published_or_final_version / Medicine / Master / Doctor of Medicine

published_or_final_version / abstract / toc / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Purpose: Infants born with Heterotaxy Syndrome (HS) often have intestinal malrotation in addition to severe congenital heart disease (CHD). Given the catastrophic risk of midgut volvulus, where the vascular supply to the gut is cut off causing necrotic bowel and possible future short‐gut syndrome following surgery, an elective Ladd procedure is recommended at the first diagnosis of malrotation. In patients with severe CHD, however, the risk of complications from prophylactic surgery is high, especially in infancy prior to stable cardiac palliation. This study sought to determine whether deferring a Ladd procedure during the first six months of life in infants with CHD is safe by focusing on the incidence of volvulus in the HS population, morbidity of volvulus and morbidity of an elective Ladd procedure. Methods: Medical records of patients with HS and intestinal malrotation at Phoenix Children’s Hospital from 2006‐2011 were reviewed. Stage of heart surgery, severity of heart disease, diagnosis of intestinal malrotation, and timing of Ladd procedure if applicable were recorded. Results: 31 patients with HS and intestinal malrotation were identified. Of the 31, 9 had a Ladd procedure prior to six months of age, 2 for volvulus and the other 7 either electively or for less severe GI symptoms that were not suggestive of volvulus. The other 22 did not have a Ladd procedure prior to six months of age. There was one death (1/22) from a non‐gastrointestinal cause in a patient who had not undergone a Ladd procedure. There were no deaths in the 9 patients who underwent a Ladd procedure (0/9). Conclusions: Given the low overall incidence of volvulus in HS, and with continued vigilance for obstructive symptoms, this study suggests that delaying the Ladd procedure in asymptomatic patients with HS and CHD and intestinal malrotation is safe. Watchful waiting may reduce the incidence of cardiac complications during the Ladd procedure by allowing for stabilizing cardiac surgical palliation prior to elective abdominal surgery.

Introduction. The relationships among military service, combat intensity and long-term health effects were investigated in a cohort of 6,355 Vietnam-era American Legionnaires who were recruited in 1984 and followed through 1998. First, the effect of Vietnam service on coronary heart disease (CHD) risk was assessed among 3,781 veterans who responded to both questionnaires. Next, the effect of serving in Vietnam and combat exposure was investigated as risk factors for the mortality of the cohort. Finally, potential threats to the validity of this study were evaluated.Methods. Military service and lifestyle factors were assessed by questionnaires in 1984 and 1998. Vital status in 1998 was determined and causes of death were ascertained through the National Death Index. Cox proportional hazards modeling was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for CHD incidence and mortality in relation to service location and combat exposure, adjusting for age, smoking, alcohol consumption, body mass, and hypertension. Response bias and reliability of self-reported data were examined.Results. Serving in Vietnam was associated with an increased hazard of developing heart disease (HR=1.37, 95% CI: 1.09, 1.73), after controlling for independent risk factors. Vietnam veterans experienced a 50% higher mortality than non-Vietnam veterans during 14-year follow-up (HR=1.48, 95% CI= 1.13 - 1.93), which increased with combat intensity after adjustment for other risk factors, (low combat: HR 1.17, 95% CI 0.79 - 1.73; medium combat HR=1.51, 95% CI 1.05 - 2.17; high combat HR=1.82, 95% CI 1.20 - 2.76). A stronger relationship was observed by level of combat for CHD mortality (low combat: HR =1.48, 95% CI 0.75 - 2.95; medium combat HR= 2.01, 95% CI 1.06 - 3.79; high combat HR= 2.27, 95% CI 1.08 - 4.79). Results showed that non-respondents differed only slightly from respondents for important variables potentially related to exposures and chronic disease outcomes. Furthermore, veteran self-report was moderately to highly reliable when measured over a 14 year period.Conclusions. Vietnam veterans are still experiencing higher rates of adverse health effects, even more than thirty years after their military service. These data support a long term and independent adverse effect of military service in Vietnam on cardiovascular health.

Motivation Cardiovascular disease (CVD) is one of the most important causes of mortality and morbidity in South Africa. The major risk factors are prevalent in both the developed and developing areas of the world, among all social classes, and are of similar public health significance in all countries regardless of their level of development. This indicates that much scope remains for further reducing coronary heart disease (CHD) death rates in developed countries and for preventing the emerging CHD epidemic in poorer nations. This study aims at identifying the beliefs of the South African adult population regarding food and cardiovascular health and to therefore identify target groups for education programs. Objectives To investigate the beliefs of South African adults towards the importance of the link between food and cardiovascular health, especially between the different races, living standards, age and gender groups. Also to determine whether this population looks for the Heart Foundation symbol on food products, as well as where the link between food and heart disease ranks in terms of importance compared to other highly prevalent diseases. Method The design of the study was a randomized cross-sectional study. Trained field workers administrated questionnaires by conducting face-to-face interviews with consumers in the language of their choice. Two thousand South African individuals (1 6 years and older) were randomly selected from metropolitan areas in South Africa. The data was weighted to be representative of the total South African metropolitan consumer population, based on gender, age and race distribution (n=10 695 000). The total population was representative of both genders (5 423 000 men and 5 272 000 women) and major race groups (2 615 000 whites, 6 252 000 blacks, 1 255 000 coloureds and 573 000 Indians), from different age and living standards groups. The market research group, MARKINOR, was contracted to collect the data. Quantitive data was statistically analysed in order to generate the relevant descriptive statistics, cross tabulations and statistical tests. Results The majority of the population found the link between food and cardiovascular risk related health issues to be important, especially the higher LSM groups within the different race groups. The link between food and weight loss was considered the least important compared to other cardiovascular risk factors (cholesterol, blood pressure, diabetes, healthy blood vessels). Only 35% of the study population agreed with the statement that they look for the Heart Foundation symbol, while 46% disagreed with the statement. There was a greater tendency for the higher LSM groups to look for the Heart Foundation symbol than the lower LSM groups. Heart disease was considered just as important and in some cases more important when compared with HIVIAIDS and cancer. Conclusions This study shows that the metropolitan South African adult population is aware of the importance of food on CVD. Nutritional education needs to be aimed at both genders and all ages of the lower socio-economic groups of South Africa. The reasons why such a large percentage of the South African metropolitan adults do not look for the Heart Foundation symbol, or are undecided about it, needs to be investigated and addressed. Prevention programs promoting a healthy lifestyle, which would address the risk factors associated with CVD, should be received with a positive attitude. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2005.

The aim was to determine whether the dietary glycemic index (GI) related to coronary heart disease (CHD) risk and whether oxidized LDL could explain this relation. Nine prospective cohorts of GI or glycemic load (GL) associations were pooled in a meta-analysis and showed an increased risk of CHD for high GI (near significant at RR=1.13, 95%CI; 1.00-1.26) and GL diets (significant at RR=1.40, 95%CI; 1.17-1.68), both with significant evidence of heterogeneity (P<0.07). Sera from 151 type 2 diabetics who completed a 6-month trial of a low GI diet demonstrated no treatment difference in measures of oxidative damage. However, when data from both treatments were pooled, oxidized LDL as a marker of CHD risk inversely related to low GI carbohydrate intake. We conclude that GI and GL relate to CHD and oxidative damage to LDL may explain part of this association.

The aim was to determine whether the dietary glycemic index (GI) related to coronary heart disease (CHD) risk and whether oxidized LDL could explain this relation. Nine prospective cohorts of GI or glycemic load (GL) associations were pooled in a meta-analysis and showed an increased risk of CHD for high GI (near significant at RR=1.13, 95%CI; 1.00-1.26) and GL diets (significant at RR=1.40, 95%CI; 1.17-1.68), both with significant evidence of heterogeneity (P<0.07). Sera from 151 type 2 diabetics who completed a 6-month trial of a low GI diet demonstrated no treatment difference in measures of oxidative damage. However, when data from both treatments were pooled, oxidized LDL as a marker of CHD risk inversely related to low GI carbohydrate intake. We conclude that GI and GL relate to CHD and oxidative damage to LDL may explain part of this association.

Context: Little is known about body image and its relationship with physical activity (PA) among people living with heart disease. Purpose: To determine the prevalence and stability of body image issues over time in heart patients, and to determine the bi-directional relationship between body image and PA over time. Method: Participants who completed cardiac rehabilitation (CR; n = 31), and who declined CR (n = 28) were recruited. Participants completed self-report questionnaires assessing body image and PA at two time intervals, three months apart. Results: Up to 9.7% of participants in CR and 10.7% of those not in CR reported high body image concerns. Repeated measures ANOVAs revealed body image changed over time in people not in CR (body surveillance, Wilk’s ? = .768, F = 8.15, p = .008; control beliefs, Wilk’s ? = .837, F = 5.28, p = .030). Linear regressions showed that minutes of moderate PA predicted body image (body shame, ? = -.372, t = -.2.12, p = .043) in people in CR, and that body image (control beliefs) predicted minutes of moderate PA (? = .384, t =2.12, p = .044) in people not in CR. Conclusion/Implications: This research has the potential to lead to the development of more effective PA interventions, thus improving the longevity and quality of life of heart patients.