Background: In South Africa, as in many other developing countries, iron deficiency (the most common micronutrient deficiency) still remains unresolved; while obesity has emerged as a public health challenge causing increases in the incidence and prevalence of cardiovascular diseases (CVDs). Research has shown that certain iron indices are associated with both anthropometric and biological markers of CVDs. Adiposity is thought to modulate the pathway linking iron status to CVDs. Objective: To examine the associations between iron indices, anthropometric and biological markers of CVDs in an African population undergoing transition. Methods: This thesis was based on secondary analysis of data generated during the Transition and Health during Urbanisation of South Africans (THUSA) study; and primary and secondary analysis of the baseline Prospective Urban and Rural Epidemiological (PURE) study. Both studies were cross–sectional in design and were conducted between 1996–1998 and in 2005 respectively in the North West Province of South Africa. The 1854 men and women participants in the THUSA study (>15years) and 1262 women participants in the PURE study (>35years) were included in the analysis. The relationship between iron and anthropometric indicators of CVD risk was examined in the THUSA study while that of iron status, anthropometric and biological markers of CVD risk was examined in the PURE study. Results: In the THUSA study, ferritin was positively associated with body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), body fat and subscapular skinfold (r=0.141, 0.359, 0.396, 0.308, 0.141 respectively for men and 0.126, 0.232, 0.319, 0.126, 0.105 respectively for women; p<0.01). Only the women showed decreased serum iron concentration with increasing BMI (p<0.05). WC and WHR increased with increasing serum ferritin concentration for both genders (p<0.05). As for the PURE study, associations between iron status parameters and CVD risk factors were generally weak (r<0.3, p<0.01) and were not retained after adjusting for valid confounders. WC and WHR increased with increasing ferritin concentration (p<0.05). Conclusion: Although these results do not indicate any significant association between iron indices and biological markers of CVD, its association with anthropometric indices gives an indication of the possible contribution of iron in the aetiology of CVDs. Thus, it may be necessary to exercise caution on the emphasis placed on iron as a nutrient and iron intervention programmes because of the suggestive role of iron in CVD development. / Thesis (Ph.D. (Nutrition))--North-West University, Potchefstroom Campus, 2011.

Background: In South Africa, as in many other developing countries, iron deficiency (the most common micronutrient deficiency) still remains unresolved; while obesity has emerged as a public health challenge causing increases in the incidence and prevalence of cardiovascular diseases (CVDs). Research has shown that certain iron indices are associated with both anthropometric and biological markers of CVDs. Adiposity is thought to modulate the pathway linking iron status to CVDs. Objective: To examine the associations between iron indices, anthropometric and biological markers of CVDs in an African population undergoing transition. Methods: This thesis was based on secondary analysis of data generated during the Transition and Health during Urbanisation of South Africans (THUSA) study; and primary and secondary analysis of the baseline Prospective Urban and Rural Epidemiological (PURE) study. Both studies were cross–sectional in design and were conducted between 1996–1998 and in 2005 respectively in the North West Province of South Africa. The 1854 men and women participants in the THUSA study (>15years) and 1262 women participants in the PURE study (>35years) were included in the analysis. The relationship between iron and anthropometric indicators of CVD risk was examined in the THUSA study while that of iron status, anthropometric and biological markers of CVD risk was examined in the PURE study. Results: In the THUSA study, ferritin was positively associated with body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), body fat and subscapular skinfold (r=0.141, 0.359, 0.396, 0.308, 0.141 respectively for men and 0.126, 0.232, 0.319, 0.126, 0.105 respectively for women; p<0.01). Only the women showed decreased serum iron concentration with increasing BMI (p<0.05). WC and WHR increased with increasing serum ferritin concentration for both genders (p<0.05). As for the PURE study, associations between iron status parameters and CVD risk factors were generally weak (r<0.3, p<0.01) and were not retained after adjusting for valid confounders. WC and WHR increased with increasing ferritin concentration (p<0.05). Conclusion: Although these results do not indicate any significant association between iron indices and biological markers of CVD, its association with anthropometric indices gives an indication of the possible contribution of iron in the aetiology of CVDs. Thus, it may be necessary to exercise caution on the emphasis placed on iron as a nutrient and iron intervention programmes because of the suggestive role of iron in CVD development. / Thesis (Ph.D. (Nutrition))--North-West University, Potchefstroom Campus, 2011.

In the latter part of the 20th century chronic diseases, especially cardio vascular-related diseases (CVDs) and Type 2 diabetes mellitus (DM) seemed to have emerged as substantial problems. This can be seen in the prevalence and the cost of CVDs in South Africa and worldwide. It was predicted that by the year 2030 more people would be dying from CVDs than from Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/Aids). The reasons for the occurrence of CVDs are linked to biological (i.e. hypertension, hyperlipidemia, obesity, insulin resistance, etc), psychological (i.e. emotional stress), and behavioural or lifestyle risk factors. It is known that physical exercise can aid in the treatment of CVDs. Institutions such as the American College of Sports Medicine (ACSM) recommended an exercise frequency of three times per week for 20 minutes. According to literature, a third of patients in exercise studies do not comply with their exercise protocol, and after three to six months, 50 percent will drop out of organised training groups. Less than a third of South Africans complied with exercising 30 minutes a day on most days of the week. Thus, there has been much interest among health-care providers to manage exercise compliance. Exercise compliance is a complex construct, and thus in the present study the role that behavioural patterns play was also investigated via psychological behavioural models. The major objectives of the study were the following: <ul> <li> Firstly, to determine if exercise compliance or non-compliance had an influence on shifts measured in the clinical parameters (i.e. blood pressure, blood lipid levels, blood glucose levels, body mass index, body fat percentage and cardiac risk percentage) over time.</li> <li> Secondly, to determine whether there were any correlation between the psychological behavioural models and the exercise compliance of the members over the course of the Best Med/Access Health-Disease Management Programme (BM/AH-DM Programme).</li></ul> In the present study, a retrospective data analysis was done on data collected from Best Med Medical Aid members (n = 400) who participated in a chronic disease management programme for three and a half years. The inclusion criteria for participation on the programme were the presence of one or more of the following CVDs namely: hypercholesterolemia, hypertension and DM. The members’ clinical parameters (height, body weight, body fat percentage, blood pressure, finger-prick non-fasting (random) blood cholesterol level, finger-prick non-fasting (random) blood glucose, sub-maximal V02 fitness test) were measured every three months. After a baseline assessment was done, an exercise programme was given to each member and a norm of exercising twice a week was prescribed. If members adhered to the norm they were considered compliant and if they did not adhere to the norm, they were considered as being non-compliant. Their exercise compliance, and relevant clinical parameters were measured over 30 months, although data analysis was only a reflection of the first 12 months’ data. At the beginning of the BM/AH-DM Programme the members’ Level of Readiness (LOR) to make a lifestyle change was measured via a questionnaire and by the end of the programme they completed an Implicit Theory Scale (ITS) questionnaire. Descriptive statistics (means, standard deviation) were used to determine the entire groups’ compliance, and to divide the group into compliant and noncompliant groups. The T-test or the Mann-Whitney Test (an equivalent nonparametric technique) was applied to determine significant differences between groups. Thus did the clinical parameters measured over time (baseline to 3 months, baseline to 6 months and baseline to 12 months), change more in the compliant than in the non-compliant group? And were there correlations between psychological questionnaires answers and the two exercise groups? The results indicated that the group’s exercise compliance trend decreased drastically over time. Statistical significant decreases were demonstrated in systolic (p = 0.007) and diastolic (p = 0.012) blood pressure, BMI (p = 0.072 and p = 0.0003), cardiac risk percentage (p = 0.003), and body weight (p = 0.003 and p = 0.0000). All of these decreases were seen in the exercise compliant group. There were no statistical correlations between the psychological questionnaires and the exercise groups. Limitations were the quality of the clinical data, the exercise compliance data that deteriorated over time, and the LOR and ITS questionnaires was neither valid nor reliable tools in making predictions regarding exercise behaviour/compliance. For future research it is recommended that measurements of blood pressure and cholesterol be done more thoroughly, and dietary fat intake must be monitored. A valid and reliable cardiac risk tool, LOR and ITS questionnaires must be designed. AFRIKAANS : Die voorkoms en kosteïmplikasies van kroniese siektetoestande in Suid–Afrika en wêreldwyd, het in die laaste gedeelte van die 20ste eeu ‘n wesenlike probleem geword. Kardiovaskulêre (KVS) siektes en tipe 2 diabetes mellitus (DM) is veral voorbeelde van sulke siektetoestande. Daar is voorspel dat in die jaar 2030, meer mense wêreldwyd aan KVS sal doodgaan, as aan Menslike Immuniteitsgebrekvirus/Verworwe Immuniteitsgebreksindroom (MIV/Vigs). Die risikofaktore wat met die oorsake van KVS geassosieer word, is die volgende: <ul> <li> Biologiese (met inbegrip van hipertensie, insulienweerstandigheid, hoë bloedcholesteroltellings, ens)</li> <li> Sielkundige (bv emosionele spanning) • Risikofaktore wat verband hou met lewenstyl.</li></ul> Literatuur bevestig dat fisiese oefening help om KVS en diabetes mellitus te behandel. Die American College of Sports Medicine (ACSM) het ‘n oefenriglyn van drie maal per week vir 20 minute lank as ‘n minimumfrekwensie daargestel. Volgens literatuur oefen ‘n derde van pasiënte wat deelneem aan oefeningnavorsingsstudies nie volgens die riglyne wat gestel word nie en binne die eerste drie tot ses maande sal 50% van die pasiënte ophou oefen. Navorsing wat op die Suid-Afrikaanse bevolking gedoen is, toon dat minder as ‘n derde 30 minute lank op meeste dae van die week oefen. Dus is die belangstelling van gesondheidsterapeute rakende die bestuur van gereelde oefeningdeelname geprikkel. Gereelde oefeningdeelname sluit ook die rol van gedragspatrone in en dus is sielkundige gedragsmodelle gebruik om dit ook in die huidige studie te ondersoek. Copyright / Dissertation (MA)--University of Pretoria, 2009 / Biokinetics, Sport and Leisure Sciences / unrestricted