title: Calcium supplementation for 2 years improves bone mineral accretion and lean body mass in Chinese adolescents.
abstract: OBJECTIVE
  to study the effects of different doses of calcium intake on bone health and body composition in Chinese adolescents.
  
  
  METHODS
  a double-blind randomized controlled trial of calcium carbonate supplementation in 257 healthy adolescents aged 12-15 years old for 24 months. Subjects were randomly assigned to four groups receiving chewable calcium carbonate tablets providing elemental calcium at 63 mg/d, 354 mg/d, 660 mg/d, 966 mg/d, respectively. At the end of intervention, we reclassified 197 adolescents into 3 groups who had received actual doses of elemental calcium of 85 mg/d (Low dose), 230 mg/d (Medium dose) and 500 mg/d (High dose). We measured bone mineral content (BMC), bone mineral density (BMD) and body composition by dual-energy X-ray absorptiometry.
  
  
  RESULTS
  BMC and BMD of total body and lumbar spine were increased significantly in both males and females after intervention at all doses (p<0.05). In males, after supplementation, total body BMC in the medium and high dose groups (2464 g and 2437 g, respectively) was significantly higher than that in the low dose group (2321 g) after adjusting for age, pubertal development, BMI, physical activity and energy intake; in addition, lean body mass in the medium and high dose groups (49.1 kg and 48.8 kg, respectively) was significantly higher than that in the low dose group (46.7 kg) (p<0.05). There was no significant effect of calcium supplementation on bone mass or body composition in females.
  
  
  CONCLUSIONS
  calcium supplementation more than 230 mg/d for two years can improve bone mineral accretion and lean body mass in Chinese male adolescents.
authors.affiliation: National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, 7 Pan Jia Yuan Nan Li, Beijing, China. mags@chinacdc.net.cn
authors.forename: Jing
authors.initials: J
authors.lastname: Yin
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ailing
authors.initials: A
authors.lastname: Liu
authors.forename: Weijing
authors.initials: W
authors.lastname: Du
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Hu
authors.forename: Guansheng
authors.initials: G
authors.lastname: Ma
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D044466:Asian People; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D002119:Calcium Carbonate / Q000008:administration & dosage; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002648:Child; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D051598:Whole Body Imaging
chemical_list: D002136:Calcium, Dietary; D002119:Calcium Carbonate