Dissertation Defense Announcement
School of Public Health announces the Final Dissertation Defense of
for the Degree of Doctor of Philosophy
February 15, 2022 at 09:00 A M virtually
Advisor: Dr. Vikki Nolan
The association between physical fitness, chronic disease, and mortality in childhood cancer survivors: A report from the St. Jude Lifetime cohort
ABSTRACT: "Childhood cancer survivors (CCS) are at an increased risk of chronic cardiovascular disease, pulmonary disease and all-cause mortality compared to their cancer free cohorts. Increasing physical fitness in the cancer free population can decrease the risk of chronic disease. However, increasing physical fitness among CCS is difficult, possibility due to survivor’s difficulty performing submaximal tasks and treatment. This may be due to survivor’s difficulty performing submaximal tasks. Also, pulmonary disease quickly, increasing their risk for mortality. Therefore, this dissertation seeks to examine the associations of physical fitness, cardiovascular disease, and all-cause mortality in CCS, as well as determine the associations between physiological cost index (PCI) and obesity. Finally, this dissertation seeks to validate the chest wall expansion test as test of pulmonary function. First, we evaluated the associations between physical fitness, incident cardiovascular disease and mortality in survivors of childhood cancer (n=1,675). The risk of all-cause mortality was significantly lower in survivors who are physical fit (>58% of predicted) compared to those who have low fitness (hazard ratio: 2.75, 95% confidence interval: 1.38, 5.47). Second, we evaluated the associations between obesity and PCI in adult survivors of childhood acute lymphoblastic leukemia (n= 1,166). The PCI of morbidly obese survivors (≥ 35 kg/m2) was significantly greater compared to survivors who have a normal BMI (0.55 vs 0.49, p <0.008). Unlike their cancer-free peers, survivors with an impaired PCI have worse adaptive physical function and quality of life compared to those who do not have impaired PCI. Lastly, we evaluated the validity of the chest wall expansion’s ability to measure pulmonary function in CCS (n= 3,413). The chest wall expansion had poor validity when compared to pulmonary function tests such as spirometry, and plethysmography. Chest wall expansion also had poor sensitivity when determining pulmonary impairment, using spirometry and plethysmography as the gold standard. The CCS benefit from physical fitness, however, some survivors have difficulty performing submaximal tasks. Additionally, the chest wall expansion test is poor at determining pulmonary function. Interventions and better field tests are needed to increase survivor’s physical fitness and to help diagnose disease earlier."