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Who is in the Near Market for Bicycle Sharing? Identifying Current, Potential, and Unlikely Users of a Public Bicycle Share Program in Vancouver, Canada

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-11-29
Abstract: 

Background: Public bicycle share programs in many cities are used by a small segment of the population. To better understand the market for public bicycle share, this study examined the socio-demographic and transportation characteristics of current, potential, and unlikely users of a public bicycle share program and identified specific motivators and deterrents to public bicycle share use. 

Methods: We used cross-sectional data from a 2017 Vancouver public bicycle share (Mobi by Shaw Go) member survey (n = 1272) and a 2017 population-based survey of Vancouver residents (n = 792). We categorized non-users from the population survey as either potential or unlikely users based on their stated interest in using public bicycle share within the next year. We used descriptive statistics to compare the demographic and transportation characteristics of current users to non-users, and multiple logistic regression to compare the profiles of potential and unlikely users. 

Results: Public bicycle share users in Vancouver tended to be male, employed, and have higher educations and incomes as compared to non-users, and were more likely to use active modes of transportation. The vast majority of non-users (74%) thought the public bicycle share program was a good idea for Vancouver. Of the non-users, 23% were identified as potential users. Potential users tended to be younger, have lower incomes, and were more likely to use public transit for their main mode of transportation, as compared to current and unlikely users. The most common motivators among potential users related to health benefits, not owning a bicycle, and stations near their home or destination. The deterrents among unlikely users were a preference for riding their own bicycle, perceived inconvenience compared to other modes, bad weather, and traffic. Cost was a deterrent to one-fifth of unlikely users, notable given they tended to have lower incomes than current users. 

Conclusion: Findings can help inform targeted marketing and outreach to increase public bicycle share uptake in the population. 

Document type: 
Article
File(s): 

Maternal Obesity Alters Uterine NK Activity Through a Functional KIR2DL1/S1 Imbalance

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-03-13
Abstract: 

In pregnancy, uterine natural killer cells (uNK) play essential roles in coordinating uterine angiogenesis, blood vessel remodeling and promoting maternal tolerance to fetal tissue. Deviances from a normal uterine microenvironment are thought to modify uNK function(s) by limiting their ability to establish a healthy pregnancy. While maternal obesity has become a major health concern due to associations with adverse effects on fetal and maternal health, our understanding into how obesity contributes to poor pregnancy disorders is unknown. Given the importance of uNK in pregnancy, this study examines the impact of obesity on uNK function in women in early pregnancy. We identify that uNK from obese women show a greater propensity for cellular activation, but this difference does not translate into increased effector killing potential. Instead, uNK from obese women express an altered repertoire of natural killer receptors, including an imbalance in inhibitory KIR2DL1 and activating KIR2DS1 receptors that favors HLA-C2-directed uNK activation. Notably, we show that obesity-related KIR2DS1 skewing potentiates TNFα production upon receptor crosslinking. Together, these findings suggest that maternal obesity modifies uNK activity by altering the response toward HLA-C2 antigen and KIR2DL1/2DS1-controlled TNFα release. Furthermore, this work identifies alterations in uNK function resulting from maternal obesity that may impact early developmental processes important in pregnancy health.

Document type: 
Article

Maternal Obesity Drives Functional Alterations in Uterine NK Cells

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2016-07-21
Abstract: 

Over one-fifth of North American women of childbearing age are obese, putting these women at risk for a variety of detrimental chronic diseases. In addition, obesity increases the risk for developing major complications during pregnancy. The mechanisms by which obesity contributes to pregnancy complications and loss remain unknown. Increasing evidence indicates that obesity results in major changes to adipose tissue immune cell composition and function; whether or not obesity also affects immune function in the uterus has not been explored. Here we investigated the effect of obesity on uterine natural killer (uNK) cells, which are essential for uterine artery remodeling and placental development. Using a cohort of obese or lean women, we found that obesity led to a significant reduction in uNK cell numbers accompanied with impaired uterine artery remodeling. uNK cells isolated from obese women had altered expression of genes and pathways associated with extracellular matrix remodeling and growth factor signaling. Specifically, uNK cells were hyper-responsive to PDGF, resulting in overexpression of decorin. Functionally, decorin strongly inhibited placental development by limiting trophoblast survival. Together, these findings establish a potentially new link between obesity and poor pregnancy outcomes, and indicate that obesity-driven changes to uterine-resident immune cells critically impair placental development.

Document type: 
Article
File(s): 

Impacts of Bicycle Infrastructure in Mid-Sized Cities (IBIMS): protocol for a natural experiment study in three Canadian cities

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-01-21
Abstract: 

Introduction: Bicycling is promoted as a transportation and population health strategy globally. Yet bicycling has low uptake in North America (1%–2% of trips) compared with European bicycling cities (15%–40% of trips) and shows marked sex and age trends. Safety concerns due to collisions with motor vehicles are primary barriers.  To attract the broader population to bicycling, many cities are making investments in bicycle infrastructure. These interventions hold promise for improving population health given the potential for increased physical activity and improved safety, but such outcomes have been largely unstudied. In 2016, the City of Victoria, Canada, committed to build a connected network of infrastructure that separates bicycles from motor vehicles, designed to attract people of ‘all ages and abilities’ to bicycling.  This natural experiment study examines the impacts of the City of Victoria’s investment in a bicycle network on active travel and safety outcomes. The specific objectives are to (1) estimate changes in active travel, perceived safety and bicycle safety incidents; (2) analyse spatial inequities in access to bicycle infrastructure and safety incidents; and (3) assess health-related economic benefits.  Methods and analysis: The study is in three Canadian cities (intervention: Victoria; comparison: Kelowna, Halifax). We will administer population-based surveys in 2016, 2018 and 2021 (1000 people/city). The primary outcome is the proportion of people reporting bicycling. Secondary outcomes are perceived safety and bicycle safety incidents. Spatial analyses will compare the distribution of bicycle infrastructure and bicycle safety incidents across neighbourhoods and across time. We will also calculate the economic benefits of bicycling using WHO’s Health Economic Assessment Tool.  Ethics and dissemination: This study received approval from the Simon Fraser University Office of Research Ethics (study no. 2016s0401). Findings will be disseminated via a website, presentations to stakeholders, at academic conferences and through peer-reviewed journal articles

Document type: 
Article
File(s): 

Evaluation of the Impact of a Public Bicycle Share Program on Population Bicycling in Vancouver, BC

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-10-03
Abstract: 

Public bicycle share programs have been implemented in cities around the world to encourage bicycling. However, there are limited evaluations of the impact of these programs on bicycling at the population level. This study examined the impact of a public bicycle share program on bicycling amongst residents of Vancouver, BC. Using an online panel, we surveyed a population-based sample of Vancouver residents three times: prior to the implementation of the public bicycle share program (T0, October 2015, n=1111); in the early phase of implementation (T1, October 2016, n=995); and one-year post implementation (T2, October 2017, n=966). We used difference in differences estimation to assess whether there was an increase in bicycling amongst those living and/or working in close proximity (≤500 m) to Vancouver's Mobi by Shaw Go public bicycle share program, compared to those living and working outside this area. Results suggest that only living or only working inside the bicycle share service area was not associated with increases in bicycling at T1 or T2 relative to those outside the service area. Both living and working inside the bicycle share service area was associated with increases in bicycling at T1 (OR: 2.26, 95% CI: 1.07, 4.80), however not at T2 (OR: 1.37, 95% CI: 0.67, 2.83). These findings indicate that the implementation of a public bicycle share program may have a greater effect on bicycling for residents who both live and work within the service area, although this effect may not be sustained over time. 

Document type: 
Article
File(s): 

Utilizing Culturally Appropriate Diet Assessment Tools: Proposal for Comprehensive Data Collection of Dietetic Information in South Asian Populations

Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2018-05
Abstract: 

Context: The growing prevalence of type 2 diabetes among South Asians has been identified as a public health concern globally, sparking interest in improving dietary data collection strategies from individuals within this population. Peer-reviewed research has suggested that dietary assessments, coupled with diet and lifestyle modifications, can improve disease outcomes. Research also suggests that the collection of dietary information needs to be culturally appropriate for the population of interest. 

Objective: To provide an overview of the use of culturally modified diet assessment tools, and their success in data collection, within nutritional epidemiology literature. 

Methods: Papers published between January 2006 and January 2018 were identified from 3 electronic databases, supplemented with manual searches of reference lists. The data extraction focused on whether culturally appropriate diet assessment tools had been used with minority or South Asian populations, and whether they yielded response rates >60%. 

Results: Twenty-four papers were identified. Food frequency questionnaires (n = 18) were the most commonly administered diet assessment, and often used in conjunction with a 24-hour diet recall. In studies where both tools where used (n = 6), the response rates were found to be >60%. All studies included in the review had used a culturally adapted version of the diet assessment tool. 

Conclusion: Although diet assessment methods can be effective for data collection, the use of culturally adapted tools and interviewer-based administration are important for improved data quality and completeness among minority populations. However, prior to implementation of any tool in a larger scale study, pilot testing of the tools on a representative sample of the study population will be required.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Dr. David Whitehurst
Department: 
Faculty of Health Sciences
Thesis type: 
MPH capstone project

Aeroallergens in Canada: Distribution, Public Health Impacts, and Opportunities for Prevention

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-07-25
Abstract: 

Aeroallergens occur naturally in the environment and are widely dispersed across Canada, yet their public health implications are not well-understood. This review intends to provide a scientific and public health-oriented perspective on aeroallergens in Canada: their distribution, health impacts, and new developments including the effects of climate change and the potential role of aeroallergens in the development of allergies and asthma. The review also describes anthropogenic effects on plant distribution and diversity, and how aeroallergens interact with other environmental elements, such as air pollution and weather events. Increased understanding of the relationships between aeroallergens and health will enhance our ability to provide accurate information, improve preventive measures and provide timely treatments for affected populations.

Document type: 
Article
File(s): 

Strategies for Recruiting Women Living with Human Immunodeficiency Virus in Community-Based Research: Lessons from Canada

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-04
Abstract: 

Objectives: This study sought to describe the recruitment of women living with HIV (WLWH) into the community-based Canadian HIV Women’s Sexual and Reproductive Health Cohort Study (CHIWOS), because women are underrepresented in HIV research.

Methods: There were 1,424 WLWH were enrolled from British Columbia, Ontario, and Québec, who completed detailed questionnaires administered by peer research associates (PRAs; WLWH with research training). During screening, participants were asked: “How did you hear about the study?” We describe recruitment strategies by subpopulation and offer reflections on challenges and successes.

Results: Of 1,131 participants with complete data, 40% identified as White, 33% African/Caribbean/Black, and 19% Indigenous. The median age was 45 years (interquartile range, 37–51) and 4% identified as trans women. Overall, 35% were recruited through PRAs/peers, 34% clinics, and 19% AIDS service organizations (ASOs). PRAs/peers were the predominant recruitment method in Ontario (49%), compared with clinics in British Columbia (40%), and Québec (43%). Nationally, PRAs/peers were more successful in recruiting WLWH commonly considered to be “harder to reach” (e.g., women identifying as trans, using drugs, not receiving HIV care). Clinics were more effective in recruiting younger women (16–29 years) and women not using ASOs. Recruitment challenges centered on engaging these harder to reach women. Successes included hiring PRAs who built participant trust, linking with clinics to reach women isolated from HIV communities, involving outreach workers to engage street-involved women, and disseminating study information to diverse stakeholders.

Conclusions: Having multiple approaches, engaging a diverse team of PRAs, ensuring flexibility, and cultivating reciprocal relationships with community stakeholders were key to recruiting a diverse and representative sample of WLWH.

Document type: 
Article
File(s): 

Cannabis Use Is Associated with Lower Rates of Initiation of Injection Drug Use Among Street-Involved Youth: A Longitudinal Analysis

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2018-02-12
Abstract: 

Introduction and Aims: Street-involved youth are known to be at elevated risk of initiating injection drug use. However, the impact of so-called “gateway” drugs, such as cannabis, on injection initiation is unknown. The objective of this study was to examine the association between cannabis use and initiation of injection drug use among a prospective cohort of street-involved youth in Vancouver, Canada.

 

Design and Methods: Data for this study were collected from the At-Risk Youth Study (ARYS). From September 2005 to May 2015, participants aged 14-26 who reported illicit drug use were recruited into this open prospective cohort study. An extended Cox regression model with time-updated covariates was used to identify factors independently associated with injection initiation.

 

Results: During the study period 481 street-involved youth were included in this study. Of these, 228 (47.4%) reported at least daily cannabis use, and 103 (21.4%) initiated injection drug use. In a multivariable analysis, ≥ daily cannabis use was associated with slower rates of injection initiation (Adjusted Relative Hazard [ARH]: 0.66, 95% Confidence Interval [CI]: 0.45 – 0.98; p = 0.038). Subanalyses revealed that cannabis use was negatively associated with initiation of injection stimulants but not initiation of injection opioids.

 

Discussion and Conclusions: Given the expansion of cannabis legalization throughout North America, it is encouraging that cannabis use was associated with slower time to initiation of injection drug use in this cohort. This finding challenges the view of cannabis as a gateway substance that precipitates the progression to using harder and more addictive drugs.

 

Document type: 
Article

Increasing Diversion of Methadone in Vancouver, Canada, 2005-2015

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-11-28
Abstract: 

Background and Aim: Although methadone, an opioid agonist, has been an effective medication used to treat opioid use disorder for over 40 years, recent studies have found that methadone was identified in more than a quarter of prescription opioid-related deaths among people who use illicit drugs in Vancouver, Canada. Thus, we sought to longitudinally examine the availability of diverted methadone among people who inject drugs (PWID).

Design and Methods: Data were collected from three prospective cohorts of PWID in Vancouver, Canada between December 2005 and May 2015. Multivariable generalized estimating equation logistic regression was used to identify temporal trends in the immediate availability of diverted methadone (defined as the ability to acquire illicit methadone in <10 minutes).

Results: A total of 2092 participants, including 727 (34.8%) women, were included in the present study. In the multivariable analyses after adjusting for a range of potential confounders, later calendar year (adjusted odds ratio [AOR] = 1.21 per year; 95% confidence interval [CI]: 1.19–1.23) was independently and positively associated with reporting immediate availability of diverted methadone.

Conclusions: We observed a significant increase in the reported availability of diverted methadone among PWID over a ten-year follow-up period. Further research is needed to identify strategies to limit methadone diversion and assess the impact of alternative medications that are equally effective but safer, such as buprenorphine/naloxone.

Document type: 
Article