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  • The inter-relationships between body build, body

    composition, body fat distribution, metabolic syndrome and

    inflammation in adult Aboriginal and Torres Strait

    Islander people

    by

    Jaquelyne Tataka Hughes

    BMed FRACP

    A thesis submitted in fulfilment of the requirements

    for the degree of Doctor of Philosophy

    Menzies School of Health Research

    Institute of Advanced Studies

    Charles Darwin University

    Australia

    April, 2013

  • i

    Originality Statement

    I hereby declare that the work herein, now submitted as a thesis for the degree of

    Doctor of Philosophy of the Charles Darwin University, is the result of my own

    investigations, and all references to ideas and work of other researchers have been

    specifically acknowledged. I hereby certify that the work embodied in this thesis has

    not already been accepted in substance for any degree, and is not being currently

    submitted in candidature for any other degree.

    Jaquelyne Tataka Hughes

    April 2013

  • ii

    Abstract

    A centralised pattern of fat distribution is a major risk factor for diabetes and

    cardiovascular disease. In Australia, Aboriginal peoples and Torres Strait Islander

    peoples have a disproportionately higher burden of disease, including diabetes,

    cardiovascular disease and indicators of chronic kidney impairment than other

    Australians. Despite this burden of illness, few studies report a detailed examination

    of the body build and composition of Indigenous Australians. This is the first

    detailed study of body composition and health indicators in large numbers of

    Aboriginal people and Torres Strait Islander people.

    The thesis reports on findings of two independent studies involving Indigenous

    Australians. A healthy young adult group who underwent detailed body composition

    and health assessment, and a larger population of Aboriginal adults and Torres Strait

    Islander adults who had a spectrum of chronic disease risk markers.

    We have reported two key differences in the dimensions of the upper body (trunk)

    between Aboriginal adults and Torres Strait Islander adults. First, Aboriginal adults

    and Torres Strait Islander adults demonstrate a proportionately shorter trunk than

    Caucasians, and this was closely related to a central pattern of obesity in Aboriginal

    adults and Torres Strait Islander adults. Second, Torres Strait Islander adults have a

    broader skeleton than Caucasian adults who in turn have a broader skeleton than

    Aboriginal participants, and skeletal size was strongly associated with proportion of

    lean body mass.

    Lean Aboriginal adults displayed numerous indicators of health. In contrast, even

    modest levels of overweight were strongly related to intra-abdominal fat deposition,

    and key cardiovascular risk markers: albuminuria, inflammation and low HDL-

    cholesterol. Adiposity was also related to the pattern of fat-related biomarkers

    (adipokines): high leptin and low adiponectin levels were associated with high body

    fat, and high intra-abdominal fat respectively. Finally, we propose a link that high

    leptin and low adiponectin levels are associated with albuminuria in Indigenous

    Australians, which is a known independent risk marker for both cardiovascular

    disease and kidney failure.

  • iii

    Acknowledgements

    As a child, I thought skin tags, acanthosis nigricans, and being overweight were

    benign family traits among Torres Strait Islander family members. As a medical

    student and trainee-physician, I learned these traits indicated preventable chronic

    diseases that contribute to earlier mortality among many Aboriginal people and

    Torres Strait Islander people.

    I am grateful for the dedicated guidance of my supervisors, Dr Louise Maple-Brown

    and Professor Kerin O’Dea. They provided a valuable opportunity for me to play a

    small part towards advancing the health status of adult Aboriginal peoples and Torres

    Strait Islander peoples with chronic diseases including chronic kidney disease

    through this study. Louise and Kerin have each been powerful mentors. They

    inspire and guide me to do better, again and again. I am extremely proud of this

    work, and it has not been without struggle. I have also acquired other valuable skills

    through this research project: including discussing health-risk in plain language,

    which has improved communication with my own nephrology patients; engaging

    individuals in health promotion and lifestyle change; confidently communicating

    with an academic audience; and developing my own advocacy skills.

    I am grateful to the participants, more than 750, who live throughout Northern and

    Central Australia who willingly participated in this research project. Their

    willingness is an indication of the support by Aboriginal communities and Torres

    Strait Islander communities to move beyond describing chronic illness, but to find

    practical solutions to the burden of preventable chronic diseases.

    The data presented in the thesis was collected and managed by a large team. I

    specifically acknowledge the Aboriginal staff and Torres Strait Islander staff with

    whom I worked closely: Maria Nickels and Sian Graham were research assistants

    who worked closely on my specific PhD project. Sian Graham and I worked

    exclusively together on the Healthy Top-Enders’ Study. Maria and Sian both worked

    on The eGFR Study; Loyla Leysley, a generous team-member who although based in

    Darwin, has an amazing network of contacts throughout Northern Australia. Mary

    Ward, my aunt, a long-serving nurse with the Thursday Island Hospital, a Torres

  • iv

    Strait Islander elder, and an invaluable and ongoing team member on Thursday

    Island who assisted in the baseline eGFR Study, and continues in the follow-up

    phase of the study. Special mention also goes to other former and current eGFR

    Study team members: Suresh Sharma, Kylie Tune and Alison Simmonds. Katrina

    Drabsch moved into the eGFR Study Project Manager role in 2010, and worked

    tirelessly arranging logistics of study recruitment, analysis of biochemical samples

    and data management and cleaning. This was an intense two years period. Katrina

    was always very generous towards assisting my PhD sub-study- thank you Katrina.

    The PhD project was supported by numerous staff at Menzies School of Health

    Research. Susan Hutton, Joanne Bex and Julie Green in Operations; Data

    management and statistical support from Robyn Liddle, Linda Ward, Joseph

    McDonnell, Mark Chatfield and Matthew Stevens. I thank Kim Piera for her

    generous and careful attention to detail with processing ELISAs for adipokines on

    the many samples I had for this project.

    Others, unrelated to Menzies deserve special mention: Dr Leonard Sunil Piers who

    has expertise in body composition techniques, but was also happy to advise on an

    appropriate analytical approach; Dr Jarrod Meerkin, who generously supplied his

    DXA unit, and his own time for the Thursday Island visit (described in Chapter 5);

    Dr Jerry Greenfield provided expert direction to devising the CT methodology, and

    introduced me to Ms Penelope Speight, who was a wonderful collaborator who

    assisted in the design of the computed tomography protocol, and flew to Darwin to

    set up the protocol with the dedicated staff of the Northern Territory Imaging group

    who performed the CT scans. Penny also provided very prompt and thorough

    analysis of data. Thank you to the NT Imaging Group: Business Managers, Mr

    Rama Genga and Mr Aaron Hatcher, radiology staff including Fiona Schenkel, and

    clerical staff who assisted with bookings. Thank you Yvonne Coleman, a brilliant

    graphic artist, who assisted in the design of feedback material to participants and

    communities, and more recently helped me format the thesis; Helen Fejo-Frith,

    Aboriginal elder, inspirational leader in her community in Darwin and a friend.

    Helen was often extremely busy, but always made me feel very welcome in her

    community, supported our study (The eGFR Study and Healthy Top-Enders’ Study),

    and facilitated community access and acceptance.

  • v

    I gratefully acknowledge my funding sources. Thank you to the National Health and

    Medical Research Council (NHMRC) Training Scholarship for Indigenous

    Australian Health Research #490348, 2008-2011. Thank you to the Rio Tinto

    Aboriginal Fund who sponsored me as a Role Model for Health, 2007-2010. Thank

    you to the following for project support: Pfizer Cardio Vascular Lipid research grant

    (2009); Douglas and Lola Douglas Scholarship Australian Academy of Science

    Award (2008); NHMRC Centre of Clinical Research Excellence in Clinical Science

    in Diabetes, University of Melbourne (2010); Gurdiminda Indigenous Health

    Research Scholarship, Menzies School of Health Research (2008). The eGFR Study

    was funded by an NHMRC Project Grant #545202.

    Finally I tha

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