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Tuite A.R.,Research Institute of the Hospital for Sick Children | Greer A.L.,Research Institute of the Hospital for Sick Children | Whelan M.,Public Health Protection and Prevention Branch | Winter A.-L.,Public Health Protection and Prevention Branch | And 7 more authors.
CMAJ | Year: 2010

Background: In the face of an influenza pandemic, accurate estimates of epidemiologic parameters are required to help guide decision-making. We sought to estimate epidemiologic parameters for pandemic H1N1 influenza using data from initial reports of laboratory-confirmed cases. Methods: We obtained data on laboratory-confirmed cases of pandemic H1N1 influenza reported in the prov ince of Ontario, Canada, with dates of symptom onset between Apr. 13 and June 20, 2009. Incubation periods and duration of symptoms were estimated and fit to parametric distributions. We used competing-risk models to estimate risk of hospital admission and case-fatality rates. We used a Markov Chain Monte Carlo model to simulate disease transmission. Results: The median incubation period was 4 days and the duration of symptoms was 7 days. Recovery was faster among patients less than 18 years old than among older patients (hazard ratio 1.23, 95% confidence interval 1.06-1.44). The risk of hospital admission was 4.5% (95% CI 3.8%-5.2%) and the case-fatality rate was 0.3% (95% CI 0.1%-0.5%). The risk of hospital admission was highest among patients less than 1 year old and those 65 years or older. Adults more than 50 years old comprised 7% of cases but accounted for 7 of 10 initial deaths (odds ratio 28.6, 95% confidence interval 7.3-111.2). From the simulation models, we estimated the following values (and 95% credible intervals): a mean basic reproductive number (R0, the number of new cases created by a single primary case in a susceptible population) of 1.31 (1.25-1.38), a mean latent period of 2.62 (2.28-3.12) days and a mean duration of infectiousness of 3.38 (2.06-4.69) days. From these values we estimated a serial interval (the average time from onset of infectiousness in a case to the onset of infectiousness in a person infected by that case) of 4-5 days. Interpretation: The low estimates for R0 indicate that effective mitigation strategies may reduce the final epidemic impact of pandemic H1N1 influenza. © 2010 Canadian Medical Association or its licensors. Source


Gray S.A.,University of Toronto | Rogers M.,University of Ottawa | Martinussen R.,University of Toronto | Tannock R.,University of Toronto | Tannock R.,Research Institute of the Hospital for Sick Children
PeerJ | Year: 2015

Introduction: Behavioral inattention, working memory (WM), and academic achievement share significant variance, but the direction of relationships across development is unknown. The aim of the present study was to determine whether WMmediates the pathway between inattentive behaviour and subsequent academic outcomes. Methods: 204 students from grades 1-4 (49.5% female) were recruited from elementary schools. Participants received assessments of WM and achievement at baseline and one year later.WMmeasures included a visual-spatial storage task and auditory-verbal storage and manipulation tasks. Teachers completed the SWAN behaviour rating scale both years.Mediation analysis with PROCESS (Hayes, 2013) was used to determine mediation pathways. Results: Teacher-rated inattention indirectly influenced math addition fluency, subtraction fluency and calculation scores through its effect on visual-spatial WM, only for boys. There was a direct relationship between inattention and math outcomes one year later for girls and boys. Children who displayed better attention had higherWMscores, and children with higherWMscores had stronger scores on math outcomes. Bias-corrected bootstrap confidence intervals for the indirect effects were entirely below zero for boys, for the three math outcomes.WMdid not mediate the direct relationship between inattention and reading scores. Discussion: Findings identify inattention and WM as longitudinal predictors for math addition and subtraction fluency and math calculation outcomes one year later, with visual-spatialWMas a significant mediator for boys. Results highlight the close relationship between inattention andWMand their importance in the development of math skills. © 2015 Gray et al. Source


Hamidi M.,A+ Network | Hamidi M.,University of Toronto | Boucher B.A.,Prevention and Cancer Control | Boucher B.A.,University of Toronto | And 6 more authors.
Osteoporosis International | Year: 2011

Summary: High fruit and vegetable intake may be associated with improved bone status among women aged ≥45 years. This is the first systematic review that specifically assessed this association and identified research gaps. The benefits of fruit and vegetables (F&V) on bone health remain unclear. Further studies are needed. Introduction: F&V have several components that are beneficial to bones. Some studies report that high F&V intake is associated with improved bone status in middle aged and aged women; however, findings are inconsistent. The objective was to systematically review observational and interventional studies that investigated the effects of F&V intake on incidence of osteoporotic fractures, bone mineral density (BMD), and bone turnover markers (BTM) in women aged ≥45 years and to identify potential research gaps. Methods: Electronic databases were searched, and peerreviewed manuscripts published in English, with F&V intake as a main dietary exposure, were included. Data selection, extraction, and evaluation of risk of bias were performed independently by two reviewers. Results: Eight studies were included. One cohort study reported cross-sectional as well as longitudinal data. There was significant between-study heterogeneity in design, definition, and amount of F&V intake, outcomes, analyses, and reporting of results. Two studies had low, two had moderate, and four had high risk of bias. Among reports with low or moderate risk of bias, two cross-sectional analyses reported positive associations between F&V intake and BMD of the forearm, lumbar spine, or total hip, whereas one randomized controlled trial and two prospective cohort analyses reported no effects. One trial reported no associations between F&V and BTM. Conclusions: Based on limited evidence, the benefits of F&V on bone health remain unclear for women aged ≥45 years. Further studies with low risk of bias are needed. © International Osteoporosis Foundation and National Osteoporosis Foundation 2010. Source


Choufani S.,Research Institute of the Hospital for Sick Children | Shuman C.,University of Toronto | Weksberg R.,University of Toronto
American Journal of Medical Genetics, Part C: Seminars in Medical Genetics | Year: 2013

Our understanding of Beckwith-Wiedemann syndrome (BWS) has recently been enhanced by advances in its molecular characterization. These advances have further delineated intricate (epi)genetic regulation of the imprinted gene cluster on chromosome 11p15.5 and the role of these genes in normal growth and development. Studies of the molecular changes associated with the BWS phenotype have been instrumental in elucidating critical molecular elements in this imprinted region. This review will provide updated information on the multiple new regulatory elements that have been recently found to contribute to in cis or in trans control of imprinted gene expression in the chromosome 11p15.5 region and the clinical expression of the BWS phenotype. © 2013 Wiley Periodicals, Inc. Source


McCabe C.J.,Research Institute of the Hospital for Sick Children | Goldie S.J.,Harvard University | Fisman D.N.,Research Institute of the Hospital for Sick Children | Fisman D.N.,University of Toronto
PLoS ONE | Year: 2010

Background: In HIV-infected pregnant women, viral suppression prevents mother-to-child HIV transmission. Directly observed highly-active antiretroviral therapy (HAART) enhances virological suppression, and could prevent transmission. Our objective was to project the effectiveness and cost-effectiveness of directly observed administration of antiretroviral drugs in pregnancy. Methods and Findings: A mathematical model was created to simulate cohorts of one million asymptomatic HIV-infected pregnant women on HAART, with women randomly assigned self-administered or directly observed antiretroviral therapy (DOT), or no HAART, in a series of Monte Carlo simulations. Our primary outcome was the quality-adjusted life expectancy in years (QALY) of infants born to HIV-infected women, with the rates of Caesarean section and HIV-transmission after DOT use as intermediate outcomes. Both self-administered HAART and DOT were associated with decreased costs and increased lifeexpectancy relative to no HAART. The use of DOT was associated with a relative risk of HIV transmission of 0.39 relative to conventional HAART; was highly cost-effective in the cohort as a whole (cost-utility ratio $14,233 per QALY); and was costsaving in women whose viral loads on self-administered HAART would have exceeded 1000 copies/ml. Results were stable in wide-ranging sensitivity analyses, with directly observed therapy cost-saving or highly cost-effective in almost all cases. Conclusions: Based on the best available data, programs that optimize adherence to HAART through direct observation in pregnancy have the potential to diminish mother-to-child HIV transmission in a highly cost-effective manner. Targeted use of DOT in pregnant women with high viral loads, who could otherwise receive self-administered HAART would be a costsaving intervention. These projections should be tested with randomized clinical trials. © 2010 McCabe et al. Source

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