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Epidemiology of general, regional and ectopic skeletal muscle fat in aging African ancestry men

Zhao, Qian (2016) Epidemiology of general, regional and ectopic skeletal muscle fat in aging African ancestry men. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

OBJECTIVE: We aim to study on the epidemiology of general, regional and ectopic skeletal muscle fat in aging African ancestry men. To be specific, we described the natural changes and identified correlates to the longitudinal changes of these adiposity measures, and evaluated their association with hypertension and mortality.
METHOD: We use Tobago Health Study to achieve the objectives. The demographic characteristics, lifestyle factors, medical history and medication use were self-reported and collected with interviewer-administered questionnaire. Total body fat percentage, trunk fat percentage and leg fat percentage were assessed with Dual-Energy X-ray Absorptiometry (DXA). Ectopic skeletal muscle fat (inter- and intra- muscular fat) was examined by Quantitative Computed Tomography (QCT). The hypertension status was defined as diastolic blood pressure over 90 mmHg or systolic blood pressure over 140 mmHg or having antihypertensive treatment. The date of death was obtained from death certificate and/or proxy. Linear regression was used to identify the potential correlates for the changes in these adiposity measures. Logistic regression was performed to evaluate the association with newly developed hypertension. Cox hazard proportional model was used to assess the association with mortality risks.
RESULTS: Baseline hypertension was associated with greater decline in the muscle attenuation and leg fat. Furthermore, intramuscular fat (reflecting by decreased muscle attenuation) was associated with newly developed hypertension after adjustment for the baseline and the change in BMI (OR (95% CI) per SD: 1.32 (1.06,1.64)) or WC measurements (OR (95% CI) per SD: 1.35 (1.08, 1.68)). Both intermuscular fat (HR (95% CI) per SD: 1.29 (1.06-1.57)) and intramuscular fat (HR (95% CI) per SD: 1.37 (1.08-1.75)) were significant associated with elevated morality risk in fully adjusted models. None of the other adiposity measures were associated with newly developed hypertension or elevated morality risks.
CONCLUSION: These novel findings confirmed that ectopic fat, though with a small amount, may be more crucial in driving cardiometabolic diseases than general body fat per se, highlighted the importance of maintaining muscle attenuation in healthy aging, and was with great public health significance. Further studies are needed to establish if these associations are independent of inflammation, visceral or other ectopic fat depots, to identify possible biological mechanisms underlying theses relationship, and to replicate our findings in other populations.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Zhao, Qianqiz39@pitt.eduQIZ39
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairMiljkovic, IvaIVM1@pitt.eduIVM1
Committee MemberZmuda, Joseph M.zmudaj@edc.pitt.eduEPIDJMZ
Committee MemberBunker, Clareann H.ras279@pitt.eduRAS279
Committee MemberYouk, Adaayouk@pitt.eduAYOUK
Date: 21 July 2016
Date Type: Publication
Defense Date: 27 July 2016
Approval Date: 21 July 2016
Submission Date: 18 July 2016
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Number of Pages: 151
Institution: University of Pittsburgh
Schools and Programs: Graduate School of Public Health > Epidemiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: "African ancestry men", "general body fat", "regional body fat", "ectopic skeletal muscle fat"
Date Deposited: 21 Jul 2016 18:47
Last Modified: 15 Nov 2016 14:34
URI: http://d-scholarship.pitt.edu/id/eprint/28691

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