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.

Submitted by Miriam Lucas (miriam.lucas@unioeste.br) on 2018-04-18T18:37:58Z No. of bitstreams: 2 Ademar_Pinezi_Junior_2017.pdf: 1033239 bytes, checksum: 0103a19bd2d8bc4841a13bdd0b2a747a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-18T18:37:58Z (GMT). No. of bitstreams: 2 Ademar_Pinezi_Junior_2017.pdf: 1033239 bytes, checksum: 0103a19bd2d8bc4841a13bdd0b2a747a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-10 / CONTEXT: There is evidence that cardiorespiratory fitness is reduced in young people with type 1 diabetes mellitus (DM1) compared to healthy individuals and others showing that the DM1 group presented cardiorespiratory fitness superior to the control group. There is a need for a systematic and updated presentation of the results in relation to the comparison of the cardiorespiratory fitness of individuals with DM1 and healthy individuals. OBJECTIVES: The objective of this study was to analyze current information on the comparisons of cardiorespiratory fitness of children and adolescents, adults and athletes with DM1 and healthy individuals. METHODS: We performed a systematic review with a meta-analysis based on the Cochrane Collaboration recommendations, and the MEDLINE studies via PubMed, LILACS, SciELO, until June 2017, in addition to the manual search with the proposed theme. The included studies were clinical or cross-sectional studies that assessed as the main or secondary endpoint the cardiorespiratory fitness of people with DM1, without reported health complications, comparing with a group of healthy paired individuals on gender, age and anthropometric data. RESULTS: The first part of the systematic review with children and adolescents was composed of 8 studies, totaling 317 elements in the DM1 group and 274 samples in the control group, aged between 9 and 20 years. In general, the cardiorespiratory fitness of the group of children and adolescents with DM1 was lower than the healthy group (SMD = -0.56, 95% CI = -0.88, -0.24, P = 0.004). Already in the second part of the systematic review with adults and adult athletes was composed of 13 studies, totaling 245 samples in the DM1 group and 240 in the control group, aged between 18 and 50 years. The adult cardiorespiratory fitness of the DM1 group was lower than the group of healthy individuals (MD = -3.51, 95% CI = -6.32, -0.69, P = 0.01). In adult athletes with DM1, no difference in cardiorespiratory fitness was found between groups (MD = -2.18, 95% CI = -5.46, 1.11, P = 0.19). CONCLUSION: Children, adolescents and adults with DM1 presented lower cardiorespiratory fitness than healthy individuals matched in age, gender and anthropometric data. Already in adult athletes with DM1, there was no statistically significant difference with the control group. / CONTEXTO: Hay evidencias que la aptitud cardiorrespiratoria es reducida en jóvenes con DM1 comparado con individuos sanos y otras mostrando que el grupo con DM1 presentó la aptitud cardiorrespiratoria superior al grupo control. Existe la necesidad de presentación de manera sistemática y actualizada de los resultados en relación a la comparación de la aptitud cardiorrespiratoria de individuos con DM1 y personas sanas. OBJETIVOS: El objetivo del trabajo fue analizar información actual sobre las comparaciones de la aptitud cardiorrespiratoria de niños y adolescentes, adultos y atletas con DM1 e individuos sanos. MÉTODO: Se realizó una revisión sistemática con metanálisis basadas en las recomendaciones de la Colaboración Cochrane, y los estudios provenientes del MEDLINE vía PubMed, LILACS, SciELO, hasta junio de 2017, además de la búsqueda manual con el tema propuesto. Los estudios incluidos fueron estudios clínicos o cruzados que evaluaron como objetivo principal o secundario, la aptitud cardiorrespiratoria de personas con DM1, sin complicaciones de salud relatadas, comparando con un grupo de individuos sanos pareados en género, edad y datos antropométricos. RESULTADOS: La primera parte de la revisión sistemática con niños y adolescentes y fue compuesta por 8 estudios, totalizando 317 muestras en el grupo DM1 y 274 muestras en el grupo control, edad entre 9 a 20 años. En general, la aptitud cardiorrespiratoria del grupo de niños y adolescentes con DM1 fue inferior al grupo de individuos sanos (SMD = -0,56, 95% CI = -0,88, -0,24, P = 0,004). En la segunda parte de la revisión sistemática con adultos y adultos atletas se compuso de 13 estudios, totalizando 245 muestras en el grupo con DM1 y 240 en el grupo control, edad entre 18 y 50 años. La aptitud cardiorrespiratoria de adultos del grupo con DM1 fue inferior al grupo de individuos sanos (MD = -3,51, 95% CI = -6,32, -0,69, P = 0,01). En adultos atletas con DM1, no se encontró diferencia en la aptitud cardiorrespiratoria entre los grupos (MD = -2,18, 95% CI = -5,46, 1,11, P = 0,19). CONCLUSIÓN: Niños, adolescentes y adultos con DM1 presentaron la aptitud cardiorrespiratoria menor que individuos sanos pareados en edad, género y datos antropométricos. En adultos atletas con DM1, no hubo diferencia estadística significativa con el grupo control. / CONTEXTO: Há evidências que a aptidão cardiorrespiratória é reduzida em jovens com Diabetes Melitus do tipo 1 (DM1) comparado com indivíduos saudáveis e outras mostrando que o grupo com DM1 apresentou a aptidão cardiorrespiratória superior ao grupo controle. Existe a necessidade de apresentação de maneira sistematizada e atualizada dos resultados em relação a comparação da aptidão cardiorrespiratória de indivíduos com DM1 e pessoas saudáveis. OBJETIVOS: O objetivo deste trabalho foi de analisar informações atuais das comparações da aptidão cardiorrespiratória de crianças e adolescentes, adultos e atletas com DM1 e indivíduos saudáveis. MÉTODO: Foi realizada uma revisão sistemática com metanálise baseadas nas recomendações da Colaboração Cochrane, e os estudos provenientes do MEDLINE via PubMed, LILACS, SciELO, até junho de 2017, além da busca manual com o tema proposto. Os estudos incluídos foram estudos clínicos ou cruzados que avaliaram como objetivo principal ou secundário, a aptidão cardiorrespiratória de pessoas com DM1, sem complicações de saúde relatadas, comparando com um grupo de indivíduos saudáveis pareados em sexo, idade e dados antropométricos. RESULTADOS: A primeira parte da revisão sistemática com crianças e adolescentes e foi composta por 8 estudos, totalizando 317 elementos no grupo DM1 e 274 no grupo controle, idade entre 9 a 20 anos. No geral a aptidão cardiorrespiratória do grupo de crianças e adolescentes com DM1 foi inferior ao grupo de indivíduos saudáveis (SMD = -0,56; 95% CI = -0,88, -0,24; P = 0,004). Já na segunda parte da revisão sistemática com adultos e adultos atletas foi composta por 13 estudos, totalizando 245 amostras no grupo com DM1 e 240 no grupo controle, idade entre 18 e 50 anos. A aptidão cardiorrespiratória de adultos do grupo com DM1 foi inferior ao grupo de indivíduos saudáveis (MD = -3,51; 95% CI = -6,32, -0,69; P = 0,01). Em adultos atletas com DM1, não foi encontrada diferença na aptidão cardiorrespiratória entre os grupos (MD = -2,18; 95% CI = -5,46, 1,11; P = 0,19). CONCLUSÃO: Crianças, adolescentes e adultos com DM1 apresentaram a aptidão cardiorrespiratória menor do que indivíduos saudáveis pareados em idade, gênero e dados antropométricos. Já em adultos atletas com DM1, não houve diferença estatisticamente significativa com o grupo controle.