哺乳妇女停止喂奶后补充碳酸钙其骨骼骨密度未见明显的干预效果

目的观察哺乳妇女骨骼骨密度的自我恢复状况,以及补充碳酸钙后对其骨骼骨密度的干预效果。方法以湖北省武汉市郊区农村的120名健康哺乳期妇女为研究对象,随机分为两组:一组为补钙组(每日600 mg钙,碳酸钙),另一组为对照组,各60名。断奶时,使用双能X线吸收骨密度测定仪测量母亲腰椎和左髋等局部骨骼基线骨密度,并通过3d、24 h的膳食调查计算其平均每日钙摄入量,随即补钙(补钙组)或给予安慰剂(对照组),1年后再次测定相同部位的骨密度。结果无论补钙组还是对照组,1年后研究对象腰椎和左髋的骨密度显著增加(P<0.05)。补钙组与对照组之间比较,无论局部骨骼的骨密度还是骨转换指标差异均无统计学意义(P>0.05)。结论尽管我国产妇日摄入钙量较少,停止喂奶后1年内其腰椎和左髋骨密度仍明显增加;补充碳酸钙没有明显的干预效果。     

绝经后女性有无胸腰椎骨折时髋骨骨密度对照研究

目的 为了探求绝经后女性有无胸腰椎骨折的髋部骨密度值来预测发生胸腰椎压缩骨折的同时髋骨骨折的发生机率.方法 使用双能X线吸收仪测量,研究对象绝经后女性胸腰椎压缩骨折髋骨BMD43例,绝经后女性胸腰椎非压缩骨折髋骨8MD41例.结果 在两组腰椎BMD值无显著性差异的前提下,胸腰椎压缩骨折髋骨BMD统计学意义明显小于绝经后女性胸腰椎无压缩骨折髋骨BMD统计学意义.结论 绝经后女性胸腰椎压缩骨折髋骨骨量丢失明显,在临床检测中,压缩骨折组髋骨BMD与无压缩骨折组髋骨BMD有显著性差异,当绝经后女性发生胸腰椎压缩骨折时,髋骨BMD对预测髋骨骨折发生率具有重要意义.     

仫佬族绝经前与绝经后女性体成分和骨密度的相关性研究

目的研究仫佬族绝经前与绝经后女性体成分和骨密度的相关关系,探讨体成分的变化对骨密度的影响。方法随机选取广西仫佬族成年女性200名,追溯其三代均为仫佬族,应用TANITA-MC180人体成分分析仪测定其肌肉量、脂肪量等体成分指标,采用SONOT3000超声骨密度仪测定其右侧跟骨的骨硬度指数。结果 (1)绝经前女性的体重、去脂体重、肌肉量、皮下脂肪量、躯干脂肪量、四肢肌肉量、推定骨量、骨硬度指数和T值等均显著高于绝经后女性(P0.01);而绝经前女性的内脏脂肪面积、腰臀比显著低于绝经后女性(P0.01)。(2)绝经前女性和绝经后女性的骨质疏松检出率分别为6%和45%,差异具有统计学意义(P0.01)。(3)相关分析发现肌肉量、四肢肌肉量和躯干肌肉量与骨密度之间存在显著的正相关关系(P0.01或P0.05),而当控制年龄和绝经状态后体成分和骨密度之间没有相关性;根据年龄分组后发现,≥50岁组的肌肉量各指标与骨密度存在较显著的关联(P0.05),而50岁组的体成分与骨密度不存在关联性(P0.05)。(4)多重逐步回归分析发现只有绝经状态、躯干肌肉量和内脏脂肪量与骨密度相关,而躯干肌肉量对骨密度影响最大。结论仫佬族绝经后女性的骨质疏松症发生率显著高于绝经前女性;控制年龄和绝经因素后,只有躯干肌肉量与骨密度较显著相关,结果可为骨质疏松症的预防和诊断提供理论依据。     

联合补充钙、镁、铜、锌和维生素D对中老年妇女骨质疏松防治效果的研究

目的观察联合补充钙、镁、锌、铜及维生素D对中老年妇女骨密度和骨钙素的影响，以及改善骨症状的效果。方法依据入选和排除标准，在上海地区筛选出中老年妇女154人，随机分成干预组和对照组。A为未绝经，B为绝经。细分成：干预组A：未绝经38名；对照组A：未绝经40名；干预组B：已绝经39名；对照组B：已绝经37名。干预组每日服用2片钙尔奇牌添佳片（每片含钙273．5mg、VitD1．62旭、镁99．7nag、锌3．08mg、铜0．51mg），连续服用1年。所有参加者研究前后均检测腰椎骨密度（BMD）及血清骨钙素（BGP），并进行24h膳食回顾调查和记录骨症状改善情况。结果①研究6个月后，干预组骨密度值较前无显著差异。研究1年后，未绝经干预组骨密度有显著增加（＋1．18％），未绝经对照组腰椎骨密度则有显著性下降（-3．74％）。已绝经干预组和对照组的骨密度研究前后没有显著变化。②研究6个月、一年后各组的骨钙素水平均有明显降低（P〈0．05），但干预组A和B的血清骨钙素水平均明显高于对照组A和B，差异有显著性（P〈0．05）。③干预后能明显改善局部关节痛、腰背痛等骨症状。结论联合补充钙、镁、锌、铜及维生素D可明显增加未绝经妇女的骨密度，有效改善骨症状；可明显改善已绝经妇女骨钙素及骨症状，但其骨密度的改善不明显。建议中老年妇女应尽早补充与骨营养有关的营养素来防治骨质丢失。     

绝经后妇女的生殖特征和骨密度相关性研究

目的探讨绝经后妇女生殖特征与骨密度之间的关系。方法 2014年3月至2016年7月入住本院收治的200例绝经后骨质疏松症女性被选为候选人。记录了一些社会人口、生活方式和生殖因素。使用双能X射线吸收测量法测量腰椎1-4(L_(1-4))的BMD。Pearson相关检验和多元回归分析评估生殖因素与骨密度的相关性。结果绝经年龄与骨密度无显著相关性,绝经年数、月经初潮年龄、妊娠次数和总泌乳期与其成负相关。在生殖因素中,调整年龄、体质指数、活动和钙摄入量后,泌乳持续时间和骨密度之间的呈现显著负相关性。结论除延长泌乳总时间外,其他生殖因素与绝经后妇女骨密度无显著相关性。     

太极对预防绝经后女性骨密度的荟萃分析

目的 评价太极对预防绝经后女性骨密度的影响。方法 通过检索数据库搜集太极对绝经后女性骨密度影响的文献。采用Revman5.1软件进行分析,评价指标为骨密度。结果 共纳入7篇文献,5篇随机对照试验提示初学太极的绝经女性经过太极训练后可减少其骨密度的丢失;2篇横断面研究提示长期有规律的进行太极锻炼可预防绝经后女性的骨密度流失。但方法学上存在差异,Meta分析的结果显示,太极未可改善绝经后女性骨密度。结论 目前尚未有足够的证据指出,太极对预防绝经后女性骨密度的影响积极有效。     

椎体骨折评估在绝经后女性骨质疏松诊断中的应用价值

目的研究利用双能X线骨密度仪扫描的脊柱影像进行椎体骨折评估在绝经后女性骨质疏松诊断中的应用价值。方法回顾499名年龄≥50岁的绝经后女性行骨密度检测同时行椎体侧位扫描,分析骨密度及椎体骨折评估(vertebral fracture assessment,VFA)的检测结果,收集研究对象的一般资料。结果对499名绝经后女性进行VFA检测结果分析:(1)椎体骨折诊断率提高了41.1%,骨质疏松诊断率提高了6.3%,严重骨质疏松诊断率提高了29.1%(P0.05);(2)当骨密度达到骨质疏松阈值时,椎体骨折率明显升高,较骨密度未达到骨质疏松阈值的椎体骨折发生率提高了29.2%(P0.05);(3)年龄增加、绝经年限延长的女性椎体骨折、骨质疏松、严重骨质疏松的患病率显著增加,骨量显著减少(P0.05);此外,体质量指数(body mass index,BMI)降低的绝经后女性骨量显著减少,骨质疏松的患病率显著增加(P0.05)。结论骨密度检测联合椎体骨折评估可以显著提高椎体骨折、骨质疏松、严重骨质疏松的诊断率;骨密度越低,年龄越大,绝经年限越长,椎体骨折的风险就越高;随年龄增长、绝经年限增加、BMI降低,骨密度减少,骨质疏松患病率增加。     

骨质疏松与病理性骨折的相关性研究

目的本研究通过定量CT进行骨密度的测定，分析随着年龄增加骨密度的变化，确定易发生骨折的骨密度标准值，即骨折阈值；并为预防骨质疏松症的发生提供理论依据。方法选择来我院就诊的深圳地区骨折患者男性60人，女性64人，通过X线平片确定为骨质疏松性骨折。用定量CT（QCT）测量椎体横断面中部的松质骨结构，通过软件处理得到L1、L2、L3总的松质骨中骨矿（Ca—HA）密度数值（mg／cm^3）。结果①骨密度值与年龄呈负相关，随着年龄增长骨密度随之降低，按P〈0．05确定易发生骨折的BMD阈值，男性为109．26mg／cm^3，女性为100．19mg/cm^3；②男性和女性间椎体、髋骨骨质疏松性骨折均有显著差别（P〈0．01）桡骨及其他部位骨折男性和女性间无差别（P〉0．05）。结论①男性易发生骨质疏松性骨折的骨密度阈值为109．26mg／cm^3，女性为100．19mg/cm^3；②随着年龄的增大，骨密度的丢失导致骨质疏松。骨质疏松是病理性骨折的病理基础，外力作用是骨质疏松性骨折的诱因。     

北京老年妇女膳食钙摄入水平与骨量关系

目的 研究老年妇女在不同膳食钙摄入水平下骨密度变化情况.方法 从北京市3个城区6个街道17个社区中随机选取60岁以上(60～86岁)的老年妇女445人作为研究对象.采用食物频率表调查过去一年的膳食摄入,用双能X线吸收仪(DXA)测定其全身、股骨和腰椎骨密度.结果 我国健康老年妇女不同部位的骨量、骨质疏松的发生率均不同,大转子发生骨质疏松的比例最高,达到19.4%.膳食钙摄人大于1000mg/d的研究对象的髋骨BMD和大转子BMD分别比钙摄入量小于1000mg/d的人高3.4%和4.9%(P＜0.05);而大转子BMD诊断为骨质疏松的比例显著下降到12.7%(P＜0.05),为"骨量正常"的比例显著增加.未观察到不同膳食钙摄入水平对全身和腰椎骨量的显著影响.结论 膳食钙摄入对不同部分的效果不同,充分的膳食钙摄入有利于改善髋骨骨量.     

长寿地区绝经后女性骨密度检测结果分析

目的 检测广西巴马地区60岁以上绝经后女性的骨密度,探讨其骨密度随年龄、身高、体重、等变化的规律。方法 随机选取当地254位60岁以上的绝经后女性,应用韩国生产跟骨超声骨密度测定仪,测定跟骨骨密度。采用SPSS16.0对数据进行分析。结果 绝经后女性的SI随年龄的增加呈现出下降的趋势。骨质疏松症的患病率随年龄的增加而升高。Pearson的相关性发现, SI和年龄呈现出负相关,与体重、身高有显著的正相关性。结论 广西巴马地区绝经后女性的SI与年龄、身高、体重均有显著相关性,本研究获得的SI值为进一步探讨长寿地区老人提供参考依据。     

Soy protein consumption and bone mass in early postmenopausal Chinese women

Recent interest has been shown in the potential beneficial effects of phytoestrogens on bone health. As the early years of menopause are a period of rapid bone loss, and the risk for osteoporosis increases substantially, the habitual intake of soy protein and isoflavones may play a role in the retardation of bone loss. This paper reports the results of the baseline cross-sectional analysis of the association between dietary soy protein intake and bone mineral density/content in a population-based study of Chinese women. The sample comprised 454 healthy Chinese women (mean age 55.1±3.57) within the first 12 years of postmenopause. We estimated the dietary intake of soy protein and isoflavones, and other key nutrients, including dietary protein and calcium, using the quantitative food frequency method. Bone mineral density (BMD) and content (BMC) at the spine, hip and total body were measured with a dual energy X-ray densitometer (Hologic 4500A). Soy protein consumption was categorized as quartiles of intake, and related to BMD values at the spine and hip, and BMC of total body. Stratified analyses were carried out among women within or at least 4 years postmenopausal. We observed few differences in BMD/BMC values among the intake quartiles in women within the first 4 years of menopause. However, among the later postmenopausal women, we noted a dose-response relationship with increasing higher BMD values at the trochanter, intertrochanter as well as the total hip and total body with increasing soy protein intake quartiles (P<0.05 from tests for trend). The BMD values differed by about 4–8% between the first and fourth soy protein intake quartiles. Though women from the fourth intake quartile had a 2.9% higher BMD value compared with those from the first intake quartile, the difference was not statistically significant. Stepwise multiple linear regression analyses showed the association between soy intake quartiles and hip BMD as well as total body BMC values remained after adjusting for body weight, which was retained in the final model. Analyses based on soy isoflavones content yielded similar results. This study demonstrated that, among women after the initial few years postmenopausal, soy protein/isoflavones intake had a modest but significant association with hip BMD as well as total body BMC. The effects of soy protein and soy isoflavones on bone health should be further explored in populations with habitual dietary soy intake.     

Determinants of bone density in 30- to 65-year-old women: a co-twin study.

Reported effects of body composition and lifestyle on bone mineral density in pre-elderly adult women have been inconsistent. In a co-twin study, we measured bone mineral density, lean and fat mass, and lifestyle factors. Analyzing within pair differences, we found negative associations between bone mineral density and tobacco use (2.3-3.3% per 10 pack-years) and positive associations with sporting activity and lean and fat mass. INTRODUCTION: Reported effects of body composition and lifestyle of bone mineral density in pre-elderly adult women have been inconsistent. METHODS: In a co-twin study of 146 female twin pairs aged 30 to 65 years, DXA was used to measure bone mineral density at the lumbar spine, total hip, and forearm, total body bone mineral content, and lean and fat mass. Height and weight were measured. Menopausal status, dietary calcium intake, physical activity, current tobacco use, and alcohol consumption were determined by questionnaire. Within-pair differences in bone measures were regressed through the origin against within-pair differences in putative determinants. RESULTS: Lean mass and fat mass were associated with greater bone mass at all sites. A discordance of 10 pack-years smoking was related to a 2.3-3.3% (SE, 0.8-1.0) decrease in bone density at all sites except the forearm, with the effects more evident in postmenopausal women. In all women, a 0.8% (SE, 0.3) difference in hip bone mineral density was associated with each hour per week difference in sporting activity, with effects more evident in premenopausal women. Daily dietary calcium intake was related to total body bone mineral content and forearm bone mineral density (1.4 +/- 0.7% increase for every 1000 mg). Lifetime alcohol consumption and walking were not consistently related to bone mass. CONCLUSION: Several lifestyle and dietary factors, in particular tobacco use, were related to bone mineral density. Effect sizes varied by site. Characterization of determinants of bone mineral density in midlife and thereafter may lead to interventions that could minimize postmenopausal bone loss and reduce osteoporotic fracture risk.     

Dietary silicon intake is positively associated with bone mineral density in men and premenopausal women of the Framingham Offspring cohort.

The role of dietary silicon in bone health in humans is not known. In a cross-sectional, population-based study (2847 participants), associations between dietary silicon intake and BMD were investigated. Dietary silicon correlated positively and significantly with BMD at all hip sites in men and premenopausal women, but not in postmenopausal women, suggesting that increased silicon intake is associated with increased cortical BMD in these populations. INTRODUCTION: Osteoporosis is a burgeoning health and economic issue. Agents that promote bone formation are widely sought. Animal and cellular data suggest that the orthosilicate anion (i.e., dietary silicon) is involved in bone formation. The intake of silicon (Si, approximately 30 mg/day) is among the highest for trace elements in humans, but its contribution to bone health is not known. MATERIALS AND METHODS: In a cross-sectional, population-based study, we examined the association between silicon intake and bone mineral density (BMD) in 1251 men and 1596 pre- and postmenopausal women in the Framingham Offspring cohort (age, 30-87 years) at four hip sites and lumbar spine, adjusting for all potential confounding factors known to influence BMD and nutrient intake. RESULTS: Silicon intake correlated positively with adjusted BMD at four hip sites in men and premenopausal women, but not in postmenopausal women. No significant association was observed at the lumbar spine in any group. Categorical analysis by Si intake, or energy-adjusted Si intake, supported these findings, and showed large differences in BMD (up to 10%) between the highest (> 40 mg Si/day) and lowest (< 14 mg Si/day) quintiles of silicon intake. A significant association at the lumbar spine in men was also observed. Further analyses indicated that some of the effects seen for moderate consumption of alcoholic beverages on BMD might be attributed to Si intake. CONCLUSIONS: These findings suggest that higher dietary silicon intake in men and younger women may have salutary effects on skeletal health, especially cortical bone health, that has not been previously recognized. Confirmation of these results is being sought in a longitudinal study and by assessment of the influence of silicon intake on bone markers in this cohort.     

Racial differences in the effect of early milk consumption on peak and postmenopausal bone mineral density.

Studies of the effect of milk consumption on bone density have focused on white women. The applicability to other races is unclear. This study of 4316 women found a racial difference in the effect of early milk consumption on bone. Further study is required to evaluate the etiology of this difference. INTRODUCTION: Early milk consumption has been found to influence bone mineral density positively throughout life. Previous studies leading to this finding focused on white women; there are no data to support the view that black women also gain an equivalent benefit from early milk consumption. MATERIALS AND METHODS: Using data from the Third National Health and Nutrition Examination Survey (NHANES III), we analyzed the relationship between reported childhood and teenage milk consumption and current hip bone mineral density at four sites (femoral neck, trochanter, intertrochanter, and total hip) among postmenopausal and 20- to 39-year-old non-Hispanic white (NHW) and black (NHB) women. Potential confounding variables were accounted for in the analysis. RESULTS: Controlling for age and body mass index, teenage milk consumption was significantly associated with higher bone mineral density at all four sites among both postmenopausal and 20- to 39-year-old white women, but was not associated with bone mineral density at any site among black women. A similar pattern was observed for childhood milk intake. The interaction between race and teenage milk consumption significantly explained postmenopausal bone mineral density at all sites, whereas the interaction between race and teenage milk consumption was significant at two of the four sites among the 20- to 39-year-old women. CONCLUSION: The results show racial differences in the effect of early milk consumption on peak and postmenopausal bone mineral density.     

Vitamin C supplement use and bone mineral density in postmenopausal women.

Vitamin C is known to stimulate procollagen, enhance collagen synthesis, and stimulate alkaline phosphatase activity, a marker for osteoblast formation. Studies of dietary vitamin C intake and the relation with bone mineral density (BMD) have been conflicting, probably because of the well-known limitations of dietary nutrient assessment questionnaires. The purpose of this study was to evaluate the independent relation of daily vitamin C supplement use with BMD in a population-based sample of postmenopausal women. Subjects were 994 women from a community-based cohort of whom 277 women were regular vitamin C supplement users. Vitamin C supplement use was validated. Daily vitamin C supplement intake ranged from 100 to 5,000 mg; the mean daily dose was 745 mg. Average duration of use was 12.4 years; 85% had taken vitamin C supplements for more than 3 years. BMD levels were measured at the ultradistal and midshaft radii, hip, and lumbar spine. After adjusting for age, body mass index (BMI), and total calcium intake, vitamin C users had BMD levels approximately 3% higher at the midshaft radius, femoral neck, and total hip (p < 0.05). In a fully adjusted model, significant differences remained at the femoral neck (p < 0.02) and marginal significance was observed at the total hip (p < 0.06). Women taking both estrogen and vitamin C had significantly higher BMD levels at all sites. Among current estrogen users, those also taking vitamin C had higher BMD levels at all sites, with marginal significance achieved at the ultradistal radius (p < 0.07), femoral neck (p < 0.07), and total hip (p < 0.09). Women who took vitamin C plus calcium and estrogen had the highest BMD at the femoral neck (p = 0.001), total hip (p = 0.05), ultradistal radius (p = 0.02), and lumbar spine. Vitamin C supplement use appears to have a beneficial effect on levels of BMD, especially among postmenopausal women using concurrent estrogen therapy and calcium supplements.     

Interaction of calcium nutrition and physical activity on bone mass in young women

We have examined the relationships among calcium intake, mechanical stress (activity) and axial (lumbar) and peripheral (midradius) bone mass in a population of 60 young normal, healthy eumenorrheic women (age 25-34 years), selected on the basis of weight for height (within 20% of expected). In this population, vertebral bone mineral density was significantly related (r = 0.41, p less than 0.005) to activity pattern but not to calcium intake. Elimination of the effects of activity, however, disclosed a significant correlation between total calcium intake and vertebral bone mass (r = 0.36, p less than 0.02). Closer examination of this relationship suggested that vertebral bone mineral density did not appear to increase with calcium intakes above 800-1000 mg/day, implying a threshold effect and vertebral density was better expressed as a function of the logarithm of calcium intake (r = p less than 0.01). Radial mineral content was not related to activity (which was mostly walking and running), but it was significantly affected by calcium intake. These data suggest that skeletal status in the vertebrae in young women may be influenced by modulation of mechanical stress. However, bone mineral density is probably also dependent on nutritional status such that the optimum calcium intake for this effect is 800-1000 mg/day. If such effects, observed here cross-sectionally, can be substantiated in longitudinal studies and persist into the aging postmenopausal population, then the average age of onset of osteoporotic fractures would be expected to be delayed approximately 10 years, by relatively simple modifications of diet and activity.     

Oral daily ibandronate prevents bone loss in early postmenopausal women without osteoporosis.

Oral daily ibandronate was investigated for the prevention of bone loss in postmenopausal women without osteoporosis (n = 653). BMD at the lumbar spine and hip were significantly increased (3.1% and 1.8%, respectively; p < or = 0.0001 versus placebo) with 2.5 mg ibandronate after 24 months. Oral ibandronate is a promising option for the prevention of postmenopausal bone loss. INTRODUCTION: Further strategies to manage patients most at risk from developing postmenopausal osteoporosis are required. The objectives of this multicenter, double-blind, randomized, placebo-controlled study were to examine the efficacy, tolerability, and optimal dose of oral daily ibandronate in the prevention of bone loss in postmenopausal women. MATERIALS AND METHODS: In total, 653 women (mean bone mineral density [BMD] T-score > -2.5 at the lumbar spine), who had been postmenopausal for at least 1 year, were allocated to one of four strata based on time since menopause and baseline lumbar spine BMD. Women were randomized to receive calcium (500 mg daily) plus either placebo (n = 162) or ibandronate 0.5 mg (n = 162), 1 mg (n = 166), or 2.5 mg (n = 163) as once-daily oral treatment for 2 years. The primary endpoint was the mean percent change in lumbar spine BMD with ibandronate versus placebo. RESULTS AND CONCLUSIONS: After 2 years, oral daily ibandronate produced a dose-related and sustained maintenance or increase in BMD at the lumbar spine and hip (total hip, femoral neck, trochanter), together with a dose-related reduction in the rate of bone turnover. The greatest nominal increases in spinal and hip BMD were observed with the 2.5-mg dose, which produced statistically significant BMD gains compared with placebo at 6 months and all subsequent time-points at the spine and hip (3.1% and 1.8% increase in lumbar spine and total hip BMD, respectively, versus placebo; p < or = 0.0001 after 24 months). Oral daily ibandronate was well tolerated with an incidence of upper gastrointestinal adverse events similar to placebo. No safety concerns were identified. In summary, oral daily ibandronate 2.5 mg decreases bone turnover, preserves or increases BMD in the spine and proximal femur, and is well tolerated. Oral ibandronate provides a promising option for the prevention of bone loss in postmenopausal women.     

The Relation of Dietary Vitamin C Intake to Bone Mineral Density: Results from the PEPI Study

Ascorbic acid is a required cofactor in the hydroxylations of lysine and proline necessary for collagen formation; its role in bone cell differentiation and formation is less well characterized. This study examines the cross-sectional relation between dietary vitamin C intake and bone mineral density (BMD) in women from the Postmenopausal Estrogen/Progestin Interventions Trial. BMD (spine and hip) was measured using dual energy X-ray absorptiometry (DXA). The PEPI participants (n = 775) included in this analysis were Caucasian and ranged in age from 45 to 64 years. At the femoral neck and total hip after adjustment for age, BMI, estrogen use, smoking, leisure physical activity, calcium and total energy intake, each 100 mg increment in dietary vitamin C intake, was associated with a 0.017 g/cm² increment in BMD (P= 0.002 femoral neck; P= 0.005 total hip). After adjustment, the association of vitamin C with lumbar spine BMD was similar to that at the hip, but was not statistically significant (P= 0.08). To assess for effect modification by dietary calcium, the analyses were repeated, stratified by calcium intake (>500 mg/day and ≤500 mg/day). For the femoral neck, women with higher calcium intake had an increment of 0.0190 g/cm² in BMD per 100 mg vitamin C (P= 0.002). No relation between BMD and vitamin C was evident in the lower calcium stratum. Similar effect modification by calcium was observed at the total hip: the β coefficient in the higher calcium stratum was similar to that for the total sample (β= 0.0172, P= 0.01), but no statistically significant relation between total hip BMD and vitamin C was found in the lower calcium subgroup. Although the relation between vitamin C and lumbar spine BMD was of marginal statistical significance in the total sample, among women ingesting higher calcium, a statistically significant association was observed (β= 0.0199, P= 0.024). These data are consistent with a positive association of vitamin C with BMD in postmenopausal women with dietary calcium intakes of at least 500 mg. Received: 12 September 1997 / Accepted: 27 January 1998     

Correlates of cortical bone mass among premenopausal and postmenopausal Japanese women

Few studies have examined the multifactorial risk factors of bone mass in Asian populations. This cross-sectional study was designed to explore relationships between bone mass and environmental variables, including dietary and life-style factors, in Japanese women living in Japan. A total of 178 Japanese women completed the study: 89 premenopausal, ages 35-40, and 89 postmenopausal, ages 55-60. Midradial bone mineral content (MBMC) and bone mineral content per unit area, referred to as bone density (MBMD), were measured using single-photon absorptiometry. The major results of this investigation were the following: (1) The postmenopausal women differed significantly from the premenopausal women in having lower radial bone parameters, lower mean height, later age of menarche, and higher dietary intakes of carbohydrates, vegetables, and milk with a lower intake of caffeine. (2) Current protein intake was a positive correlate of MBMC in both groups. (3) Intake of vegetables (leafy green, yellow, orange, and white) and current milk intake were positively associated with MBMC in the postmenopausal women. (4) For the premenopausal women, irregular menstrual cycles was a negative correlate of MBMC, and for the postmenopausal women, years of menopause was negatively associated with MBMC and MBMD. Longitudinal studies are needed to establish more conclusively associations among diet, life-style, and reproductive history and bone mass of Japanese women.     

Potential risk factors for development of postmenopausal osteoporosis — Examined over a 12-year period

In a longitudinal study, we investigated the influence of risk factors on bone mass at menopause and postmenopausal bone loss in 121 healthy postmenopausal women. These women had completed a 2-year prospective study in 1979 and a follow-up examination in 1989. Measurements of the bone mineral content in the distal forearm (single photon absorptiometry) were performed 9 times during the initial study and once at the follow-up examination. Bone mass at menopause (initial measurement), rate of early postmenopausal bone loss, and the subsequent rate of bone loss over 10 years were thus determined. In addition, the bone mineral density of the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA) in 1989. Information about risk factors was assessed by standardized questionnaires and included reproductive history and lifestyle factors (intake of calcium and vitamin D supplements, consumption of alcohol and caffeine, smoking habits, and physical activity). Lactation, oral contraceptive use, and dietary calcium intake above 1500 mg per day was associated with significantly increased bone mass at menopause. The number of pregnancies reduced the rate of early postmenopausal bone loss, whereas moderate alcohol consumption reduced the subsequent rate of bone loss. Smoking significantly reduced femoral bone mineral density. In conclusion, the present prospective study showed that some of the examined putative risk factors positively influenced bone mass at menopause, especially calcium intake, whereas the postmenopausal bone loss was virtually unaffected. Assessment of risk factors in postmenopausal women thus seems to have limited value for reducing future risk of osteoporosis.