Magister Public Health - MPH / Introduction: The control of type 2 diabetes mellitus (T2DM) is pivoted on adherence to a healthy lifestyle (healthy diet, physical activity and non-smoking). Zimbabwe reports a high burden of T2DM related complications suggesting an increased inability by patients to control their blood glucose levels. This study, therefore, sought to describe the healthy lifestyle practices of T2DM patients in Harare, Zimbabwe and associate these practices with their glycated haemoglobin (HBA1C) levels, a marker for the control of diabetes. Methodology: A descriptive cross-sectional study was done. Participants were T2DM patients who were 18 years and older from two tertiary hospital diabetes clinics in Harare. Data collection was done using a structured questionnaire which was interviewer-administered along with height, weight and HBA1C measurements. Descriptive statistics were used to describe the study populations. Chi square test was used to calculate statistically significant associations between healthy lifestyle behaviours and demographics or HBA1C levels at the significant level of 0.05%.

<p>Objectives: To evaluate the long term total imprecision of HbA1c testing within the county of Uppsala in relation to the Swedish analytical goal of coefficient of variation (CV) <3% for HbA1c and to study the cost of an external quality assurance program for point-of-care HbA1c The county uses Bayer DCA 2000™ for point-of care HbA1c testing currently having 23 of these instruments.</p><p>Methods: Method imprecision was assessed by analysis of patient samples performed as split samples during a 3 year period (2002-2004) as part of the quality assurance program for point-of-care HbA1c testing. The samples were first analysed on a Bayer DCA 2000™ and the samples were then sent to the centralised laboratory for reanalysis with an HPLC system (Variant II™, Biorad). The testing was performed approximately 8 times per year with each instrument.</p><p>Results: The median CV between the HPLC method and the point-of-care instruments for each unit was slightly higher than 3%.</p><p>Conclusion: The DCA 2000™ systems have an acceptable imprecision and agreement with the central laboratory. The test results show acceptable agreements within the county regardless where the patient is tested. The cost of the external quality assurance program is calculated to be approximately SEK 1340 (Euro 150) per instrument.</p>

Objectives: To evaluate the long term total imprecision of HbA1c testing within the county of Uppsala in relation to the Swedish analytical goal of coefficient of variation (CV) &lt;3% for HbA1c and to study the cost of an external quality assurance program for point-of-care HbA1c The county uses Bayer DCA 2000™ for point-of care HbA1c testing currently having 23 of these instruments. Methods: Method imprecision was assessed by analysis of patient samples performed as split samples during a 3 year period (2002-2004) as part of the quality assurance program for point-of-care HbA1c testing. The samples were first analysed on a Bayer DCA 2000™ and the samples were then sent to the centralised laboratory for reanalysis with an HPLC system (Variant II™, Biorad). The testing was performed approximately 8 times per year with each instrument. Results: The median CV between the HPLC method and the point-of-care instruments for each unit was slightly higher than 3%. Conclusion: The DCA 2000™ systems have an acceptable imprecision and agreement with the central laboratory. The test results show acceptable agreements within the county regardless where the patient is tested. The cost of the external quality assurance program is calculated to be approximately SEK 1340 (Euro 150) per instrument.

>Magister Scientiae - MSc / Type 2 diabetes mellitus is a progressive disease characterised by defects in insulin secretion, insulin action or both. Proper management of diabetes with appropriate drug and lifestyle interventions, guided by proper glycaemic monitoring has shown improved glycaemic control and a substantial decrease in morbidity associated with complications and mortality. Evidence-based guidelines for the appropriate management of diabetes, suggests the use of glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) as monitoring indicators and have set targets levels that indicate appropriate glucose control. In the event of suboptimal control, actions steps to adjust pharmacotherapeutic treatment has been set out. Of the two aforementioned glycaemic monitoring indicators, HbA1c is termed the 'gold standard' as it provides the most comprehensive data i.e. it reflects both fasting and postprandial glucose concentrations over a 3 months period as compared to FPG which only show glucose levels for a few hours. The aim of this study was to describe the use of glycaemic monitoring indicators in patients with type 2 diabetes mellitus, classified as stable, treated at primary health care facilities in the Cape Town Metropolitan Region in South Africa. The study was a descriptive, retrospective and quantitative in design. Data were collected from patient medical records and included glycaemic monitoring tests and results as well as prescribing records for a maximum period of 18 months. The study comprised of 575 participants from five primary health care facilities in the Western Cape Metropole region. All participants had FPG results, while HbA1c results were recorded for 86% of participants at least once. More than 70% of participants with either a FPG or HbA1c result showed suboptimal glucose control i.e. were outside of the target range. In 181 opportunities for intervention in participants with HbA1c results outside target, 113 (62.4%) did not have any therapy adjustments, 19 (10.5%) had the total daily dose increased, 6 (3.3%) had total daily dose decreased, 9 (5.0%) had a step-up in regimen, 5 (2.8%) had a step down in regimen and 29 (16.0%) had a lateral regimen change. In 852 opportunities for intervention in participants with FPG results outside target, 609 (71.5%) did not have any therapy adjustments, 47 (5.5%) had the total daily dose increased, 18 (2.1%) had the total daily dose decreased, 16 (1.9%) had a step-up in regimen, 15 (1.8%) had a step down in regimen and 147 (17.3%) had a lateral change in regimen. This study has demonstrated that in the primary healthcare facilities investigated, FPG was the most often used gycaemic monitoring indicator, glycaemic monitoring of patients mostly show suboptimal glucose control and that opportunities to optimise pharmacotherapy in diabetes management are mostly missed.

Objetivos: Este Estudo randomizado duplo cego placebo controlado comparou, clínica, sitemica e imunologicamente um protocolo de Terapia fotodinâmica antimicrobiana (TFA) de aplicações múltiplas com um protocolo já consagrada com o uso da Doxiciclina sistêmica no tratamento da doença periodontal em pacientes diabéticos tipo 2 descontrolados. Materiais e Métodos: Vinte seis pacientes com HbA1c> 7% foram selecionados e randomicamente alocados em dois grupos que receberam raspagem e alisamento radicular. Um dos grupos recebeu a aplicação adjunta de aplicações múltiplas de TFA (n=12) e o outro utilizando a doxiciclina sistêmica na dose de 100mg (n=14). Os parâmetros monitorados foram índice de placa, Sangramento à sondagem, Profundidade de sondagem, Supuração, Recessão gingival e nível clinico de inserção relativo, o parâmetro sistêmico avaliado foi a HbA1c, medida antes e 3 meses pós tratamento. Os níveis de IL1-&beta;, TNF-&alpha; e TGF-&beta; foram medidos antes, 1 e 3 meses pós tratamento através da coleta de fluido crevicular gengival. Resultados: Não houveram diferenças significantes em nenhum dos parâmetros clínicos avaliados e nos níveis de HbA1c. O uso do antibiótico sistêmico demonstrou ser superior na redução de IL1-&beta; até o período de 1 mês pós tratamento, porém, em 3 meses a TFA se mostrou superior. Não houve diferença na redução dos níveis de TNF-&alpha; e TGF-&beta; entre os grupos. Conclusões: Ambos tratamentos foram eficientes nas melhoras dos parâmetros clínicos e sistêmicos. A TFA parece possuir maior estabilidade na redução dos níveis de citocinas inflamatórias. / Aim: This randomized, double-blind, placebo-controlled, clinical study compared a multiple application Antimicrobial Photodynamic Therapy (aPDT) treatment protocol with systemic doxycycline as adjuvant to scaling and root planning, to treat chronic periodontitis on type 2 diabetic patients on clinical, systemic and immune-inflammatory outcomes. Materials and Methods: Twenty six patients with Hba1c >7% were randomically allocated in two groups, SRP+Doxy (n=14) using systemic doxycycline 100 mg and SRP+aPDT (n=12) with multiple applications (0, 3, 7 and 14 days). Monitored parameters of plaque score (PS), bleeding on probe (BOP), probing depth (PD), suppuration (S), gingival recession, and relative clinical attachment level (RCAL), glycated haemoglobin (HbA1c) were measured at baseline and 3 months after therapy, the cytokine profile was assessed at 0, 1 and 3 month to measure IL1-&beta;, TNF-&alpha; and TGF-&beta; on Gingival Crevicular Fluid. Results: There were no statistically significant differences on intergroup on clinical parameters and HbA1c levels. Systemic doxycycline shoed difference in reduction of IL1-&beta; at 1 month, but aPDT better results at 3 months IL1-&beta; levels. There were no differences between TNF-&alpha; and TGF-&beta; trough experimental times Conclusions: Both treatments were effective to improve clinical and systemic outcomes and aPDT seems to have a great stability on of IL1-&beta; reductions. (Clinicaltrials.gov Identifier: NCT01175720).

Objetivos: Este Estudo randomizado duplo cego placebo controlado comparou, clínica, sitemica e imunologicamente um protocolo de Terapia fotodinâmica antimicrobiana (TFA) de aplicações múltiplas com um protocolo já consagrada com o uso da Doxiciclina sistêmica no tratamento da doença periodontal em pacientes diabéticos tipo 2 descontrolados. Materiais e Métodos: Vinte seis pacientes com HbA1c> 7% foram selecionados e randomicamente alocados em dois grupos que receberam raspagem e alisamento radicular. Um dos grupos recebeu a aplicação adjunta de aplicações múltiplas de TFA (n=12) e o outro utilizando a doxiciclina sistêmica na dose de 100mg (n=14). Os parâmetros monitorados foram índice de placa, Sangramento à sondagem, Profundidade de sondagem, Supuração, Recessão gingival e nível clinico de inserção relativo, o parâmetro sistêmico avaliado foi a HbA1c, medida antes e 3 meses pós tratamento. Os níveis de IL1-&beta;, TNF-&alpha; e TGF-&beta; foram medidos antes, 1 e 3 meses pós tratamento através da coleta de fluido crevicular gengival. Resultados: Não houveram diferenças significantes em nenhum dos parâmetros clínicos avaliados e nos níveis de HbA1c. O uso do antibiótico sistêmico demonstrou ser superior na redução de IL1-&beta; até o período de 1 mês pós tratamento, porém, em 3 meses a TFA se mostrou superior. Não houve diferença na redução dos níveis de TNF-&alpha; e TGF-&beta; entre os grupos. Conclusões: Ambos tratamentos foram eficientes nas melhoras dos parâmetros clínicos e sistêmicos. A TFA parece possuir maior estabilidade na redução dos níveis de citocinas inflamatórias. / Aim: This randomized, double-blind, placebo-controlled, clinical study compared a multiple application Antimicrobial Photodynamic Therapy (aPDT) treatment protocol with systemic doxycycline as adjuvant to scaling and root planning, to treat chronic periodontitis on type 2 diabetic patients on clinical, systemic and immune-inflammatory outcomes. Materials and Methods: Twenty six patients with Hba1c >7% were randomically allocated in two groups, SRP+Doxy (n=14) using systemic doxycycline 100 mg and SRP+aPDT (n=12) with multiple applications (0, 3, 7 and 14 days). Monitored parameters of plaque score (PS), bleeding on probe (BOP), probing depth (PD), suppuration (S), gingival recession, and relative clinical attachment level (RCAL), glycated haemoglobin (HbA1c) were measured at baseline and 3 months after therapy, the cytokine profile was assessed at 0, 1 and 3 month to measure IL1-&beta;, TNF-&alpha; and TGF-&beta; on Gingival Crevicular Fluid. Results: There were no statistically significant differences on intergroup on clinical parameters and HbA1c levels. Systemic doxycycline shoed difference in reduction of IL1-&beta; at 1 month, but aPDT better results at 3 months IL1-&beta; levels. There were no differences between TNF-&alpha; and TGF-&beta; trough experimental times Conclusions: Both treatments were effective to improve clinical and systemic outcomes and aPDT seems to have a great stability on of IL1-&beta; reductions. (Clinicaltrials.gov Identifier: NCT01175720).

Recent statistics show that approximately 415 million people worldwide have diabetes. Glycated haemoglobin (HbA1c) measurements were introduced many years ago as the gold standard tool for detecting and monitoring treatment as well as making management decisions for diabetic patients. Glycated haemoglobins are formed by the non-enzymatic glycation of haemoglobin molecules. This non-enzymatic glycation process has been strongly related to pathogenesis of chronic complications associated to diabetes. It was suggested that this glycation process may be moderated by an enzymatic deglycation process thought to involve a deglycating enzyme known as Fructosamine-3-kinase (FN3K), an enzyme that deglycates the glycated haemoglobin in erythrocytes and other glycated proteins in other tissues. FN3K acts through phosphorylation of fructosamines on the third carbon of their sugar moiety, making them unstable and consequently causing them to detach from the protein. The degree of deglycation is thought to depend on the activity of the FN3K enzyme. Moreover, variation in the activity of FN3K between individuals is hypothesised to lead to apparent differences in glycated haemoglobin levels: some individuals have high rates of deglycation so that they tend to have lower average glycaemia than actually the case, while others with low rates of deglycation appear to have higher than actual glycaemia (known as the glycation gap, G-gap). The G-gap has been reported to be associated with alteration of diabetic complications risk. The G-gap reflects the discrepancy between average glycaemia as determined from glycated haemoglobin (measured as HbA1c) and that from the determination of fructosamine. The positive G-gap is defined as a higher level of glycation of proteins than expected whereas a negative G-gap means a lower level of glycation than expected. To explore the role of FN3K in diabetes and other associated morbidities, we decided to divide our research into 3 studies. Each study was categorised according to the type and the source of samples involved. The first study explored the correlation between FN3K activity and protein level with G-gap data; it involved 148 diabetic patients who were recruited at New Cross Hospital, Wolverhampton, selected as having a consistent positive G-gap > +0.5 and a consistent negative G-gap > -0.5 over a minimum of 2 estimations. Age, gender, race and BMI were collected from patients in this study. Blood samples were also 3 collected to measure FN3K activity, protein levels, and markers of CVD in relation to G-gap. The second study involved 23 AECOPD patients who were recruited from St George’s Hospital (London) and were treated with either metformin or a placebo. Serum samples were collected from these patients for a larger study: we assayed those 23 serum samples for FN3K protein levels to explore any possible correlation between FN3K with metformin therapy in COPD patients. The third study utilised 36 human peripheral lung samples from healthy individuals, asymptomatic smokers and stable COPD patients (GOLD 2) who were recruited at The Section of Respiratory Medicine, University Hospital of Ferrara, Italy. Those samples were assessed for FN3K expression by means of immunohistochemistry to explore the difference in FN3K activity between those three categories. It was found that the intracellular activity and protein expression of the FN3K enzyme in diabetic patients negatively correlated with the values of G-gaps where FN3K activity was high in patients with negative G-gap. FN3K serum protein levels were shown to be enhanced with metformin administration in COPD diabetic patients, suggesting a protective role for FN3K enzyme against protein damaged caused by the non-enzymatic glycation of proteins. Therefore, patients with positive G-gap have lower FN3K activity than those with negative G-gap, and in turn they are more susceptible to diabetes related complications. Our data also indicate that metformin has a beneficial effect in reducing damage caused by carbonyl stress from cigarette smoking in COPD patients by the action of FN3K. Our research has demonstrated that FN3K contributes to the protein repair system which protects against damage caused by non-enzymatic glycation. The high activity for the FN3K enzyme was associated with low levels of AGEs and low carbonyl stress levels in observed among patients with diabetes and COPD. In contrast, COPD patients tend to have low FN3K-mediated protection against protein damage in comparison to the normal population. These patients tend to be at risk for developing more complications, particularly CVD complications, than normal, healthy individuals. Treatment with metformin enhances FN3K action in COPD diabetic patients, possibly as a protective enzyme against the damaged caused by the non-enzymatic glycation.

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No. of bitstreams: 1 Dissertação - Raissa Afonso da Costa.pdf: 2822299 bytes, checksum: 2bef6491accd0173c49963abed1e3e86 (MD5) Previous issue date: 2015-04-24 / Não Informada / Periodontal disease (PD) and diabetes mellitus (DM) are high prevalent chronic diseases in the adult population worldwide. There is evidence of bidirectional relationship between both diseases, i.e., DM represents a risk factor for PD and PD can impair diabetes control, resulting in a cycle of cause and effect with harmful consequences to the health of individuals. This cross-sectional study aimed to determine the socioeconomic profile of the diabetic population registered in Hiperdia program in the city of Manaus, Amazonas and to measure their periodontal status, looking for a possible relationship between periodontal and glycemic control parameters. A total of 209 type 2 diabetic patients participated of the survey, which consisted of three stages: interview, physical and periodontal examination and laboratorial tests. Data were analysed using the software Stata SE version 10.1. Chi-square tests, Spearman’s correlation, bivariate analysis and multivariate logistic regression were applied. The study population presented a mean age of 55 years, with majority of females, mixed race, income of 1-3 times the minimum wage, complete high school, average of 8 years of DM, most of them were hypertensive and 37.8% had other comorbidities, such as nephropathy and retinopathy; the average fasting plasma glycemia (FPG) and glycated hemoglobin (HbA1c) were 181.96 mg/dL and 7.92%, respectively. There was a significant positive correlation between HbA1c and plaque index - PI (r = 0.31; p <0.001), gingival index - GI (r = 0.24; p <0.001), probing depth - PD (r = 0, 19; p = 0.007) and clinical attachment level - CAL (r = 0.23; p <0.001) and between the FPG and PI (r = 0.42; p <0.001), GI (r = 0.37; p <0.001), PD (r = 0.30; p <0.001), CAL (r = 0.26 p <0.001) and dental mobility (r = 0.14; p = 0.031). Individuals diagnosed with periodontitis (208) were divided into two groups: mild/moderate periodontitis and severe periodontitis. In the bivariate analysis, it was verified association between the variables: age ≥ 50 years (p = 0.019), more than 2 years of no dental care (p = 0.021), not flossing (p = 0.039), time with DM> 4 years (p = 0.013), GI and PI ≥ 50% (p <0.001 and p = 0.003), HbA1c ≥ 9% (p <0.001) and FPG> 110 mg/dL (p <0.001) like risk factors and sex female (p = 0.025), ), 9-12 years of study (p = 0.025), ), not using insulin (p = 0.032) like protection factors in the severe periodontitis outcome. After multivariate logistic regression, it was observed that age ≥ 50 years (OR = 2.36; CI: [1.10 to 5.04]; p = 0.027) and HbA1c ≥ 9% (OR = 9.05; CI: [2.98 to 27.51 ]; p <0.001) are risk factors and female gender (OR = 0.47; CI: [from 0.23 to 0.99]; p = 0.047), 9-12 years of education (OR = 0.51; CI: [0.17 to 1.69]; p = 0.287) and no use insulin (OR = 0.33; CI: [from 0.12 to 0.85]; p = 0.023) are protector factors for severe periodontitis. It was concluded that individuals with HbA1c ≥ 9% are 9.05 times more likely to have severe periodontitis and that, considering the high prevalence of PD in diabetics and the significant correlation between periodontal and glycemic control parameters, it is required greater attention on the oral health of diabetics. / Doença Periodontal (DP) e Diabetes Mellitus (DM) são patologias crônicas de alta prevalência na população adulta e idosa em todo o mundo. Há evidências da relação bidirecional entre ambos os agravos, ou seja, o DM constitui-se como fator de risco para a DP e a DP pode dificultar o controle do diabetes, resultando em um ciclo de causas e efeitos com consequências danosas à saúde dos indivíduos. Esse estudo transversal almejou traçar o perfil socioeconômico da população diabética cadastrada no programa Hiperdia na cidade de Manaus, Amazonas e mensurar a condição periodontal desses usuários, buscando uma possível relação entre os parâmetros periodontais e de controle glicêmico. Um total de 209 diabéticos tipo 2 provenientes dos 4 distritos urbanos de saúde participou da pesquisa que consistiu de três etapas: entrevista, exame físico e periodontal e exame laboratorial. Os dados foram analisados no software estatístico Stata SE versão 10.1. Foram aplicados os testes de qui-quadrado, correlação de Spearman, análise bivariada e regressão logística multivariada. A população do estudo apresentou idade média de 55 anos, com prevalência do sexo feminino, raça parda, renda de 1 a 3 salários mínimos, ensino médio completo, média de 8 anos de DM, sendo a maioria hipertensa e 37,8% tinham outras comorbidades, como nefropatia e retinopatia; as médias de glicemia (GJ) e hemoglobina glicada (HbA1c) foram 181,96 mg/dL e 7,92%, respectivamente. Houve correlação positiva significativa entre HbA1c e índice de placa - IP (r = 0,31; p < 0,001), índice gengival - IG (r = 0,24; p < 0,001), profundidade de sondagem - PS (r = 0,19; p = 0,007) e nível de inserção clínica - NIC (r = 0,23; p < 0,001) e entre a GJ e IP (r = 0,42; p < 0,001), IG (r = 0,37; p < 0,001), PS (r = 0,30; p < 0,001), NIC (r = 0,26 p < 0,001) e mobilidade (r = 0,14; p = 0,031). Os indivíduos com diagnóstico periodontite (208) foram divididos em dois grupos: periodontite leve/moderada e periodontite severa. Na análise bivariada foi constatada associação entre as variáveis idade ≥ 50 anos (p = 0,019), tempo sem assistência odontológica maior que 2 anos (p = 0,021), não uso do fio dental (p = 0,039), tempo de experiência com o DM > 4 anos (p = 0,013), IP e IG ≥ 50% (p < 0,001 e p = 0,003), HbA1c ≥ 9% (p < 0,001) e GJ > 110 mg/dL (p < 0,001) como fatores de risco e sexo feminino (p =0,025), 9 a 12 anos de estudo (p = 0,025) e não uso de insulina (p = 0,032) como fatores de proteção para o desfecho periodontite severa. Após a regressão logística multivariada, observou-se que idade ≥ 50 anos (RC = 2,36; IC: [1,10-5,04]; p = 0,027) e HbA1c ≥ 9% (RC = 9,05; IC: [2,98-27,51]; p < 0,001) eram fatores de risco e sexo feminino (RC = 0,47; IC: [0,23-0,99]; p = 0,047), 9 a 12 anos de estudo (RC = 0,51; IC: [0,17-1,69]; p = 0,287) e não uso de insulina (RC = 0,33; IC: [0,12-0,85]; p = 0,023) eram fatores protetores para periodontite severa. Concluiu-se com os resultados obtidos que indivíduos com HbA1c ≥ 9% têm 9,05 vezes mais chance de ter periodontite severa e que, considerando a alta prevalência da DP nos diabéticos e a correlação significativa entre os parâmetros periodontais e de controle glicêmico, faz-se necessária uma maior atenção quanto à saúde bucal dos diabéticos.

Motivation: The prevalence of non-communicable diseases such as diabetes mellitus (DM) and cardiovascular disease (CVD) is rapidly increasing in industrialized societies. Experts believe that lifestyle, and in particular its nutritional aspects, plays a decisive role in increasing the burden of these chronic conditions. Dietary habits would, therefore, be modified to exert a positive impact on the prevention and treatment of chronic diseases of lifestyle. It is believed that the state of hyperglycaemia that is observed following food intake under certain dietary regimes contributes to the development of various metabolic conditions. This is not only true for individuals with poor glycaemic control such as some diabetics, but could also be true for healthy individuals. It would, therefore, be helpful to be able to reduce the amplitude and duration of postprandial hyperglycaemia. Selecting the correct type of carbohydrate (CHO) foods may produce less postprandial hyperglycaemia, representing a possible strategy in the prevention and treatment of chronic metabolic diseases. At the same time, a key focus of sport nutrition is the optimal amount of CHO that an athlete should consume and the optimal timing of consumption. The most important nutritional goals of the athlete are to prepare body CHO stores pre-exercise, provide energy during prolonged exercise and restore glycogen stores during the recovery period. The ultimate aim of these strategies is to maintain CHO availability to the muscle and central nervous system during prolonged moderate to high intensity exercise, since these are important factors in exercise capacity and performance. However, the type of CHO has been studied less often and with less attention to practical concerns than the amount of CHO. The glycaemic index (GI) refers to the blood glucose raising potential of CHO foods and, therefore, influences secretion of insulin. In several metabolic disorders, secretion of insulin is inadequate or impossible, leading to poor glycaemic control. It has been suggested that low GI diets could potentially contribute to a significant improvement of the conditions associated with poor glycaemic control. Insulin secretion is also important to athletes since the rate of glycogen synthesis depends on insulin due to it stimulatory effect on the activity of glycogen synthase. Objectives: Three main objectives were identified for this study. The first was to conduct a meta-analysis of the effects of the GI on markers for CHO and lipid metabolism with the emphasis on randomised controlled trials (RCT's). Secondly, a systematic review was performed to determine the strength of the body of scientific evidence from epidemiological studies combined with RCT's to encourage dieticians to incorporate the GI concept in meal planning. Finally, a systematic review of the effect of the GI in sport performance was conducted on all available literature up to date to investigate whether the application of the GI in an athlete's diet can enhance physical performance. Methodology: For the meta-analysis, the search was for randomised controlled trials with a cross-over or parallel design published in English between 1981 and 2003, investigating the effect of low GI vs high GI diets on markers of carbohydrate and lipid metabolism. The main outcomes were serum fructosamine, glycosylated haemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerols (TG). For the systematic review, epidemiological studies as well as RCT's investigating the effect of LGI vs HGI diets on markers for carbohydrate and lipid metabolism were used. For the systematic review on the effect of the GI on sport performance, RCT's with either a cross-over or parallel design that were published in English between January 1981 and September 2004 were used. All relevant manuscripts for the systematic reviews as well as meta-analysis were obtained through a literature search on relevant databases such as the Cochrane Central Register of Controlled Trials, MEDLINE (1981 to present), EMBASE, LILACS, SPORTDiscus, ScienceDirect and PubMed. This thesis is presented in the article format. Results and conclusions of the individual manuscripts: For the meta-analysis, literature searches identified 16 studies that met the strict inclusion criteria. Low GI diets significantly reduced fructosamine (p<0.05), HbA1c, (p<0.03), TC(p<0.0001) and tended to reduce LDL-c (p=0.06) compared to high GI diets. No changes were observed in HDL-c and TG concentrations. Results from this meta analysis, therefore, support the use of the GI concept in choosing CHO-containing foods to reduce TC and improve blood glucose control in diabetics. The systematic review combined the results of the preceding meta-analysis and results from epidemiological studies. Prospective epidemiological studies showed improvements in HDL-c concentrations over longer time periods with low GI diets vs. high GI diets, while the RCT's failed to show an improvement in HDL-c over the short-term. This could be attributed to the short intervention period during which the RCT's were conducted. Furthermore, epidemiological studies failed to show positive relationships between LDL-c and TC and low GI diets, while RCT's reported positive results on both these lipids with low GI diets. However, the epidemiological studies, as well as the RCT's showed positive results with low GI diets on markers of CHO metabolism. Taken together, convincing evidence from RCT's as well as epidemiological studies exists to recommend the use of low GI diets to improve markers of CHO as well as of lipid metabolism. 3 From the systematic review regarding the GI and sport performance it does not seem that low GI pre-exercise meals provide any advantages over high GI pre-exercise meals. Although low GI pre-exercise meals may better maintain CHO availability during exercise, low GI pre-exercise meals offer no added advantage over high GI meals regarding performance. Furthermore, the exaggerated metabolic responses from high GI compared to low GI CHO seems not be detrimental to exercise performance. However, athletes who experience hypoglycaemia when consuming CHO-rich feedings in the hour prior to exercise are advised to rather consume low GI pre-exercise meals. No studies have been reported on the GI during exercise. Current evidence suggests a combination of CHO with differing Gl's such as glucose (high GI), sucrose (moderate GI) and fructose (low GI) will deliver the best results in terms of exogenous CHO oxidation due to different transport mechanisms. Although no studies are conducted on the effect of the GI on short-term recovery it is speculated that high GI CHO is most effective when the recovery period is between 0-8 hours, however, evidence suggests that when the recovery period is longer (20-24 hours), the total amount of CHO is more important than the type of CHO. Conclusion: There is an important body of evidence in support of a therapeutic and preventative potential of low GI diets to improve markers for CHO and lipid metabolism. By substituting high GI CHO-rich with low GI CHO-rich foods improved overall metabolic control. In addition, these diets reduced TC, tended to improve LDL-c and might have a positive effect over the long term on HDL-c. This confirms the place for low GI diets in disease prevention and management, particularly in populations characterised by already high incidences of insulin resistance, glucose intolerance and abnormal lipid levels. For athletes it seems that low GI pre-exercise meals do not provide any advantage regarding performance over high GI pre-exercise meals. However, low GI meals can be recommended to athletes who are prone to develop hypoglycaemia after a CHO-rich meal in the hour prior to exercise. No studies have been reported on the effect of the GI during exercise. However, it has been speculated that a combination of CHO with varying Gl's deliver the best results in terms of exogenous CHO oxidation. No studies exist investigating the effect of the GI on short-term recovery, however, it is speculated that high GI CHO-rich foods are suitable when the recovery period is short (0-8 h), while the total amount rather than the type of CHO is important when the recovery period is longer (20-24 h). Therefore, the GI is a scientifically based tool to enable the selection of CHO-containing foods to improve markers for CHO and lipid metabolism as well as to help athletes to prepare optimally for competitions. Recommendations: Although a step nearer has been taken to confirm a place for the GI in human health, additional randomised, controlled, medium and long-term studies as well as more epidemiological studies are needed to investigate further the effect of low GI diets on LDL-c. HDL-c and TG. These studies are essential to investigate the effect of low GI diets on endpoints such as CVD and DM. This will also show whether low GI diets can reduce the risk of diabetic complications such as neuropathy and nephropathy. Furthermore, the public at large must be educated about the usefulness and application of the GI in meal planning. For sport nutrition, randomised controlled trials should be performed to investigate the role of the GI during exercise as well as in sports of longer duration such as cricket and tennis. More studies are needed to elucidate the short-term effect of the GI post-exercise as well as to determine the mechanism of lower glycogen storage with LGI meals post-exercise. / Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2005.

Motivation: The prevalence of non-communicable diseases such as diabetes mellitus (DM) and cardiovascular disease (CVD) is rapidly increasing in industrialized societies. Experts believe that lifestyle, and in particular its nutritional aspects, plays a decisive role in increasing the burden of these chronic conditions. Dietary habits would, therefore, be modified to exert a positive impact on the prevention and treatment of chronic diseases of lifestyle. It is believed that the state of hyperglycaemia that is observed following food intake under certain dietary regimes contributes to the development of various metabolic conditions. This is not only true for individuals with poor glycaemic control such as some diabetics, but could also be true for healthy individuals. It would, therefore, be helpful to be able to reduce the amplitude and duration of postprandial hyperglycaemia. Selecting the correct type of carbohydrate (CHO) foods may produce less postprandial hyperglycaemia, representing a possible strategy in the prevention and treatment of chronic metabolic diseases. At the same time, a key focus of sport nutrition is the optimal amount of CHO that an athlete should consume and the optimal timing of consumption. The most important nutritional goals of the athlete are to prepare body CHO stores pre-exercise, provide energy during prolonged exercise and restore glycogen stores during the recovery period. The ultimate aim of these strategies is to maintain CHO availability to the muscle and central nervous system during prolonged moderate to high intensity exercise, since these are important factors in exercise capacity and performance. However, the type of CHO has been studied less often and with less attention to practical concerns than the amount of CHO. The glycaemic index (GI) refers to the blood glucose raising potential of CHO foods and, therefore, influences secretion of insulin. In several metabolic disorders, secretion of insulin is inadequate or impossible, leading to poor glycaemic control. It has been suggested that low GI diets could potentially contribute to a significant improvement of the conditions associated with poor glycaemic control. Insulin secretion is also important to athletes since the rate of glycogen synthesis depends on insulin due to it stimulatory effect on the activity of glycogen synthase. Objectives: Three main objectives were identified for this study. The first was to conduct a meta-analysis of the effects of the GI on markers for CHO and lipid metabolism with the emphasis on randomised controlled trials (RCT's). Secondly, a systematic review was performed to determine the strength of the body of scientific evidence from epidemiological studies combined with RCT's to encourage dieticians to incorporate the GI concept in meal planning. Finally, a systematic review of the effect of the GI in sport performance was conducted on all available literature up to date to investigate whether the application of the GI in an athlete's diet can enhance physical performance. Methodology: For the meta-analysis, the search was for randomised controlled trials with a cross-over or parallel design published in English between 1981 and 2003, investigating the effect of low GI vs high GI diets on markers of carbohydrate and lipid metabolism. The main outcomes were serum fructosamine, glycosylated haemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerols (TG). For the systematic review, epidemiological studies as well as RCT's investigating the effect of LGI vs HGI diets on markers for carbohydrate and lipid metabolism were used. For the systematic review on the effect of the GI on sport performance, RCT's with either a cross-over or parallel design that were published in English between January 1981 and September 2004 were used. All relevant manuscripts for the systematic reviews as well as meta-analysis were obtained through a literature search on relevant databases such as the Cochrane Central Register of Controlled Trials, MEDLINE (1981 to present), EMBASE, LILACS, SPORTDiscus, ScienceDirect and PubMed. This thesis is presented in the article format. Results and conclusions of the individual manuscripts: For the meta-analysis, literature searches identified 16 studies that met the strict inclusion criteria. Low GI diets significantly reduced fructosamine (p<0.05), HbA1c, (p<0.03), TC(p<0.0001) and tended to reduce LDL-c (p=0.06) compared to high GI diets. No changes were observed in HDL-c and TG concentrations. Results from this meta analysis, therefore, support the use of the GI concept in choosing CHO-containing foods to reduce TC and improve blood glucose control in diabetics. The systematic review combined the results of the preceding meta-analysis and results from epidemiological studies. Prospective epidemiological studies showed improvements in HDL-c concentrations over longer time periods with low GI diets vs. high GI diets, while the RCT's failed to show an improvement in HDL-c over the short-term. This could be attributed to the short intervention period during which the RCT's were conducted. Furthermore, epidemiological studies failed to show positive relationships between LDL-c and TC and low GI diets, while RCT's reported positive results on both these lipids with low GI diets. However, the epidemiological studies, as well as the RCT's showed positive results with low GI diets on markers of CHO metabolism. Taken together, convincing evidence from RCT's as well as epidemiological studies exists to recommend the use of low GI diets to improve markers of CHO as well as of lipid metabolism. 3 From the systematic review regarding the GI and sport performance it does not seem that low GI pre-exercise meals provide any advantages over high GI pre-exercise meals. Although low GI pre-exercise meals may better maintain CHO availability during exercise, low GI pre-exercise meals offer no added advantage over high GI meals regarding performance. Furthermore, the exaggerated metabolic responses from high GI compared to low GI CHO seems not be detrimental to exercise performance. However, athletes who experience hypoglycaemia when consuming CHO-rich feedings in the hour prior to exercise are advised to rather consume low GI pre-exercise meals. No studies have been reported on the GI during exercise. Current evidence suggests a combination of CHO with differing Gl's such as glucose (high GI), sucrose (moderate GI) and fructose (low GI) will deliver the best results in terms of exogenous CHO oxidation due to different transport mechanisms. Although no studies are conducted on the effect of the GI on short-term recovery it is speculated that high GI CHO is most effective when the recovery period is between 0-8 hours, however, evidence suggests that when the recovery period is longer (20-24 hours), the total amount of CHO is more important than the type of CHO. Conclusion: There is an important body of evidence in support of a therapeutic and preventative potential of low GI diets to improve markers for CHO and lipid metabolism. By substituting high GI CHO-rich with low GI CHO-rich foods improved overall metabolic control. In addition, these diets reduced TC, tended to improve LDL-c and might have a positive effect over the long term on HDL-c. This confirms the place for low GI diets in disease prevention and management, particularly in populations characterised by already high incidences of insulin resistance, glucose intolerance and abnormal lipid levels. For athletes it seems that low GI pre-exercise meals do not provide any advantage regarding performance over high GI pre-exercise meals. However, low GI meals can be recommended to athletes who are prone to develop hypoglycaemia after a CHO-rich meal in the hour prior to exercise. No studies have been reported on the effect of the GI during exercise. However, it has been speculated that a combination of CHO with varying Gl's deliver the best results in terms of exogenous CHO oxidation. No studies exist investigating the effect of the GI on short-term recovery, however, it is speculated that high GI CHO-rich foods are suitable when the recovery period is short (0-8 h), while the total amount rather than the type of CHO is important when the recovery period is longer (20-24 h). Therefore, the GI is a scientifically based tool to enable the selection of CHO-containing foods to improve markers for CHO and lipid metabolism as well as to help athletes to prepare optimally for competitions. Recommendations: Although a step nearer has been taken to confirm a place for the GI in human health, additional randomised, controlled, medium and long-term studies as well as more epidemiological studies are needed to investigate further the effect of low GI diets on LDL-c. HDL-c and TG. These studies are essential to investigate the effect of low GI diets on endpoints such as CVD and DM. This will also show whether low GI diets can reduce the risk of diabetic complications such as neuropathy and nephropathy. Furthermore, the public at large must be educated about the usefulness and application of the GI in meal planning. For sport nutrition, randomised controlled trials should be performed to investigate the role of the GI during exercise as well as in sports of longer duration such as cricket and tennis. More studies are needed to elucidate the short-term effect of the GI post-exercise as well as to determine the mechanism of lower glycogen storage with LGI meals post-exercise. / Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2005.