The Association between Rheumatoid Arthritis, Bone Strength, and Body Composition within the Women's Health Initiative

Persistent Link:
http://hdl.handle.net/10150/195197
Title:
The Association between Rheumatoid Arthritis, Bone Strength, and Body Composition within the Women's Health Initiative
Author:
Wright, Nicole C.
Issue Date:
2010
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Introduction: Osteoporotic fractures, a major public health problem in aging populations, can lead to increased disability and mortality. Though rheumatoid arthritis (RA) patients have a higher risk for fractures than healthy populations, it is not known how hip structural geometry and body composition, two factors associated with bone strength, affect fracture risk in this population. The overall goal of this dissertation is to examine the association between RA, fracture, hip structural geometry, and body composition, in the participants of the Women's Health Initiative (WHI).Methods: The association between probable RA and fracture risk was tested using the entire WHI cohort (n=161,808). The association between probable RA and hip structural geometry was tested, both cross-sectionally and longitudinally, in a smaller sample (n=11,020) of participants from the WHI Bone Density Centers (WHI-BMD). The last study, testing the association between probable RA and body composition was also conducted in the WHI-BMD cohort.Results: In comparison to the non-arthritic group, the probable RA group had a significant 50%, 2-fold, and 3-fold increase in any, spine, and hip fracture, respectively. The association was not mot modified by age or ethnicity, but glucocorticoid use altered the association between RA and spine fractures. In terms of geometry, the probable RA had a significantly lower (p<0.05) mean hip BMD, outer diameter, cross-sectional area, and section modulus at the narrow neck region compared to control groups, indicating reduced bone strength. Body composition changes were present between the probable RA and the control group, with the probable RA group having statistically lower estimate of lean mass and statistically higher estimates of fat mass compared to the non-arthritic control group cross-sectionally and over the study.Conclusion: These studies confirm the increased risk for fracture among RA patients, while providing evidence that RA alters bone strength, especially at the hip, and negatively effects body composition by reducing lean mass and increasing fat mass. Additional research is needed link structural geometry and body composition to bone strength to lead to tailored interventions to minimize decreases in bone strength in this high fracture risk population.
Type:
text; Electronic Dissertation
Keywords:
Body Composition; Bone Strength; Fracture; Osteoporosis; Rheumatoid Arthritis; Women's Health
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Epidemiology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Chen, Zhao

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe Association between Rheumatoid Arthritis, Bone Strength, and Body Composition within the Women's Health Initiativeen_US
dc.creatorWright, Nicole C.en_US
dc.contributor.authorWright, Nicole C.en_US
dc.date.issued2010en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIntroduction: Osteoporotic fractures, a major public health problem in aging populations, can lead to increased disability and mortality. Though rheumatoid arthritis (RA) patients have a higher risk for fractures than healthy populations, it is not known how hip structural geometry and body composition, two factors associated with bone strength, affect fracture risk in this population. The overall goal of this dissertation is to examine the association between RA, fracture, hip structural geometry, and body composition, in the participants of the Women's Health Initiative (WHI).Methods: The association between probable RA and fracture risk was tested using the entire WHI cohort (n=161,808). The association between probable RA and hip structural geometry was tested, both cross-sectionally and longitudinally, in a smaller sample (n=11,020) of participants from the WHI Bone Density Centers (WHI-BMD). The last study, testing the association between probable RA and body composition was also conducted in the WHI-BMD cohort.Results: In comparison to the non-arthritic group, the probable RA group had a significant 50%, 2-fold, and 3-fold increase in any, spine, and hip fracture, respectively. The association was not mot modified by age or ethnicity, but glucocorticoid use altered the association between RA and spine fractures. In terms of geometry, the probable RA had a significantly lower (p<0.05) mean hip BMD, outer diameter, cross-sectional area, and section modulus at the narrow neck region compared to control groups, indicating reduced bone strength. Body composition changes were present between the probable RA and the control group, with the probable RA group having statistically lower estimate of lean mass and statistically higher estimates of fat mass compared to the non-arthritic control group cross-sectionally and over the study.Conclusion: These studies confirm the increased risk for fracture among RA patients, while providing evidence that RA alters bone strength, especially at the hip, and negatively effects body composition by reducing lean mass and increasing fat mass. Additional research is needed link structural geometry and body composition to bone strength to lead to tailored interventions to minimize decreases in bone strength in this high fracture risk population.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectBody Compositionen_US
dc.subjectBone Strengthen_US
dc.subjectFractureen_US
dc.subjectOsteoporosisen_US
dc.subjectRheumatoid Arthritisen_US
dc.subjectWomen's Healthen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEpidemiologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorChen, Zhaoen_US
dc.contributor.committeememberMohler, M. Janeen_US
dc.contributor.committeememberSherrill, Duane Len_US
dc.contributor.committeememberLisse, Jeffrey Ren_US
dc.identifier.proquest11156en_US
dc.identifier.oclc752261010en_US
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