title: Fat mass increase in 7-year-old children: more bone area but lower bone mineral density.
abstract: The main aims of this study were, to evaluate what effect a change in fat mass (FM) and lean body mass (LBM) has on bone parameters over 2 years' time, in 7-year-old school children and to see what effect fitness had on bone parameters in these children. A repeated-measures design study was conducted where children born in 1999 from six elementary schools in Reykjavik, Iceland were measured twice. All children attending second grade in these six schools were invited to participate. Three hundred twenty-one children were invited, 211 underwent dual-energy X-ray absorptiometry (DXA) scans at the age of seven, and 164 (78 %) of the 211 had DXA scans again 2 years later. Increase in both FM and LBM was associated with increased total body bone mineral content (BMC) and bone area (BA). An increase in FM was more strongly positively associated with BA while an increase in LBM was more strongly associated with an increase in BMC. An increase in FM was negatively associated with change in bone mineral density (BMD), but an increase in LBM was positively associated with change in BMD. Fitness was positively associated with bone parameters when weight, height and sex were accounted for. The present results suggest that an increase in fat mass over 2 years is associated with an increase in BA and BMC, but a decrease in BMD in the whole body. An increase in LBM accrual, on the other hand, is positively associated with all bone parameters in the body. Fitness is associated with both BMC and BMD but not BA.
authors: University of Iceland, Reykjavik, Iceland.
authors: Hannes
authors: H
authors: Hrafnkelsson
authors: Gunnar
authors: G
authors: Sigurdsson
authors: Kristjan Th
authors: KT
authors: Magnusson
authors: Emil L
authors: EL
authors: Sigurdsson
authors: Erlingur
authors: E
authors: Johannsson
mesh_terms: D050154:Adiposity / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000502:physiology*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male; D010809:Physical Fitness
references: J Bone Miner Metab. 2004;22(4):376-81
references: 15221498
references: J Bone Miner Metab. 2008;26(1):73-8
references: 18095067
references: Bone. 2003 Nov;33(5):853-9
references: 14623062
references: J Pediatr. 2006 Jun;148(6):793-9
references: 16769389
references: J Bone Miner Res. 2008 Dec;23(12):1946-53
references: 18684083
references: Med Sci Sports Exerc. 2004 Jul;36(7):1124-31
references: 15235315
references: Am J Clin Nutr. 2010 Nov;92(5):1257-64
references: 20861173
references: Osteoporos Int. 2012 Apr;23(4):1453-61
references: 21850549
references: J Bone Miner Res. 2008 Jul;23(7):994-1001
references: 18302503
references: Eur J Appl Physiol. 2011 Nov;111(11):2671-80
references: 21394637
references: Lancet. 2000 Feb 5;355(9202):469-70
references: 10841134
references: Arch Dis Child. 2005 Apr;90(4):373-8
references: 15781927
references: J Clin Endocrinol Metab. 2007 Jan;92(1):143-7
references: 17047019
references: Bone. 2010 Feb;46(2):330-5
references: 19836005
references: Bone. 2011 Feb;48(2):212-7
references: 20858556
references: Bone. 2009 May;44(5):752-7
references: 19103314
references: Lancet. 2006 Jul 22;368(9532):299-304
references: 16860699
references: Bone. 2007 Jan;40(1):14-27
references: 16956802
references: Osteoporos Int. 2003 Jul;14(7):539-47
references: 12844213
references: J Bone Miner Res. 2010 Oct;25(10):2221-8
references: 20499353
references: Int J Behav Nutr Phys Act. 2010 May 11;7:40
references: 20459784
references: J Bone Miner Res. 2006 Sep;21(9):1489-95
references: 16939408
references: Joint Bone Spine. 2009 Dec;76(6):680-4
references: 19945325
references: J Bone Miner Metab. 2012 Jan;30(1):47-53
references: 21644057
references: Trends Endocrinol Metab. 2001 Jan-Feb;12(1):22-8
references: 11137037
references: J Clin Invest. 1973 Nov;52(11):2800-8
references: 4795916
references: Bone. 2010 Apr;46(4):977-84
references: 20060079
references: J Clin Densitom. 2008 Apr-Jun;11(2):260-5
references: 18296091
references: Bone. 2010 Apr;46(4):1058-62
references: 19969116
references: Pediatrics. 2009 May;123(5):e932-9
references: 19403485
references: J Pediatr. 2009 Jan;154(1):79-85.e2
references: 18692201
references: Am J Clin Nutr. 2004 Oct;80(4):966-72
references: 15447907
references: Pediatr Nephrol. 2005 Mar;20(3):356-9
references: 15688231
references: Calcif Tissue Int. 2006 Jul;79(1):7-14
references: 16868665
references: Bone. 2012 Feb;50(2):562-7
references: 21600324
references: Int J Sports Med. 2010 Jun;31(6):416-20
references: 20301044