Journal article
Mediating Effect of Muscle on the Relationship of Physical Activity and Bone
Medicine and science in sports and exercise, Vol.51(1), pp.202-210
01/2019
DOI: 10.1249/MSS.0000000000001759
PMCID: PMC6995038
PMID: 30157107
Abstract
This study analyzed prospective associations between distinct trajectories of objectively measured physical activity (PA) and late adolescent bone parameters and explored the mediating effects of lean soft tissue, a surrogate of muscle mass to associations. Physical activity was measured by accelerometry starting at age 5 yr and continuing at 8, 11, 13, 15, and 17 yr in approximately 524 participants from the Iowa Bone Development Study. Sex-specific group-based trajectory modeling was used to construct developmental trajectories of moderate- and vigorous-intensity PA (MVPA) from childhood to late adolescence. At age 17 yr, proximal femur bone mineral density (aBMD) was assessed by dual X-ray energy absorptiometry, and its distribution was calculated by aBMD ratios. Specific geometric measures of the proximal femur were assessed using hip structural analysis. A significant portion of the total effect of MVPA from age 5 to 17 yr on bone parameters at age 17 yr was explained by an increase in leg lean soft tissue in both sexes. For males and females, indirect effects were observed on the total and all regional proximal femur aBMD, and on the ratio between the inferomedial and superolateral neck aBMD. The effect on the ratio between the trochanter and the total proximal femur was specific to females, whereas the effect on the hip axis length was specific to males. Direct effects of MVPA on aBMD were identified only in males. Using robust mediation analysis, this is the first study addressing the indirect effect (through muscle) of PA across childhood and adolescence on proximal femur bone parameters. To improve bone health at the proximal femur, the results suggest PA interventions during growth that increase muscle mass, particularly in females.
Details
- Title: Subtitle
- Mediating Effect of Muscle on the Relationship of Physical Activity and Bone
- Creators
- Vera Zymbal - Department of Sport and Health, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, PORTUGALFátima Baptista - Department of Sport and Health, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, PORTUGALElena M Letuchy - Department of Epidemiology, The University of Iowa, Iowa City, IAKathleen F Janz - Department of Health and Human Physiology, The University of Iowa, Iowa City, IASteven M Levy - Department of Preventive and Community Dentistry, College of Dentistry, The University of Iowa, Iowa City, IA
- Resource Type
- Journal article
- Publication Details
- Medicine and science in sports and exercise, Vol.51(1), pp.202-210
- Publisher
- United States
- DOI
- 10.1249/MSS.0000000000001759
- PMID
- 30157107
- PMCID
- PMC6995038
- ISSN
- 0195-9131
- eISSN
- 1530-0315
- Grant note
- R03 DE023784 / NIDCR NIH HHS M01 RR000059 / NCRR NIH HHS R01 DE009551 / NIDCR NIH HHS U01 DE028522 / NIDCR NIH HHS UL1 RR024979 / NCRR NIH HHS R01 DE012101 / NIDCR NIH HHS R56 DE012101 / NIDCR NIH HHS
- Language
- English
- Date published
- 01/2019
- Academic Unit
- Preventive and Community Dentistry; Epidemiology; Health and Human Physiology
- Record Identifier
- 9983917666702771
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