Association between cancer, adipose tissue and selected systemic markers : a possible classification according to body shape

Mentoor, Ilze Lauren (2016-03)

Thesis (MSc)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: Background: The metabolic syndrome (MetS) is a cluster of risk factors associated with an increased risk of developing chronic diseases of lifestyle, and has more recently been associated with cancer risk. Currently, the pathophysiology of the MetS and cancer risk is still unknown; however it is proposed to involve several factors. These include the effects of body composition (android and gynoid shapes), and insulin resistance on the bioavailability of growth factors, inflammatory markers and sex hormone profiles. Various anthropometrical measurements have been used to investigate body composition, however, due to their limitations, a new metric namely a body shape index (ABSI) has been proposed to be a better measure of fat distribution and body shape. Aims: To determine the prevalence of the MetS, and the possible risks of developing cancer in relation to metabolic status, body composition, growth factors as well as inflammatory and sex hormone parameters. Methods: Female participants between the ages of 20-60 years were classified according to the International Diabetes Federation’s (IDF) definition of the MetS and according to body shape (android/gynoid) by photoscopic somatotyping. A series of tests and assessments were conducted; such as blood pressure assessments, anthropometric measurements, bioelectrical impedance analyses (BIA) and blood analyses. Blood analysis included fasting glucose, fasting insulin, lipid profile, insulin-like growth factor-1 (IGF-1), inflammatory marker (C-reactive protein (CRP)); and sex hormone parameters (oestrogen, female testosterone, sex hormone binding globulin; and free androgen index). Results: The prevalence of the MetS was found to be 57.5 %; with abdominal obesity (73.8 %), elevated blood pressure (BP, 68.8 %) and low high density lipoprotein-cholesterol (HDL-c) levels (68.8 %) being the more prevalent risk factors. Both metabolic status; and body shape alone were found to be predictors influencing anthropometric, BIA, physiological and biochemical blood parameters. Metabolic status was found to have an effect on several parameters in the gynoid body shape groups, i.e. body mass (BM) (p<0.001), hip circumference (HC) (p<0.01), body mass index (BMI) (p<0.001), fat mass (FM) (%) (p<0.01), fat free mass (FFM) (%) (p<0.01), waist circumference (WC) (p<0.001), HDL-c (p<0.001), triglycerides (TG) (p<0.05), systolic blood pressure (SBP) (p<0.05) and diastolic blood pressure (DBP) (p<0.01), while metabolic status showed an effect on BM (p<0.001), BMI (p<0.01), TG (p<0.05), SBP (p<0.01) and DBP (p<0.01) in the android body shape groups. Both metabolic status and body shape did not show any effect on ABSI, total cholesterol (TC), low density lipoprotein-cholesterol (LDL-c), fasting insulin, CRP and all sex hormone parameters. Correlation analyses revealed significant correlations for several anthropometric, BIA and blood parameters. Conclusion: This study showed that metabolic status, body shape and/or both could predict changes in various body composition, physiological and biochemical parameters in women. However, no effects were evident for any parameters linking the MetS to cancer risk. Thus, no accurate conclusion could be drawn regarding the pathophysiology. Our findings on ABSI, still warrants future investigation to substantiate the use of this metric in relation to the MetS, body shape and cancer risk.

AFRIKAANSE OPSOMMING: Agtergrond: Die metaboliese sindroom (MetS), wat bestaan uit ‘n groep risiko faktore wat met ʼn toename in die ontwikkeling van chroniese lewenstyl siektes geassosieër word, is onlangs ook met kanker geassosieër. Tans, is die patofisiologie van die MetS en kanker risiko onbekend; hoewel dit moontlik verskeie faktore kan insluit. Hierdie faktore sluit onder andere in; liggaamsamestelling (androïede en genoïede vorme), asook insulienweerstandigheid en die biobeskikbaarheid van groei faktore, inflammatoriese merkers en geslagshormoon profiele. Verskeie antropometriese metings word gebruik om liggaamsamestelling te bepaal, maar as gevolg van beperkinge, word ʼn nuwe maatstaf, naamlik die liggaamsvorm indeks (LVI) voorgestel as ʼn beter meting om vet verspreiding en liggaamsvorm te beskryf. Doelwitte: Om die voorkoms van die MetS, en die moontlike risiko vir die ontwikkeling van kanker wat verwant is aan die MetS, liggaamsamestelling, groei faktore, asook inflammatoriese en geslagshormoon parameters te bepaal. Metodes: Vroulike deelnemers tussen die ouderdomme 20-60 jaar is volgens die MetS definisie van die Internasionale Diabetes Federasie (IDF), asook die liggaamsvorme (androïed/genoïed) deur middel van fotoskopiese somatotipering, geklassifiseer. ʼn Reeks ondersoeke is gedoen insluitend bloeddruk, antropometrie, bio-elektriese impedansie (BIA), en bloed analises. Bloed analises het vastende glukose, insulien, lipied profiel, insulien-agtige groeifaktor-1 (IGF-1), inflammatoriese merker (C-reaktiewe proteïen (CRP)); en geslagshormoon parameters (estrogeen, vroulike testosteroon, geslags hormoon bindings globulien; en vry-androgeen indeks) ingesluit. Resultate: Die voorkoms van die MetS was 57.5 %; waaronder abdominale vetsug (73.8 %), verhoogde bloeddruk (BP, 68.8 %), en hoë digtheids lipoproteïen cholesterol (HDL-c) vlakke (68.8 %) die mees prevalente risiko faktore was. Beide die metaboliese status; en liggaamsvorm alleen, is as moontlike voorspellers geïdentifiseer wat die antropometriese, BIA, fisiologiese en biochemiese parameters aanbetref. Die metaboliese status het verder ʼn effek op verskeie parameters in die genoïede liggaamsvorm groep getoon, i.e. liggaamsmassa (LM) (p<0.001), heup omtrek (HO) (p<0.01), liggaamsmassa indeks (LMI) (p<0.001), vet massa (VM) (%) (p<0.01), vetvrye massa (VVM) (%) (p<0.01), middellyf omtrek (MO) (p<0.001), HDL-c (p<0.001), trigliseriede (TG) (p<0.05), sistoliese bloeddruk (SBD) (p<0.05) en diastoliese bloeddruk (DBD) (p<0.01), terwyl die metaboliese status ʼn effek getoon het op LM (p<0.001), LMI (p<0.01), TG (p<0.05), SBD (p<0.01) en DBD (p<0.01) in die androïede liggaamsvorm groep. Beide die metaboliese status en liggaamsvorm het geen effek op die LVI, totale cholesterol (TC), lae digtheids lipoproteïen cholesterol (LDL-c), vastende insulien, CRP en alle geslagshormoon parameters getoon nie. Betekenisvolle korrelasie analises is verkry onder verskeie antropometriese, BIA en bloed parameters. Gevolgtrekking: Hierdie studie toon dat die metaboliese status, liggaamsvorm, en/of beide veranderinge in verskeie liggaamssamestelling, fisiologiese en biochemiese parameters in vroue kan voorspel. Geen effekte is waargeneem vir enige parameter wat die MetS met kanker risiko kan verbind nie. Dus, kan geen akkurate afleiding gemaak word oor die patofisiologie hiervan nie. Ons bevindinge oor die LVI noodsaak verdere ondersoek met betrekking tot die MetS, liggaamsvorm en kanker risiko.

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