{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/64865"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/64865","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Utilizing pQCT and Biomarkers of Bone Turnover to Study Influences of Physical Activity or Bariatric Surgery on Structural and Metabolic Status of Bone","abstract":"Bone health in the context of two common maladies, osteoporosis and obesity, has spurred research in the area of physical activity (PA) and bariatric surgery (BarS). Objectives: To examine: 1) relationships between PA and the skeleton utilizing the peripheral Quantitative Computed Tomography (pQCT) and Dual-energy X-ray Absorptiometry (DXA) in pre-menopausal women; 2) effects of adjustable gastric banding (AGB) vs. Roux-en-Y gastric bypass (RYGB) surgeries on pQCT and DXA measures; 3) 6-month time course changes on serum biomarkers of bone turnover and associated adipokines induced by AGB vs. RYGB. Methods: Standard DXA and pQCT measurements were taken for all subjects. PA tertiles (PA-L, PA-M, PA-H) were based on a calculated average MET-min/day determined from 4-d self-reported PA and pedometer step counts. For BarS subjects, bone measurements were taken pre-surgery, 3- and 6-months post-surgery along with serum (or plasma) from fasting blood draws, with ELISA assays for total OC, undercarboxylated OC, CTx, adiponectin, and leptin. Results: Minimal DXA differences between the highest and lowest PA tertiles were seen, while pQCT tibial measures and polar strength-strain index (SSIp) indicated differences along the tibial shaft. Comparing the two instruments and adjusting for BMI, the DXA leg and hip BMD and BMC showed differences (p<0.05) between PA-M and PA-L as well as PA-H and PA-L. Similarly, the pQCT tibial cortical area, BMC, and SSIp were progressively greater for the different levels of PA (p<0.05). 3- and 6-months post-BarS weight, fat-free mass, fat mass, central body fat, tibial and radial subcutaneous fat, and radial MCSA decreased (p<0.05). Comparing the AGB and RYGB and adjusting for weight, DXA BMC showed decreases (p<0.01) at both time points for RYGB. RYGB demonstrated differences (p<0.05) in bone measures at 3- and 6-months post-surgery along the tibial shaft that are indicative of increases in bone strength, and at 6-months, total OC, undercarboxylated OC, and HMW adiponectin increased, while leptin decreased. Conclusions: PA is associated with increases in bone, but pQCT data are more discriminatory and sensitive. 6-months post-RYGB, pQCT measures indicate increases in bone strength parameters, and greater bone adaptation was evidenced by biomarkers of increased osteoblastic activity.","abstract_html":"Bone health in the context of two common maladies, osteoporosis and obesity, has spurred research in the area of physical activity (PA) and bariatric surgery (BarS). Objectives: To examine: 1) relationships between PA and the skeleton utilizing the peripheral Quantitative Computed Tomography (pQCT) and Dual-energy X-ray Absorptiometry (DXA) in pre-menopausal women; 2) effects of adjustable gastric banding (AGB) vs. Roux-en-Y gastric bypass (RYGB) surgeries on pQCT and DXA measures; 3) 6-month time course changes on serum biomarkers of bone turnover and associated adipokines induced by AGB vs. RYGB. Methods: Standard DXA and pQCT measurements were taken for all subjects. PA tertiles (PA-L, PA-M, PA-H) were based on a calculated average MET-min/day determined from 4-d self-reported PA and pedometer step counts. For BarS subjects, bone measurements were taken pre-surgery, 3- and 6-months post-surgery along with serum (or plasma) from fasting blood draws, with ELISA assays for total OC, undercarboxylated OC, CTx, adiponectin, and leptin. Results: Minimal DXA differences between the highest and lowest PA tertiles were seen, while pQCT tibial measures and polar strength-strain index (SSIp) indicated differences along the tibial shaft. Comparing the two instruments and adjusting for BMI, the DXA leg and hip BMD and BMC showed differences (p&lt;0.05) between PA-M and PA-L as well as PA-H and PA-L. Similarly, the pQCT tibial cortical area, BMC, and SSIp were progressively greater for the different levels of PA (p&lt;0.05). 3- and 6-months post-BarS weight, fat-free mass, fat mass, central body fat, tibial and radial subcutaneous fat, and radial MCSA decreased (p&lt;0.05). Comparing the AGB and RYGB and adjusting for weight, DXA BMC showed decreases (p&lt;0.01) at both time points for RYGB. RYGB demonstrated differences (p&lt;0.05) in bone measures at 3- and 6-months post-surgery along the tibial shaft that are indicative of increases in bone strength, and at 6-months, total OC, undercarboxylated OC, and HMW adiponectin increased, while leptin decreased. Conclusions: PA is associated with increases in bone, but pQCT data are more discriminatory and sensitive. 6-months post-RYGB, pQCT measures indicate increases in bone strength parameters, and greater bone adaptation was evidenced by biomarkers of increased osteoblastic activity.","abstract_has_math":false,"creators":["Creamer, Kyle William"],"institution":"Virginia Tech","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Human Nutrition, Foods, and Exercise","degree_department":"Human Nutrition, Foods, and Exercise","school":null,"contributors":[],"advisors":[],"committee_chairs":["Herbert, William G."],"committee_members":["De Vita, Raffaella","Nickols, Sharon M.","Ramp, Warren","Hulver, Matthew W.","Hosig, Kathryn W.","Williams, Jay H."],"year":2014,"date_issued":"2014-09-03","date_published":"2014-09-03","updated_at":"2026-07-22T22:20:07Z","subjects":["Physical Activity","Bariatric Surgery","Bone","peripheral Quantitative Computed Tomography","pQCT"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:3374"],"render_values":[{"text":"vt_gsexam:3374","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/64865","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Herbert, William G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["De Vita, Raffaella","Nickols, Sharon M.","Ramp, Warren","Hulver, Matthew W.","Hosig, Kathryn W.","Williams, Jay H."]},{"key":"dc:contributor.department","label":"Department","values":["Human Nutrition, Foods, and Exercise"]},{"key":"dc:creator","label":"Author","values":["Creamer, Kyle William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-02-26T07:00:14Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-26T07:00:14Z"]},{"key":"dc:date.issued","label":"Date","values":["2014-09-03"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Human Nutrition, Foods, and Exercise"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physical Activity","Bariatric Surgery","Bone","peripheral Quantitative Computed Tomography","pQCT"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:3374"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/64865"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Bone health in the context of two common maladies, osteoporosis and obesity, has spurred research in the area of physical activity (PA) and bariatric surgery (BarS). Objectives: To examine: 1) relationships between PA and the skeleton utilizing the peripheral Quantitative Computed Tomography (pQCT) and Dual-energy X-ray Absorptiometry (DXA) in pre-menopausal women; 2) effects of adjustable gastric banding (AGB) vs. Roux-en-Y gastric bypass (RYGB) surgeries on pQCT and DXA measures; 3) 6-month time course changes on serum biomarkers of bone turnover and associated adipokines induced by AGB vs. RYGB. Methods: Standard DXA and pQCT measurements were taken for all subjects. PA tertiles (PA-L, PA-M, PA-H) were based on a calculated average MET-min/day determined from 4-d self-reported PA and pedometer step counts. For BarS subjects, bone measurements were taken pre-surgery, 3- and 6-months post-surgery along with serum (or plasma) from fasting blood draws, with ELISA assays for total OC, undercarboxylated OC, CTx, adiponectin, and leptin. Results: Minimal DXA differences between the highest and lowest PA tertiles were seen, while pQCT tibial measures and polar strength-strain index (SSIp) indicated differences along the tibial shaft. Comparing the two instruments and adjusting for BMI, the DXA leg and hip BMD and BMC showed differences (p<0.05) between PA-M and PA-L as well as PA-H and PA-L. Similarly, the pQCT tibial cortical area, BMC, and SSIp were progressively greater for the different levels of PA (p<0.05). 3- and 6-months post-BarS weight, fat-free mass, fat mass, central body fat, tibial and radial subcutaneous fat, and radial MCSA decreased (p<0.05). Comparing the AGB and RYGB and adjusting for weight, DXA BMC showed decreases (p<0.01) at both time points for RYGB. RYGB demonstrated differences (p<0.05) in bone measures at 3- and 6-months post-surgery along the tibial shaft that are indicative of increases in bone strength, and at 6-months, total OC, undercarboxylated OC, and HMW adiponectin increased, while leptin decreased. Conclusions: PA is associated with increases in bone, but pQCT data are more discriminatory and sensitive. 6-months post-RYGB, pQCT measures indicate increases in bone strength parameters, and greater bone adaptation was evidenced by biomarkers of increased osteoblastic activity."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Utilizing pQCT and Biomarkers of Bone Turnover to Study Influences of Physical Activity or Bariatric Surgery on Structural and Metabolic Status of Bone"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Herbert, William G."],"dc:contributor.committeemember":["De Vita, Raffaella","Nickols, Sharon M.","Ramp, Warren","Hulver, Matthew W.","Hosig, Kathryn W.","Williams, Jay H."],"dc:contributor.department":["Human Nutrition, Foods, and Exercise"],"dc:creator":["Creamer, Kyle William"],"dc:date.accessioned":["2016-02-26T07:00:14Z"],"dc:date.available":["2016-02-26T07:00:14Z"],"dc:date.issued":["2014-09-03"],"dc:description.abstract":["Bone health in the context of two common maladies, osteoporosis and obesity, has spurred research in the area of physical activity (PA) and bariatric surgery (BarS). Objectives: To examine: 1) relationships between PA and the skeleton utilizing the peripheral Quantitative Computed Tomography (pQCT) and Dual-energy X-ray Absorptiometry (DXA) in pre-menopausal women; 2) effects of adjustable gastric banding (AGB) vs. Roux-en-Y gastric bypass (RYGB) surgeries on pQCT and DXA measures; 3) 6-month time course changes on serum biomarkers of bone turnover and associated adipokines induced by AGB vs. RYGB. Methods: Standard DXA and pQCT measurements were taken for all subjects. PA tertiles (PA-L, PA-M, PA-H) were based on a calculated average MET-min/day determined from 4-d self-reported PA and pedometer step counts. For BarS subjects, bone measurements were taken pre-surgery, 3- and 6-months post-surgery along with serum (or plasma) from fasting blood draws, with ELISA assays for total OC, undercarboxylated OC, CTx, adiponectin, and leptin. Results: Minimal DXA differences between the highest and lowest PA tertiles were seen, while pQCT tibial measures and polar strength-strain index (SSIp) indicated differences along the tibial shaft. Comparing the two instruments and adjusting for BMI, the DXA leg and hip BMD and BMC showed differences (p<0.05) between PA-M and PA-L as well as PA-H and PA-L. Similarly, the pQCT tibial cortical area, BMC, and SSIp were progressively greater for the different levels of PA (p<0.05). 3- and 6-months post-BarS weight, fat-free mass, fat mass, central body fat, tibial and radial subcutaneous fat, and radial MCSA decreased (p<0.05). Comparing the AGB and RYGB and adjusting for weight, DXA BMC showed decreases (p<0.01) at both time points for RYGB. RYGB demonstrated differences (p<0.05) in bone measures at 3- and 6-months post-surgery along the tibial shaft that are indicative of increases in bone strength, and at 6-months, total OC, undercarboxylated OC, and HMW adiponectin increased, while leptin decreased. Conclusions: PA is associated with increases in bone, but pQCT data are more discriminatory and sensitive. 6-months post-RYGB, pQCT measures indicate increases in bone strength parameters, and greater bone adaptation was evidenced by biomarkers of increased osteoblastic activity."],"dc:description.degree":["Ph. D."],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:3374"],"dc:identifier.uri":["http://hdl.handle.net/10919/64865"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Physical Activity","Bariatric Surgery","Bone","peripheral Quantitative Computed Tomography","pQCT"],"dc:title":["Utilizing pQCT and Biomarkers of Bone Turnover to Study Influences of Physical Activity or Bariatric Surgery on Structural and Metabolic Status of Bone"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Human Nutrition, Foods, and Exercise"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:07Z"}