钙摄入量对青春前期女童骨量增长的影响—两年随机干预实验

目的研究不同钙摄入量对于青春前期女童骨量增长的影响,为该人群钙适宜摄入量的修订提供科学依据。方法以年龄10.0±0.7岁的241名青春前期健康女童为对象,设计普通膳食组、牛奶补充组和钙剂补充组三组,总钙摄入量分别为600、900和1200mg/d,进行2年干预,采用多次称量及3d膳食询问法获得2年间日均膳食钙摄入量,使用双能X线骨密度仪测量干预前后全身、腰椎及近端股骨骨矿物密度和骨矿物含量。结果2年间三组的平均钙摄入量分别为552±61、864±139和1166±207mg/d;日均钙摄入量与全身、多位点骨矿物含量和骨矿物密度显著正相关;当日均钙摄入量达到864mg/d时,全身骨矿物含量增加值显著高于钙摄入量为552mg/d膳食组;当日均钙摄入量达到1166mg/d时,股骨颈骨矿物含量及骨矿物密度和腰椎骨矿物密度的增加值显著高于未达到1166mg/d的干预组。结论9～11.5岁的青春前期女童钙摄入量达到1166mg/d,全身特别是负重部位能获得较高骨矿物含量和骨矿物密度增长,提示青春前期钙适宜摄入量可能为1200mg/d。     

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。     

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。     

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。     

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。     

膳食钙、磷以及奶制品对绝经后妇女骨密度的影响

目的探讨膳食中钙、磷以及奶制品的摄入量对骨密度及骨盐含量的影响,为研究骨质疏松的预防提供相关线索和依据。方法在广州市越秀区农林街社区发放传单招募调查对象,并采用自编的结构化标准问卷,对320名广州绝经后妇女的膳食习惯进行调查,并测量其全身、股骨全身、股骨颈、股骨干、大粗隆、Ward’s三角以及腰锥1～4的骨密度和骨量,采用多因素逐步回归分析探讨膳食钙、磷及奶制品对骨盐含量及骨密度的影响。结果 320名调查对象平均57.1岁,平均绝经年限7.3年,平均每天摄入钙、磷及奶制品分别为822 mg、949 mg和126 g,平均全身骨密度为1.054 g/cm2,磷与7个部位的骨密度及骨盐含量呈正相关关系（P〈0.05）。随着磷摄入量增加,全身及腰锥1～4骨密度增加,偏回归系数值分别为0.121和0.184 g.（cm2）-1.g-1.d-1。随着奶制品摄入量增加,股骨全身、股骨干骨密度也相应增加,骨密度偏回归系数值分别为0.686、0.841mg.（cm2）-1.g-1.d-1。钙与全身、股骨全身、股骨颈、大粗隆、股骨干和Ward’s三角的BMC具有正相关性,而在钙与BMD关系中,钙只与股骨全身、大粗隆和股骨干呈正相关性,且每日膳食中每增加100 g钙的摄入量,则股骨全身、大粗隆、股骨干的骨密度相应增加5.3、4.8和7.6 g/cm2。结论增加膳食中钙、磷以及奶制品的摄入量有利于绝经后妇女的骨盐含量及骨密度的提高。     

护骨素基因多态性对青春前期女童骨量的影响

目的:了解护骨素(osteoprotegerin,OPG)基因启动子区A163G、T245G和T950C位点多态性对青春前期汉族女童骨密度(BMD)的影响。方法:采用PCR-RFLP技术检测广州地区214名青春前期女童护骨素基因三个位点的基因型。采用双能X线骨密度仪测量全身、腰椎(L1-4)、股骨颈和Ward三角区骨矿含量(BMC)和骨密度。同时测定三种骨代谢生化指标。结果:OPG基因启动子区A163G、T245G和T950C位点基因型分布频率均符合Hardy-Weinberg遗传平衡定律,分布频率分别为:A163G:AA-74.8%,AG-21.5%,GG-3.7%;T245G:TT-77.1%,TG-21.5%,GG-1.4%;T950C:TT-41.1%,TC-50.5%,CC-8.4%。T950C位点CC基因型女童的全身骨量、骨密度及股骨颈和Ward三角区骨密度均显著高于TT、TC基因型女童(P<0.05),而TT和TC基因型女童未见显著差异(P>0.05)。A163G和T245G位点多态性与女童BMC和BMD的相关性未发现有统计学意义(P>0.05)。结论:护骨素基因T950C位点含有T等位基因的青春前期女童,其全身骨密度及股骨颈和Ward’s三角区骨密度均较低,该等位基因可能为我国青春期女童低骨量者筛选的遗传学标志提供了研究方向。     

膳食矿物质与骨密度关系调查

目的 研究老年人膳食中矿物质含量对骨密度（BMD）的影响，探讨防治老年骨质疏松的措施。方法 对309例60岁以上老人进行了膳食调查及健康检查。结果 老年女性骨矿物质含量（BMC）和骨密度（BMD）显低于男性。健康老人平均每日摄入钙、锰、铜、硒的量男性均显高于女性。OP患与同性别健康老人每日矿物质摄入量相比，OP组钾钙、镁、铁、锰、锌、磷、来源于奶的钙（简称奶钙）、硒摄入量均显低于同性别健康老人组，BMD与钾、钙、镁、锌、铜、磷、硒、奶钙摄入量和钙磷比值均呈显正相关。结论 膳食矿物质与BMD存在一定的关系，膳食钾、钙、锌等摄入量不足可能导致BMD降低。     

青春前期女童骨钙素基因多态性与骨量的相关关系

目的:了解我国青春前期女童骨钙素基因多态性分布并探讨其对骨量的影响。方法:选择152名9～11.5岁未月经初潮的健康女童,采用双能X线骨密度仪(DXEA)检测对象全身、L1-L4腰椎、左侧近端股骨的骨矿含量、骨密度以及体成分,采用PCR-RFLP技术检测骨钙素基因多态性。结果:152名女童OC基因HindⅢ位点多态性基因型的分布频率分别为:突变型纯合子(HH)5.26%,杂合子(Hh)36.84%,野生型纯合子(hh)为58.90%,各基因型TBBMC、全身及各部位的BMD、血骨钙素水平均存在显著差异(P<0.05),表现为HH相似文献   

乳母膳食与乳汁中矿物质含量研究

目的探讨膳食矿物质摄入水平及对乳汁矿物质含量的影响。方法选择婴儿月龄在30天~50天母乳喂养的健康乳母为调查对象,共56人,年龄23~35岁。于产后30天由专人进行入户调查。采用24小时回顾法,记录调查对象每餐摄入食物的种类和数量,并同时采集乳汁,用火焰原子吸收光度法测其钙、铁、锌、镁、铜、锰的含量。结果济南市乳母膳食中禽蛋摄入较高149g,豆类较低14g。与营养素推荐摄入量(RNI)比较,膳食能量摄入偏低(77.5%)。膳食矿物质铜、铁、锰、镁的摄入量均达到RNI的90%,钙摄入量较低,仅为RNI的62.5%。乳汁中钙、铁、锰、镁、铜、锌含量分别为0.39g/L、1.35mg/L、17.5μg/L、36mg/L、0.33mg/L、2.18mg/L。膳食矿物质摄入量与乳汁中矿物质含量的相关性分析结果显示,膳食钙、锌、锰的摄入量与乳汁中含量显著相关(P<0.01)。结论济南市乳母膳食组成中禽蛋摄入较高,豆类摄入偏低,膳食钙、维生素B1摄入不足。     

Effect of habitual dietary calcium intake on calcium supplementation in 12-14-y-old girls

BACKGROUND: There is no agreement on how much calcium young girls need for optimal bone mineralization. OBJECTIVE: We evaluated whether the effect of calcium supplementation on whole-body bone mineral accretion depends on habitual calcium intake. DESIGN: This was a randomized, double-blind, placebo-controlled, 1-y calcium intervention study of girls aged 12-14 y selected from a larger group according to habitual calcium intake: subgroup A (n = 60) habitually consumed 1000-1307 mg/d (40th-60th percentile), and subgroup B (n = 53) habitually consumed <713 mg/d (<20th percentile). The girls from each subgroup were randomly assigned to receive either 500 mg Ca/d or placebo. Whole-body bone mineral content (BMC), bone area (BA), bone mineral density (BMD), and BMC adjusted for BA, height, and weight (size-adjusted BMC) were measured at baseline and after 1 y. RESULTS: There was no significant effect modification of baseline habitual calcium intake on the relation between calcium supplementation and height, weight, BMC, size-adjusted BMC, BA, BMD, or alkaline phosphatase. Calcium supplementation had an effect on BMD (0.8%; P = 0.049) and tended to show signs of an effect on size-adjusted BMC (0.5%; P = 0.08). CONCLUSION: A modest effect of calcium supplementation on BMD was shown. However, the effect was independent of habitual calcium intake.     

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.     

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.     

Effect of calcium supplementation on bone mineral accretion in gambian children accustomed to a low-calcium diet

BACKGROUND: Rural Gambian children have poor growth, delayed puberty, a low bone mineral content, and a low calcium intake. OBJECTIVE: We investigated the effect of a calcium supplement on bone mineral accretion in rural Gambian children. DESIGN: A randomized, double-blind, placebo-controlled study was conducted in 160 children (80 boys, 80 girls) aged 8.3-11.9 y. Bone mineral content (BMC), bone mineral density (BMD), and BMC adjusted for bone width, body weight, and height (size-adjusted BMC) were measured at the midshaft and distal radius. Each child received either 1000 mg Ca/d (as calcium carbonate) or a placebo 5 d/wk for 12 mo. Supplementation increased calcium intake from 342 to 1056 mg/d (8.6 to 26.4 mmol/d). RESULTS: Calcium supplementation resulted in a higher BMC, BMD, and size-adjusted BMC (&xmacr; difference +/- SE): midshaft radius-BMC (3.0 +/- 1.4%; P = 0.034), BMD (4.5 +/- 0.9%; P 相似文献   

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。     

Calcium intake and bone mass development among Israeli adolescent girls.

OBJECTIVE: To determine the possible relationship between food and life style habits and bone health in adolescent Israeli females. METHODS: 2,000 adolescent Israeli Jewish and Arab high-school girls (mean age 14.5) completed a semi-quantitative food frequency questionnaire and a personal history questionnaire. 27 food components were calculated for each subject. Bone mineral content and density were determined for 112 subjects with calcium intake below 800 mg/day. RESULTS: Average calcium intake was found to be 1,260 mg/day, but 20% of all girls had a calcium intake below 800 mg/day. All low-energy diets were very low in calcium, as mean calcium intake per 1,000 calories was 411 128 grams. A large percentage of diets with less than 800 mg calcium were also deficient in phosphorus (95.2%), magnesium (84.8%). iron (90.5%) and zinc (100%). Due to differences in food sources. Jewish girls had more phosphorus in their diet, but less magnesium and iron compared to Arab girls. Calcium and zinc deficiencies in Jewish and Arab diets were similar. A negative correlation was found between body mass index (BMI) and age at menarche for all girls in the study. Bone mineral density (BMD) measured for girls with calcium intake below 800 mg/day distributed normally around the average when compared to age matched controls despite their low calcium intake. There was a strong positive correlation between BMD and bone mineral content (BMC) at all sites and body weights. CONCLUSIONS: Low calcium intake, other nutritional deficiencies and delayed menarche due to low-energy diet in the growing period and in adolescence may prevent the formation of healthy bones. There is no evidence of lower bone mass among the low calcium intake group in the study population at this stage. It remains to be documented if the window of opportunity for optimal bone accretion for this group will be missed in the future. possibly leading to increased risk of osteoporosis.