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。     

济南市7～13岁儿童骨矿物质含量及其影响因素分析

目的 ]分析济南市儿童骨矿物质含量及其影响因素 ,为儿童合理营养 ,促进发育、预防疾病提供依据。 [方法 ] 1998年采用SD -10 0 0型单光子骨矿物测量仪 ,检测了济南市山东医科大学附属小学与山东师范大学附属小学761名 7～ 13岁健康儿童 (其中正常体重儿童 65 6名 ,中度以上肥胖儿童 10 5名 )左前臂中上 1/3处桡骨和尺骨的骨矿物质含量线密度 (BMC)和面密度 (BMD) ,并测量了身高、体重、胸围、皮脂厚度、肺活量等 ,进行了多元逐步回归分析 ,并比较肥胖儿童与正常儿童桡骨BMD。 [结果 ]桡骨和尺骨的BMC与BMD均随年龄的增长而增加 ,各年龄组桡、尺骨骨矿物质含量BMC差异均有高度显著性。体重和体块指数 (BMI)与骨矿物质含量关系密切。肥胖组骨矿物质含量显著高于对照组。 [结论 ]济南市 7～ 13岁儿童骨发育状况良好 ,体重和体块指数是影响骨矿物质含量的主要因素。     

体育锻炼对女性儿童少年骨矿物质及骨密度的影响

目的 ]研究体育锻炼对儿童少年骨骼发育的影响。 [方法 ]对蚌埠市凤阳路第二小学 60名 8～ 10岁小学女生进行为期 4个月的中等强度 ( 110～ 14 0次 /min心率 )的体育锻炼 ,并在锻炼前及锻炼后测定其骨矿物质(BMC)及骨密度 (BMD)。 [结果 ]实验组桡骨及股骨颈BMC和BMD均值高于对照组 ,差异分别有高度显著性 (P<0 0 1)和显著性 (P <0 0 5 )。 [结论 ]体育锻炼对儿童少年各部位骨骼发育有良好的影响。     

青春期和年轻女性应用COCs对BMD的影响

<正>青春期是骨骼发育和矿物化的关键时期,年龄12～18岁的青春期女性全身骨矿物质密度(Bone mineral density,BMD)增加50%以上,所以青春期对骨骼的生长和固化具有非常重要的影响〔1〕。Lu等1994年证实围初潮期骨矿物质密度每年增长2～10%,20～22岁达到骨密度峰值,如果青春期骨矿     

儿童骨密度的测定及其影响因素

骨密度又称骨矿密度(Bone mineral density,BMD),是单位面积的骨矿含量.就测量精度而言,面积骨矿密度并不逊色于体积骨矿密度.由于骨矿物质的主要成分是钙,所以BMD是评估骨钙含量、骨钙丢失率和疗效的重要客观指标.众多疾病和人体衰老过程均可影响骨钙代谢,引发骨矿物质含量的改变.     

钙的生物利用率与骨健康

骨健康主要取决于矿化程度 ,即骨矿物质密度 (BMD) ,表型差异则取决于遗传和环境因素。由于几乎所有储存钙都用于骨的矿化和重建 ,因此可将BMD作为反映膳食钙生物利用率的一种长期 (>6个月 )的标志物。然而 ,由于BMD是一种反映钙生物利用率的非常敏感的标志物 ,因此其在膳食干预研究中的应用仅限于显著的骨生长和骨丢失时期。骨代谢的生化标志物可用于预测短期内 (>4个月 )膳食钙的总生物利用率 ,但由于其变异系数较高 ,因此可能不适用于一些膳食干预研究。目前 ,一些欧洲实验室利用一种长期存在的放射性同位素 (4 1Ca)标记骨钙 ,然后直接检测经尿的钙丢失率。钙吸收率与摄入量呈负相关 ,整个机体的矿物质平衡取决于吸收率和排泄率 ,并受肠道内钙结合物的限制。膳食资料数据和对骨健康的间接检测数据表明 ,当经常性钙摄入量较低时 ,尤其是在骨生长或丢失期间 ,生物利用率非常重要。需要进一步研究以定量钙平衡的主要膳食调节因素对骨健康的影响 ,研究其与遗传和生理变量间的关系     

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。     

雌激素受体基因多态性与青春期少女骨骼发育状况相关性研究

目的了解青春期女性中雌激素受体(ER-α)基因多态性的分布频率;探讨其对少女骨密度(BMD)和骨转换生化指标的影响,及是否存在弱势ER基因型别的群体。方法选取年龄12～14岁、无相关疾病的健康志愿者158名。采用(1)聚合酶链反应-限制性片段长度多态性法对ER-α进行多态性分析;(2)双能X线吸收仪测量全身及前臂的BMD;(3)进口酶联免疫检测试剂盒测定骨转换生化指标(骨钙素BGP、骨碱性磷酸酶BAP、抗酒石酸酸性磷酸酶TRACP)和钙调激素(活性维生素D、雌二醇)水平。分析ER-α基因多态性与机体BMD及骨转换生化指标的相关性。结果(1)各骨转换生化指标在ER-α基因型别间差异无统计学意义,但其在PvuⅡ的各基因型别间表现出pp>PP>Pp的趋势。在XbaⅠ各基因型别间未见明显趋势。Px单倍体组与non-Px组间也未显示出差异(P> 0．05);(2)未见ER-α基因型别间全身及前臂BMD的差异有统计学意义(P>0．05),non-Px单倍体组各部位的BMD普遍大于Px单倍体组,但两组间的差异无统计学意义(P>0．05)。结论中国青春期少女的ER-α基因多态性未显示出对其骨骼生长发育(BMD和骨转换生化指标)有明显影响,该基因型可能不是主要影响该人群的遗传因素。     

036钙的生物利用率与骨健康

骨健康主要取决于矿化程度,即骨矿物质密度(BMD),表型差异则取决于遗传和环境因素.由于几乎所有储存钙都用于骨的矿化和重建,因此可将BMD作为反映膳食钙生物利用率的一种长期(＞6个月)的标志物.然而,由于BMD是一种反映钙生物利用率的非常敏感的标志物,因此其在膳食干预研究中的应用仅限于显著的骨生长和骨丢失时期.骨代谢的生化标志物可用于预测短期内(＞4个月)膳食钙的总生物利用率,但由于其变异系数较高,因此可能不适用于一些膳食干预研究.目前,一些欧洲实验室利用一种长期存在的放射性同位素(41Ca)标记骨钙,然后直接检测经尿的钙丢失率.钙吸收率与摄入量呈负相关,整个机体的矿物质平衡取决于吸收率和排泄率,并受肠道内钙结合物的限制.膳食资料数据和对骨健康的间接检测数据表明,当经常性钙摄入量较低时,尤其是在骨生长或丢失期间,生物利用率非常重要.需要进一步研究以定量钙平衡的主要膳食调节因素对骨健康的影响,研究其与遗传和生理变量间的关系.     

钙吸收利用与钙摄入量关系的动物实验研究

为探讨钙吸收利用与钙摄入量间的相互关系 ,给初断乳Wistar大鼠喂饲 3周缺钙饲料后 ,按体重随机分为缺钙组、钙适宜组和高钙组 ,进行 12周喂养 ,并于实验第 5周进行 3天代谢试验。结果表明 ,适宜补钙可明显增加骨钙、骨密度、骨矿物质含量和股骨的重量 (P <0 0 5 ) ,加大补钙剂量 ,补钙效果未见增加。相关分析发现摄入钙与骨钙、骨密度、骨矿物质含量呈正相关 ,而与吸收率、存留率呈负相关。量效研究发现 ,大鼠钙摄入量 (X)与吸收率 (^Y)间的关系呈双曲线函数形式 ,所得回归方程为 :^Y =e6 80 68×X- 0 882 1 +2 0 ,(F =47 315 4,P <0 0 0 0 1)。实验结果显示 ,用原子吸收分光光度计测定 ,骨钙与用单光子骨密度仪测定的骨矿物质含量具有良好的线性关系     

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 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.     

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 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.     

A pilot intervention to increase calcium intake in female collegiate athletes

Calcium intake in adolescent and young adult female athletes often is inadequate to optimize peak bone mass, an important determinant of osteoporosis risk. The purpose of this study was to determine if calcium supplementation in eumenorrheic female collegiate athletes increases intake to recommended levels and promotes increases in bone mineral density (BMD). Forty-eight eumenorrheic female athletes from several college teams (15 soccer, 7 cross-country, 8 indoor track, and 18 basketball) were randomized at the beginning of a competitive season to receive either an oral calcium supplement (1000 mg calcium citrate/400 I.U. Vitamin D) or placebo daily throughout the training season (16 weeks). Self-reported daily pill intake was obtained every 2 weeks to assess adherence. Calcium intake was evaluated using the Rapid Assessment Method, and total body and leg BMD was measured at pre-, mid-, and postseason using dual energy x-ray absorptiometry (DEXA; Hologic QDR-2000). Pre-season calcium intake was lower than national recommendations for this age group (12), averaging 842 mg/d (SD = 719) and was lower in the placebo group compared to the supplemented group (649 +/- 268 vs. 1071 +/- 986 mg/d, respectively; p = .064). Adherence to supplementation was good, averaging 70% across the training season. Supplementation boosted total calcium intake to a mean of 1397 +/- 411 mg/d, which is consistent with recommended levels for this group (37). Supplementation did not influence BMD change during this 16-week intervention. Across teams, a small increase of 0.8% was observed in leg BMD. Change in total body BMD was modified by team, with a significant increase of 1.5% observed in basketball players. These results indicate that providing calcium supplements of 1000 mg/d is adequate to boost total intake to recommended levels during athletic training. Longer intervention trials are required to determine whether calcium supplementation has a positive effect on BMD.     

The effect of dietary calcium intake on bone mineral density in healthy adolescent girls and young women in southern Italy.

BACKGROUND: The association between forearm bone mineral areal density (BMD) and dietary calcium, anthropometric characteristics, puberty, and physical activity was studied for the first time in 200 girls (aged 11-15 years) and 100 women (aged 20-23 years) living in Southern Italy. METHODS: The BMD was assessed by dual energy x-ray absorptiometry at ultradistal (ud) and proximal (pr) radial sites and dietary calcium was evaluated using Food Frequency Questionnaires and detailed 3-day food records. RESULTS: For population samples grouped according to low and high calcium intake levels, forearm densities were quite similar among both girls and women. Independently of calcium intake, girls displayed strong correlations between ud/pr-BMD and age, bone age, weight, height and BMI. Furthermore, in girls of similar age and BMI, radial densities were substantially increased following menarche. Positive relationships between weight, BMI and both ud/pr-BMD were only evident in women with high calcium intake. CONCLUSIONS: This study showed that different calcium intake values do not appear to affect forearm mineral densities at the ages investigated, however puberty represents the major event in radial bone mass acquisition during adolescence.     

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   

Effects of two years' milk supplementation on size-corrected bone mineral density of Chinese girls

Much existing data on the effects of calcium or milk products on bone mineral accretion are based on bone mineral content (BMC) or areal bone mineral density (aBMD), neither of which accounts for changing bone size during the growing period. The aim of this study was to investigate the effects of 2-year milk supplementation on total body size-corrected BMD in Chinese girls with low habitual dietary calcium intake. Chinese girls aged 10 years were randomised, according to their school, to receive calcium fortified milk (Ca milk), or calcium and vitamin D fortified milk (CaD milk) for two years or act as unsupplemented controls. Dual-energy X-ray absorptiometry total body bone measures were obtained from 345 girls at baseline and 2 years. Size-corrected total body and regional BMD was calculated as: BMDsc = BMC/BApc, where pc was the regression coefficient of the natural logarithm transformed total body BMC and bone area. After 2 years, both supplemented groups had significantly greater gain in BMDsc of total body (3.5-5.8%, p < 0.05) and legs (3.0-5.9%, p < 0.05) than did the control group. Milk supplementation showed positive effects on bone mineral accretion when accounting for the changing skeletal size during growth. The effects were mainly on the lower limbs.     

Dietary iron is associated with bone mineral density in healthy postmenopausal women

Healthy nonsmoking postmenopausal women (n = 242; ages 40-66 y) were included in the Bone, Estrogen, and Strength Training (BEST) Study. Bone mineral density (BMD) was measured at five sites (lumbar spine L2-L4, trochanter, femur neck, Ward's triangle and total body) using dual energy X-ray absorptiometry (DXA). Mean nutrient intakes were assessed using a 3-d diet record. Regression models were calculated using each BMD site as the dependent variable and iron as the independent variable. Covariates included in the models were years past menopause, fat-free mass, fat mass, use of hormone replacement therapy, total energy intake and dietary intake of protein and calcium. Using linear models, iron was associated with greater BMD at all sites (P < or = 0.01), even after adjusting for protein and/or calcium. Increasing levels of iron intake (>20 mg) were associated with greater BMD at several bone sites among women with a mean calcium intake of 800-1200 mg/d. Elevated iron intake was not associated with greater BMD among women with higher (>1200 mg/d) or lower calcium intakes (<800 mg/d). Dietary iron may be a more important factor in bone mineralization than originally thought and, its combined effect with calcium on BMD warrants exploration in future studies.