Acute respiratory infections (ARI) caused by influenza and other respiratory viruses affect millions of people annually. Although usually self-limiting a more complicated or severe course may occur in previously healthy people but are more likely in individuals with underlying illnesses. The most common viral agent is rhinovirus whereas influenza is less frequent but is well known to cause winter epidemics. In primary care, rapid diagnosis of influenza virus infections is essential in order to provide treatment. Clinical presentations vary among the different pathogens but may overlap and may also depend on host factors. Predictive models have been developed for influenza but study results may be biased because only individuals presenting with fever were included. Most of these models have not been adequately validated and their predictive power, therefore, is likely overestimated. The main objective of this thesis was to compare different mathematical models for the derivation of clinical prediction rules in individuals presenting with symptoms of ARI to better distinguish between influenza, influenza A subtypes and entero-/rhinovirus-related illness in children and adults and to evaluate model performance by using data-splitting for internal validation. Data from a completed prospective cluster-randomized trial for the indirect effect of influenza vaccination in children of Hutterite communities served as a basis of my thesis. There were a total of 3288 first episodes per season of ARI in 2202 individuals and 321 (9.8%) influenza positive events over three influenza seasons (2008-2011). The data set was divided into children under 18 years and adults. Both data sets were randomly split by subjects into a derivation (2/3 of the dataset) and a validation population (1/3 of the dataset). All predictive models were developed in the derivation sets. Demographic factors and the classical symptoms of ARI were evaluated with logistic regression and Cox proportional hazard models using forward stepwise selection applying robust estimators to account for non-independent data and by means of recursive partitioning. The beta coefficients of the independent predictors were used to develop different point scores. These scores were then tested in the validation groups and performance between validation and derivation set was compared using receiver operating characteristics (ROC) curves. We determined sensitivities and specificities, positive and negative predictive values, and likelihood ratios at different cut-points which could reflect test and treatment thresholds. Fever, chills, and cough were the most important predictors in children whereas chills and cough but not fever were most predictive of influenza virus infection in adults. Performance of the individual models was moderate with areas under the receiver operating characteristic curves between 0.75 and 0.80 for the main outcome influenza A or B virus infection. There was no statistically significant difference in performance between the derivation and validation sets for the main outcome. The results have shown, that various mathematical models have similar discriminative ability to distinguish influenza from other respiratory viruses. The scores could assist clinicians in their decision-making. However, performance of the models was slightly overestimated due to potential clustering of data and the results would first needed to be validated in a different population before application in clinical practice. / Thesis / Master of Science (MSc) / Every year, millions of people are attacked by "the flu" or the common cold. Certain signs and symptoms apparently are more discriminative between the common cold and the flu. However, the decision between starting a simple symptom orientated treatment, treating empirically for influenza or ordering a rapid diagnostic test that has only moderate sensitivity and specificity can be challenging. This thesis, therefore, aims to help physicians in their decision-making process by developing simple scores and decision trees for the diagnosis of influenza versus non-influenza respiratory infections. Data from a completed trial for the indirect effect of influenza vaccination in children of Hutterite communities served as a basis of my thesis. There were a total of 3288 first seasonal episodes of ARI in 2202 individuals and 321 (9.8%) influenza positive events over three influenza seasons (2008-2011). The data set was divided into children under 18 years and adults. Both data sets were split into a derivation and a validation set (=holdout group). Different mathematical models were applied to the derivation set and demographic factors as well as the classical symptoms of ARI were evaluated. The scores generated from the most important factors that remained in the model were then tested in the validation group and performance between validation and derivation set was compared. Accuracy was determined at different cut-points which could reflect test and treatment thresholds. Fever, chills, and cough were the most important predictors in children whereas chills and cough but not fever were most predictive of influenza virus infection in adults. Performance of the individual models was moderate for the main outcome influenza A or B virus infection. There was no statistically significant difference in performance between the derivation and validation sets for the main outcome. The results have shown, that various mathematical models have similar discriminative ability to distinguish influenza from other respiratory viruses. The scores could assist clinicians in their decision-making. However, the results would first needed to be validated in a different population before application in clinical practice.

Enteroviruses are associated with various diseases accompanied by rare but severe complications. In recent years, outbreaks of enterovirus D68 and enterovirus A71 associated with severe respiratory infections and neurological complications have been reported worldwide. Since information on molecular epidemiology in respiratory samples is still limited, the genetic diversity of enteroviruses was retrospectively analysed over a 4-year period (2013–2016) in respiratory samples from paediatric patients. Partial viral major capsid protein gene (VP1) sequences were determined for genotyping. Enteroviruses were detected in 255 (6.1%) of 4187 specimens. Phylogenetic analyses of 233 (91.4%) strains revealed 25 different genotypes distributed to Enterovirus A (39.1%), Enterovirus B (34.3%), and Enterovirus D (26.6%). The most frequently detected genotypes were enterovirus D68 (26.6%), coxsackievirus A6 (15.9%), and enterovirus A71 (7.3%). Enterovirus D68 detections were associated with lower respiratory tract infections and increased oxygen demand. Meningitis/encephalitis and other neurological symptoms were related to enterovirus A71, while coxsackievirus A6 was associated with upper respiratory diseases. Prematurity turned out as a potential risk factor for increased oxygen demand during enterovirus infections. The detailed analysis of epidemiological and clinical data contributes to the non-polio enterovirus surveillance in Europe and showed high and rapidly changing genetic diversity of circulating enteroviruses, including different enterovirus D68 variants.

Résumé : PROBLÉMATIQUE: L’exposition résidentielle à l’humidité excessive ou aux moisissures est maintenant reconnue comme un facteur important influençant la santé respiratoire. Cette problématique a été peu étudiée chez les étudiants universitaires, bien que vulnérables par leur faible revenu et leur statut de locataire. OBJECTIFS: Cette maîtrise vise à décrire la prévalence (a) de l’exposition résidentielle à l’humidité excessive ou aux moisissures et (b) des maladies respiratoires chez les étudiants universitaires, ainsi qu’à (c) examiner l’association entre l’exposition résidentielle à l’humidité excessive ou aux moisissures et ces maladies. MÉTHODES: En 2014, une enquête électronique a été réalisée auprès de 2097 étudiants enregistrés à l’Université de Sherbrooke (Québec, Canada). Lorsque possible, des questions et des scores validés ont été utilisés pour estimer les prévalences des maladies respiratoires (rhinite allergique, asthme et infections respiratoires), de l’exposition résidentielle à l’humidité excessive ou aux moisissures et des covariables (ex. : revenu annuel familial, statut tabagique, atopie familiale, caractéristiques de l’étudiant). Les associations entre cette exposition et ces maladies ont d’abord été examinées par des tests de chi-carré en utilisant un seuil alpha de 0,05. Des régressions logistiques multivariées ont ensuite été utilisées pour déterminer les associations brutes et ajustée entre cette exposition et les maladies respiratoires. Les analyses descriptives ont été pondérées pour le sexe, l’âge et le campus d’étude. RÉSULTATS: L’exposition à l’humidité excessive ou aux moisissures était fréquente parmi les participants (36,0%; Intervalle de confiance (IC)95% : 33,9-38,1). Ceux-ci ont également été nombreux à rapporter une rhinite allergique (23,9%; IC95% :22,0-25,8), de l’asthme (32,6%; IC95% : 30,5-34,7) et des infections respiratoires (19,4%; IC95% :17,7-21,2) au cours de la dernière année. Après ajustement, les associations demeuraient significatives entre l’exposition à l’humidité excessive ou aux moisissures et la rhinite allergique (Rapport de cote (RC) : 1,30; IC95% : 1.05-1.60), l’asthme RC : 1,75; IC95% : 1,42-2,16), mais pas les infections respiratoires (RC : 1,07; IC95% : 0,85-1.35). CONCLUSIONS: La prévalence élevée de l’exposition résidentielle des étudiants universitaires à l’humidité excessive ou aux moisissures, de même que son association avec l’asthme et la rhinite allergique, mettent en lumière sa contribution potentielle à la forte prévalence des maladies respiratoires ayant une composante allergique dans cette population. Cette étude fournit un nouveau levier pour les organisations de santé publique et leurs partenaires afin d’adapter les stratégies préventives ciblant les logements insalubres, particulièrement chez les populations vulnérables. / Abstract : PROBLEMATIC: Indoor residential dampness and mold is now recognised as a major respiratory health determinant. University students are vulnerable to such exposure by their low income and high mobility, but few studies have assessed their exposure. OBJECTIVES: This project aims to describe prevalence of (a) residential dampness or mold exposure and (b) respiratory diseases in University students as well as to (c) examine the independent contribution of residential excessive dampness and mold to these diseases. METHODS: In 2014, an online survey was conducted among 2097 students registered at the University of Sherbrooke (Quebec, Canada). Validated questions, and scores when possible, were used to assess respiratory diseases (allergic rhinitis, asthma-like symptoms, respiratory infections), residential excessive dampness and mold, and covariates (e.g. family annual income, smoking status, parental atopy, student characteristics). Associations between exposure and diseases were first evaluated using bivariate analyses (khi-square tests) with an alpha value of 0.05. Using logistic regressions, the crude and adjusted relationships between residential excessive dampness or mold and respiratory diseases were examined. Results were weighted for sex, age and campus affiliation. RESULTS: Residential dampness or mold exposure was frequent (36.0%; 95%Confidence Interval (CI) : 33.9-38.1). Respondents also reported high prevalence of allergic rhinitis (32.6%; 95%CI : 30.5-34.7), asthma-like symptoms (23.9%; 95%CI : 22.0-25.8) and respiratory infections (19.4%; 95%CI : 17.7-21.2). After adjustment, associations with residential excessive dampness or mold were significant for allergic rhinitis (Odd Ratio(OR) : 1.30; 95%CI : 1.05-1.60) and asthma-like symptoms (OR : 1.75; 95%CI : 1.42-2.16), but not for respiratory infections (OR : 1.07; 95%CI : 0.85-1.35). CONCLUSIONS: High frequency of residential excessive dampness and mold, as well as its associations with asthma and allergic rhinitis highlight this exposure’s potential contribution to high atopy prevalence among university students. These results emphasize the importance for public health organizations to tackle poor housing, especially for vulnerable populations.

Pseudomonas aeruginosa est un pathogène opportuniste responsable de pneumonies. Il est particulièrement impliqué dans la mortalité des patients sous ventilation mécanique et des patients atteints de la mucoviscidose. Ces infections sont difficiles à traiter en raison de l’existence de nombreuses résistances aux antibiotiques chez cette bactérie et des alternatives thérapeutiques s’avèrent donc nécessaires. Nous avons ainsi émis l’hypothèse qu’une application oropharyngée de lactobacilles pourrait permettre de limiter les infections à P. aeruginosa et leurs effets chez les patients concernés. L’objectif principal de ce travail était d’évaluer les effets d’un mélange de lactobacilles dans un modèle murin de pneumonie à P. aeruginosa. Les effets de lactobacilles isolés dans les cavités orales de volontaires sains sur la formation de biofilm et l’activité élastolytique de P. aeruginosa PAO1 ont été mesurés in vitro. Les effets des lactobacilles sélectionnés ont ensuite été évalués dans un modèle d’infection de cellules épithéliales respiratoires(A549) par P. aeruginosa PAO1 puis dans un modèle murin de pneumonie à P. aeruginosa PAO1. Les effets de 87 lactobacilles sur la formation de biofilm et l’activité élastolytique de P. aeruginosa PAO1 ont été déterminés in vitro,aboutissant à la sélection de 3 et 5 souches ayant respectivement inhibé la formation de biofilm et l’activité élastolytique de P. aeruginosa PAO1. Parmi ces souches, L. fermentum K.C6.3.1E, L. paracasei ES.D.88 et L. zeae Od.76,qui étaient les souches les plus actives contre la formation de biofilm ou l’activité élastolytique et les plus acidifiantes lors de croissances dans une salive artificielle, ont été associées dans un mélange testé dans un modèle cellulaire d’infection à P. aeruginosa PAO1. Ce mélange n’a pas eu d’effet cytotoxique et a démontré un effet cytoprotecteur vis-à-vis de l’infection à P. aeruginosa PAO1. In vivo, l’administration intratrachéale de ces mêmes bactéries de façon prophylactique a permis d’une part de réduire les charges pulmonaires en P. aeruginosa PAO1 et d’autre part de réduire ses effets pro-inflammatoires au niveau pulmonaire (IL-6, TNF-α). Ces résultats prometteurs laissent entrevoir la possibilité de nouvelles applications thérapeutiques pour les probiotiques. / Pseudomonas aeruginosa is an opportunistic pathogen that causes pneumonia and which is involved in themortality of mechanically-ventilated or cystic fibrosis patients.These infections are difficult to treat because of the existence of many antibiotic resistances in P. aeruginosa and therapeutic alternatives are needed. Our hypothesis was that the use of probiotics could be an alternative to antibiotic therapy in order to reduce P. aeruginosa infections and its injurious and pro-inflammatory effects in lungs.The main goal of this work was to evaluate the effects of lactobacilli in a murine model of P. aeruginosa pneumonia.The first step of this work was to screen lactobacilli isolated from oral cavities of healthy volunteers against biofilmformation and elastolytic activity of P. aeruginosa PAO1. The effects of selected lactobacilli were then evaluated in amodel of infection of lung epithelial cells by P. aeruginosa PAO1 and in a murine model of P. aeruginosa PAO1pneumonia. Eighty-seven lactobacilli were tested in vitro, leading to the selection of 3 and 5 strains respectively active against biofilm formation and elastolytic activity. The most active strains (L. fermentum K.C6.3.1E, L. paracasei ES.D.88and L. zeae Od.76) toward biofilm formation and elastolytic activity were chosen to be tested in vitro, in a cell model of P. aeruginosa PAO1 infection. This mix showed cytoprotective effect against P. aeruginosa PAO1. Finally, the prophylactic intratracheal administration of the mix of lactobacilli in mice allowed to reduce the pulmonary loads in P.aeruginosa PAO1. In the same time, the pro-inflammatory effects(IL-6 and TNF- α) of the infection were reduced. These promising results suggest the possibility of new therapeutic applications for probiotics.

Ma Shuang-Cheng. / "March 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 289-324). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Introducció. Una tercera part de les consultes en atenció primària obeeixen a una malaltia infecciosa i en més de la meitat d'aquestes es deu a una infecció del tracte respiratori. Malgrat l'efecte marginal dels antibiòtics en la majoria de les infeccions respiratòries, la prescripció antibiòtica en aquestes infeccions és molt elevada. Material i mètodes. L’objectiu d’aquesta tesi va ser avaluar l’efectivitat d’un programa d’intervenció en la reducció de la prescripció antibiòtica en les infeccions del tracte respiratori. Es tracta d’un estudi multicèntric de garantia de qualitat abans-després fet en atenció primària amb metges de família de diverses Comunitats Autònomes d’Espanya. Tots els metges van enregistrar durant 15 dies en els mesos de gener i febrer de 2008 (fase preintervenció) tots els contactes amb infeccions del tracte respiratori, recollint en una plantilla les següents variables: edat, sexe, dies amb símptomes, signes i símptomes acompanyants, sospita etiològica, diagnòstic, antibiòtic prescrit, al•lèrgia a la penicil•lina, demanda d’antibiòtic i derivació a un altre nivell assistencial o no. Amb els resultats globals i de cada investigador es van realitzar les activitats d’intervenció que incloïen una reunió presencial amb presentació i discussió de resultats i diverses reunions de formació en guies d'infeccions del tracte respiratori, fullets d'informació per als pacients, taller en tests diagnòstics ràpids – tècniques antigèniques per a la detecció de l’estreptococ β-hemolític del grup A (StrepA) i test ràpid de proteïna C reactiva en sang capil•lar (PCR) – i provisió d’aquests tests diagnòstics ràpids a la consulta. Tots els metges participants en l'estudi a excepció de Catalunya van dur a terme tota aquesta intervenció (grup d’intervenció completa); en canvi, els metges catalans van realitzar la mateixa intervenció menys el taller en mètodes diagnòstics ni tampoc es van oferir els tests ràpids (grup d’intervenció parcial). En una segona fase es va repetir el mateix registre a començaments de l'any 2009 (fase postintervenció). A més, en aquest segon any es van incloure nous metges que van emplenar el mateix registre (grup control) sense fer cap intervenció. Es va efectuar una anàlisi de regressió logística multinivell considerant la prescripció antibiòtica com a variable dependent. Resultats. D’un total de 309 metges d’atenció primària que van fer el primer registre en el 2008, 281 van realitzar tota la intervenció i el segon registre (90,9%), dels quals 210 van fer la intervenció completa i 71 la intervenció parcial. El grup control el conformaren 59 metges. La infecció més freqüent va ser el refredat (40,2% de tots els casos) i el símptoma més freqüent fou la tos (75,4% dels casos). Es donaren antibiòtics en més del 85% dels casos en pneumònia, amigdalitis aguda, otitis mitjana aguda i sinusitis aguda. L’antibiòtic que més freqüentment es prescrigué va ser l’associació d’amoxicil•lina i àcid clavulànic, seguit d’amoxicil•lina. Els signes que més prediren prescripció antibiòtica abans de la intervenció foren exsudat amigdalar, otorrea i purulència de l’esput, observant-se més de divuit vegades més prescripció antibiòtica quan aquests es presentaren que quan no. La intervenció parcial no va modificar el percentatge de prescripció antibiòtica mentre que els metges que van realitzar la intervenció completa sí la van modificar, passant d’un 27,4% global a l’inici a un 16,9%, principalment en grip (passant del 3% el 2008 al 0,3% el 2009), refredat comú (2,9% a 0,7%), bronquitis aguda (62,3% a 30,2%) i faringitis aguda (18,8% a 5,1%). Aquests metges van donar menys pes a l’exsudat faringoamigdalar i a l’esput purulent com a predictors d’antibioteràpia. Els metges que empraren l’StrepA prescrigueren menys antibiòtics que aquells que no l’utilitzaren en la faringoamigdalitis i el resultat negatiu del test va ser el factor protector més important d’antibioteràpia (OR:0,008; IC95%: 0,004-0,014). Semblantment, la prescripció antibiòtica va ser menor en les infeccions del tracte respiratori inferior quan es va utilitzar la PCR (43,9% vs. 61,8%; p<0,001). Quan els valors de PCR foren inferiors a 10 mg/L es donaren antibiòtics en menys del 15% dels casos tant en la sinusitis com en les infeccions respiratòries baixes. A més, només els metges que van rebre la intervenció completa, però no els que van rebre la parcial, van modificar qualitativament la prescripció antibiòtica. Conclusions. Els resultats obtinguts en l’estudi Happy Audit confirmen que la participació activa dels metges d’atenció primària amb la realització de tests diagnòstics ràpids a la consulta s’acompanya d’una reducció dràstica d’antibiòtics en les infeccions del tracte respiratori, principalment en aquelles infeccions considerades majoritàriament virals. / Introduction. A third of primary care consultations are due to an infectious disease and more than half are caused by a respiratory tract infection. Despite the marginal effect of antibiotics in most respiratory infections, antibiotic prescriptions in these infections is very high. Material and methods. The objective of this thesis was to evaluate the effectiveness of an intervention program in reducing antibiotic prescribing in respiratory tract infections. This is a before-after quality assurance multicenter study carried out in primary care with family physicians in various regions of Spain. All doctors registered for 15 days in January and February 2008 (pre-intervention) all contacts with respiratory tract infections byfilling out a template containing the following variables: age, sex, days with symptoms, signs and symptoms accompanying, suspected etiology, diagnosis, prescribed antibiotic, penicillin allergy, antibiotic prescribed, demand of antibiotic, and referral to another setting of care or not.All physicians participating in the study with the exception of Catalonia carried out the whole intervention (full intervention group: guidelines, information brochures for patients CRP and strepA );conversely, Catalan doctors performed the same intervention excepted for the workshop on rapid tests andpoint-of-care tests were not provided (partial intervention group) without intervention. The same registry was repeated in early 2009 (postintervention). Moreover, in this second year new physicians were included who completed the same record (control group). We performed a multilevel logistic regression analysis considering antibiotic prescription as the dependent variable. Results. Out of a total of 309 primary care physicians who performed the first registry in 2008 and 281 completed the intervention and the second registry (90.9%).The most common infection was common cold (40.2% of all cases) and the most frequent symptom was cough (75.4% of cases). Antibiotics were given more than 85% of cases in pneumonia, acute tonsillitis, otitis media and acute sinusitis. The most frequently antibiotic prescribed was amoxicillin and clavulanate followed by amoxicillin. The signs that predicted more frequently the prescription of antibiotics before the intervention were tonsillar exudate, otorrhea, and sputum purulence (more than eighteen-fold more frequently if they were observed). The partial intervention did not alter the rate of antibiotic prescription while doctors assigned to the complete intervention reduced the prescription of antibiotics from an overall 27.4% before to 16.9% after the intervention. These physicians gave less weight to pharyngeal exudate and purulent sputum as predictors of antibiotic prescribing. Doctors who used StrepA prescribed fewer antibiotics than those who did not use it and negative test result was the most important protective factor for antibiotic prescription for pharyngotonsillitis (OR: 0.008, 95%CI: 0.004 to 0.014). Similarly, antibiotic prescribing was lower in the lower respiratory tract infections among ohysicians who used the CRP rapid test (43.9% vs. 61.8%, p <0.001). Conclusions.On the basis of the results of Happy Audit study we can assure that active participation of primary care physicians with the performance of point-of-care tests in the consultation is accompanied by a drastic reduction of antibiotics in respiratory tract infections, primarily in those considered as mainly viral infections.

[Truncated abstract] Pneumococcal exposure is high and life-long in developing countries including Papua New Guinea (PNG), with children under 2 years of age being at most risk for early upper respiratory tract pneumococcal carriage and infection. Deaths from pneumococcal diseases such as pneumonia and meningitis are common and likely the result of an absence of vaccination programmes. The need for effective and affordable pneumococcal vaccines has led to the testing of protein antigens including pneumolysin (Ply) and pneumococcal surface protein A (PspA) as novel vaccine antigens. Little is known on the immune responses to these proteins in humans, particularly in high-risk populations where such vaccines will be of most benefit. In this study, we examined the roles of naturally acquired antibody and cellular immune responses in mothers and newborns to Ply and PspA family 1 (PspA1) and family 2 (PspA2) in protection against or risk for early carriage in a high-risk PNG population. Antibodies to Ply, PspA1 and PspA2 were measured in plasmas of 241 mothers and 115 newborns (cords) from PNG, and 50 Australian mothers using an enzyme-linked immunosorbent assay (ELISA). Pernasal swabs were collected from PNG mothers at the time of delivery, one month post-partum, and weekly within the first month of life from their newborns to determine pneumococcal carriage. Cellular immune responses to Ply, PspA1 and PspA2, the TLR2/TLR4 ligands, LTA and LPS and to PHA were measured in cord blood mononuclear cells (CBMC) of 84 PNG versus 33 Australian newborns. Innate and T-cell cytokine responses in the PNG newborns were then analysed to determine their effect on infant pneumococcal carriage. ... No protective effect against infant pneumococcal carriage was observed with maternal and cord IgG levels for all antigens. Maternal carriage at time of delivery increased the risk for infant pneumococcal carriage in the first month of life (HR: 1.93, 95% CI 1.36 – 2.73, p = 0.001) with 70% of infants being colonised. Papua New Guinean newborns produced higher innate IL-10 and IFN-¿ (p = 0.003) and TNF-a (p < 0.001) to Ply compared to Australian newborns with no significant differences observed for IL-6 or IL-12. IFN-¿ responses to LPS and LTA (p = 0.005 and p < 0.001) were higher in PNG than Australian newborns, while IL-6, IL-10 (p < 0.001) and TNF-a (p = 0.002) to LPS with LTA-induced IL-6 and IL-10 (p < 0.001) were higher in Australian newborns. T-cell IL-5, IL-10, IL-13, IFN-¿, IL-6 and TNF-a response levels to PspA and PHA stimulation were significantly high in PNG newborns. No differences were observed for cytokine responses to Ply and PspA between PNG infant pneumococci carriers and non-carriers. Papua New Guinean infants are colonised by pneumococci very early in life and this may be influenced by high maternal carriage rates. PspA- and Ply-IgG levels are high in PNG mothers and undergo cross placental transfer but do not appear to be protective against early pneumococcal carriage. In PNG newborns, PspA elicits T-cell responses, while Ply drives more innate cellular responses, neither were demonstrated to have a protective effect against early carriage though further work is required to better define these and their relation to immune development in early childhood.

DISSERTATION (PH.D.)--THE UNIVERSITY OF MICHIGAN / CO-CHAIRMEN: ARNOLD MONTO; GENE HIGASHI

DISSERTATION (PH.D.)--THE UNIVERSITY OF MICHIGAN / CO-CHAIRMEN: ARNOLD MONTO; GENE HIGASHI

Thesis (MNutr)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Background: The Ironman® triathlon is an ultra-endurance event. It has previously been shown that heavy training schedules and racing ultra-endurance events can lead to immune impairment. Evidence supporting the potential role of dietary intake and body composition on immune impairment or upper respiratory tract infections (URTIs) is currently lacking. Aim: To investigate the relationship between dietary intake, body composition and the incidence of URTI in triathletes residing in Port Elizabeth (PE), during training and competition for the Ironman® 2011 triathlon. Method: An observational longitudinal descriptive study with an analytical component was conducted. The study population included triathletes living in PE, who completed an Ironman® distance event one year prior to, and who were training for the April 2011 Ironman®. Habitual dietary intake was assessed with a quantitative food frequency questionnaire; and race dietary strategies with a three day food record. Body composition was determined with anthropometry and the incidence of URTI was assessed with the WURSS-44. A general health screen (SF-36) was also administered. Results: Habitual dietary intake during the three months pre- and post-Ironman® 2011 triathlon was adequate for all nutrients except for carbohydrate intake in female and male participants (pre-Ironman® of 4.0 (1.7) g/kg body weight (BW)/day and 5.4 (1.8) g/kg BW/day; and post-Ironman® 3.0 (1.0) g/kg BW/day and 4.7 (1.5) g/kg BW/day respectively). Carbohydrate-loading strategies were below recommendations with intakes of 6.0 (2.9) and 5.1 (2.5) g/kg BW/day for female and male participants respectively. Race day nutrition strategies were below recommendations for carbohydrate intake. Post-race dietary intake was below recommendations for carbohydrate in the female participants (0.9 (0.5) g/kg BW). Body mass index was 26.6 (3.4) kg/m2 and 26.1 kg/m2 (1.40) for female and male study participants respectively. Body fat percentage was at the upper end for endurance athletes (29.3 (9.4) % and 13.7 (5.1) % for females and males respectively). In this study 25 % of the triathletes (N=20) developed an episode of URTI during the 3 months post-Ironman®. Dietary intake parameters measured three months pre-Ironman® that had a significant influence on URTI were: potassium (p=0.04) and thiamine (p=0.02) and dietary intake parameters measured 3 months post-Ironman® that had a significant influence on URTI were: total protein (p=0.04); isoleucine (p=0.03); leucine (p=0.03); phenylalanine (p=0.03); valine (p=0.02); thiamine (p=0.01); and Beta-tocopherol (p=0.03). Dietary intake parameters measured during the race that had a significant influence on URTI were: selenium (p=0.04); folate (p=0.04) and proline (p=0.02). Body composition did not have a significant influence on URTI. Conclusion: Habitual dietary intake three months pre- and post-Ironman® as well as pre- and post Ironman race strategies were low for carbohydrate. Body composition indicated that athletes were at the upper end associated with endurance sport. There was a relationship found between an episode of URTI and dietary intake. / AFRIKAANSE OPSOMMING: Agtergrond: Die Ironman® driekamp is 'n ultra-uithouvermoë kompetisie. Daar is voorheen bewys dat swaar oefening skedules en ultra-uithouvermoë kompetisies kan lei tot ‘n immuungebrek. Daar is tans ‘n tekort aan wetenskaplike bewyse wat die potensiële rol van dieetinname en liggaamsamestelling op immuungebrek of boonste lugweginfeksies ondersoek. Doel: Die doel van die studie was om ondersoek in te stel oor die verhouding tussen dieetinname, liggaamsamestelling en die insidensie van boonste lugweg infeksies in driekamp atlete woonagtig in Port Elizabeth (PE), tydens oefening en deelname aan die Ironman® 2011 driekamp. Metodes: 'n Waargenome, longitudinale beskrywende studie is gedoen met 'n analitiese komponent. Die studiepopulasie het bestaan uit driekampatlete woonagtig in PE, wat 'n Ironman® afstand kompetisie voltooi het een jaar voor en wat oefen vir die April 2011 Ironman® kompetisie. Gewoontelike dieetinname is bepaal met 'n kwantitatiewe voedselfrekwensie vraelys, en dieet strategieë rondom die byeenkoms met 'n drie dag voedselrekord. Liggaamsamestelling is bepaal met antropometrie en die insidensie van boonste lugweg infeksies is bepaal met die WURSS-44. 'n algemene gesondheid vraelys (SF- 36) is ook ingevul. Resultate: Die gewoontelike dieetinname gedurende die drie maande voor- en na-Ironman® 2011 was voldoende vir alle voedingstowwe, behalwe vir koolhidraat-inname in die vroulike en manlike deelnemers (voor Ironman® 4.0 (1.7) g / kg liggaamsmassa (LM) / dag en 5.4 (1.8) g / kg LM / dag, en na Ironman® 3.0 (1.0) g / kg LM / dag en 4.7 (1.5) g / kg LM / dag onderskeidelik). Koolhidraatlading strategieë was ontoereikend met innames van 6.0 (2.9) en 5.1 (2.5) g / kg BW / dag vir vroulike en manlike deelnemers onderskeidelik. Die inname op die dag van die byeenkoms was onvoldoende vir koolhidraat. Die dieetinname na die byeenkoms was onvoldoende vir koolhidraat inname in die vroulike deelnemers (0.9 (0.5) g / kg LM). Die liggaamsmassa-indeks was 26.6 (3.4) kg/m2 en 26.1 (1.4) kg/m2 vir vroulike en manlike deelnemers onderskeidelik. Persentasie liggaamsvet was aan die boonste grens geassosieer met uithouvermoë oefening atlete 29.3 (9.4) % en 13.7 (5.1) % vir vrouens en mans onderskeidelik. Die insidense van boonste lugweg infeksies was 25% (N=20) gedurende die drie maande na Ironman®. Dieetinname paramters wat gemeet was drie maande voor Ironman® wat beduidende beïnvloed met boonste lugweginfeksies getoon het, was, kalium (p=0.04) en tiamien (p=0.02) en die dieetinname parameters wat drie maande na Ironman® gemeet is en betekenisvolle beïnvloed getoon het met boonste lugweginfeksies was, totale proteïen (p=0.04); isoleusien (p=0.03), leusien (p=0.03), fenielalanien (p=0.03), valien (p=0.02), tiamien (p=0.01), en B-tocopherol (p=0.03). Die dieetinname parameters wat gemeet was tydens die wedloop wat beduidende beïnvloed met boonste lugweginfeksies getoon het na Ironman® 2011 was, selenium (p=0.04), folaat (p=0.04) en prolien (p=0.02). Die antropometriese parameters gemeet het nie beïnvloed op boonste lugweginfeksies gehad nie. Gevolgtrekking: Die gewoontelike dieetinname drie maande voor- en na Ironman® sowel as voor- en na Ironman® kompetisie strategieë was onvoldoende vir koolhidrate. Liggaamsamestelling het aangedui dat atlete aan die boonste grens geassosieer met uithouvermoë oefening geval het. Daar was beduidende beïnvloed gevind tussen dieetinname en boonste lugweginfeksies.