Browsing by Author "Eliasziw, Misha"

Now showing 1 - 12 of 12
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    The Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study: rationale and methods
    (Maternal & Child Nutrition, 2014-01) Kaplan, Bonnie; Giesbrecht, Gerald; Leung, Brenda; Field, Catherine; Dewey, Deborah; Bell, Rhonda; Manca, Donna; O'Beirne, Maeve; Johnston, David; Pop, Victor; Singhal, Nalini; Gagnon, Lisa; Bernier, Francois; Eliasziw, Misha; McCargar, Linda; Kooistra, Libbe; Farmer, Anna; Cantell, Marja; Goonewardene, Laki; Casey, Linda; Letourneau, Nicole; Martin, Jonathan; APrON Study Team
    The Alberta Pregnancy Outcomes and Nutrition (APrON) study is an ongoing prospective cohort study that recruits pregnant women early in pregnancy and, as of 2012, is following up their infants to 3 years of age. It has currently enrolled approximately 5000 Canadians (2000 pregnant women, their offspring and many of their partners).The primary aims of the APrON study were to determine the relationships between maternal nutrient intake and status, before, during and after gestation, and (1) maternal mood; (2) birth and obstetric outcomes; and (3) infant neurodevelopment. We have collected comprehensive maternal nutrition, anthropometric, biological and mental health data at multiple points in the pregnancy and the post-partum period, as well as obstetrical, birth, health and neurodevelopmental outcomes of these pregnancies. The study continues to follow the infants through to 36 months of age.The current report describes the study design and methods, and findings of some pilot work. The APrON study is a significant resource with opportunities for collaboration.
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    Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill’s epidemiologic criteria for causality
    (BioMed Central, 2011-04-30) Fenton, Tanis R.; Tough, Suzanne C.; Lyon, Andrew W.; Eliasziw, Misha; Hanley, David A.
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    Final 2 year results of the vascular imaging of acute stroke for identifying predictors of clinical outcome and recurrent ischemic eveNts (VISION) study
    (BioMed Central, 2011-04-23) Coutts, Shelagh B.; Hill, Michael D.; Eliasziw, Misha; Fischer, Karyn; Demchuk, Andrew M.
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    Log-Binomial Models: Maximum Likelihood and Failed Convergence
    (2011) Williamson, Tyler Scott; Eliasziw, Misha; Fick, Gordon H.
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    Low urine pH and acid excretion do not predict bone fractures or the loss of bone mineral density: a prospective cohort study
    (BioMed Central, 2010-05-10) Fenton, Tanis R.; Eliasziw, Misha; Tough, Suzanne C.; Lyon, Andrew W.; Brown, Jacques P.; Hanley, David A.
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    Measuring Observer Agreement on Categorical Data
    (2015-04-23) Soo, Andrea; Eliasziw, Misha; Fick, Gordon
    In order for a patient to receive proper and appropriate health care, one requires error-free assessment of clinical measurements. For example, a diagnostic test that assesses whether an individual will be classified as having the disease or not having the disease needs to produce accurate and reliable results in order to ensure that an individual who needs treatment receives the correct therapy. Agreement and reliability studies aim to evaluate the accuracy and consistency of diagnostic tests or measurement tools. A model developed by Shoukri and Donner allows for the concurrent assessment of inter-rater (between rater) agreement and intra-rater (within rater) reliability, by incorporating two measurements per rater per subject. The main purpose of this research was to develop methods for the maximum likelihood (ML) approach using the Shoukri-Donner model and compare those methods to the method of moments (MM) approach using Monte Carlo computer simulation studies. Little differences between ML and MM were observed in point estimation. In general, the MM Wald test and MM confidence interval (CI) performed better than any of the other methods. In fact, the goodness of fit (GOF) test and GOF CI (for both ML and MM) were shown to have high empirical type I errors and low coverage levels, respectively, for the inter-rater agreement parameter in some parameter combinations for the 3 parameter case and all considered parameter combinations in the 4 parameter case. Further investigation as to why there is poor performance with the GOF approach needs to be done before one could recommend this approach as a better alternative to the MM approach. Also, it does not appear that the ML approach is necessarily better than the MM approach. Lastly, extending this research to a more general 5 parameter model requires the resolution of several issues before it can be evaluated in point estimation, hypothesis testing, and CI construction.
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    Morphologic complexity of epithelial architecture for predicting invasive breast cancer survival
    (BioMed Central, 2010-11-31) Tambasco, Mauro; Eliasziw, Misha; Magliocco, Anthony M.
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    Operationalizing frailty among older residents of assisted living facilities
    (BioMed Central, 2011-05-13) Freiheit, Elizabeth A.; Hogan, David B.; Strain, Laurel A.; Schmaltz, Heidi N.; Patten, Scott B.; Eliasziw, Misha; Maxwell, Colleen J.
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    Predicting the demand of physician workforce: an international model based on "crowd behaviors"
    (BioMed Central, 2012-03-26) Tsai, Tsuen-Chiuan; Eliasziw, Misha; Chen, Der-Fang
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    Studying cerebral hemodynamics and metabolism using simultaneous near-infrared spectroscopy and transcranial Doppler ultrasound: a hyperventilation and caffeine study
    (Wiley-Blackwell on behalf of The Physiological Society and the American Physiological Society, 2015-03-25) Yang, Runze; Brugniaux, Julien; Dhaliwal, Harinder; Beaudin, Andrew; Eliasziw, Misha; Poulin, Marc; Dunn, Jeff F.
    Caffeine is one of the most widely consumed psycho-stimulants in the world, yet little is known about its effects on brain oxygenation and metabolism. Using a double-blind, placebo-controlled, randomized cross-over study design, we combined transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS) to study caffeine's effect on middle cerebral artery peak blood flow velocity (Vp), brain tissue oxygenation (StO2), total hemoglobin (tHb), and cerebral oxygen metabolism (CMRO2) in five subjects. Hyperventilation-induced hypocapnia served as a control to verify the sensitivity of our measurements. During hypocapnia (~16 mmHg below resting values), Vp decreased by 40.0 ± 2.4% (95% CI, P < 0.001), while StO2 and tHb decreased by 2.9 ± 0.3% and 2.6 ± 0.4%, respectively (P = 0.003 and P = 0.002, respectively). CMRO2, calculated using the Fick equation, was reduced by 29.3 ± 9% compared to the isocapnic-euoxia baseline (P < 0.001). In the pharmacological experiments, there was a significant decrease in Vp, StO2, and tHb after ingestion of 200 mg of caffeine compared with placebo. There was no significant difference in CMRO2 between caffeine and placebo. Both showed a CMRO2 decline compared to baseline showing the importance of a placebo control. In conclusion, this study showed that profound hypocapnia impairs cerebral oxidative metabolism. We provide new insight into the effects of caffeine on cerebral hemodynamics. Moreover, this study showed that multimodal NIRS/TCD is an excellent tool for studying brain hemodynamic responses to pharmacological interventions and physiological challenges.
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    Validating the weight gain of preterm infants between the reference growth curve of the fetus and the term infant
    (BioMed Central, 2013-06-11) Fenton, Tanis R; Nasser, Roseann; Eliasziw, Misha; Kim, Jae H; Bilan, Denise; Sauve, Reg
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    Vitamin D during Pregnancy
    (2016) Aghajafari, Fariba; Ross, Susan; O'Beirne, Maeve; Field, Catherine; Eliasziw, Misha; Dewey, Deborah
    Vitamin D plays an important role in promoting healthy pregnancy and fetal development. There is a lack of knowledge on (1) the effect of vitamin D deficiency/ insufficiency on pregnancy and neonatal outcomes, (2) the association between maternal plasma vitamin D concentration and dietary intake, and (3) the prevalence of vitamin D deficiency/ insufficiency during pregnancy and the contribution of vitamin D metabolites to estimate vitamin D. This dissertation attempts to address these knowledge gaps about vitamin D during pregnancy. In a systematic review and meta-analysis of observational studies, low maternal 25(OH)D concentrations were found to be associated with higher risks of gestational diabetes (pooled OR 1.49, 95% CI: 1.18 to 1.89), preeclampsia (pooled OR 1.79, 95% CI: 1.25 to 2.58), small for gestational age (SGA) (pooled OR 1.85, 95% CI: 1.52 to 2.26) and lower birth weight (weighted mean difference: -130.92 g (95% CI: -186.69 to -75.14). However, that quality of individual studies was not always optimal due to inconsistent reporting on confounding factors. The two studies in this work involved pregnant women from a large Alberta cohort study to measure vitamin D. 3-epi-25(OH)D3 was found in all of the pregnant women’s blood in mid-pregnancy, at the time of delivery and in cord blood. When the 3-epimer was included in the estimation of status, the prevalence of vitamin D <75 nmol/L was significantly lower (P<0.005). A significant relationship between maternal reported dietary vitamin D intake and plasma 25(OH)D and 3-epi-25(OH)D3 concentration were identified. Consuming the Recommended Dietary Allowance (RDA) (600 IU/ day) was found to be insufficient to achieve vitamin D <75 nmol/L in half of participants. This research highlighted the potentially important association between maternal vitamin D status and pregnancy health and the variability that can arise in study results when different measures of vitamin D status are used. In addition, it extends the literature suggesting that current RDA may not be adequate to ensure that Canadian pregnant women achieving vitamin D status. Furthermore, this research showed that the method employed to measure vitamin D in pregnant women and cord blood can influence the estimates of status.