Assessment of Lifestyle and Metabolic Factors in Renal Transplant Recipients

ABSTRACT Introduction: Renal transplant recipients (RTR) with abnormal glucose tolerance (AGT) are at an increased risk of graft failure and cardiovascular disease (CVD). CVD is the major cause of death in RTR. Whilst there are numerous known risk factors for AGT in RTR, it is unknown whether lifestyle factors are found in the presence or play a role in the development of AGT in RTR. The nutritional status of RTR in an Australian population has also not been extensively investigated. Investigation into these areas could help identify modifiable areas for change in the RTR population. Multidisciplinary lifestyle modification, including diet and physical activity (PA) advice from a dietitian, may help reduce modifiable risk factors for CVD in RTR with AGT. Aims: The principle aims of this thesis are to; 1) assess the incidence of obesity and central obesity in RTR and compare to rates in the general Australian population, 2) investigate and compare modifiable lifestyle factors and adipokine levels in RTR with AGT and normal glucose tolerance (NGT) and 3) investigate the effect of a multidisciplinary lifestyle intervention (including dietetic advice) on modifiable CVD risk factors in RTR with AGT. Methods: Chapter 1 presents a review of the literature describing the main nutritional challenges in RTR, cardiovascular risk factors in RTR including adipokine profiles and the role of body composition, diet and PA in RTR. Chapter 2 details the clinical, biochemical, nutritional, body composition, PA and statistical methodologies used in this thesis. In Chapter 3 a descriptive analysis of the anthropometry and cardiovascular risk profile of RTR in an Australian setting is investigated. Chapter 4 investigates the nutritional status of RTR with NGT and AGT in more detail, assessing diet, PA, adipokines and body composition. In Chapter 5, the current literature on lifestyle intervention management (including nutritional management) for obesity and type 2 diabetes mellitus in the general population is discussed. Building on previous chapters, Chapter 6 investigates the effect of a multi-disciplinary lifestyle intervention (with dietetic input) on modifiable cardiovascular risk factors in RTR with AGT. Results: In Chapter 3 it was found that RTR are significantly more centrally obese than those in the general population, and this was particularly the case in younger RTR. Central obesity was associated with CVD risk factors in RTR. Chapter 4 found that a lower level of PA, obesity and central obesity are associated with AGT in RTR, whereas no difference in adipokines or dietary intake was found. In Chapter 6, multidisciplinary lifestyle intervention with dietetic input was found to improve certain risk factors for CVD in RTR with AGT, such as dietary factors (total fat and saturated fat intake) and lipid levels. Conclusions: Central obesity is a common problem in RTR, particularly in those with AGT. Higher levels of PA are associated with lower risk of AGT in RTR, and may help reduce the incidence of central obesity in RTR. Multidisciplinary lifestyle intervention, with dietetic input, can improve some modifiable CVD risk factors in RTR with AGT, however more intensive intervention is required to significantly reduce the incidence of obesity. Key Words: Renal Transplant; Abnormal Glucose Tolerance, Obesity; Cardiovascular Disease; Physical Activity Australian and New Zealand Standard Research Classifications (ANZSRC) 1111 Nutrition and Dietetics, 1102 Cardiovascular medicine and Haematology, 1199 Other Medicine and Health Science