Marian Vermeulen - Academia.edu (original) (raw)

Papers by Marian Vermeulen

Academic Emergency Medicine, Jun 1, 2004

Epidemiology, Apr 1, 2002

... Am J Clin Nutr 1999; 70: 234-239. ... 5. Wilson A, Platt R, Wu Q, et al. A common variant in ... more ... Am J Clin Nutr 1999; 70: 234-239. ... 5. Wilson A, Platt R, Wu Q, et al. A common variant in methionine synthase reductase combined with low cobalamin (vitamin B12) increases risk for spina bifida. Mol Genet Metab 1999; 67: 317-323. ... 6. Ray JG, Cole DE, Boss SC. ...

Qjm Monthly Journal of the Association of Physicians, Jul 1, 2001

Canadian Family Physician Medecin De Famille Canadien, Sep 1, 2007

Epidemiology, 2005

Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Ep... more Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Epidemiology. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but is committed ...

Open Medicine, 2011

BackgroundPractice pattern variations are often attributed to physician decision-making with no a... more BackgroundPractice pattern variations are often attributed to physician decision-making with no accounting for patient preferences.ObjectiveTo test whether a mass media television broadcast unrelated to health was associated with changes in the rate and characteristics of visits for acute emergency care.DesignTime-series analysis of emergency department visits for any reason.SubjectsPopulation-based sample of all patients seeking emergency care in Ontario, Canada.MeasuresThe broadcast day was defined as the Olympic men’s gold medal ice hockey game final. The control days were defined as the 6 Sundays before and after the broadcast day.ResultsA total of 99 447 visits occurred over the 7 Sundays, of which 13 990 occurred on the broadcast day. Comparing the broadcast day with control days, we found no significant difference in the hourly rate of visits before the broadcast (544 vs 537, p = 0.41) or after the broadcast (647 vs 639, p = 0.55). In contrast, we observed a significant reduction in hourly rate of visits during the broadcast (647 vs 783, p < 0.001), equal to an absolute decrease of 409 patients, a relative decrease of 17% (95% confidence interval 13–21), or about 136 fewer patients per hour. The relative decrease during the broadcast was particularly large for adult men with low triage severity. The greatest reductions were for patients with abdominal, musculoskeletal or traumatic disorders.ConclusionMass media television broadcasts can influence patient preferences and thereby lead to a decrease in emergency department visits.

Journal of Obstetrics and Gynaecology Canada Jogc Journal D Obstetrique Et Gynecologie Du Canada Jogc, Dec 1, 2005

Placental dysfunction (PD), which may manifest partly as the hypertensive disorders of pregnancy ... more Placental dysfunction (PD), which may manifest partly as the hypertensive disorders of pregnancy and abruption or infarction of the placenta, occurs more commonly in women with obesity, chronic hypertension, diabetes mellitus, and dyslipidemia-each a major feature of the metabolic syndrome. However, the relationship between the metabolic syndrome and the future risk of PD or fetal demise is unknown. We completed a retrospective cohort study of 1.03 million women who had a first documented delivery in the province of Ontario between 1990 and 2002. Using linked administrative databases, we categorized women as having zero, one, two, or three to four features of the metabolic syndrome up to 24 months before their index delivery hospitalization. Women were considered to have placental dysfunction if they had a diagnosis of preeclampsia, gestational hypertension, placental abruption, or placental infarction during their first hospitalization for delivery in the period of study. At the time of delivery, 75 380 women (7.3%) were diagnosed as having PD. There was a progressive increase in the risk of PD in women with one (adjusted odds ratio [OR] 3.1; 95% confidence interval [CI] 3.0-3.1), two (OR 5.5; 95% CI 5.2-5.8), or three to four (OR 7.7; 95% CI 6.7-8.9) features of the metabolic syndrome, compared with none. A similar gradient effect was seen for the combined outcome of PD with poor fetal growth, or of PD with concomitant fetal death. Women who exhibit features of the metabolic syndrome before pregnancy have a higher graded risk of PD and fetal demise. Studies are needed to determine whether modifying a woman&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s metabolic profile before pregnancy, through modest caloric restriction and increased physical activity, can lower her future risk of PD.

Journal of Obstetrics and Gynaecology Canada Jogc Journal D Obstetrique Et Gynecologie Du Canada Jogc, Dec 1, 2008

Canadian journal of public health. Revue canadienne de santé publique

Adolescence

Although the effect of low socioeconomic status on the health of adolescents has been documented,... more Although the effect of low socioeconomic status on the health of adolescents has been documented, the mechanism by which this occurs is not well understood. Furthermore, improving adolescent health through public health policy typically requires the presence of one or more modifiable risk factors which can be targeted for intervention. In spite of the well-documented negative associations between poverty and health, few modifiable risk factors have been identified. This study used the Evans-Stoddart Model of Health and Well-Being as a framework to examine data on 1,759 adolescents, aged 12 to 19, collected as part of the 1994 National Population Health Survey. Results not only confirm the relationship between income and health, but suggest how the pathway operates through the social environment, lifestyle differences, access to health care, and a reduced sense of self-esteem and self-mastery. Bivariate and multivariate analyses found positive associations between physical activity levels and self-esteem and mastery. We interpret these findings as preliminary evidence that it might be possible to buffer the impact of poverty on health through policies which increase physical activity levels among those living in poverty. Such policies could also include a secondary goal of increasing the activity levels among inactive adolescents who are not living in poverty, as they will derive benefits from this increase, both psychologically and physiologically.

Canadian family physician Médecin de famille canadien

To review the importance of and practical application of sample size determination for clinical s... more To review the importance of and practical application of sample size determination for clinical studies in the primary care setting. A MEDLINE search was performed from January 1966 to January 1998 using the MeSH headings and text words &amp;amp;amp;quot;sample size,&amp;amp;amp;quot; &amp;amp;amp;quot;sample estimation,&amp;amp;amp;quot; and &amp;amp;amp;quot;study design.&amp;amp;amp;quot; Article references, medical statistics texts, and university colleagues were also consulted for recommended resources. Citations that offered a clear and simple approach to sample size estimation were accepted, specifically those related to statistical analyses commonly applied in primary care research. The chance of committing an alpha statistical error, or finding that there is a difference between two groups when there really is none, is usually set at 5%. The probability of finding no difference between two groups, when, in actuality, there is a difference, is commonly accepted at 20%, and is called the beta error. The power of a study, usually set at 80% (i.e., 1 minus beta), defines the probability that a true difference will be observed between two groups. Using these parameters, we provide examples for estimating the required sample size for comparing two means (t test), comparing event rates between two groups, calculating an odds ratio or a correlation coefficient, or performing a meta-analysis. Estimation of sample size needed before initiation of a study enables statistical power to be maximized and bias minimized, increasing the validity of the study. Sample size estimation can be done by any novice researcher who wishes to maximize the quality of his or her study.

Canadian Journal of Emergency Medicine

Canadian Medical Association Journal

Emergency department overcrowding sometimes results in diversion of ambulances to other locations... more Emergency department overcrowding sometimes results in diversion of ambulances to other locations. We sought to determine the resulting prehospital delays for cardiac patients. Data on consecutive patients with chest pain who were transported to Toronto hospitals by ambulance were obtained for a 4-month period in 1997 and a 4-month period in 1999, which represented periods of low and high emergency department overcrowding respectively. Multivariate analyses were used to model 90th percentile system response (initiation of 9-1-1 call to arrival on scene), on-scene (arrival on scene to departure from scene) and transport (departure from scene to arrival at hospital) intervals. Predictor variables were study period (1997 or 1999), day of the week, time of day, geographic location of the patient, dispatch priority, case severity, return priority and number of other patients with chest pain transported within 2 hours of the index transport. A total of 3609 patients (mean age 66.3 years, 50.3% female) who met the study criteria were transported by ambulance during the 2 study periods. There were no significant differences in patient characteristics between the 2 periods, despite the fact that more patients were transported during the second period (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). The 90th percentile system response interval increased by 11.3% from the first to the second period (9.7 v. 10.8 min, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), whereas the on-scene interval decreased by 8.2% (28.0 v. 25.7 min, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). The longest delay was in the transport interval, which increased by 28.4% from 1997 to 1999 (13.4 v. 17.2 min, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). In multivariate analyses, the study period (1997 v. 1999) remained a significant predictor of longer transport interval (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) and total prehospital interval (p = 0.004). An increase in overcrowding in emergency departments was associated with a substantial increase in the system response interval and the ambulance transport interval for patients with chest pain.

American journal of obstetrics and gynecology, Jan 14, 2015

Middle aged women are at higher risk than men of death following coronary artery revascularizatio... more Middle aged women are at higher risk than men of death following coronary artery revascularization. Maternal placental syndromes (MPS) - gestational hypertension, preeclampsia, placental abruption and placental infarction - are associated with premature coronary artery disease, but their influence on survival following coronary artery revascularization is unknown. To determine whether a history of MPS alters the risk of death following coronary artery revascularization in middle aged women. We completed a population-based retrospective cohort study among all hospitals in Ontario, Canada, where universal healthcare includes all aspects of antenatal and delivery care, as well as all outpatient and inpatient healthcare, including coronary revascularization. We included 1985 middle aged women who underwent a first percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) between 1993 and 2012, and who had ≥ 1 prior delivery. We excluded those with cardiovascular...

BMJ quality & safety, Jan 13, 2015

We sought to determine whether patients seen in hospitals who had reduced overall emergency depar... more We sought to determine whether patients seen in hospitals who had reduced overall emergency department (ED) length of stay (LOS) in the 2 years following the introduction of the Ontario Emergency Room Wait Time Strategy were more likely to experience improvements in other measures of ED quality of care for three important conditions. Retrospective medical record review using difference-in-differences analysis to compare changes in performance on quality indicators over the 3-year period between 11 Ontario hospitals where the median ED LOS had improved from fiscal year 2008 to 2010 and 13 matched sites where ED LOS was unchanged or worsened. Patients with acute myocardial infarction (AMI), asthma and paediatric and adult upper limb fractures in these hospitals in 2008 and 2010 were evaluated with respect to 18 quality indicators reflecting timeliness and safety/effectiveness of care in the ED. In a secondary analysis, we examined shift-level ED crowding at the time of the patient vis...