Objective: Acute lower respiratory infection (ALRI) is the leading cause of mortality in pediatric group all around the world. Vitamin D has been demonstrated to play a possible role in the prevention of ALRI in children because of its physiological importance in the immune system. This systematic review aims to explore the protective role of vitamin D on ALRIs among children and its preventive effectiveness by synthesizing RCTs. And the other objective is to determine dosage of vitamin D with the best effect by investigating the association of different level of vitamin D supplementation with risk of ALRIs. Methods: Studies were searched through three databases PubMed, ISI Web of Knowledge and Cochran Central Register of Controlled Trials and Cochran Library databases among publication from April2003 to April 2013 with a combination of key terms. Inclusion and exclusion criteria were used to select studies. And then CONSORT guideline and JADAD scale were used to assess quality of these studies. Data on outcome measurements including health outcomes (e.g. incidence of pneumonia and influenza A, duration of recovery of pneumonia and bronchiolitis, the risk of relapse of pneumonia, the number of parent-reported ARIs); and surrogate outcomes (e.g. measuring scores of ATAQ test) were extracted and tabulated. The association with vitamin D level of risk of ALRIs were explored as well. Results: Eight RCTs were found to be relevant and adopted in this systematic review of the 796 identified articles in English or Chinese. The findings were mixed, but most studies suggested vitamin D supplementation reduced risk or illness duration of ALRIs significantly among children with different levels of vitamin D deficiency. Four studies suggested statistically significant risk reduction on incidence of repeat pneumonia (by29%, 95%CI 6% to 46%), parent-reported ARIs (by 48%, 95%CI 11% to 69), influenza A (by 42%, 95%CI 1% to 66%), and asthma exacerbation triggered by ALRIs (P= 0.029), while one study showed an insignificant outcome. For recovery events and hospitalization of ALRIs, three studies suggested statistically significant reduction on recovery time from pneumonia (P= 0.008), severe asthma (P= 0.004) and bronchiolitis (P< 0.05), and two studies suggested significant decrease on duration of hospitalization for bronchiolitis (P< 0.05) and pneumonia (P= 0.005). The increasing changes in serum 25(OH)D were consistent with the significant difference of ALRIs events between intervention and control groups. Conclusion: Overall, the evidence is insufficient to conclude that vitamin D supplementation is beneficial to all kinds of children in preventing or assistant treating ALRIs. More number of high quality, large scale and unbiased RCTs should be conducted to confirm the effectiveness of vitamin D among children in Hong Kong and different areas in mainland China. / published_or_final_version / Public Health / Master / Master of Public Health

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The Proopiomelanocortin gene, (POMC), produces many biologically active peptides including the endogenous opioid, &beta;-endorphin, and the melanocortins: &alpha;-Melanocyte Stimulating Hormone, (&alpha;MSH), &gamma;MSH, &beta;MSH and Adrenocorticotropic Hormone, (ACTH). &beta;endorphin is released by the brain in response to stress or injury and is a potent analgesic. Melanocortins are well known for regulating pigmentation, metabolism, and cortisol levels. Additionally, opioids and melanocortins are known to have opposing actions in several settings including the regulation of pain and metabolism. The Melanocyte Stimulating Hormones are expressed in the skin where they bind the Melanocortin 1 Receptor on melanocytes and promote pigmentation. It has been reported that &beta;-endorphin is also produced in the skin, however it was not believed to have a central effect. In this thesis I show that expression of these peptides in the skin is reflected in blood levels and affects nociception and behavior.

Research has identified a linear relationship between saturated fat intake and colon cancer, and has demonstrated that high fat diets enhance tumorigenesis through elevation of secondary bile acids such as deoxycholic acid (DCA). We and others have shown that DCA can manipulate cell adhesion by decreasing expression of E-cadherin and increasing expression of beta-catenin. We have also shown that DCA significantly reduces EphB2 expression, which regulates cell positioning and segregation. Importantly, vitamin D can reinstate membranous E-cadherin/beta-catenin interactions and increase E-cadherin expression. In the present study, we sought to analyze the effects of DCA and vitamin D (cholecalciferol) treatment on EphB2 in colorectal cancer cells. Pre-treatment with cholecalciferol restored EphB2 expression in a dose-dependent manner, even with combined DCA treatment. This observation may be EGFR-dependent, suggesting that cholecalciferol may antagonize the effects of DCA. Taken together, these results suggest that cholecalciferol may represent an adjuvant therapy for colorectal cancer patients.

Background: Vitamin D may be important in the causal pathway to breast cancer (BC) by influencing mammographic breast density (MD). However, previous study results in postmenopausal women are inconsistent. Study objectives were to prospectively examine the relationship between biomarkers of vitamin D (25-OH-D) and percent MD in postmenopausal women at northern latitudes. Potential effect modification by exemestane therapy, calcium or genetic polymorphisms in the vitamin D pathway was also examined. Methods: This study evaluated a sub-cohort of postmenopausal women at elevated BC risk who participated in the NCIC Clinical Trials Group placebo-controlled MAP.3 trial with exemestane. Levels of 25-OH-D were measured using LC-MS/MS from serum samples collected at baseline and year 1, averaged and adjusted for month of collection. Baseline and follow-up (≥ 3 year) percent MD was centrally assessed from film and digital mammograms with Cumulus software. Multivariable linear regression was used to estimate the effect of 25-OH-D on log transformed percent MD at follow-up and on the change in percent MD from baseline. Percent MD was also dichotomized and multivariable logistic regression was used to evaluate 25-OH-D levels between 1) women with lower (<25%) compared with higher (≥25%) percent MD and 2) women with a decrease compared with no change or an increase in percent MD over time. Results: Percent MD was measured for 568 participants with a follow-up mammogram and for 388 participants with a baseline mammogram in the same format as the follow-up. The geometric mean percent MD of the follow-up mammograms was 4.3% and few women (13.4%) had percent MD ≥ 25%. The unadjusted mean 25-OH-D concentration was 36.5 ng/mL (SD=10.6) based on pooled baseline and year one samples. After controlling for age, month of sampling and potential confounders, 25-OH-D was not predictive of log transformed percent MD at follow-up (p=0.36) or with annual mean changes from baseline (p=0.33). Similarly, results from the logistic regression analyses were not statistically significant and no interactions with exemestane, calcium or genetic polymorphisms were detected. Conclusion: No association was observed between vitamin D levels and percent MD at ≥3 year follow-up or change in percent MD from baseline. / Thesis (Ph.D, Community Health & Epidemiology) -- Queen's University, 2014-03-31 11:20:23.963

We determined whether children older than 1 year from non-western immigrant families had lower serum 25-hydroxyvitamin D levels than children from western born families. Children ages 1-6 years were recruited through the TARGet Kids! practice based research network. Univariable analysis revealed that non-western immigrant children had 4 nmol/L lower 25-hydroxyvitamin D (p=0.006; 95% CI:1.4-8.0) and increased odds of 25-hydroxyvitamin D <50 nmol/L (OR 1.9, 95% CI:1.3–2.9). After adjustment for known vitamin D determinants, cow’s milk intake, vitamin D supplements, season and age were significant covariates and current vitamin D supplementation had the strongest confounding effect. In order to use the ethnicity variable, we developed a new standardized geographically based closed-ended ethnicity question, which was a practical alternative to the widely used open-ended ethnicity questions. There was an association between non-western immigration and lower 25-hydroxyvitamin D in early childhood and this appears primarily related to known vitamin D determinants.

We determined whether children older than 1 year from non-western immigrant families had lower serum 25-hydroxyvitamin D levels than children from western born families. Children ages 1-6 years were recruited through the TARGet Kids! practice based research network. Univariable analysis revealed that non-western immigrant children had 4 nmol/L lower 25-hydroxyvitamin D (p=0.006; 95% CI:1.4-8.0) and increased odds of 25-hydroxyvitamin D <50 nmol/L (OR 1.9, 95% CI:1.3–2.9). After adjustment for known vitamin D determinants, cow’s milk intake, vitamin D supplements, season and age were significant covariates and current vitamin D supplementation had the strongest confounding effect. In order to use the ethnicity variable, we developed a new standardized geographically based closed-ended ethnicity question, which was a practical alternative to the widely used open-ended ethnicity questions. There was an association between non-western immigration and lower 25-hydroxyvitamin D in early childhood and this appears primarily related to known vitamin D determinants.

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Objective: This thesis aims to construct a framework for studying vitamin D deficiency in young Canadian children. Methods: A practice based research network was created to collect vitamin D data from children 1-5 years of age in Toronto, Canada (TARGet Kids!). A cross-sectional pilot study was completed and a larger study proposed to determine the prevalence and predictors of low vitamin D. Results: The prevalence of low vitamin D (<50nmol/L) in the pilot study was 32% (29/92, 95% CI: 22-42%). Using multivariable linear regression, lower vitamin D level was associated with lower milk volume, higher BMI and watching TV during snacks. A larger study involving 2400 children 1-5 years of age has been proposed. Interpretation: Pilot data has suggested that 30-80% of toddlers in this setting have low vitamin D. A study to clarify these findings and form the basis of a large longitudinal vitamin D cohort has been proposed.

Objective: This thesis aims to construct a framework for studying vitamin D deficiency in young Canadian children. Methods: A practice based research network was created to collect vitamin D data from children 1-5 years of age in Toronto, Canada (TARGet Kids!). A cross-sectional pilot study was completed and a larger study proposed to determine the prevalence and predictors of low vitamin D. Results: The prevalence of low vitamin D (<50nmol/L) in the pilot study was 32% (29/92, 95% CI: 22-42%). Using multivariable linear regression, lower vitamin D level was associated with lower milk volume, higher BMI and watching TV during snacks. A larger study involving 2400 children 1-5 years of age has been proposed. Interpretation: Pilot data has suggested that 30-80% of toddlers in this setting have low vitamin D. A study to clarify these findings and form the basis of a large longitudinal vitamin D cohort has been proposed.