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It has long been known that vitamin D is important for calcium absorption and bone health. More recently, vitamin D has been found to modulate breast cancer cell growth and increasingly epidemiologic studies suggest vitamin D may be associated with reduced breast cancer risk. The primary objective of this thesis was to evaluate the associations between vitamin D from all sources (food, supplements and sunlight exposure) and breast cancer. Secondary objectives were focused on methodological issues including the development of a solar vitamin D score and adapting the measurement of vitamin D from foods for use among Canadians. The data source for this study was the “Ontario Women’s Diet and Health Study”, a population-based case-control study of women in Ontario. Cases (n = 3,101) diagnosed between 2002 and 2003 were identified through the Ontario Cancer Registry and controls (n = 3,471) were identified through random digit dialing of Ontario households. Study participants completed mailed risk factor and food frequency questionnaires. Vitamin D intake from supplements (>400 IU/day compared to none) was found to be associated with reduced breast cancer risk (OR = 0.76; 95% CI: 0.59, 0.98). However, total vitamin D intake (from food and supplements) and intake from food alone were not associated with breast cancer risk. Time spent outdoors during 4 periods of life (including adolescence) was associated with reduced breast cancer (e.g., highest versus lowest categories of exposure at age 40 to 59: OR = 0.74; 95% CI: 0.61, 0.88). The novel solar vitamin D score, derived from time spent outdoors, skin color, sun protection practices, and ultraviolet radiation of residence, was also associated with reduced breast cancer risk. In summary, there is some evidence to suggest that vitamin D intake from supplements and determinants of cutaneous vitamin D production are associated with reduced breast cancer risk.

It has long been known that vitamin D is important for calcium absorption and bone health. More recently, vitamin D has been found to modulate breast cancer cell growth and increasingly epidemiologic studies suggest vitamin D may be associated with reduced breast cancer risk. The primary objective of this thesis was to evaluate the associations between vitamin D from all sources (food, supplements and sunlight exposure) and breast cancer. Secondary objectives were focused on methodological issues including the development of a solar vitamin D score and adapting the measurement of vitamin D from foods for use among Canadians. The data source for this study was the “Ontario Women’s Diet and Health Study”, a population-based case-control study of women in Ontario. Cases (n = 3,101) diagnosed between 2002 and 2003 were identified through the Ontario Cancer Registry and controls (n = 3,471) were identified through random digit dialing of Ontario households. Study participants completed mailed risk factor and food frequency questionnaires. Vitamin D intake from supplements (>400 IU/day compared to none) was found to be associated with reduced breast cancer risk (OR = 0.76; 95% CI: 0.59, 0.98). However, total vitamin D intake (from food and supplements) and intake from food alone were not associated with breast cancer risk. Time spent outdoors during 4 periods of life (including adolescence) was associated with reduced breast cancer (e.g., highest versus lowest categories of exposure at age 40 to 59: OR = 0.74; 95% CI: 0.61, 0.88). The novel solar vitamin D score, derived from time spent outdoors, skin color, sun protection practices, and ultraviolet radiation of residence, was also associated with reduced breast cancer risk. In summary, there is some evidence to suggest that vitamin D intake from supplements and determinants of cutaneous vitamin D production are associated with reduced breast cancer risk.

Yes / Context: Vitamin D is essential for bone health in adolescence, where there is rapid bone mineral content accrual. As cutaneous sun-exposure provides vitamin D, there is no recommended oral intake for UK adolescents. Objective: Assess seasonal vitamin D status and its contributors in white Caucasian adolescents, and examine bone health in those found deficient. Design: Prospective cohort study. Setting: Six schools in Greater Manchester, UK. Participants: 131 adolescents, 12–15 years. Intervention(s): Seasonal assessment of circulating 25-hydroxyvitamin D (25OHD), personal sunexposure and dietary vitamin D. Adolescents deficient (25OHD <10 ng/mL/25 nmol/L) in ≥one season underwent dual-energy X-ray absorptiometry (lumbar spine, femoral neck), with bone mineral apparent density (BMAD) correction for size, and peripheral quantitative computed tomography (distal radius) for volumetric (v)BMD. Main Outcome Measure: Serum 25OHD; BMD. Results: Mean 25OHD was highest in September: 24.1 (SD 6.9) ng/mL and lowest in January: 15.5 (5.9) ng/mL. Over the year, 16% were deficient in ≥one season and 79% insufficient (25OHD <20 ng/mL/50 nmol/L) including 28% in September. Dietary vitamin D was low year-round while personal sun-exposure was seasonal and predominantly across the school week. Holidays accounted for 17% variation in peak 25OHD (p<0.001). Nineteen adolescents underwent bone assessment, which showed low femoral neck BMAD versus matched reference data (p=0.0002), 3 with Z≤ -2.0 distal radius trabecular vBMD. Conclusions: Sun-exposure levels failed to provide adequate vitamin D, ~one-quarter adolescents insufficient even at summer-peak. Seasonal vitamin D deficiency was prevalent and those affected had low BMD. Recommendations on vitamin D acquisition are indicated in this age-group. / The Bupa Foundation (Grant number TBF-M10-017).

Background: Prevalence of obesity in US children has increased substantially. The influence of vitamin D intake on body mass index (BMI) is yet to be clearly defined. Results are mixed regarding the relationship of vitamin D deficiency with obesity in children. The objective of this study was to examine the association between vitamin D intake and BMI over a 6 month period in pre-to early adolescent children in Pittsburgh, PA. Methods: Secondary analysis was done on 256 healthy 6-14 year old (54% male) Caucasian and African American (70%) children from Pittsburgh, PA. Participants completed a food frequency questionnaire (FFQ) and a Sun Exposure Questionnaire (SEQ) and provided anthropometric measures at 2 time points 6 months apart. Vitamin D intake was compared by BMI status (normal = <85th percentile, overweight = 85th to 95th percentile, obese = >95th percentile) as well as by change in BMI over 6 months. Statistical analysis included descriptive statistics, Kruskal-Wallis analysis of variance, Spearman’s correlation, Chi Square test, and regression analysis (vitamin D intake, gender, race, baseline BMI, total energy intake, sun exposure and sunscreen use). Results: Median reported vitamin D intake was 245.85 IU at baseline and 382.51 IU at 6 month follow up. After subdividing children by BMI, at baseline the obese group reported lowest median intake (188 IU) and at 6 month follow up the normal group reported lowest median intake (374 IU) (P=0.03). Overall relation between vitamin D intake and BMI was significant (P=0.033) but weak (r=-0.015). Regression analysis revealed only baseline BMI status (P=<0.001) as a predictor of 6 month follow up BMI. No relation was observed between change in BMI and vitamin D intake. Conclusion: The results of this study do not support a strong relationship between vitamin D intake and change in BMI status over a 6 month time period.

In healthcare environments, elements like nature, daylight and sound have been found to significantly influence the healing process of patients, by enhancing the quality of their recovery, shortening their hospital stay and consequently reducing hospital costs. For instance, it has been shown that exposure to nature triggers positive responses in people, daylight affects human psychology, and different sounds have varying behavioral effects on different groups of people. But, while these effects have been carefully studied in adult patients, leading to clear design standards, less is known about their impact on premature infants. Interestingly, the care that many newborns receive in Neonatal Intensive Care Units provides countless benefits, but there are also many aspects of it that can cause stress to babies, staff and families. Exposure to continuous light, high levels of noise, separation from their mothers, minimal physical contact and painful procedures are all stressful factors that can have tremendous effects on a baby's recovery. So, while highly specialized treatments can greatly improve a newborn's medical condition, physical surroundings are rarely regarded as influential in his or her care. This thesis exploration focuses on the design of a Women's and Infant's Medical Center prototype where the emphasis will be to promote well-being and healthy development through the physical environment. Attention will be given to the controversial effects of natural light on babies and its benefit will be determined through analysis of collected evidence. Equally, noise sources and methods to control it will be explored in order to minimize stress and discomfort in newborns. Finally, the importance of access to the natural environment will be studied, and even though this would normally not be directly associated with a baby's healing process, it could be an essential factor in the well-being of mothers and caregivers, which in turn will benefit the baby. Through evidence, research, analysis and a prototype design various strategies will be developed to demonstrate how the proposed elements (access to nature, daylight, and noise control) could successfully be integrated into a NICU setting. The resulting environment should promote faster recovery and healthier development of babies, both directly and via their caregivers (parents and medical staff).

L’objectif de ce travail est de développer des matériaux à base de titane sous la forme de monolithe capable d’assurer des réactions photo catalytiques en flux, sous la lumière du soleil ou la lumière visible. Ces matériaux doivent présenter des propriétés physiques et chimiques particulières afin de pallier aux inconvénients des photocatalyseurs classiques qui limitent leur efficacité, à savoir : la stabilité mécanique, la perte de charge, le faible transport de masse, et le controle du temps de contact, la gamme de longueur d’onde d’absorption réduite, le temps de vie de la charge photo-générée. Trois voies de synthèse de monolithes TiO2 ont ainsi été élaborées et optimisées pour atteindre la forme et la dimension adéquate à l’application visée. Les monolithes TiO2 présentant une porosité bimodale macro-mésoporeux interconnectée, avec une stabilité mécanique et chimique élevée, ont été utilisés comme un microréacteur photocatalytique sous flux sous différentes conditions de flux. Les monolithes synthétisés ont montré une absorption plus élevée dans la lumière du visible, ce qui leur permet d’être efficaces dans une plus grande gamme de rayonnements. L’absorption dans le visible des monolithes de TiO2 est attribuée aux espèces carbonées et/ou azotées contenues dans le matériau. Ces matériaux on été testes dans la dégradation de l’orange G en milieu aqueux. Ce suivi a été réalisé à la fois en réacteur en batch et en flux, à la lumière du soleil, sous lumière du visible et sous lumière UV. Tous les tests catalytiques ont conduit à une dégradation totale du polluant avec une cinétique plus rapide que pour le matériau de référence (TiO2 P25) sous rayonnement visible. De plus aucune désactivation n’est détectée après 85 h sous circulation de la solution dans les conditions du flux opératoire. L’autre utilisation envisagée pour ces monolithes est le water-splitting (dissociation de l’eau en hydrogène et oxygène). Pour cela des films autoportés (~ 1 mm d’épaisseur) de compositions similaires aux précédents matériaux ont été synthétisés afin de permettre une activité photo-catalytique de dissociation de l’eau sous lumière visible. Afin d’augmenter la production d’hydrogène, des matériaux associant une couche d’oxyde de cuivre et une couche de TiO2 ont été réalisés par l’optimisation de la méthode précédente. / The aim of this study is to develop titania based materials able to perform photocatalytic reaction in flow condition, under sunlight or visible light, with special physical and chemical properties in order to overcome common photocatalysts’ deficiencies like: mechanical stability, pressure drop, low mass transfer and contact time, reduced wavelength range absorption, photo-generated charge lifetime, and in general all features that limit photocatalysts efficiencies. Three synthesis methods have been developed and optimized to obtain TiO2 monoliths with shape and dimension that can be adapted to any specific application. TiO2 monoliths, displaying bimodal macro-mesoporous interconnected network together with an elevated mechanical and chemical stability, have been used as flow photocatalyst microreactor under different flow rate conditions. Synthesized monoliths displayed enhanced visible light absorption, enabling them to efficiently operate in a vast range of illumination. TiO2 monoliths absorption on the visible range of the spectrum is attributed to carbon-nitrogen containing species within the material. Orange G degradation in aqueous medium have been performed both in batch and flow reactors under sunlight, visible light and UV light. All reactions resulted in complete mineralization of pollutant, with higher degradation rate than TiO2 nanoparticles benchmark material (P-25) when visible light is used. No photocatalyst deactivation have been detected after 85 hours of wastewater treatment in flow conditions. Similar TiO2 material, with a free-standing thick-film shape, have been used to perform photocatalytic water splitting under visible light. Another strategy has been developed to synthesize a TiO2/CuO self-standing film to enhance charge separation giving unexpected results in terms of hydrogen production.