Abstract Cardiovascular diseases are the leading cause of death worldwide and type 2 diabetes is reaching a global epidemic. Epidemiological studies have identified numerous risk factors and pharmacotherapies in relation to these cardiometabolic diseases. However, the detailed molecular mechanisms of these risk factors and drug therapies generally remain incompletely understood. Elucidating the underlying molecular effects would be essential for better understanding of the disease pathogenesis and also for discovering new therapeutic targets. Quantitative serum metabolomics, which allows for simultaneous quantification of multiple circulating metabolic measures, provides a hypothesis-free approach to systematically inspect the metabolic changes in response to endogenous and exogenous stimuli. Metabolomics thus presents a valuable tool to study the detailed molecular effects of disease risk factors and drug therapies. However, current metabolomics studies are mostly conducted in small cross-sectional studies and the causal relations of the risk factors on the metabolic measures are generally unclear, providing limited public health impact. The present thesis serves as a proof-of-concept to illustrate that well-designed observational studies can be used to infer causality. With the exemplars of assessing molecular effects of two risk factors (body mass index and sex hormone-binding globulin) and two drug therapies (statins and oral contraceptives), the thesis demonstrates that an improved causal inference can be achieved in observational studies via the combination of multiple study designs, including cross-sectional, longitudinal and Mendelian randomization analysis. This robust study design approach together with metabolomics data can be also extended to study the molecular effects of other risk factors and drug therapies. With an improved molecular understanding of a wide range of risk factors and therapies, better understanding of disease pathogenesis is ensured. / Tiivistelmä Sydän- ja verisuonitaudit ovat johtava kuolinsyy maailmassa ja tyypin 2 diabetes on saavuttamassa globaalin epidemian mittasuhteet. Epidemiologiset tutkimukset ovat löytäneet useita riskitekijöitä ja lääkehoitoja edellä mainituille yleisille taudeille. Tyypin 2 diabetekseen ja sydän- ja verisuonitauteihin liittyvät yksityiskohtaiset molekylaariset mekanismit ymmärretään kuitenkin puutteellisesti. Molekylaaristen yksityiskohtien tarkempi ymmärtäminen olisi siten erittäin merkittävää sekä tautiprosessien ymmärtämiseksi että lääkehoitojen kehittämiseksi. Seerumin kvantitatiivinen metabolomiikka mahdollistaa useiden metabolisten suureiden samanaikaisen määrittämisen verenkierrosta ja tarjoaa siten hypoteesittoman lähestymistavan sekä sisäisten että ulkoisten ärsykkeiden aiheuttamien metabolisten muutosten systemaattiseen tutkimukseen. Metabolomiikka on siten arvokas työkalu yksityiskohtaisten molekylaaristen mekanismien tutkimuksessa, olipa kyseessä taudin riskitekijät tai lääkehoito. Metabolomiikkatutkimuksia on kuitenkin pääasiassa tehty pienissä poikittaistutkimuksissa ja riskitekijöihin liittyvien metabolisten suureiden syy- ja seuraussuhteet ovat yleisesti epäselviä, josta johtuen metabolisten suureiden kansanterveydellinen sovellettavuus on ollut heikkoa. Tämä väitöskirja esittelee tutkimuskonseptin hyvin suunniteltujen havaintotutkimuksien soveltamiseksi syy- ja seuraussuhteiden arvioinnissa. Työ sisältää esimerkit kahden riskitekijän (painoindeksi ja sukupuolihormoneja sitova globuliini) ja kahden lääkehoidon (statiinit ja ehkäisypillerit) molekylaaristen vaikutusten kausaalisista tutkimuksista. Tulokset havainnollistavat, että kausaalisten johtopäätösten luotettavuutta voidaan parantaa yhdistämällä useita tutkimusasetelmia, kuten poikittais- ja pitkittäistutkimuksia sekä Mendelististä satunnaistamista. Esitettyjä luotettavia tutkimusasetelmia, yhdessä metabolomiikkadatan kanssa, voidaan laajentaa muiden riskitekijöiden ja lääkehoitojen molekylaaristen vaikutusten tutkimuksiin. Parantunut molekyylitason ymmärrys useista riskitekijöistä ja lääkehoidoista johtaa myös parempaan tautiprosessien ymmärtämiseen.

Orientadores: Gil Guerra Júnior, Roberto Teixeira Mendes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T03:51:40Z (GMT). No. of bitstreams: 1 Samur-SanMartin_JuanEduardo_D.pdf: 1683906 bytes, checksum: 919ec09c31bfe0bfe0e71a27f12c92e7 (MD5) Previous issue date: 2015 / Resumo: Estrutura da Tese: Estudo estruturado pelo "modelo Escandinavo", denominado de "modelo alternativo" no Programa de Pós-Graduação em Saúde da Criança e do Adolescente da Faculdade de Ciências Médicas da Universidade Estadual de Campinas (FCM ¿ Unicamp). Esta tese está composta por introdução geral, objetivos, capítulos (1 e 2) e conclusão geral. A introdução geral aborda: aspectos sobre a síndrome de Down (SD); da obesidade com temas direcionados à fisiopatologia, tipos, incidência e diagnóstico em crianças e adolescentes; da obesidade na SD; da associação da obesidade com a doença cardiovascular (DCV), como também a avaliação dos fatores de risco cardiovascular em indivíduos com e sem SD. Os capítulos 1 e 2 estão em formato de artigo. Na conclusão geral foram apresentadas as principais conclusões dos dois artigos. As referências bibliográficas foram apresentadas no final de cada capítulo e da tese. Objetivos: Os objetivos do presente estudo são: (1) estimar o ponto de corte do Índice de Massa Corporal (IMC) para o diagnóstico de obesidade em adolescentes com SD de acordo com diferentes referências para classificação do IMC em relação ao percentual de gordura corporal (%GC) avaliado pela absorciometria com raios-X de dupla energia (DXA) e (2) avaliar os fatores de risco cardiovascular em adolescentes com SD e compará-los em relação ao diagnóstico de obesidade estabelecido pelo escore z do IMC da World Health Organization (WHO). Casuística e Métodos: Participaram no primeiro artigo (capítulo 1) 34 adolescentes com SD e no segundo artigo (capítulo 2) 32, de ambos os sexos (idade: 10 e 17 anos). No capítulo 1, duas técnicas foram utilizadas para avaliar a composição corporal: IMC e DXA. O IMC foi avaliado de acordo com as referências da International Obesity Task Force (IOTF), da WHO para população geral, e de Myrelid et al. e Styles et al. para população com SD. O %GC foi avaliado pela DXA de corpo inteiro e classificado de acordo NHANES 2011. No capítulo 2, o IMC considerado como alterado foi ?2,00. Foram avaliados circunferência da cintura, pressão arterial, perfil lipídico, HOMA-IR e proteína C reativa (PCR). O colesterol total, o HDL, o LDL, os triglicérides, o HOMA-IR e a PCR foram considerados fatores de risco cardiovascular e analisados em relação ao escore z do IMC. Resultados: No capítulo 1, apenas os meninos apresentaram a altura significativamente maior que as meninas e estas %GC maior que os meninos. Todas as referências que usaram IMC para avaliar obesidade apresentaram associação positiva com o %GC avaliado pela DXA no diagnóstico de obesidade. Utilizando a curva ROC em relação ao %GC pela DXA, todas as referências apresentaram alta sensibilidade, porém, o escore z do IMC pela WHO apresentou melhor especificidade, com o valor da acurácia de 82% para o ponto de corte >2,14. No capítulo 2, seis adolescentes não apresentaram nenhum dos seis fatores de risco cardiovascular, 15 apresentaram um ou dois fatores de risco e 11 apresentaram três ou mais. O escore z do IMC com melhor sensibilidade (81,8%), especificidade (71,4%) e acurácia (72%) para identificar os grupos com menos de três ou três ou mais fatores de risco cardiovascular foi o 2,14. Conclusão: De todas as referências utilizadas para o diagnóstico de obesidade o ponto de corte do escore z >2,14 de IMC da WHO mostrou melhor especificidade. O ponto de corte do escore z >2,14 de IMC da WHO confirmou ser o melhor ponto de corte para diagnóstico de obesidade relacionada a risco de DCV entre adolescentes com SD / Abstract: Structure of the Thesis: This study is structured by "Scandinavian Model," called "Alternative Model" in the Postgraduate Program in Child and Adolescent Health of the School of Medical Sciences, at State University of Campinas (FCM - Unicamp). This thesis is composed of general introduction, objectives, chapters (1 and 2) and general conclusion. The general introduction approach aspects of the history of Down syndrome (DS), prevalence, genetics, clinical features and demonstrations in DS; as well as dealing with obesity issues directed to the pathophysiology, types, prevalence and diagnosis in children and adolescents, diagnostic methods and obesity in DS; the association of obesity with cardiovascular disease (CVD), as well as the assessment of cardiovascular risk factors in children, adolescents and adults with and without DS. Chapters 1 and 2 are in article format. In general conclusion were presented the main conclusions of the two articles. References were presented at the end of each chapter and of the thesis. Objectives: The aims of this study are: (1) to estimate the cutoff point of the body mass index (BMI) for the diagnosis of obesity in adolescents with DS according to different references for BMI in relation to the percentage of body fat (%BF) measured by absorptiometry dual-energy X-ray absorptiometry (DXA) and (2) to assess the cardiovascular risk factors in adolescents with DS and compare them in relation to obesity diagnosis determined by z-score for BMI of the World Health Organization (WHO). Materials and Methods: In this study, participated in the first article (Chapter 1) 34 adolescents with DS and the second article (Chapter 2) 32 adolescents with DS, of both sexes (age: 10 to 17 years). In Chapter 1, two techniques were used to assess body composition: BMI and DXA. BMI was evaluated according to the references of the International Obesity Task Force (IOTF), the WHO for the general population, and Myrelid et al. and Styles et al. for people with DS. The %BF was assessed by whole body DXA and classified according to NHANES. In chapter 2, weight and height were measured and BMI calculated. BMI considered abnormal was >2.14. We evaluated waist circumference, blood pressure, lipid profile, HOMA-IR and C-reactive protein (CRP). Total cholesterol, HDL, LDL, triglycerides, HOMA-IR and CRP were considered cardiovascular risk factors and analyzed in relation to BMI z score. Results: In Chapter 1, all references who have used BMI to assess obesity was positively associated with %BF measured by DXA in the diagnosis of obesity. Using the ROC curve in relation to %BF by DXA, all references showed high sensitivity, but the z-score of BMI by WHO showed better specificity, with the value of the accuracy of 82% for the cutoff point above 2.14. In Chapter 2, six teenagers do not show any of the six cardiovascular risk factors, 15 had one or two risk factors and 11 had three or more. The z scores of BMI with better sensitivity (81.8%), specificity (71.4%) and accuracy (72%) to identify the groups with less than three or three or more cardiovascular risk factors was 2.14. Conclusion: All the references used for the diagnosis of obesity of the cutoff point of z-scores above 2.14 by WHO showed better specificity. WHO BMI z scores greater than 2.14 confirmed to be the best cutoff point for obesity diagnosis related to risk of the cardiovascular disease among adolescents with DS / Doutorado / Saude da Criança e do Adolescente / Doutor em Ciências

Introducción: La circunferencia de cuello (CCu) es una medida útil para evaluar riesgo de enfermedades crónicas no transmisibles. El objetivo fue determinar la correlación y establecer los mejores puntos de corte que correspondan entre CCu e Índice de Masa Corporal (IMC) y Circunferencia de Cintura (CCi). Métodos: Se utilizó la base de datos de Perú del Estudio Latinoamericano de Nutrición y Salud (ELANS). Se evaluó por sexo: (i) la correlación de Pearson entre CCu e IMC y CCi, (ii) la Sensibilidad (Se) y Especificidad (Sp) para sobrepeso y obesidad (IMC) y para obesidad central (CCi), con el Índice de Youden. Resultados: Se encontró correlación fuerte por sexo entre CCu y CCi (hombres: r=0,81 y mujeres: r=0,80) y moderada entre CCu e IMC (r=0,80 y r=0,76 respectivamente). El punto de corte para definir sobrepeso/obesidad por CCu (IMC≥25.0 kg/m2) en hombres fue 36,95 cm y en mujeres 32,85 cm (Se: 81% y 78%; Sp: 77% y 88%, respectivamente), para obesidad (IMC≥30.0 kg/m2) fue 39,15 cm para hombres y 33.85 cm para mujeres (Se: 92% y 88%; Sp: de 84% y 73%, respectivamente) y para obesidad central fue 38,65 cm en hombres y 32,75 cm para mujeres (Se: 80% y 77%; Sp: de 89% y 89%, respectivamente). Conclusión: Se encontró una correlación fuerte entre CCu y CCi y moderada entre CCu e IMC. La CCu es una medida práctica y poco invasiva. Podría ser usada en salud pública para identificar riesgo de enfermedades crónicas no transmisibles. / Background: Neck circumference (NC) is being used lately to identify the risk of chronic noncommunicable diseases. The aim of this study was to determine the correlation and establish the best cut-off points that correspond between NC and Body Mass Index (BMI) and Waist Circumference (WC). Methods: Data were obtained from the Latin American Study of Nutrition and Health (ELANS). The following were evaluated by sex: (i) Pearson's correlation between NC and BMI and WC, (ii) Sensitivity (Se) and Specificity (Sp) for overweight and obesity (BMI) and for central obesity (WC), with the Index of Youden. Results: A strong correlation by sex was found between NC and WC (men: r = 0.81 and women: r = 0.80, respectively) and a moderate correlation between NC and BMI (r = 0.80 and r = 0.76 respectively). The cutoff points to define overweight /obesity by NC (BMI≥25.0 kg / m2) in men was 36.95 cm and in women 32.85 cm (Se: 81% and 78%; Sp: 77% and 88%, respectively) and for obesity (BMI≥30.0 kg / m2) it was 39.15 cm for men and 33.85 cm for women (Se: 92% and 88%; Sp: 84% and 73%, respectively). For central obesity, the cutoff points is 38.65 cm for men and 32.75 cm for women (Se: 80% and 77%; Sp: 89% and 89%, respectively). Conclusion: A strong correlation was found between NC and WC and a moderate one between NC and BMI. The NC is a practical and minimally invasive measure that could be used in public health to identify the risk of chronic non-communicable diseases. / Tesis

Introducción: La valoración del estado nutricional de las gestantes es fundamental para lograr un estado óptimo de ellas y de sus hijos. Objetivo: Determinar la relación entre la ganancia de peso gestacional y el peso del recién nacido en puérperas atendidas en el Servicio de Ginecología del Centro Médico Naval. Materiales y métodos: Estudio cuantitativo, descriptivo de tipo correlacional y transversal. La población estuvo conformada por 61 puérperas y sus recién nacidos en el Centro Médico Naval. Se trabajó con la población encontrada durante el periodo de agosto a setiembre donde se diseñó una ficha para la recolección de datos. Para el análisis estadístico se utilizaron las pruebas de Rho de Spearman y coeficiente de contingencia de Pearson. Resultados: La edad materna promedio fue de 29± 4.27 años, la mitad estaba casada con grado de instrucción superior. En índice de masa corporal pre gestacional de las puérperas fue para normal de 52.5%; sobrepeso, 41% y; obesas ,6.6%. Correspondiendo al 49% de gestantes con ganancia adecuada; mientras que la ganancia inadecuada por exceso fue del 31.1% y 19.6% a ganancia insuficiente de peso. Los recién nacidos con macrosomía representó el 4.9%. Se obtuvo correlación no significativa entre la ganancia de peso gestacional y el peso del recién nacido, según pruebas estadísticas por Spearman ρ (rho)=0.083 y por coeficiente de contingencia de Pearson (CC= 0.35). Conclusiones: No se evidenció una relación significativa entre la ganancia de peso gestacional y el peso del recién nacido. El promedio de edad fue 29.72 años, la mayoría de procedencia costeña, casadas y con grado de instrucción superior. Asimismo, se evidencio que un 49% alcanzo un peso adecuado, 20% bajo peso y 31% peso excesivo. En cuanto al recién nacido un 95.1% fueron normosómicos y un 4.9% macrosómico. / Introduction: The assessment of the nutritional status of pregnant women is essential to achieve an optimal state of them and their children. Objective: To determine the relationship between gestational weight gain and the weight of the newborn in postpartum nurses treated in the Gynecology Service of the Naval Medical Center. Materials and methods: Quantitative, descriptive, correlational and cross-sectional study. The population consisted of 61 puerperal women and their newborns at the Naval Medical Center. We worked with the population found during the period from August to September where a file for data collection was designed. For the statistical analysis, Spearman's Rho tests and Pearson's contingency coefficient were used. Results: The average maternal age was 29 ± 4.27 years, half were married with higher education. In the pre-gestational body mass index of the puerperal women, it was normal for 52.5%; overweight, 41% and; obese, 6.6%. Corresponding to 49% of pregnant women with adequate earnings; while the inadequate excess gain was 31.1% and 19.6% to insufficient weight gain. Newborns with macrosomia accounted for 4.9%. No significant correlation was obtained between gestational weight gain and newborn weight, according to statistical tests by Spearman ρ (rho) = 0.083 and by Pearson's contingency coefficient (CC = 0.35). Conclusions: There was no significant relationship between gestational weight gain and newborn weight. The average age was 29.72 years, most of them from the coast, married and with a higher education level. Likewise, it was evidenced that 49% reached an adequate weight, 20% underweight and 31% overweight. As for the newborn, 95.1% were normosomal and 4.9% macrosomic. / Trabajo de investigación

Introducción: El consumo de bebidas azucaradas (SSB) se ha relacionado con un incremento en el Índice de Masa Corporal (IMC), lo cual sería especialmente preocupante en poblaciones con un potencial de exposición prolongada, tales como estudiantes. Objetivo: Evaluar la relación entre el consumo calórico proveniente de SSB medido mediante el cuestionario Bevq-15 e IMC en estudiantes de carreras de ciencias de la salud de una universidad peruana. Materiales y métodos: Estudio transversal analítico en base a la medición del consumo calórico de 15 bebidas mediante la administración del cuestionario BEVQ-15 y la toma de medidas antropométricas a universitarios durante 2018 - 2019. Se evaluó la asociación cruda y ajustada usando modelos de regresión lineal. Resultados: Se incluyó a 350 personas. La mediana fue de 21 años y el 58.29% fueron mujeres. La mediana del IMC fue de 24.00 (21.75 - 26.90). El consumo promedio de calorías provenientes de bebidas azucaradas fue de 25.35 kcal/día. Se asoció un IMC menor con el sexo femenino (p<0.001), la carrera de nutrición (p=0.002) y nunca haber consumido tabaco (p=0.027). Se asoció un IMC mayor a la dislipidemia (p=0.014) y a un mayor consumo de calorías diarias provenientes de SSB (p<0.001). En el análisis multivariado se encontró asociación significativa entre el consumo de calorías provenientes de SSB y el IMC, ajustado por edad, sexo y tabaquismo (coeficiente β: 0.68; IC95% 0.04-1.33; p=0.037). Conclusiones: Se encontró asociación entre el consumo de calorías derivadas de SSB y un mayor IMC. Se debe impulsar intervenciones destinadas a la disminución de su consumo en estudiantes. / Introduction: The consumption of sugar sweetened beverages (SSB) has been related to an increase in the Body Mass Index (BMI), which would be especially worrisome in populations with a prolonged exposure potential, such as students. Objective: To evaluate the relationship between the caloric intake from SSB measured by the Bevq-15 questionnaire and BMI in health sciences students at a Peruvian university. Materials and methods: Cross-sectional analytical study based on the measurement of the caloric consumption of 15 beverages based on the administration of the BEVQ-15 questionnaire and the measurement of college students’ anthropometric measurements during 2018-2019. The crude and adjusted association were evaluated using linear regression models. Results: We enrolled 350 participants. The median age was 21 years and 58.29% were women. The median BMI was 24.00 (21.75 - 26.90). The average consumption of calories from SSB was 25.35 kcal/day. A lower BMI was associated with the female sex (p <0.001), the nutrition career (p = 0.002) and never having used tobacco (p = 0.027). A higher BMI was associated with dyslipidemia (p = 0.014) and a greater consumption of daily calories from SSB (p <0.001). In the multivariate analysis, a significant association was found between the consumption of calories from SSB and BMI, adjusted for age, sex and smoking (β coefficient: 0.68, 95% CI 0.04-1.33, p = 0.037). Conclusions: An association was found between the consumption of calories derived from SSB and a higher BMI. Interventions aimed at reducing student consumption should be promoted. / Tesis

No description available.

Contexte. L’avènement de nouvelles technologies a pris de l’ampleur au cours des dernières années, jusqu’à ce que celles-ci deviennent partie intégrante de la réalité d’aujourd’hui. Les études antérieures démontrent qu’une exposition excessive aux écrans présente un risque important au niveau du développement physique et psychologique chez les enfants. L’identification des facteurs modifiables précoces afin de prédire les risques possibles relié aux habitudes télévisuelles des jeunes représente un défi important à ce jour, car leurs impacts néfastes peuvent avoir des conséquences importantes pendant la durée de l’enfance, l’adolescence, voir même la vie adulte. Toutefois, la littérature fournit peu d’informations sur de possibles facteurs de protection contre ces risques biopsychosociaux. La participation à des activités sportives a su démontrer, à travers les années, ses nombreux bienfaits sur la santé des jeunes ainsi que sur leur développement à long terme. À la lumière des nombreux bénéfices reliés au développement, il est tout à fait possible de croire que la participation à des activités sportives extrascolaires pourrait agir à titre de facteur de protection afin de contrer les risques biopsychosociaux reliés aux habitudes télévisuelles excessives en bas âge. / Background. The advent of new technologies in recent years has grown to be an integral part of today's reality. Previous studies show that excessive exposure to screens poses a significant risk to physical and psychological development of children. Identifying early factors that modify associated risks related to youth screen viewing habits is an important challenge to date. However, the literature shows little information on possible protective factors against such biopsychosocial risks. Over the years, participation in sporting activity has demonstrated its numerous benefits on the health of young people as well as for long-term development. Given the established benefits related to physical activity, it is quite plausible that participation in extracurricular sporting activity could act as a protective factor which counters the biopsychosocial risks related to excessive televiewing at a young age.

Les enfants sont exposés au p,p’-dichlorodiphényltrichloroéthane (p,p’-DDT) et au p,p’-dichlorodiphényldichloroéthylène (p,p’-DDE) par transfert placentaire et par le lait maternel. Plusieurs études laissent croire que cette exposition pourrait avoir un impact sur l’indice de masse corporelle (IMC) pendant l’enfance. Le but de notre étude était d’évaluer l’association entre l’exposition par le lait maternel et l’IMC des enfants japonais âgés de 42 mois. Nous avons utilisé les données d’une étude pilote (n=290) de la Japan Environment and Children Study (JECS). Le p,p’-DDT et le p,p’-DDE ont été mesurés dans le lait maternel, et les concentrations chez l’enfant ont été estimées pour trois périodes (0-6 mois, 6-12 mois, 12-24 mois) à l’aide d’un modèle de toxicocinétique. Les associations avec l’IMC à 42 mois ont été évaluées à l’aide de modèles de régression linéaire multivariée. Aucune association n’a été observée avec les concentrations de p,p’-DDT mesurées dans le lait maternel, ni avec les concentrations estimées chez les enfants. Des associations positives avec les concentrations de p,p’-DDE estimées ont été observées chez les filles. Chaque augmentation d’un logarithme naturel dans les concentrations estimées était associée avec une augmentation du score z de l’IMC de 0.23 (I.C. 95% : 0.01, 0.45) pour la période d’exposition 0-6 mois, de 0.26 (I.C. 95% : 0.06, 0.47) pour la période 6-12 mois, et de 0.24 (I.C. 95% : 0.05, 0.43) pour la période de 12-24 mois. Ces associations étaient dans le même ordre de grandeur que l’association observée dans une méta-analyse publiée récemment (augmentation du score z de l’IMC de 0.13 par augmentation d’un logarithme naturel dans l’exposition prénatale), ce qui supporte l’hypothèse que l’exposition développementale au p,p’-DDE est associée avec une augmentation de l’IMC durant l’enfance. / Children are exposed to p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) and p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) through placental and lactational transfer. Studies have revealed that these exposures could lead to increased body mass index (BMI) during childhood. Our aim was to assess whether exposure through breast milk is associated with BMI in Japanese children at 42 months of age. We used data from a pilot study (n=290) of the Japanese Environment and Children Study (JECS). p,p’-DDT and p,p’-DDE levels were measured in breast milk, and levels in children were estimated using a toxicokinetic model for three exposure periods (0-6 months, 6-12 months, 12-24 months). Associations with BMI at 42 months of age were assessed using multivariate linear regression models. Our study revealed no significant association with levels of p,p’-DDT measured in breast milk or estimated in children. Positive associations with p,p’-DDE were found in girls during all exposure periods. For each log increase in the estimated p,p’-DDE levels, BMI z-score increased by 0.23 (C.I. 95%: 0.01, 0.45) for the 0-6 months exposure period, 0.26 (C.I. 95%: 0.06, 0.47) for the 6-12 months exposure period and 0.24 (C.I. 95%: 0.05, 0.43) for the 12-24 months exposure period. Our results in girls were similar to those found in a previous meta-analysis that included boys and girls (BMI z-score increase of 0.13 by log increase in prenatal p,p’-DDE levels), supporting that early-life exposure to p,p’-DDE may be associated with increased BMI during childhood.

Recent decades have seen an explosion of research centered on understanding the influential impact that job stressors have on employees' subjective well-being, and now more recently, on objective assessments of physical health. Utilizing baseline data from a larger study funded by the National Institute for Occupational Safety and Health (NIOSH), I conducted a field study on blue-collar employees from two organizations in the construction industry, with the goal of exploring the impact of job stressors on job satisfaction (subjective well-being) and body mass index (objective health), as well as the influence of organizational justice as a moderator and exercise as a mediator in those relationships. In support of previous research, results show that job stressors (job demands, low skill discretion, and low decision authority) all had significant direct effects on job satisfaction in the expected directions, signifying that the fewer demands and more control one has in their work role, the more satisfied one is. Results also indicate that distributive and procedural justice have significant main effects on job satisfaction, illustrating that higher perceptions of justice are related to higher levels of job satisfaction. With respect to objective health, the data provides empirical support for the relationship between job control (skill discretion and decision authority) and BMI; however, job demands did not have a significant main effect on BMI. More importantly, the rarely studied relationship between organizational justice and BMI was investigated (Robbins et al., 2012), with results indicating that procedural and distributive justice are important influences on one's BMI level. Post hoc analyses revealed that distributive and procedural justice are two relevant mediators to consider in the job stressor-job satisfaction relationship, illustrating the importance of considering employees' fairness perceptions with regards to their satisfaction levels. Moreover, exercise was found to be a significant moderator to the relationship between job demands and BMI, as well as the relationship between distributive justice and job satisfaction, shedding light on physical activity within the work and health contexts as a factor that interacts with employees' perceptions of justice and their workload demands to impact their psychological and physical health. Considering the cross-sectional nature of these data, all mediation and moderation results should be interpreted with caution. With empirical support found for the direct association between job stressors and organizational justice and the outcomes of job satisfaction and BMI, this study has significant implications for researchers and practitioners alike to further expand upon these findings and implement them into organizational practice in support of the Total Worker Health initiative, which aims to promote employee safety and health (Schill & Chosewood, 2013). Results suggest a healthy workforce is the result of the combination of employers transforming the work environment into a more just, transparent and trustworthy place to work, starting with the dynamics between supervisors and their employees, in conjunction with targeted interventions on employees' modifiable behaviors, such as engaging in physical activity and healthier eating habits.

Contexte: L'obésité infantile est un facteur de risque majeur de mortalité et de morbidité, car les enfants avec obésité ont tendance à maintenir leur obésité à l’âge adulte. Parmi les enfants canadiens, 27% ont un surpoids ou une obésité, ce qui pose un grave problème de santé publique, vu les conséquences en termes de morbidité et mortalité de l’obésité à l’âge adulte. Objectifs: Les principaux objectifs de ma recherche sont les suivants: (1) examiner le lien entre l'activité physique durant la pré-puberté et les trajectoires d'adiposité de l’enfance à l'adolescence; (2) examiner le lien entre les comportements sédentaires dans la pré-puberté et les trajectoires d'adiposité de l’enfance à l'adolescence; et (3) examiner les associations entre les apports alimentaires dans la pré-puberté et les trajectoires d'adiposité de l’enfance à l'adolescence. Mon hypothèse est que moins d'activité physique, plus de temps sédentaire et une alimentation moins saine (ex. moins de fruits et légumes, plus de boissons sucrées) pendant l'enfance seront associés à des trajectoires défavorables d’obésité de l’enfance à l'adolescence. Méthodes: Cette recherche porte sur les données de l’étude QUALITY (QUebec Adipose and Lifestyle Investigation in Youth). Cette cohorte comprend 630 enfants caucasiens âgés de 8 à 10 ans, recrutés au départ sur la base d’antécédent d'obésité chez leurs parents. De ce nombre, 377 ont été suivis à 10-12 ans et à 15-17 ans. Les comportements sédentaires et l'activité physique ont été mesurés par accélérométrie sur une période de 7 jours, le temps d'écran a été mesuré par questionnaire et l'apport alimentaire avec trois rappels alimentaires de 24 heures. Le poids et la taille ont été mesurés à chaque période et transformés en scores z de l'indice de masse corporelle (IMC-z) selon les normes de l'OMS (Organisation Mondiale de la Santé). La modélisation des trajectoires basée sur les groupes a été utilisée pour identifier les trajectoires longitudinales de l'IMC-z. Des régressions logistiques multinomiales ont ensuite été utilisées pour examiner les associations entre les habitudes de vie durant l’enfance et les trajectoires d’adiposité, en ajustant l’âge, le sexe, les stades du développement pubertaire de Tanner et l’éducation parentale. Résultats principaux: Six trajectoires distinctes d’IMC-z ont été identifiées: Poids-Faible-à-Normal-Stable (5,7%), deux groupes de Poids-Normal-Stable qui ont ensuite été combinés (33,0% et 24,8%), Surpoids-Stable (19,8%), Obèse-Stable (8,8%) et Surpoids-Décroissants (7,9%). Pour chaque portion supplémentaire de fruits et légumes à 8-10 ans, la probabilité de faire partie du groupe en Surpoids-Décroissants est augmentée de 26% (OR 1,26, IC 95% 1,06-1,49) par rapport à ceux du groupe Poids-Normal-Stable. Pour chaque heure supplémentaire de comportement sédentaire mesurée par l'accéléromètre à 8-10 ans, la probabilité d'appartenir au groupe Surpoids-Décroissants est augmentée de 51% (OR 1,51, IC à 95% 1,03- 2,22) par rapport au groupe Poids-Normal-Stable. En termes d'activité physique, toutes les 10 minutes supplémentaires d'activité physique modérée à vigoureuse (APMV) au départ étaient associées à une probabilité plus faible d'appartenir au groupe Obèse-Stable (OR 0,75, IC à 95% 0,61-0,91) et Groupe Surpoids-Décroissants (OR 0,78, IC 95% 0,62-0,98) par rapport au groupe Poids-Normal-Stable. Importance: Cette étude a permis d’identifier différents groupes de trajectoires de développement du score IMC-z qui restent stables de l’enfance à la fin de l'adolescence ainsi qu’un groupe d’enfants qui sont passés d'un surpoids à un poids normal. Ces derniers avaient un apport alimentaire plus favorable en fruits et légumes à 8-10 ans. Cependant, ils avaient également une APMV inférieure et un comportement plus sédentaire comparativement au groupe de Poids-Normal-Stable. / Background: Childhood obesity is a major risk factor for mortality and morbidity as children with obesity tend to remain obese into adulthood. Among Canadian children, 27 % have overweight or obesity, which is a serious public health concern. Objectives: The main objectives of my research are to (1) examine the associations between physical activity in pre-puberty or early puberty and obesity trajectories across childhood and adolescence; (2) examine the associations between sedentary behaviors in pre-puberty or early puberty and obesity trajectories across childhood and adolescence; and (3) to examine associations between dietary intake in pre-puberty or early puberty and obesity trajectories across childhood and adolescence. My hypothesis is that lower physical activity, more time spent in sedentary behaviours and unhealthy diets (e.g., higher sugar-sweetened beverage consumption, lower fruit and vegetable intake) in childhood (pre to early puberty) will be associated with adverse patterns of obesity into adolescence. Methods: This study uses data from the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) study. This cohort includes 630 Caucasian children aged 8-10 years, recruited at baseline based on a parental history of obesity. Of these, 377 were re-assessed at 10-12 years and at 15-17 years. Sedentary behavior and physical activity using 7-day accelerometry, self-reported screen time and dietary intake with three 24-hr diet recalls were measured. Weight and height were measured at each time period and transformed to body mass index (BMI) z-scores using WHO (World Health Organization) Standards. Group based trajectory modeling was used to identify longitudinal trajectories of z-BMI. Multinomial logistic regressions were used to examine associations between lifestyle behaviors at 8-10 years and distinct obesity trajectory groups, while adjusting for age, sex, tanner stage and parental education. Results: Six distinct z-BMI trajectory groups were identified: Stable-Low-Normal-Weight (5.7%), two Stable-Normal-Weight groups that were subsequently combined (33.0% and 24.8%), Stable-Overweight (19.8%), Stable-Obese (8.8%) and Overweight-Decreasers (7.9%). For every additional vegetable and fruit serving at baseline, the likelihood of being in the Overweight–Decreasers group increased by 26% (OR 1.26, 95% CI: 1.06, 1.49) compared to those in the Stable-Normal-Weight group. For every additional hour of sedentary behavior at baseline, the likelihood of belonging to the Overweight-Decreasers group increased by 51% (OR 1.51, 95% CI: 1.03, 2.22) as compared to Stable-Normal-Weight group. In terms of physical activity, every additional 10 mins of Moderate to Vigorous Physical Activity (MVPA) at baseline was associated with a lower likelihood of belonging to the Stable-Obese group (OR 0.75, 95% CI: 0.61, 0.91) and to the Overweight-Decreasers group (OR=0.78, 95% CI: 0.62, 0.98) compared to the Stable-Normal-Weight group. Conclusion: Stable trajectories of z-BMI from childhood to late adolescence were found, with the exception of one decreasing trajectory from overweight in childhood to normal weight in adolescence. The latter had more favourable dietary intake of fruits and vegetables at baseline, however, they also had lower MVPA and more sedentary behavior.