膳食钙摄入量与青春前期女童骨量关系的研究

目的:研究青春前期女童膳食钙摄入量与骨量的关系,为指导合理钙营养提供科学依据。方法:采用双能X线骨密度测量仪测量年龄在10±1岁的194名青春前期女童全身及多位点骨密度和骨矿物质含量,采用食物频数及3d膳食询问法调查膳食钙摄入量,问卷法调查体力活动。结果:日均钙摄入量与所测各位点骨矿物质含量及骨密度均呈显著正相关;日均钙摄入量平均从257mg增加到759mg,不同位点的骨矿物质含量和骨密度分别增加13%～22%和3.6%～16%。结论:增加青春前期女童膳食钙摄入量有助于获得较高骨量和骨密度。     

青春前期女童钙代谢实验研究

目的:研究我国青春前期女童钙代谢状况,初步探讨该时期女童钙需要量。方法:选择49名处于生长突增期、未月经初潮的青春前期女童,采用经典钙代谢实验方法,在600～1500mg/d范围内设计4个不同的钙摄入剂量组,观察研究对象的钙代谢状况。结果:在600～1500mg/d钙摄入量范围内,各组对象钙表观钙吸收率未发现差别,平均吸收率为(53±0.12)%(范围52%～55%)。采用非线性回归模型对钙摄入量和钙储留量的关系进行拟合,钙摄入量在500mg/d时,钙储留量处于较低水平,钙摄入量在500～1000mg/d时,储留量快速增加,当钙摄入量达到1100mg/d时,钙储留量稳定在500mg/d左右的平台水平。结论:我国青春前期女童钙的表观吸收率为(53±0.12)%;青春前期女童达到最大钙储留量的最低钙摄入量是1100mg/d。     

补钙16个月对青春期男女生骨量的影响

目的探讨不同钙摄入量对我国青少年骨量的影响。方法对北京郊区337人(平均年龄为13.6岁)开展为期16个月的双盲对照干预研究,每天给予3次不同剂量碳酸钙片,每片含60IU维生素D,用双能X线吸收仪(DXA)测定全身、腰椎和前臂骨量。结果女生全身骨矿物密度的年增长率由低钙摄入组到高钙摄入组逐渐升高,调整混杂因素后差异消失。女生前臂远端1/3处和男生前臂远端1/10处的骨矿物含量年增长率和骨面积年增长率均以每天钙摄入900～1100mg/d的人群(平均钙摄入量984mg/d)最高,其中调整混杂因素后男生差异消失。结论青春期钙摄入量达到1000mg/d以上可促进青少年骨量增长,此结果有性别差异。     

49名9～11.5岁青春前期女童钙吸收率研究

目的研究中国青春前期女童钙代谢状况,了解中国青春前期女童钙吸收率和影响钙吸收率的因素。方法选择49名处于生长突增期、未月经初潮的青春前期女童,采用经典钙代谢实验方法,在600～1500mgd范围内设计4个不同的钙摄入剂量组,观察研究对象的钙代谢状况。结果在600～1500mgd钙摄入量范围内,各组对象钙表观钙吸收率未发现差别,平均吸收率为(53±0.12)%(范围52%～55%)。膳食蛋白质水平与钙吸收率、粪钙量无相关关系,尿钙与膳食磷含量、蛋白质含量显著负相关(P<0.01)。结论中国青春前期女童钙的表观吸收率为53%;高膳食蛋白质能增加尿钙的排出。     

补钙对青年女性全身各部位骨密度的影响

目的探讨不同钙摄入量对我国青年女性全身及各部位骨密度的影响,为进一步研究制定我国居民钙的适宜摄入量提供科学依据。方法为期13个月设有对照的双盲干预研究。将某军校平均年龄19.8岁女学员179人,以基线调查的全身骨密度及膳食钙摄入量为指标,随机分为4组,每天给予不同剂量碳酸钙片,使总钙摄入量分别达到400、800、1000及1200mg/d,每片钙片中均强化60IU的维生素D。干预前后分别使用食堂记帐法、称重法和24小时记录法了解膳食摄入,体力活动问卷了解体力活动情况,双能X线骨密度仪测定全身、腰椎和前臂的骨密度。结果4组平均摄入的膳食钙加上补充钙的中位数分别是517mg/d(1组)、810mg/d(2组)、964mg/d(3组)、1185mg/d(4组)。实验前后各部位骨密度增加值的组间比较分析显示,3组和4组的全身、下肢和尺骨远端1/3处骨密度增加值均显著高于1组和2组(P<0.05);3组和4组的3处骨密度增加值差异均无显著性。结论随着钙摄入量的增加,青年女性全身各部位骨密度增加,当钙摄入量达到约1000mg/d时,全身、下肢和尺骨远端1/3处骨密度增加值达到最大,再增加钙摄入至1200mg/d时,骨密度不再显著增加。提示我国青年女性钙的适宜摄入量可能在1000mg/d左右。     

不同钙摄入量对青年男性骨密度的影响

目的 探讨不同钙摄入量对我国青年男性骨密度的影响，为进一步研究制定我国居民钙的适宜摄入量提供科学依据。方法 为期13个月的双盲对照干预研究。将某军校男学员155人，平均年龄21．3岁，随机分为4组，以干预前全身骨密度及膳食钙摄入量为基线，进行不同剂量碳酸钙片营养干预，使总钙摄入量分别达到约500、800、1000及1200mg／d，每片钙片中均强化60IU的维生素D。干预前后分别使用食堂记帐法、称重法和24小时记录法了解膳食摄入，双能X线骨密度仪（DEXA）测定全身、腰椎和前臂的骨密度。结果 4组平均摄入的膳食钙加上补充钙的中位数分别是514mg／d（1组）、821mg／d（2组）、987mg／d（3组）、1209mg／d（4组）。实验前后各部位骨密度增加值的组间比较分析显示，第2、3、4组全身、前臂、骨盆的骨密度增加值显著高于第1组，且三组之间无显著性差异；第3、4组下肢骨密度增加值显著高于第1、2组，且3、4组之间无显著性差异。结论 随着钙摄入量的增加，青年男性全身各部位骨密度增加，当钙摄入量达到约1000mg／d时，全身、前臂、骨盆和下肢骨密度增加值达到最大，再增加钙摄入至1200mg／d时，骨密度不再显著增加。提示我国青年男性钙的适宜摄入量可能在1000mg／d左右。     

青春早期女童体力活动与骨量关系的研究

目的探讨体力活动与青春前期女童骨量的关系。方法采用双能X线骨密度测量仪测量年龄在（10±1）岁的194名青春早期女童全身、股骨颈、Ward三角区和L1-L4的骨密度（BMD）和骨矿物质含量（BMC）,采用问卷和跟踪记录调查女童的体力活动和膳食钙摄入。结果日均承重和日均总体力活动能耗与上述位点BMD和BMC均显著正相关,而非承重体力活动与BMD和BMC无显著相关。BMD和BMC随着承重体力活动能耗增高而增高,平均能耗从950kJ（227kcal／d）增加到1737kJ（415kcal／d）时,各位点BMC增加17．5％～29．0％,BMD增加8．8％-17．1％。结论青春前期女童适当增加体力活动量,尤其是承重体力活动量,有助于获得更多的骨量积累。     

青春前期儿童膳食中铁的吸收状况研究

目的探讨青春前期儿童膳食铁的吸收率及相关影响因素。方法选择60名北京地区青春前期儿童,男女各半,依当地饮食习惯制定食谱,进行为期11d的代谢平衡试验,收集试验期内全部粪便样品,以双份饭法收集膳食及水样。样品经冷冻干燥、粉碎、微波消解后,以原子吸收法(AAS)测定铁量,同时对膳食样品中可能影响铁吸收的因子含量进行测定,并以代谢平衡法(MB法)测定铁吸收率。结果男、女性儿童铁的吸收率(%)为8.05±0.90和9.13±0.57,女性显著高于男性,(t=2.38,P<0.05),日均铁摄入量(mg)分别为13.6±2.4和12.8±1.7,分别占推荐营养素摄入量(RNI)的85.0%和71.1%;蛋白质日摄入量(g)分别为75.5±4.1和69.3±6.2,分别占RNI的107.8%和106.6%;维生素C(VC)摄入量(mg)分别为43.2±3.6和38.9±2.1,占RNI的48.0%和43.2%,低于推荐量;膳食纤维和植酸摄入量(g)分别为16.3±3.5、15.1±2.0和1.2±0.2、1.0±0.3。结论北京地区青春前期儿童铁的吸收率仍处于较低水平,女性高于男性。建议在增加膳食中血红素铁和VC摄入的同时,适当降低植酸和纤维素的摄入,以提高铁的吸收率。     

东莞市孕中期妇女膳食营养状况与妊娠结局的追踪研究

目的以东莞市孕中期妇女为对象,研究其膳食营养状况与妊娠结局之关联。方法采用连续3天24小时膳食回顾法,对2014年纳入东莞市某医院队列研究的孕中期妇女膳食进行调查,与膳食营养素参考摄入量和膳食指南推荐食物摄入量进行比较,并分析比较不同妊娠结局孕妇营养状况是否存在差异。结果共纳入890名孕中期妇女,年龄(26.21±3.15)岁,孕前BMI 19.83±2.45。日均能量摄入为2042 kcal,蛋白质摄入量74.0 g,碳水化合物和脂肪供能比分别为55.20%和30.63%,基本符合推荐摄入量;而膳食纤维、钙、视黄醇当量、维生素B1和维生素B2摄入量分别为12.0 g/d、558.7 g/d,236.7μgRE/d、1.0 mg/d、1.1 mg/d,均低于推荐摄入量;磷、锌和铜日均摄入量分别为1114.8 mg、12.5 mg和2.2 mg,超过推荐摄入量。蔬菜和水果日均摄入量分别为302.3 g和412.3 g,蔬菜在推荐摄入量的下限,水果比推荐摄入上限略高;鱼禽蛋肉日均摄入量合计为254.7 g/d,达到推荐摄入量;而奶及奶制品日均摄入量仅为156.6 g,低于推荐摄入量。贫血组孕妇蛋白质、脂肪、维生素B_1、维生素B_2和钙摄入量低于非贫血组,差异有统计学意义(P0.05);新生儿不同出生体重、妊高症与非妊高症组间营养素摄入量比较未发现显著差异。结论东莞市孕中期妇女大部分营养素和食物的摄入量达到了推荐摄入量,但维生素B_1、维生素B_2、膳食纤维、钙、铁和视黄醇当量、蔬菜、奶制品等仍存在摄入不足,贫血孕妇有不同程度蛋白质、脂肪、维生素B_1、维生素B_2和钙的摄入量不足。     

甲状旁腺激素基因多态性与钙摄入量对青春期女童骨量增长的交互作用

目的:探讨甲状旁腺激素(PTH)基因多态性与钙摄入量对青春期女童骨量增长的交互作用。方法:选择228名9～11.5岁未月经初潮的健康女童进行2年追踪,用双能X线骨密度仪(DEXA)检测对象追踪前后全身、左侧近端股骨(包括股骨颈、大转子、粗隆间和华氏三角区)、L1～L4腰椎骨矿含量和骨密度,采用PCR-RFLP技术检测PTH基因BstBⅠ位点多态性。结果:BB基因型女童L1～L4腰椎骨矿含量增长率、左侧近端股骨、粗隆间和L1-L4腰椎骨密度增长率均高于含b等位基因女童(P=0.022～0.047)。BB基因型女童在高钙摄入(>950mg/d)时,粗隆间骨矿含量(ITBMC)增长率较中等和低钙摄入时分别高29.4%和35.0%,股骨颈骨密度(FNBMD)增长率分别高66.7%和46.2%。而含b等位基因女童的ITBMC和FNBMD增长率在不同钙摄入量之间没有显著性差异。结论:PTH基因BstBⅠ多态性与钙摄入量对青春期女童骨量增长存在交互作用,BB基因型女童高钙摄入可促进其骨量增长。     

Calcium supplementation provides an extended window of opportunity for bone mass accretion after menarche

BACKGROUND: High calcium intakes during adolescence may increase bone acquisition. The magnitude of the effect of dietary calcium supplementation and the timing of its administration to achieve significant effects on bone health are still incompletely defined. OBJECTIVE: The objective of this study was to assess the effect of calcium supplementation on bone mass accretion in postmenarcheal adolescent girls with low calcium intakes. DESIGN: A double-blind, placebo-controlled calcium supplementation study was implemented. One hundred girls with a mean (+/- SD) age of 14 +/- 0.5 y with habitual calcium intakes < 800 mg/d completed a 12-mo protocol. The treatment group received a daily supplement containing 1000 mg elemental calcium. Bone mineral density (BMD) and bone mineral content (BMC) of the total body, lumbar spine, and femoral neck were determined at inclusion, 6 mo, and 12 mo. Also measured were serum concentrations of biochemical markers of bone turnover (osteocalcin and deoxypyridinoline), parathyroid hormone, and vitamin D. RESULTS: The calcium-supplemented group had greater accretion of total-body BMD and lumbar spine BMD but not BMC than did the control group. Calcium supplementation appeared selectively beneficial for girls who were 2 y postmenarcheal. Calcium supplementation significantly decreased bone turnover and decreased serum parathyroid hormone concentrations. CONCLUSION: Calcium supplementation of postmenarcheal girls with low calcium intakes enhances bone mineral acquisition, especially in girls > 2 y past the onset of menarche.     

Calcium supplementation and bone mineral accretion in adolescent girls: an 18-mo randomized controlled trial with 2-y follow-up

BACKGROUND: A recent meta-analysis raised doubt as to whether calcium supplementation in children benefits spine and hip bone mineral density (BMD). OBJECTIVE: We used state-of-the-art measures of bone (fan-beam dual-energy X-ray absorptiometry and 4 bone turnover markers) to determine whether girls with low habitual calcium intake benefited from supplementation with a soluble form of calcium (calcium citrate malate dissolved in a fruit drink). DESIGN: The trial was an 18-mo randomized trial of calcium supplementation (792 mg/d) with follow-up 2 y after supplement withdrawal. Subjects were 96 girls (mean age: 12 y) with low calcium intakes (mean: 636 mg/d). The main outcome measure was change in total-body, lumbar spine, and total hip bone mineral content (BMC) during supplementation and 2 y after supplement withdrawal. Changes in BMD and bone turnover markers were secondary outcome measures. RESULTS: The mean additional calcium intake in the supplemented group was 555 mg/d. Compared with the control group, the supplemented group showed significantly (P < 0.05) greater gains in BMC (except at the total hip site) over the 18-mo study. BMD change was significantly (P < 0.05) greater for all skeletal sites, and concentrations of bone resorption markers and parathyroid hormone were significantly (P < 0.01) lower in the supplemented group than in the control group after 18 mo. After 42 mo, gains in BMC and BMD and differences in bone resorption were no longer evident. CONCLUSIONS: Calcium supplementation enhances bone mineral accrual in teenage girls, but the effect is short-lived. The likely mechanism for the effect of the calcium is suppression of bone turnover, which is reversed upon supplement withdrawal.     

Effects of antioxidant supplementation on bone mineral density,bone mineral content and bone structure in healthy men during 60 days of 6° head-down tilt bed rest: Results from a randomised controlled trial

Dietary countermeasures to mitigate detrimental spaceflight-induced effects on bone health would alleviate the requirements and the consequences imposed by other types of countermeasures for this risk. We hypothesised that antioxidant supplementation during 60 days of 6° head-down tilt bed rest (HDBR), an analogue of spaceflight, would have a protective effect on bone mineral density (BMD), content (BMC) and bone structure parameters. An exploratory, randomised, controlled, single-blind intervention trial was conducted in a parallel design with 20 healthy male volunteers (age 34 ± 8 y, weight 74 ± 6 kg). The study included 14 days of baseline data collection (BDC) before bed rest, followed by 60 days of HDBR and a 14-day recovery period. Ten subjects in the antioxidant group received a supplement (741 mg/d polyphenols, 2.1 g/d omega-3 fatty acids, 168 mg/d vitamin E and 80 μg/d selenium) daily. Ten subjects in the control group received no supplement. The diet was consistent with dietary reference intakes, individually tailored based on the subject's bodyweight and strictly controlled. We measured whole-body, lumbar spine and femur BMD and BMC, as well as BMD of the cortical and trabecular compartments of the distal radius and tibia, and cortical and trabecular thickness during BDC, HDBR and recovery. Data were analysed using linear mixed models. The supplementation of an antioxidant cocktail did not mitigate the deteriorating effects of HDBR on BMD, BMC and bone structure parameters. Our findings do not support a recommendation for antioxidant supplementation for astronauts.     

不同钙摄入量的两地南方儿童骨矿物质含量

用单光子吸收仪测量５岁儿童（１１５名江门市儿童和１２８名香港儿童）桡骨远端１／３处骨矿物质含量（ＭＢＣ）。江门市和香港儿童钙平均摄入量分别为２４４±４６及５４２±３３２ｍｇ／ｄ。江门市儿童骨矿物质含量、体重和身高均明显低于香港儿童的相应数值，分别低１４％、１０％和４％（Ｐ＜０．００１）。经多元回归分析调整后，骨矿物质含量的地区差异仍是０．０３０３ｇ／ｃｍ。比较两地低钙摄入量的５岁儿童骨矿物质含量，江门市儿童骨矿物质含量同样明显低于香港儿童（Ｐ＜０．００３）。本研究结果提示，儿童骨矿物质含量的地区性差异可能与其长期钙摄入量和体力活幼不同有关     

补充钙剂对青春期骨矿含量的影响

为研究补充钙剂对青少年骨矿含量以及体格发育的影响 ,选取 1 61例 9～ 2 0岁健康青少年 ,按性别和性发育程度分为补钙组和对照组。实验前后评价两组膳食钙摄入量、运动量水平、性发育程度 ,并测定两组青少年身高、体重和桡骨远端 1 3处骨矿含量、骨宽和血清总碱性磷酸酶水平。结果表明本组青少年膳食钙摄入量低于每日膳食钙参考摄入量的适宜摄入量水平 ,补充钙剂对青少年身高、体重无明显影响 ;骨矿含量增长除女性青春期后期有显著性差异外 ,其余各组增长与对照组比较无显著性。结果提示 ,青春期存在体格快速发育和骨量迅速积累的特点 ,补充钙剂对骨矿含量的增长作用有限 ,对体格发育也无明显影响 ;在女性骨量增长较少阶段补充钙剂则可能有助于骨矿含量的增加 ,且这种作用可能通过降低骨代谢率实现     

大鼠骨矿物质含量与组织中钙水平的相关性研究

用ＳＤ１０００型单光子骨矿物测定仪研究了９８只１５周龄Ｗｉｓｔａｒ大鼠的股骨矿物质含量（ＢＭＣ）和骨密度（ＢＭＤ，ＢＭＣ／ＢＷ）与组织和血中钙含量的相关性。结果显示：雌、雄动物的身长、体重、骨宽度（ＢＷ）、ＢＭＣ、ＢＭＣ／体重、ＢＭＤ／体重及ＢＭＤ／身长均有显著性差异，活体ＢＭＤ与动物的钙总摄入量、身长、体重、及钙存留率显著相关（Ｐ＜０．０５）；ＢＭＣ与钙总摄入量、身长、体重、性别和肝脏钙含量显著相关（Ｐ＜０．０５）。多元回归分析表明：动物身长、体重、钙总摄入量和心脏钙含量与活体ＢＭＤ呈线性关系，动物身长和血浆钙含量与离体ＢＭＤ呈线性关系。活体测量结果ＢＭＣ、ＢＭＤ由于其与动物的生长发育、钙存留率及肌肉和血浆钙含量具有相关和直线关系，且简便易行、不需要处死动物，因而认为可以反映动物体内钙营养状况和骨质积累情况。     

Sustained effect of short-term calcium supplementation on bone mass in adolescent girls with low calcium intake

BACKGROUND: The effect of short-term calcium supplementation on peak bone mass in adolescent girls is not completely defined. In our previous double-blind, placebo-controlled, calcium-supplementation study (1000 mg calcium carbonate/d), we showed that calcium supplementation of postmenarcheal girls with low calcium intakes enhances bone mineral acquisition. OBJECTIVE: The objective of this follow-up study, conducted 3.5 y after the end of calcium supplementation, was to investigate the sustained effect of calcium supplementation on bone mineral mass. DESIGN: Anthropometric data, nutrient intakes, and bone variables were reassessed in 96 of the 100 adolescent girls whose data had been studied at the end of the supplementation period. Bone mineral content and bone mineral density (BMD) of the total body, lumbar spine, and femoral neck were determined by dual-energy X-ray absorptiometry. RESULTS: The calcium-supplemented group tended to have a greater accretion of total-body BMD (TBBMD) than did the control group 3.5 y after the end of supplementation. The finding was statistically significant in the active-treatment cohort (n = 17 in the calcium-supplemented group and 28 in the placebo group), who had a compliance rate of > or =75% during the intervention study. In a multivariate linear-regression analysis, TBBMD accretion from the beginning of the intervention study to the follow-up study in the active-treatment cohort was attributed to calcium supplementation and to the time since inclusion in the initial study. CONCLUSION: Calcium supplementation for 1 y in postmenarcheal girls with low calcium intakes may provide a sustained effect on the basis of TBBMD measurements in participants with compliance rates of > or =75%.