years who ranged in exercise patterns from sedentary to active. Mineral density of the right proximal femur (hip) and spine (L2-4) was evaluated by dual-energy x-ray absorptiometry. BMD at the midradius was measured by single-photon absorptiometry. Dynamic strength (one repetition maximum) was measured for the following muscle groups: back, elbow flexors (biceps), leg extensors (quadriceps), and the hip flexors, extensors, adductors, and abductors. Isometric grip strength was assessed by dynamometry. Mineral density at the hip correlated independently with muscle strength and body weight, but not with age. Specifically, femoral neck BMD was significantly correlated with back strength and weight, whereas trochanter and overall hip mineral density were significantly related to biceps, back, and hip adductor strength. Hip mineral density was not related to strength of the quadriceps groups or to that of the hip flexors, extensors, or abductors. In addition, muscle strength was an independent predictor of lumbar spine and midradius mineral density. In stepwise multiple regression analysis, biceps strength proved the most robust predictor of hip BMD and grip strength best predicted bone density at the lumbar spine and radius. We conclude that muscle strength is an independent predictor of bone mineral density, accounting for 15-20% of the total variance in bone density of young women.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bone mineral density in healthy Kuwaiti women

Objective This study aimed to measure bone mineral density (BMD) of the lumber spine and femur regions in healthy adult Kuwaiti women, and to evaluate the influence of body size on BMD results. Methods Bone mass measurement was performed by dual-energy X-ray absorptiometry at the lumbar spine (L2-L4) and femur (four regions) of healthy ambulatory Kuwaiti females aged between 20 and 80 years. Body size measurements and a detailed questionnaire on past medical and gynecologic history, as well as lifestyle factors, were administered to all subjects. After excluding those with apparent or suggested abnormalities affecting bone mass, only 805 women from 4,887 were included and served as the target subjects. Results The spine BMD values for Kuwaiti women up to 69 years old were lower than their US counterparts; the peak value was established in the fifth decade. Femur neck BMD was relatively stable up to menopause. Spine osteoporosis was prevalent among 10% of the subjects, compared with 4% in the femoral neck. Regression analysis revealed that each kilogram of body weight has a change of 0.3% in premenopausal women and 0.5–0.6% in the older group. In multiple regressions that included the three factors (height, weight and age), the effect of age superseded that of weight in the older group of women, where there was a detrimental annual effect on spine and femur (neck and total hip) BMD by 0.9%, while each kilogram of body weight had a constructive effect by 0.4 and 0.3%. In the premenopausal women, the positive effect of 1 kg of body weight was equivalent to about 1 year of aging in the trochanter region and half a year in the total hip region. Conclusion The BMD value of healthy Kuwaiti women tend to be lower than the US reference at the lumber spine in all age groups but showed higher values for femur neck only in the age group of late 30s through 60 years. Weight has a stronger effect on BMD than does the height. The prevalence of osteoporosis in the lumber spine was more than double that in the femur neck in postmenopausal women.     

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.     

Bone mineral density, muscle strength, and recreational exercise in men.

Muscle strength has been shown to predict bone mineral density (BMD) in women. We examined this relationship in 50 healthy men who ranged in age from 28 to 51 years (average 38.3 years). BMD of the lumbar spine, proximal femur, whole body, and tibia were measured by dual-energy x-ray absorptiometry (Hologic QDR 1000W). Dynamic strength using one repetition maximum was assessed for the biceps, quadriceps, and back extensors and for the hip abductors, adductors, and flexors. Isometric grip strength was measured by dynamometry. Daily walking mileage was assessed by 9 week stepmeter records and kinematic analysis of video filming. Subjects were designated as exercisers and nonexercisers. Exercisers participated in recreational exercise at least two times each week. The results demonstrated that BMD at all sites correlated with back and biceps strength (p < 0.01 to p = 0.0001). Body weight correlated with tibia and whole-body BMD (p < 0.001); age negatively correlated with Ward's triangle BMD (p < 0.01). In stepwise multiple regressions, back strength was the only independent predictor of spine and femoral neck density (R2 = 0.27). Further, back strength was the most robust predictor of BMD at the trochanter, Ward's triangle, whole body, and tibia, although biceps strength, age, body weight, and leg strength contributed significantly to BMD at these skeletal sites, accounting for 35-52% of the variance in BMD. Exercisers and nonexercisers were similar for walking (3.97 versus 3.94 miles/day), age (37.8 versus 38.5) years, and weight (80.0 versus 77.7 kg). However, BMD and muscle strength were significantly greater in exercises than in nonexercisers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Correlation of Bone Density to Strength and Physical Activity in Young Men with a Low or Moderate Level of Physical Activity

The objective of this study was to evaluate the relationship among bone mineral density (BMD), physical activity, muscle strength, and body constitution, in young men with a low or moderate level of physical exercise. Another aim was to investigate whether the head is unaffected by physical activity. The subjects consisted of 33 Caucasian healthy men, mean age 24.8 ± 2.3 years. BMDs of the total body, lumbar spine (L2-L4), femoral neck, Ward's triangle and trochanter, humerus, and head were measured using dual-energy-X-ray absorptiometry (DXA). Bivariate correlations were measured among the different BMD sites and age, weight, height, body mass index (BMI), fat mass, lean body mass, amount of physical activity (hours/week), hamstrings strength, and quadriceps strength. Significant predictors were found for all BMD sites except the head. Using all these variables, only 6% of the variation in BMD of the head could be explained, whereas 46% (total body), 31% (humerus), 17% (lumbar spine), 38% (femoral neck, Ward's), and 41% could be explained for the trochanter. Physical activity and muscle strength were found to be independent significant predictors of BMD of the total body and the sites at the proximal femur. These results suggest that at the time of peak bone mass attainment, physical activity is an important predictor of the clinically relevant proximal femur in young men with a low or moderate level of physical activity. Furthermore, since head BMD was not related to the level of physical activity, we suggest that head BMD may be used as an internal standard, to control for selection bias, in studies investigating the effect of physical activity on bone mass. Received: 5 February 1996 / Accepted: 24 September 1996     

Total and regional bone mass in female soccer players

This cross-sectional study investigated bone mass in female athletes participating in an impact-loading sport (soccer), and evaluated whether any changes in bone mass could be related to the type of weight-bearing loading and muscle strength. The group of soccer players consisted of 16 second-division female players (age 20.9±2.2 years) training for about 6 hours/week. The reference group consisted of 13 nonactive females (age 25.0±2.4 years) not participating in any kind of regular or organized sport activity. The groups were matched according to weight and height. Areal bone mineral density (BMD) was measured in total body, head, lumbar spine, femoral neck, Ward's triangle, trochanter, the whole femur and humerus, and in specific sites in femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric peak torque of the quadriceps and hamstring muscles was measured using an isokinetic dynamometer. The soccer players had significantly (P<0.05-0.01) higher BMD in the lumbar spine (10.7%), femoral neck (13.7%), Ward's triangle (19.6%), nondominant femur and humerus (8.2 and 8.0%, respectively), distal femur (12.6%), and proximal tibia (12.0%) compared with the nonactive women. There was no significant difference in muscle strength of the thigh between the two groups. In the nonactive group, muscle strength in the quadriceps and especially hamstrings, was correlated to BMD of the adjacent bones (whole femur, hip sites) and also to distant sites (humerus). In the soccer group, there were no correlations between muscle strength and BMD of the adjacent and distant bones. Soccer playing and training appears to have a beneficial effect on bone mass in young females, and it seems that there is a site-specific skeletal response to the type of loading subjected to each BMD site. Muscle strength in the thigh is not related to bone mass in female soccer players.     

Muscle strength, physical fitness, and weight but not age predict femoral neck bone mass

Hip fractures are the most serious complication of osteoporosis. Although low proximal femoral bone mineral density (BMD) does not cause hip fractures directly, it is clearly a prerequisite for the increased risk associated with aging. To investigate the mechanism of the age-related decline in proximal femoral bone mineral density, we have examined the relative importance of muscle strength, physical fitness, and body mass index (BMI) in addition to age in the determination of proximal femoral BMD in 73 healthy female volunteers age 20-75 years. Muscle strength was an independent predictor of BMD at all three sites in the proximal femur as well as in the lumbar spine and forearm; proximal femur BMD was also predicted by physical fitness. BMI was a positive predictor of bone mass at all sites. In the proximal femur, age was not an independent predictor of BMD at any site. In postmenopausal women muscle strength was a significant predictor of bone mass in the femur and forearm, but not in the spine. However, BMI remained predictive of bone mineral at all sites. Muscle strength, physical fitness, and weight appear to exert independent effects upon bone mass. Age effects may be mediated indirectly through associated changes in these factors. The integrated physical load on the skeleton may be a final common pathway.     

Determinants of bone density and prevalence of osteopenia among female runners in their second to seventh decades of age

This is a cross-sectional study of spine and hip bone density (BMD) in 124 female athletes, aged 16–68 years, who trained for at least 3 hs/week. The aim was to document the effects of competitive running on BMD in women over a broad age range. Thirty-three subjects, aged <35 years, were currently oligo- or amenorrheic and, of the 50 who were >40 years, and who were now menstruating normally, 13 had previously been oligo- or amenorrheic. Fifty-two women <50 years of age had never had disturbed menses. Twenty-four older women were postmenopausal. Women who had never had menstrual disturbance had significantly increased bone density at the lumbar spine, femoral neck, and femoral trochanter, as compared with young normal European reference data (range from +0.4 population SD or T-score units to +1.2 units according to measurement site and age group). In contrast, young amenorrheic or oligomenorrheic runners had reduced bone density, particularly at the spine (mean T score < −1.1), whereas older runners who previously had disturbed menses, but were now menstruating normally, had bone densities that were similar to sedentary young controls. Postmenopausal runners had bone density values that differed little from sedentary postmenopausal controls matched for time since menopause, after adjusting for the runners’ lower body weight. Bone density outcomes were related to candidate explanatory variables. After taking into account the other variables, age, per se, influenced only the femoral neck and Ward’s area. Years since last exposure to estrogen (at premenopausal levels) was an important determinant of bone loss at both hip and spine. Body weight had a beneficial influence on the femoral neck region, whereas (in contrast) height had a positive influence on the lumbar spine. Months of breastfeeding (totaled for all children) had a modest, positive influence, which was larger in the femoral measurement sites. There was no evidence of an effect of calcium intake or percent body fat on BMD at any site independent of these other effects. It is concluded that, with the consistent presence of normal premenopausal estrogen levels, running at least 3 hs/week substantially improves bone density, particularly at the proximal femur. This beneficial effect is reversed in the absence of the consistent past and current presence of normal menstrual function. There was no clear benefit of running seen on BMD in postmenopausal women, but premenopausal veteran athletes who started running after the age of 30 years were not disadvantaged compared with early starters.     

Contributions of chronological age,age at menarche and menopaus and of anthropometric parameters to axial and peripheral bone densities

Bone mineral density (BMD) was measured in 128 normal postmenopausal women at different skeletal sites: lumbar spine and proximal femur, using dual-energy X-ray absorptiometry (DXA), and the cancellous and cortical envelopes of the distal third of radius and tibia, using precise low-dose quantitative computed tomography (QCT). Multivariate analysis included chronological age, ages related to menstrual history (menopause and menarche) and anthropometric factors, e.g. height and weight, as independent predictive variables. Weight is a much-studied predictor of bone density. At sites of high bone turnover, i.e. cancellous envelope, the effect of weight appeared overshadowed by estrogen-related parameters: age-past-menopause was the first predictor of BMD in the cancellous compartment of radius and in Ward's triangle, and the number of reproductive years was the strongest predictor of BMD in the cancellous compartment of tibia and in the spine (L2–4). This suggests that in addition to menopause, the length of menstrual life should be considered as an explanation for the variations in current bone mass in postmenopausal women.At the cortical level of radius, the effect of chronological age was predominant. At the cortical level of tibia, height and weight were the best predictors of BMD.We conclude that the influence of parameters related to menstrual history is predominant in sites with mainly cancellous tissue and that anthropometric factors constitute the best predictors of BMD in the cortical sites of weight-bearing bones.     

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.     

Dissimilar Spine and Femoral Z-Scores in Premenopausal Women

The purpose of this study was to determine if differences exist in premenopausal women between z-scores for lumbar spine and proximal femoral bone mineral densities (BMD). Participants were 237 women ranging in age from 20 to 45 years. BMDs of the lumbar spine and proximal femur (femoral neck, Ward's area, and trochanter) were assessed using dual-energy X-ray absorptiometry (Lunar DPX). Mean (±SD) age, height, and weight of the participants were 29.4 ± 6.9 years, 164.4 ± 6.1 cm, and 64.9 ± 12.1 kg, respectively. Lumbar spine BMD and BMD at the femoral neck, Ward's area, and trochanter were significantly correlated with large SEEs (r = 0.59–0.65; SEE = 0.09–0.11). No positive correlation with age and BMD at any site was seen in this population but a significant negative correlation with age was seen in the proximal femur beginning at age 30. Twenty to 24% of the 20–29-year-olds exhibited a difference in z-scores of greater than 1 between the spine and sites in the proximal femur. This percentage increased to 32–46% in the 30–45-year-olds but the nature of the observed differences changed. The differences in spine and proximal femoral z-scores that are seen in the older age group appear to be the result of the earlier onset of bone loss in the proximal femur rather than an initial difference in peak bone mass which has been maintained. Received: 28 August 1996 / Accepted: 25 April 1997     

Bone status in primary hyperparathyroidism assessed by regional bone mineral density from the whole body scan and QUS imaging at calcaneus

To assess the bone mineral density status in primary hyperparathyroidism (PHPT), we studied 64 females with PHPT and 17 healthy women. Regional BMD (arms, trunk, legs) from the whole body scan and conventional sites (lumbar spine, femur, radius) were assessed by DXA. Quantitative ultrasound (QUS) imaging measurements were performed at calcaneus. Sixteen women had history of renal lithiasis, 11 had low impact fracture and 37 women had neither renal lithiasis nor fracture. In the entire group, the mean Z-scores were significantly decreased at all sites (lumbar spine, femur, radius). In all clinical subgroups, the mean Z-scores were significantly decreased at radius. The mean Z-scores in premenopausal women were significantly decreased comparatively to postmenopausal women at lumbar spine and femur. In a group of PHPT females matched to controls for age and BMI, only BMD values at radius were lower in PHPT patients than in control (P < 0.03). However, from the whole body scan data, all sites but no trunk were significantly involved in PHPT patients (P < 0.04). Using QUS measurements at calcaneus, the BUA but not SOS in PHPT females was significantly lower (P = 0.03) than in controls. Our results suggest that low BMD at lumbar spine and femur is encountered preferentially in premenopausal women. The BMD decrease predominates at limbs in PHPT with presumably a gradient from proximal to distal part of the limbs. Indeed, the distal part of the limbs are the most affected areas in PHPT whatever the amount of cortical or trabecular bone.     

Dual-energy X-ray absorptiometry in normal women: A cross-sectional study of 717 finnish volunteers

The bone mineral density (BMD) of the lumbar spine and proximal femur was measured using dual-energy X-ray absorptiometry in 717 healthy women aged 20–70 years. The maximal mean BMD was found at the age of 35–39 years in the spine and at the age of 20–24 in the femoral neck and Ward's triangle. No significant change in lumbar BMD was found from the age of 20 to 39 years. The spinal BMD values were relatively stable from age 20 to 39 years, whereas a linear decrease in BMD in the femoral neck and Ward's triangle was already apparent in the youngest age group (20–24 years). The major fall in BMD in all sites was related to the menopause. The overall decreases in BMD from the peak values to those at age 65–70 years were 20.4%, 19.0% and 32.6% in the lumbar spine, femoral neck and Ward's triangle, respectively. The correlation of trochanteric BMD with age was poor. BMD was positively correlated with weight in all measurement sites. Nulliparity was found to be a risk factor for osteoporosis. The present study confirmed that the menopause has a significant effect not only on spinal BMD but also on femoral BMD. Lumbar BMD was lower and BMDs in the proximal femur were higher in Finnish women than in white American women. This emphasizes the importance of national reference values for BMD measurements.     

Risk for developing osteoporosis in untreated premature menopause

Summary The bone mineral density (BMD) of the lumbar spine and proximal femur was determined by dual photon absorptiometry in 32 women with untreated premature menopause (cessation of menses before 45 years of age). The BMD of the spine and proximal femur in four obese patients was not different from the BMD of the age-matched controls. On the contrary, the BMD of the nonobese females with premature menopause was significantly lower with respect to the average values found in healthy young women, in age-matched and menopause-matched controls. The BMD deficit was greater over the lumbar spine than in the proximal femur. Forty three percent of nonobese patients were already under the vertebral fracture threshold and 25% of nonobese patients were below the hip fracture threshold. The BMD deficit in the lumbar spine was correlated to the loss observed in the femoral neck (r=0.59, P<0.001), in the trochanter (r=0.65, P<0.001) and in the Ward's triangle (r=0.73, P<0.001). A negative correlation was observed between years of menopause and the BMD of the lumbar spine (r=-0.39, P<0.05). The results indicate the high individual risk for osteoporotic fractures in nonobese females with untreated premature menopause. The BMD loss was greater over the skeletal areas that are predominantly composed of trabecular bone compared with cortical bone.     

Sexual differences in bone markers and bone mineral density of normal Chinese

We measured bone mineral density (BMD) at lumbar (L2–L4) vertebrae and proximal femurs of 385 healthy Chinese women aged 40–70 years and 156 healthy Chinese men aged 20–85, and four markers—bone alkaline phosphatase isozyme (BAP), procollagen-I C terminal propeptide (PICP), osteocalcin (BGP) in serum, and a bone resorption marker, urinary cross-linked N-telopeptide of type I collagen (NTX), of these subjects. The results indicate that in postmenopausal women, levels of all the markers increased with age. In men, serum BAP, PICP, and urinary NTX decreased significantly, and serum BGP decreased with borderline significance (P=0.08). With increasing age, bone density decreased at both sites in post-menopausal women and at the proximal femur in men. The lumbar bone density showed no significant age-related changes in men. In premenopausal women, BMD at either site showed no significant change with increasing age. Despite the different trends between men and women of agerelated changes in BMD and bone markers, bone density of both proximal femur and spine in both sexes correlated inversely with levels of the bone markers in a manner independent of age or body weight. The meaning of opposite age effects on bone markers in men and women needs further investigation. In addition, higher bone marker levels, implying faster bone turnover rate, are associated with lower BMD in both sexes.     

绝经后女性的体成分与年龄和绝经的关系及其对不同部位骨密度的影响

目的 调查绝经后女性的体成分与年龄、绝经年龄、绝经年限和腰椎、髋部BMD之间的关系.方法 用双能X线骨密度仪测量919例绝经后女性的体成分、正位腰椎和髋部BMD.结果 下身脂肪量、全身脂肪量和全身瘦组织量与年龄、绝经年龄和绝经年限都相关(P＜0.05～0.01),但只有绝经年限进入体成分的多元逐步回归方程,采用复合或三次回归模型拟合优度最佳.体成分随绝经年限的延长有下降趋势.绝经10年以上女性的下身脂肪量和全身瘦组织量显著减少,分别较绝经年限5年以内女性下降8.6%和3.1%.所有部位的体成分与所测区域的BMD 均呈正相关(P＜0.05～0.01),控制体重变量后,仅有全身脂肪量与腰椎BMD 呈正相关(P＜0.05),而全身瘦组织量与髋部BMD 呈正相关(P＜0.05).多元逐步回归分析发现体成分是影响腰椎和髋部BMD的一个重要因素,但对腰椎BMD影响最大的是全身脂肪量,而对髋部BMD影响最大的是全身瘦组织量.BMD 越低者,全身脂肪量和全身瘦组织量也越低,组间比较有显著性差异.结论 绝经后女性的体成分与年龄、绝经年龄、绝经年限和腰椎、髋部BMD相关,其中,绝经年限对体成分的影响最大,体成分组分对BMD的影响存在部位差异.     

Differential effects of hormone replacement therapy on bone mineral density and axial transmission ultrasound measurements in cortical bone

The menopause has a large effect on bone density, and hormone replacement therapy (HRT) has been shown to be an effective treatment for preventing postmenopausal bone loss. The aim of this study was to compare the effects of HRT use on speed of sound (SOS) measurements at the radius, tibia, phalanx, and metatarsal with bone mineral density (BMD) measurements of the lumbar spine and proximal femur. The study population consisted of 278 healthy premenopausal women, 194 healthy postmenopausal women, and 126 healthy postmenopausal women currently receiving HRT for one or more years. SOS measurements were taken at the radius, tibia, phalanx, and metatarsal using the Sunlight Omnisense, and BMD measurements at the lumbar spine and proximal femur using Hologic QDR-4500 densitometers. Z-scores were calculated using the postmenopausal control group. Z-score differences between the postmenopausal controls and HRT group, for the entire group and with the HRT group subdivided into three groups based on duration of HRT usage, were calculated. Significant postmenopausal bone loss was found for all SOS and BMD measurements. A positive effect of HRT usage was found for all SOS measurement sites and lumbar spine BMD, although only the radius and tibia SOS and lumbar spine BMD reached statistical significance. The Z-score differences between the two groups were 0.44, 0.37, 0.15, and 0.26 for the radius, tibia, phalanx, and metatarsal SOS respectively, and 0.28, 0.00, and -0.03 for the lumbar spine, femoral neck, and total hip BMD respectively. A clear effect of the duration of HRT use was seen for the radius measurements, the differences being less marked elsewhere. In conclusion, these results demonstrate a positive effect of HRT on SOS measurements at the radius and tibia and BMD measurements of the lumbar spine.     

Association of upper arm circumference at muscle flexion with lumbar spine bone mineral density

We investigated the association of upper arm circumference at muscle flexion with lumbar spine (L2–L4) bone mineral density (BMD) in 252 postmenopausal Japanese women (mean age, 62.0 ± 7.6 years; range, 43–78 years) with right-side dominance. Age, age at menopause, years since menopause (YSM), weight, and height were recorded. Dominant upper arm circumference (cm) was measured at muscle flexion. Lumbar spine BMD was measured by dual-energy X-ray absorptiometry (DXA). Correlations between BMD and variables were determined using Pearson's correlation coefficient. Significant predictors of the lumbar spine BMD were determined using stepwise multiple regression analysis. Upper arm circumference, weight, and height were positively correlated with BMD (r = 0.397, 0.343, and 0.323, respectively), whereas YSM and age were inversely correlated with BMD (r = −0.415 and −0.392, respectively). On stepwise multiple regression analysis, YSM, upper arm circumference, and weight were significant predictors of BMD (R ² = 0.322, P < 0.0001). Predicted value of the lumbar spine BMD was calculated by the following formula: Predicted BMD = 0.249 − 0.0078 (YSM) + 0.016 (upper arm circumference) + 0.0046 (weight). Dominant upper arm circumference at muscle flexion in combination with YSM and weight is a useful predictor of lumbar spine BMD. Received: July 21, 1998 / Accepted: April 1, 1999     

Lifestyle influences on 9-year changes in BMD in young women.

The effects of dietary calcium intake and physical activity on longitudinal changes in BMD over a mean of 9.4 years were examined in 62 healthy young women. Proximal femur BMD declined, lumbar spine BMD increased, and physical activity was associated with BMD change at intertrochanter and total hip sites. INTRODUCTION: Maximizing premenopausal BMD is an important strategy for the prevention of osteoporosis and resultant fractures later in life. MATERIALS AND METHODS: Young women who previously participated in a placebo-controlled 2-year calcium intervention study at a mean age of 18.5 +/- 0.3 years were remeasured at 27.8 +/- 1.0 years of age. DXA (Hologic QDR 1000W) was used to measure changes in BMD, and lifestyle factors were ascertained by questionnaire. RESULTS AND CONCLUSIONS: Early decline in BMD at the neck of femur (-3.3%/decade) and the converse gain in BMD at the lumbar spine (+4.3%/decade) and intertrochanter (+1.9%/decade) suggest site-specific changes in BMD in young premenopausal women. No effect of previous calcium supplementation was seen on current BMD or changes in BMD (p > 0.10). Lifestyle predictors of change in BMD were determined using hierarchical regression analysis after forced correction for the covariates baseline BMD and previous calcium supplementation. Physical activity was positively associated with change in BMD at total hip and intertrochanter sites (beta-coefficients, beta = 0.26 and 0.26 respectively; p < 0.05). Calcium intake was negatively associated with change in BMD at the lumbar spine (beta = -0.27, p < 0.05). Parity was negatively associated with change in BMD at all sites (beta = -0.40 to -0.26, p < 0.05). These data show that BMD is already declining at the proximal femur in these healthy young women. Physical activity assists in maintenance of BMD at some sites and thus may contribute to lifelong fracture prevention. There was no positive association between calcium intake and change in BMD.