A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Medicine Johannesburg, 2018. / There has been an increase in the percentage of individuals employed in sedentary occupations over the last 50 years. Prolonged sedentary time has been associated with poorer cardiometabolic health. Interrupting prolonged sedentary activity may attenuate the risk of developing cardiometabolic disease. This study aimed to determine whether prompts delivered via a mobile phone were effective in reducing sedentary behaviour (measured objectively using an Actigraph and activPAL accelerometer) in people with sedentary occupations. Twenty men and women were randomly assigned to either a control or intervention (PROMPT) group. Only participants in the PROMPT group were instructed to interrupt their sedentary behaviour. During the intervention participants in the PROMPT group spent less time in sedentary behaviour (5.5±0.5 hrs/day) during their working day, compared to the control group (6.7±0.6 hrs/day) as measured using the activPAL (p=0.04). There was no association between the intervention and cardiometabolic health variables. There were differences in the outputs of ActiGraph and activPAL accelerometers. Interrupting prolonged sedentary time via mobile phone messages may be an effective strategy in reducing total sedentary time in the workplace. / LG2018

Cardiovascular disease (CVD) and type two diabetes mellitus (T2D) are among the leading causes of death worldwide. Insulin resistance (IR) and hyperglycaemia are risk factors for CVD and T2D and are known to be prevalent in youth. Physical activity (PA) is known to improve IR and glucose tolerance in youth, but current levels of PA are low meaning alternative PA recommendations are needed. The purpose of this thesis is to investigate the effect of low volume high-intensity interval exercise (HIIE) on insulin and glucose health outcomes in male children and adolescents. Additionally, the thesis will explore the potential for HIIE to improve glycaemic control in paediatric patients with type one diabetes mellitus (T1D). Chapter 4 examines the relationship between estimates of insulin sensitivity (IS) based on oral glucose tolerance test (OGTT) and fasted assessment methods, in addition to the day-to-day reliability of these measures in children and adolescents. Results from this chapter advocated the Cederholm index to measure IS in this sample due to the low day to day reliability (coefficient of variation (%CV) of 6.4%). Chapter 5 demonstrates comparable results, reporting moderate improvements to IS and glucose tolerance measured via an OGTT 10 minutes after a single bout of HIIE and work-matched moderate-intensity exercise (MIE) in adolescent boys (13-15 y old). The findings from Chapter 5 are extended in Chapter 6, where changes to OGTT derived IS and glucose tolerance were measured up to 24 h post exercise and fasting measures of IS up to 48 h after exercise. Improvements to IS and glucose tolerance after the OGTT persisted for up to 24 h after HIIE and MIE, but no changes to fasting outcomes were observed over the 48 h period. In contrast to Chapter 5, Chapter 7 reports that a single bout of HIIE but not work-matched MIE resulted in only a small improvement in IS in 8-10 year old boys. Chapter 8 assesses the efficacy of 6 sessions of HIIE performed over 2 weeks to alter fasting and postprandial (mixed-meal tolerance test) insulin and glucose outcomes in adolescent boys. In contrast to acute exercise (Chapters 5 and 6), HIIE training over 2 weeks did not improve insulin and glucose outcomes in this population. Finally, Chapter 9 presents a case study on three adolescents with T1D to examine the effect of acute HIIE and MIE on glycaemic control. This study indicates that both MIE and HIIE have the potential to improve short-term (24 h) glycaemic control within this clinical population. Taken collectively, the studies from this thesis demonstrate that HIIE offers an effectual and feasible alternative to MIE to improve insulin and glucose health outcomes in healthy children and adolescents, and short-term glycaemic control in adolescents with T1D.

A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree Master of Science. / Sprint interval training (SIT) is a time-efficient strategy to improve cardiorespiratory fitness; however, most protocols have been studied in a laboratory setting and require specialized equipment. We investigated the efficacy of brief intense stair climbing as a practical model of SIT to improve cardiometabolic health, with a key measure being cardiorespiratory fitness as indicated by peak oxygen uptake (VO2peak). Two separate studies, each consisting of an acute and chronic phase, were conducted in a total of 31 sedentary women (age=24±10 y; BMI=23±4 kg•m-2). The acute phase of Study 1 established that the heart rate (HR), blood lactate concentration (BLa), and rating of perceived exertion (RPE) responses were similar when participants (n=8) performed a SIT protocol that involved 3x20-s “all-out” efforts of either continuous stair climbing or cycling, interspersed with 2 min of recovery. The chronic phase demonstrated that when participants (n=12) performed the 3x20-s stair climbing protocol 3 d•wk-1 for 6 wk, absolute and relative VO2peak increased by 12%, or ~1 metabolic equivalent (1.80±0.25 to 2.02±0.27 L•min-1, p<0.001), as there were no changes in body mass (p=0.35), fat free mass (FFM; p=0.09) or % body fat (p=0.42). There were also no changes in resting systolic and diastolic blood pressure (BP; p=0.82 and p=0.97, respectively), resting HR (p=0.62), and fasting insulin sensitivity (p=0.52). The acute phase of Study 2 established that the HR and RPE responses were similar when participants (n=11) performed three different stair climbing protocols. The protocols investigated include the 3x20-s continuous ascent model used in Study 1 (protocol 1), as well as 3x60-s bouts of ascending and descending either one or two flights of stairs, with 60-s of recovery (protocol 2 and 3, respectively). The chronic phase demonstrated that when the same group of subjects performed the 3x60-s 1-flight protocol 3 d•wk-1 for 6 wk, absolute and relative VO2peak increased by 8 and 7%, respectively (1.79±0.36 to 1.93±0.39 L•min-1, p=0.001; 31.2±4.6 to 33.3±5.3 mL•kg-1•min-1; p=0.01). Despite no changes in % body fat (p=0.10), there was an increase 3% increase in FFM (p<0.001). There was no change in systolic (p=0.50) and diastolic BP (p=1.00), but resting HR improved by 8% after training (p=0.03). The change in insulin sensitivity derived from an OGTT was 7.1±11 mg I2•mmol-1•mIU-1•min-1 (p=0.056). These findings demonstrate that brief intense stair climbing is a practical, time-efficient strategy to improve cardiorespiratory fitness in previously untrained women. / Thesis / Master of Science (MSc) / Sprint interval training (SIT), involving brief bouts of very intense exercise separated by short periods of recovery, is a time-efficient alternative to traditional endurance training for improving fitness. This has largely been established in laboratory settings using specialized equipment, which is impractical for many individuals. This project examined whether brief intense stair climbing was a practical model of SIT to elicit adaptations previously shown with cycling protocols. Subjects performed either three 20-s ascents interspersed with 2 min recovery periods, or three 60-s bouts of ascending and descending one or two flights of stairs, with 60-s recovery periods. Both protocols were 10 min in duration including warm-up and cool-down, and subjects trained three days per week for six weeks. The main finding was that stair climbing is a practical, time-efficient model to improve fitness in previously sedentary individuals.

Cardiometabolic diseases are the leading causes of worldwide mortality, of which metabolic syndrome is a major contributor. Increased sedentary behavior and decreased physical activity have been independently associated with increased risk of developing metabolic syndrome and subsequent maladies. Likewise, the development of more contemporary methodologies of measuring metabolic syndrome allow for a more nuanced examination of risk. However, these new methodologies lack extensive utilization among the physical activity epidemiology literature. The scarcity of research incorporating the independent relations between sedentary behavior, physical activity, and contemporary methodologies to measure metabolic syndrome warrants additional investigation. This dissertation aimed to further discern these relations using three different cohort data sets. Data from the National Health and Nutritional Examination Survey (NHANES), the Jackson Heart Study (JHS), and the Coronary Artery Risk Development in Young Adults (CARDIA) Study were utilized to further elucidate the relations between sedentary behavior, physical activity, and metabolic syndrome in three separate studies. The studies observed the majority of waking hours were spent engaged in sedentary behaviors; although, each cohort also appeared to meet the Physical Activity Guidelines for Americans. Metabolic syndrome positive individuals from NHANES engaged in similar amounts of physical activity as the general population. While the diversity of physical activity type was less, the physical activities engaged in were typically at the same prevalence among metabolic syndrome positive and the general populations. Sedentary behaviors were associated with increased metabolic syndrome severity score, but this relation was attenuated when moderate-to-vigorous physical activity and cardiorespiratory fitness were added to the model for both JHS and CARDIA studies. Decreasing sedentary time and with an equivalent amount of physical activity, of any intensity, is beneficial for cardiometabolic health. Understanding which physical activities subpopulations engage in can be paired with culturally competent interventions to increase physical activity engagement. Exceeding the minimum requirements for the Physical Activity Guidelines for Americans can produce increases in cardiorespiratory fitness, which have an independent positive impact on cardiometabolic health. Strategies should aim to increase physical activity among sedentary individuals, while limiting sedentary time among those physically active.

The principle aims of this work were two fold; firstly to identify the current dietary intakes (specifically dietary glycaemic carbohydrate (CHO)) and physical activity (PA) and cardiorespiratory fitness (CRF) levels of a UK, postpubertal, adolescent population (n = 105) and assess the relationship between these factors, adiposity and cardiometabolic health. Diet and health relationships were assessed whilst accounting for energy misreporting and controlling for levels of PA and CRF. The effect of excluding dietary misreporters on the associations between glycaemic CHO and health was assessed whilst comparing an established technique (the Goldberg equation) to a novel approach (the ratio of energy intake (EI) to energy expenditure (EE)), which utilised RT3 accelerometry data (EI:EE(RT3)). Associations of PA and metabolic risk factors were also assessed whilst comparing two child specific PA thresholds for the assessment of PA subcomponents. Secondly, the impact of a flexible, ad libitum, low GI dietary intervention on cardiometabolic health was examined in an „at risk‟, overweight, postpubertal, adolescent population. Glycaemic index (GI) but not glycaemic load (GL) was shown to be associated significantly with anthropometric measures (body mass index (BMI), waist circumference (WC)) and adiposity (body fat percentage (BF%)) in this general group of post-pubertal adolescents from Bedfordshire. When adjusting for dietary intake, CRF was also associated with adiposity but PA was not. The prevalence of misreporting varied depending on the method used to assess the validity of dietary intakes; between 23% and 31% increasing to 62.1% (in overweight) of adolescents under reported energy intakes and up to 11.1% over reported. The novel application of a triaxial accelerometer to measure EE resulted in more under and over reporters being identified than when compared to the widely used Goldberg equation. Increased dietary GI was associated with increased odds of having a high WC; however, associations between GL and other risk factors were less clear; no associations with risk were observed. Excluding dietary misreporters from analysis had important implications for these associations. Only after removal of misreporters by EI:EE(RT3) was a borderline significant positive association between GL and blood glucose (BG) revealed using multiple analysis of covariance (MANCOVA), that was not present in prior analyses. Increased GI (moderate vs low GI intake) was significantly associated with reduced high density lipoprotein cholesterol (HDL) and increased triglyceride (TG) levels (borderline significant) after removal of misreporters. In addition, using different PA thresholds to assess PA intensity resulted in different relationships between PA subcomponents and metabolic risk factors. Regardless of the threshold used, evidence suggested that limiting sedentary (SED) behaviour and engaging in moderate to vigorous PA (MVPA) is beneficial for blood pressure (BP) in this adolescent population. Additionally, irrespective of the threshold utilised, higher levels of vigorous PA (VPA) were associated with reduced odds of having a high clustered risk score and the associations observed between CRF and risk factors were stronger than those observed with PA. Despite a lack of significant improvement in individual metabolic risk factors as a result of the low GI (LGI) dietary intervention, there was a significant reduction in clustered risk score for the LGI group at week 12. A borderline significant improvement in glycated haemoglobin (HbA1c) was also observed as a result of the LGI intervention compared to those in the control group. Conversely, there appeared to be an unfavourable effect of the LGI diet on fasting insulin levels and thus the diet‟s impact on health overall is unclear. The small sample size of this randomised controlled trial (RCT) means that caution is required when interpreting the results. These data suggest that future research in this age group should target improvements in CRF and a lower dietary GI to reduce adiposity. Controlling for dietary misreporting appears to have a significant impact on associations of glycaemic CHO and cardiometabolic health and should be an important consideration of future research. The low GI intervention may be an effective approach for reducing glycaemic CHO, whilst maintaining a healthy macronutrient intake, in comparison to more restricted dietary regimens published in the literature. However, the impact of this regime needs to be confirmed utilising a larger sample of adolescents. This may provide a useful approach for future research aiming to assess the impact of reduced GI and GL.

Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder that increases a woman’s risk of developing cardiovascular disease and diabetes. Women with PCOS have extremely high rates of obesity, insulin resistance, cardiovascular morbidity and mortality. Obese women with PCOS also tend to have elevated sympathetic nerve activity and systemic markers of inflammation, which likely contribute to cardiometabolic risk and PCOS pathogenesis. While few medication or lifestyle intervention options for women with PCOS target elevated sympathetic nerve activity, inflammation, and insulin resistance, passive heat exposure shows promise as a novel intervention for improving cardiovascular and metabolic health in this population. Therefore, the purpose of this study was to examine changes in inflammation, cardiovascular, autonomic, and metabolic health in obese women with PCOS following a 30-session, 8-10 week chronic passive heat intervention (termed ‘heat therapy’). Eighteen obese women with PCOS (Age: 27±1y, BMI 41.3±1.1 kg·m2) were matched for age and body mass index (BMI), then divided into heat therapy (HT) or time control (CON). At the beginning (Pre), middle (Mid), and end (Post) of 8-10 weeks, subjects participated in study days to assess vascular, autonomic, and metabolic function, and additionally underwent a subcutaneous fat biopsy in Pre and Post. HT subjects took part in 30 one-hour hot tub sessions over 8-10 weeks (3-4 per week) in 40.5˚C water, while CON subjects completed all other testing but were not exposed to heat. No change in BMI was observed over the study in HT or CON; however; HT subjects exhibited dramatically improved vascular and metabolic function, as well as reduced sympathetic nerve activity and circulating inflammatory markers. In fat biopsies, insulin signaling was improved in HT subjects, while CON subjects remained stable over time. These findings show promise for HT as a treatment option for obese women with PCOS to improve cardiovascular and metabolic risk profiles. This dissertation includes previously published co-authored material.

BACKGROUND: Metabolic syndrome, elevated blood pressure (BP), elevated cholesterol and type 2 diabetes mellitus are health conditions that increase cardiometabolic risk (CMR). Sleep, physical activity, diet, are modifiable risk factors for the prevention of cardiometabolic disorders. Dietary fiber which is associated with higher fruit and vegetable intakes is known to lower the effects of obesity-related health issues. Further, these foods have an abundance of beneficial vitamins and minerals as well as low energy density. There is controversial, however, regarding the effect of fruit juice intake on CMR, particularly due to its lower fiber content. The objectives of this research were to estimate the effect of intakes of whole fruit and fruit juice on CMR, including effects on Body Mass Index (BMI), overweight/obesity, hypertension/prehypertension, lipid, and blood glucose levels. METHODS: The National Heart, Lung, and Blood Institute’s National Growth and Health Study (NGHS) cohort of white and black girls ages 9-10 years at baseline participated in a 10-year longitudinal study. Cardiometabolic outcomes included repeated measures of adiposity (e.g., body mass index (BMI)), and blood pressure, as well as laboratory measures such as fasting glucose and lipid levels. Linear regression and logistic regression were used to assess the association of fruit intake and fruit juice intake on CMR, while adjusting for age, race, tv/video, total vegetables, lean meat, and % calories from fat. Statistical Analysis Software (SAS Institute 15.2) analysis of data was performed. Results were considered statistically significant when p-value was <0.05. RESULTS: For girls in NGHS, BMI at the end of adolescence (ages 17-20 years) averaged to 21.3 kg/m2 for those who ate ≥0.75 cups of fruit and 22.1 kg/m2 for girls who ate <0.25 cups fruit. Similarly, girls with higher fruit juice consumption (≥0.75 cup-equivalents of juice per day) had a statistically significantly lower BMI than those with the lowest juice intake (<0.25 cup-eq/day). For each additional cup of whole fruit consumed on average per day between the ages of 9-17 was associated with 0.18 kg/m2 lower BMI (p<0.0001), after adjusting for age, race, tv/video viewing, total vegetable, lean meat intake, and % calories from fat. Adolescent girls (17 years or older) who drank < 0.25 or 0.25 - < 0.5 cup equivalent fruit juice were 1.60 or 1.63 (respectively) times more likely to become overweight (p-value 0.0005). Neither fruit intake nor fruit juice was associated with elevated fasting glucose risk or with high LDL risk. Whole fruit consumption was associated with a beneficial effect on HDL-cholesterol. Those with low whole fruit intake had a 1.42-fold increased risk of low HDL. CONCLUSIONS: These results indicate that 100% fruit juice and whole fruit consumption are both associated with beneficial effects on BMI and blood pressure among adolescent girls, suggesting that these foods may aid in the prevention of obesity and hypertension in the early adult years. KEY WORDS: adolescents, adiposity, body mass index, blood pressure, cardiometabolic health, dietary fiber, dyslipidemia, juice, glucose, metabolic syndrome, obesity, fruit.

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This thesis sought to advance our understanding of the physiological and health-related adaptations to low-volume interval training. Three separate studies were conducted in previously sedentary adults who trained three times per week. High-intensity interval training (HIIT) involved ten, 60-second cycling efforts at an intensity that elicited ~90% of maximal heart rate, interspersed with 60 seconds of recovery, whereas sprint interval training (SIT) involved three, 20-second ‘all-out’ cycling efforts interspersed with 2 minutes of recovery. Both protocols involved a brief warm-up and cool-down, resulting in 25- and 10-minute sessions for HIIT and SIT, respectively. Peak oxygen uptake (VO2peak), skeletal muscle mitochondrial content as reflected by the maximal activity and protein content of mitochondrial enzymes, and glycemic control based on oral glucose tolerance tests (OGTTs), intravenous glucose tolerance tests (IVGTTs) or continuous glucose monitoring (CGM), were determined before and after training. Study 1 found that 6 weeks of HIIT in the fed or fasted state increased VO2peak and mitochondrial content in women, but insulin sensitivity based on OGTTs was unchanged. Study 2 showed that 6 weeks of SIT increased VO2peak and mitochondrial content in men and women, whereas mean 24-hour glucose based on CGM was reduced in men only. Study 3 directly compared 12 weeks of SIT to traditional moderate-intensity continuous training (MICT) in men. The two protocols elicited similar improvements in VO2peak, mitochondrial content and insulin sensitivity based on IVGTTs, despite SIT involving a five-fold lower exercise volume and time commitment. This work advances our understanding of the potency of brief, intense exercise training to induce physiological remodeling and improve cardiometabolic health. It also highlights potential sex-specific adaptations to interval training that warrant clarification. Further investigation into the mechanisms of physiological remodeling to HIIT and SIT is needed, as are large-scale randomized clinical trials that compare these protocols to MICT. / Thesis / Doctor of Philosophy (PhD) / This thesis examined physiological and health-related adaptations to interval training, which involves brief bouts of intense exercise interspersed with recovery periods. One protocol involved alternating 60-second hard and easy cycling efforts for 20 minutes; the other involved three, 20-second ‘all-out’ sprints interspersed with 2 minutes of recovery. Both protocols improved indices of cardiometabolic health in previously inactive adults who trained three times per week for 6 weeks, even though the amount of exercise performed was lower than typically recommended in public health guidelines. When the latter protocol was directly compared against traditional endurance training, the improvement in cardiometabolic health after 12 weeks was the same, despite a five-fold difference in the total amount of exercise performed. Our findings highlight the effectiveness of short bursts of high-intensity exercise for improving health. These results may appeal to individuals who cite “lack of time” as a barrier to exercise.

Les survivants du cancer pédiatrique présenteront, au cours de leur vie, des séquelles cardiométaboliques liées à leur maladie et aux traitements qu’ils ont reçus. Nous pensons qu’il est possible d’améliorer la qualité de leur alimentation et leur profil de santé cardiométabolique en intervenant dès le début de leur parcours en oncologie. Ce projet d’inscrit dans l’initiative VIE (Valorisation-Implication-Éducation) dont l’objectif est d’offrir un support aux patients et leur famille afin de prévenir les effets secondaires aigus et tardifs des traitements antinéoplasiques. Objectifs. Évaluer l’impact d’une intervention nutritionnelle précoce en oncologie pédiatrique sur la qualité alimentaire des patients. Évaluer l’évolution des indicateurs de santé cardiométabolique après un an d’intervention nutritionnelle. Méthodologie. Soixante-deux enfants traités en oncologie au CHU Ste-Justine ont été recrutés dans l’étude moins de 12 semaines après leur diagnostic et ont été suivis tous les deux mois par une nutritionniste de recherche. Les données ont été collectées à l’évaluation initiale et après un an d'interventions nutritionnelles auprès de 36 patients. L’intervention nutritionnelle consistait en accompagnement individualisé ayant pour but d’encourager une alimentation équilibrée durant le traitement du cancer chez l’enfant. La collecte de données comprenait des journaux alimentaires, des informations cliniques, dont la pression artérielle, des prélèvements sanguins et des prises de mesures anthropométriques. La qualité alimentaire était déterminée à l’aide des scores de qualité alimentaire : Diet Quality Index (DQI) et Healthy Diet Indicator (HDI) calculés à partir des données provenant des journaux alimentaires. Les paramètres anthropométriques et biochimiques ont été comparés aux normes pour les enfants en bonne santé du même sexe et du même âge afin de déterminer l’évolution de leur profil cardiométabolique. Résultats. Lors de l'évaluation initiale, l'âge moyen était de 7,9 ans, 52,8% étaient des garçons et 50% souffraient de leucémie aiguë lymphoblastique. Le nombre moyen de suivis était de 4,72  1,06. Par rapport à l’évaluation initiale, dont la moyenne et l’écart-type sont de 48.53 ± 10.45 sur une possibilité maximale de 100 points, la différence avec l’évaluation initiale était de 5,22 ± 9,95 points (P= 0,003) et de 4,75 ± 12,98 points (P= 0,04) pour l’évaluation de 6 mois. De même, la proportion de participants ayant une adhésion modérée et forte (par rapport à une faible adhésion) au score HDI était plus importante après six mois (n= 12 ; 35,29% ; P= 0,027) et un an d’intervention (n=14 ; 39% ; P= 0,012) que lors de l’évaluation initiale (n=5 ; 13,89%). Entre l’évaluation initiale et l’évaluation effectuée après un an d’intervention, une augmentation du score Z moyen du poids et de l’IMC et des concentrations moyennes de HDL-C et du 25-hydroxy vitamine D ont été observés. Conclusion. Dans l'ensemble, cette étude confirme qu'une intervention nutritionnelle d'un an, déployée tôt après le diagnostic de cancer pédiatrique, permet d'améliorer la qualité de l’alimentation des enfants. / Pediatric cancer survivors will have lifelong cardiometabolic sequelae related to their disease and their treatments. We believe that improving their dietary quality and cardiometabolic health profile is possible by intervening early in their oncology journey. This project is part of the VIE (Valorisation-Implication-Éducation) initiative, which aims to support patients and their families to prevent antineoplastic treatments' acute and late side effects. Objectives. Evaluate the impact of an early nutritional intervention in pediatric oncology on the nutritional quality of patients. To assess changes in cardiometabolic health indicators after one year of nutritional intervention. Methodology. Sixty-two children treated in oncology at CHU Ste-Justine were recruited less than 12 weeks after their cancer diagnosis and were followed every two months by a registered dietitian. The nutritional intervention consisted of individualized support to encourage a balanced diet during childhood cancer treatment. Data was collected at baseline and after one year of nutritional intervention for 36 participants. Data collection included food diaries, clinical information including blood pressure, blood sampling and anthropometric measurements. Dietary quality was determined using the Diet Quality Index (DQI) and Healthy Diet Indicator (HDI) scores calculated from data obtained from food journals. Anthropometric and biochemical parameters were compared with sex and age norms for healthy children to determine their cardiometabolic profile evolution. Results. At initial assessment, the mean age was 7.9 years, 52.8% were male, and 50% had leukemia. The mean number of dietitian follow-up visits during the intervention was 4.72  1.06. Compared with the initial assessment, which had a mean and standard deviation of 48.53 ± 10.45 out of a maximum possibility of 100 points, the difference with the initial assessment was 5.22 ± 9.95 points (P = 0.003) and 4.75 ± 12.98 points (P = 0.04) for the 6-month assessment. Similarly, the proportion of participants with moderate and strong adherence (vs. low adherence) to the HDI score was greater at six months (n= 12; 35.29%; P=0.027) and one year evaluation (n=14; 39%; P= 0.012) than at the initial assessment (n=5; 13.89%). Between the initial and 1-year assessments, an increase in mean Z-score weight and BMI and mean HDL-C and 25-hydroxy vitamin D concentrations were observed. Conclusion. Overall, this study confirms that a 1-year nutrition intervention deployed early after diagnosis of pediatric cancer improves children's diet.