【作者】 朱炜；

【导师】 蔡东联；

【作者基本信息】 第二军医大学 ， 营养与食品卫生学， 2012， 硕士

【摘要】 近年来，随着全世界范围内肥胖发病率的激增，对肥胖干预治疗越来越受到关注。国外有研究表明，钙的摄入与体重呈负相关关系，而在中国尚未见相关报道；此外，钙的抗肥胖作用在干预性研究中尚存在争议。基于此，本课题分两部分进行研究：一、膳食钙的摄入同肥胖关系的病例-对照研究目的通过病例-对照研究，分析膳食钙和奶类的摄入同肥胖的关系，旨在为进一步研究肥胖的干预措施提供依据。方法1.以2011年4月至9月期间进入一项肥胖干预试验筛选阶段的119名大专院校女生为病例组，年龄18～22周岁；同时，选择同性别、同年龄、同身高，体重正常的同校健康学生作为对照组，以1:1配对。2.对病例组和对照组进行食物频率调查问卷（FFQ），并测量身高、体重、腰围、臀围和血压，计算体质指数（BMI）和腰臀比（WHR）；采用生物电阻抗法（BIA, ZEUS9.9, JAWON）测得体脂含量（BFM）、体脂百分比（BFP）、瘦体组织重量（LBM）、内脏脂肪量（VFM）及内脏脂肪面积（VFA）。3.根据钙和奶的摄入量由低到高，分别取四分位数（P25、P50和P75），将病例组和对照组分别划分为4个摄入量水平。采用条件Logistic回归法，分析不同钙摄入量和不同奶类摄入量同肥胖的关系；通过Person相关系数法，探究钙的摄入和奶的摄入是否同体质指数和体脂百分比存在相关性。结果1.非参数检验结果显示：病例组和对照组膳食钙的4个不同摄入量水平有显著性差异(P＜0.001)；而两组奶类的4个不同摄入量水平差异未达到显著性水平（P＝0.014）；2.条件Logistic回归分析结果显示：膳食钙的摄入是肥胖的保护性因素，且中高及高摄入量水平相对于最低摄入量水平具有统计学意义，其OR值分别为0.19（95%CI0.07–0.50; P＝0.001）和0.05（95%CI0.02–0.15; P＜0.001）；奶类的高和高摄入量水平相对于最低摄入水平的保护性作用亦达到显著性水平，其OR值分别为0.36（95%CI0.15–0.88; P＝0.02）和0.16（95%CI0.06–0.41; P＜0.001）。3. Person相关系数法分析发现：钙和奶的摄入同BW、BMI、BFM、BFP、VFA和WHR均存在显著负相关的关系（P＜0.05）。将摄入能量作为协变量调整后，钙的摄入与BW、BMI、BFM、BFP、VFA和WHR的偏相关系数（r）依次为–0.31、–0.37、–0.33、–0.34、–0.36、–0.35（P＜0.001），与收缩压和舒张压的偏相关系数（r）分别为–0.19和–0.15（P＜0.05）；奶的摄入同以下指标的偏相关系数依次为：BW（r＝–0.19,P＝0.01）、BMI（r＝–0.24, P＝0.001）、BFM（r＝–0.24, P＜0.001）、BFP（r＝–0.27, P＜0.001）、VFM（r＝–0.27, P＜0.001）、WHR（r＝–0.29，P＜0.001），奶的摄入与LBM、VFA和血压均无显著相关性（P＞0.05）。结论1.膳食钙的摄入是肥胖的保护性因素，其摄入量同体质指数及体脂百分比呈负相关。2.奶类，作为钙的良好来源，奶的摄入亦对肥胖具有保护性作用，且其摄入量同体质指数及体脂百分比呈负相关。3.增加奶类的摄入一方面具有潜在的预防肥胖的作用，另一方面，可以有效地解决目前中国人群中普遍缺钙的问题。二、补充钙剂对超重和肥胖患者体重控制的干预研究及效果评价目的通过对低钙摄入人群进行随机对照干预试验，验证增加钙摄入量可促进体重和体脂减轻的假设，并观察相关代谢性指标的变化。方法1.于2011年4月至9月期间，在浦东和杨浦若干大专院校和职业技术学校中通过张贴校园海报和分发宣传单的形式招募受试者。通过FFQ确定受试者的钙摄入量水平，并经入选排除标准筛选后，最终入选53人。2.由SPSS13.0软件分析系统产生与样本量对等的连续流水编号，并以等比例构成的样本数产生随机号，将所有受试者分为钙剂组（26人）和对照组（27人）。给予钙剂组每日600mg钙（钙尔奇D，每片含钙600mg，维生素D125IU），每日1次，每次1片，口服，早餐后服用。与此同时，对两组受试者均进行饮食控制，限能500kcal/d，进行为期12周的干预。3.采用两因素四水平重复测量设计的方差分析，检验0周、4周、8周和12周两组受试者体重、体脂含量、体脂百分比、瘦体组织重量、内脏脂肪量和内脏脂肪面积的变化；采用两因素两水平重复测量设计的方差分析，检验0周和12周两组受试者腰围（WC）、腹围（AC）、臀围（HC）、腰臀比（WHR）、血压（BP）、空腹血糖（FPG）、空腹胰岛素（FIN）、胰岛素抵抗指数（Homa-IR）、甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白（HDL）和低密度脂蛋白（LDL）水平的变化。将所有研究对象作为一个整体，通过Person相关系数法，探究初始钙摄入量水平是否同体重和体脂的减轻程度存在相关性。结果1.共计43人（男性6名；女性37名）完成整个干预试验，脱落率为18.9%。2.经12周的干预试验，两组受试者的BW、BMI、BFM、BFP、LBM、VFM、VFA，以及腰围、腹围、臀围和WHR均有显著性下降（P＜0.001）。3.钙剂组受试者体重平均减轻5.1±2.9kg，对照组则为3.4±1.9kg，即钙剂组比对照组多减轻了50%（P＝0.045）；钙剂组BFM减少量较对照组而言，增加了87%（3.4±1.9vs1.8±1.2kg; P＝0.002）；此外，钙剂组VFM和VFA的下降率均显著高于对照组（P＜0.01）；两组受试者LBM变化无差异（P＞0.05）。4.初始钙摄入量的高低与部分人体测量指标的变化具有相关性：将年龄、性别、初始体重作为协变量调整后，初始钙摄入量与体重、BMI、BFM、VFM、腰围、腹围、臀围的变化程度呈负相关（r依次为－0.38，－0.36，－0.35，－0.36，－0.40，－0.39，－0.34，P＜0.05）。5.干预12周后，两组受试者BP、FPG、FIN、Homa-IR、TG、TC、HDL和LDL均无显著性变化，亦无组间差异（P＞0.05）。结论1.两组受试者的体重、体成分，及腰、腹、臀围和WHR均有显著改善，说明为期12周的限能干预措施有效。2.在同样限能的前提下，钙剂组的减肥减脂效果优于对照组，说明在低钙摄入人群中补充钙剂，具有促进体重和体脂减轻的作用，钙的抗肥胖作用得以证实。3.干预12周后，两组受试者LBM均下降，且无组间差异，说明增加钙的摄入，对于减肥过程中保存瘦体组织重量无明显作用。4.初始钙摄入量的高低与BW、BMI、BFM、VFM的减轻和腰、腹、臀围的减小呈显著负相关，提示初始钙摄入量越低，在同等条件下越有利于体重和体脂的减轻。5.干预前后对血糖、胰岛素、血脂水平及血压无明显变化，说明短期的干预试验尚不能对这些代谢性指标构成显著影响。6.在中国，大部分人群均处于长期低钙摄入水平，增加奶类等含钙量丰富的食物，具有潜在的预防和治疗肥胖的作用，故应大力倡导中国营养学会推荐的每日饮奶300mL的建议，以接近或达到钙的适宜摄入量（AI）。更多还原

【Abstract】 The skyrocketed prevalence of obesity during the past few decades has stimulatedgreat interest in identifying approaches that may contribute to weight reduction or to theprevention of weight gain. Epidemiologic studies showed an inverse relationship betweencalcium intake and body weight, however, there has been no such report in the Chinesepopulation. In addition, intervention studies provided inconsistent results for the beneficialeffect of calcium supplementation on weight management. From this perspective, weinitiated the present study, which can be categorized into two sections as follows:1. A case-control study on the relationship of dietary calcium intake and dairyconsumption with risk of obesityObjectiveThe aim of this study was to assess the relationship of dietary calcium intake and dairyconsumption with risk of obesity in a case-control study design, so as to provide evidencefor further study on feasible interventions for obesity.Methods1) Cases were119obese or overweight female Chinese college students aged18to22y,who were pre-screening volunteers for a weight loss program, recruited from April toOctober,2011. Control subjects were pair matched at1:1ratio by age, gender and bodyheight.2) Anthropometric data, including body height, weight, blood pressure, as well as waist,abdominal, and hip circumference were collected and a food frequency questionnaire (FFQ)was performed with each participant. WHR was calculated as waist circumference (cm)/hipline (cm). Bioelectric impedance analysis (BIA, ZEUS9.9, JAWON) was used todetermine body fat mass (BFM), body fat percentage (BFP), Lean Body Mass (LBM), aswell as visceral fat mass (VFM) and visceral fat area (VFA).3) Subjects in case and control groups were divided into4subgroups via quartiles（P25,P50, and P75）of calcium or dairy consumption. Conditional logistic regression was used toidentify predictive factors related to calcium or dairy intake for obesity. Pearsoncorrelations were performed in the total sample of subjects between body fat percentageand dairy (or calcium) intake. Results1) Significant trend was obtained for calcium intake as protective effects (P＜0.001). The3rd and4th quartiles of calcium intake achieved statistical significance (OR0.19,95%CI0.07–0.50, P＝0.001; OR0.05,95%CI0.07–0.50; P＜0.001, respectively). Quartiles ofdairy consumption did not reach statistical significance (P＝0.07) by noparametric test,however, it seemed to have protective effects for obesity with the3rd and4th quartiles ofdairy consumption (OR0.36,95%CI0.15–0.88; P＝0.02; OR0.16,95%CI0.06–0.41forthe3rd and4th quartiles; P＜0.001, respectively) as protective effects.2) Consumption of dairy, or calcium intake, was proven to be inversely related to BW, BMI,BFM, BFP, VFA, and WHR (P＜0.05). After adjustment for energy intake, calcium intakewas inversely correlated with BW (r＝–0.31), BMI (r＝–0.37), BFM (r＝–0.33), BFP (r＝–0.34), VFA (r＝–0.36), WHR (r＝–0.35)(P＜0.001for all) and with SBP and DBP (r＝–0.19and–0.15, respectively; P＜0.05), whereas dairy consumption was inverselycorrelated with BW (r＝–0.19, P＝0.01), BMI (r＝–0.24, P＝0.001), BFM (r＝–0.24, P＜0.001), BFP (r＝–0.27, P＜0.001), VFA (r＝–0.27, P＜0.001), WHR (r＝–0.29,P＜0.001),and have no significant association with LBM, VFM, SBP and DBP (P＞0.05).Conclusion1) Dietary calcium intake and dairy consumption, which are inversely correlated with BMIand BFP, are important predictive factors for obesity.2) Dairy, as fairly good sources of calcium, is also prove to be predictive factors for obesityand inversely correlated with BMI and BFP.3) Increasing dairy consumption could not only attenuate calcium insufficient status, buthave potential anti-obesity effect.2. Effect of calcium supplementation on weight management in obese and overweightsubjectsObjectiveThe present study aimed to test the hypothesis that calcium supplementation canenhance weight and fat loss during energy restriction, and to evaluate the effect of calciumplus vitamin D supplementation on metabolic profiles in overweight or obese subjects withvery-low habitual calcium consumption.Methods1) Participants were recruited through informational flyers and advertisements posted on campus of colleges and vocational schools in Pudong and Yangpu Districts in Shanghai,China. A pre-screening telephone interview for evaluating habitual calcium intake via foodfrequency questionnaire (FFQ) was conducted with each volunteer, who were evaluated byinclusion and exclusion criteria afterwards for eligibility.2) Subjects were randomly assigned in an open label manner to either the calcium group(n=26) or the control group (n=27). Randomization was computer-generated, andrandomization sequence was created using SPSS13.0for windows with a1:1allocation.Block randomization was by a computer generated random number list prepared by aninvestigator with no clinical involvement in the trial. The calcium group received calciumplus and vitamin D supplementation (600mg calcium carbonate,125IU vitamin D),administered as the dose of one tablet daily taken after breakfast. In addition, both groupsreceived500kcal/d of caloric deficit for a period of12weeks.3) A2-factor (4level) analysis of variance with repeated measures, controlling for initialbody weight, was performed to evaluate the significance of the differences between groupsfor changes in anthropometric values, including body weight, body fat mass (BFM), bodyfat percentage (BFP), Lean Body Mass (LBM), visceral fat mass (VFM) and visceral fatarea (VFA) at baseline, week4, week8, and at the end of the12-week intervention.Besides, a2-factor (2level) analysis of variance with repeated measures, controlling forinitial body weight, was performed to evaluate the significance of the differences betweengroups for changes in waist, abdominal and hip circumference, waist-to-hip ratio (WHR),and metabolic variables, including blood pressure (BP), fasting plasma glucose (FPG),fasting insulin (FIN), Homa-IR, as well as lipid-lipoprotein profile. Simple Pearsoncorrelations were performed between initial calcium intake and changes in outcomevariables in the total sample of subjects and then repeated with age, gender and initial bodyweight as covariates, so as to indicate the relations between initial calcium intake and thefacilitation of calcium supplementation on weight and fat loss.Results1) A total of43subjects (37females,6males) completed the trial, with an estimateddrop-off rate at18.9%after enrollment.2) Subjects in both groups experienced significant reductions in all anthropometricvariables at the end of the12-week intervention (P＜0.001).3) Subjects in the calcium group lost5.1±2.9kg of body weight, increased by50%(P＝0.045) compared with those in the control group, who experienced3.4±1.9kg of weight loss. A greater trend of augmentation was observed in the calcium group for BFM loss,which was increased by87%(3.4±1.9vs1.8±1.2kg; P＝0.002). Moreover, subjects in thecalcium group also exhibited greater decrease in VFM and VFA (P＜0.01for both)compared with those in the control group. No significant difference was detected inchanges in LBM (P＞0.05).4) Initial calcium intake was found significantly correlated with changes in body weight (r＝－0.38), BMI (r＝－0.36), fat mass (r＝－0.35), visceral fat (r＝－0.36), waistcircumference (r＝－0.40), abdominal circumference (r＝－0.39) and hip circumference (r＝－0.34) after adjustments for age, gender and initial body weight (P＜0.05for all).5. No statistically significant changes was observed in fasting plasma glucose, fastinginsulin, Homa-IR, total cholesterol, triacylglycerol, HDL cholesterol, LDL cholesterol,systolic and diastolic blood pressure from pre-to post-treatment during the short period ofthe study (P＞0.05for all). There was no significant difference for any of the outcomevariables between the calcium and the control group, either (P＞0.05for all).Conclusion1) Significant improvements in anthropometric variables in both groups indicated theeffectiveness of the12-week intervention of energy restriction.2) On the premises of caloric deficit, subjects in the calcium group exhibited greaterweight and fat loss compared with those in the control group, thus supported thehypothesis that calcium supplementation can enhance weight and fat loss during energyrestriction in overweight or obese subjects.3) The present study observed no significant difference for changes in lean body massbetween the two groups after12weeks of intervention, which suggested no beneficialeffect of calcium supplement on preserving fat-free mass during energy restriction.4) Initial calcium intake was found significantly correlated with changes in body weight,BMI, BFM, VFM, as well as with changes in waist, abdominal and hip circumference,indicating those with lower calcium intake are expected to lose more weight and fat on anenergy-restricted diet.5) No significant changes were observed in FPG, FIN, BP and lipid-lipoprotein profileeither from baseline to endpoint or between treatment arms, suggesting these metabolicvariables will not be affected in such a short term.6) The habitual calcium intakes of majority of Chinese population were relatively low.Therefore, it will be of great benefit for them to follow a calcium-rich diet, preferably from dairy sources, to prevent or combat obesity. The recommended dairy intake of300mL/dby the Chinese Nutrition Society should be advocated so as to reach the Acquit Intake (AI).更多还原