Building CapaCITY/É for sustainable transportation: protocol for an implementation science research program in healthy cities

INTRODUCTION

Improving sustainable transportation options will help cities tackle growing challenges related to population health, congestion, climate change and inequity. Interventions supporting active transportation face many practical and political hurdles. Implementation science aims to understand how interventions or policies arise, how they can be translated to new contexts or scales and who benefits. Sustainable transportation interventions are complex, and existing implementation science frameworks may not be suitable. To apply and adapt implementation science for healthy cities, we have launched our mixed-methods research programme, CapaCITY/É. We aim to understand how, why and for whom sustainable transportation interventions are successful and when they are not.

METHODS AND ANALYSIS

Across nine Canadian municipalities and the State of Victoria (Australia), our research will focus on two types of sustainable transportation interventions: all ages and abilities bicycle networks and motor vehicle speed management interventions. We will (1) document the implementation process and outcomes of both types of sustainable transportation interventions; (2) examine equity, health and mobility impacts of these interventions; (3) advance implementation science by developing a novel sustainable transportation implementation science framework and (4) develop tools for scaling up and scaling out sustainable transportation interventions. Training activities will develop interdisciplinary scholars and practitioners able to work at the nexus of academia and sustainable cities.

ETHICS AND DISSEMINATION

This study received approval from the Simon Fraser University Office of Ethics Research (H22-03469). A Knowledge Mobilization Hub will coordinate dissemination of findings via a website; presentations to academic, community organisations and practitioner audiences; and through peer-reviewed articles.

Comparison of the number of pedestrian and cyclist injuries captured in police data compared with health service utilisation data in Toronto, Canada 2016-2021

INTRODUCTION

Pedestrian and cyclist injuries represent a preventable burden to Canadians. Police-reported collision data include information on where such collisions occur but under-report the number of collisions. The primary objective of this study was to compare the number of police-reported collisions with emergency department (ED) visits and hospitalisations in Toronto, Canada.

METHODS

Police-reported collisions were provided by Toronto Police Services (TPS). Data included the location of the collision, approximate victim age and whether the pedestrian or cyclist was killed or seriously injured. Health services data included ED visits in the National Ambulatory Care Reporting System and hospitalisations from the Discharge Abstract Database using ICD-10 codes for pedestrian and cycling injuries. Data were compared from 2016 to 2021.

RESULTS

Injuries reported in the health service data were higher than those reported in the TPS for cyclists and pedestrians. The discrepancy was the largest for cyclists treated in the ED, with TPS capturing 7.9% of all cycling injuries. Cyclist injuries not involving a motor vehicle have increased since the start of the pandemic (from 3629 in 2019 to 5459 in 2020 for ED visits and from 251 in 2019 to 430 for hospital admissions).

IMPLICATIONS

While police-reported data are important, it under-reports the burden. There have been increases in cyclist collisions not involving motor vehicles and decreases in pedestrian injuries since the start of the pandemic. The results suggest that using police data alone when planning for road safety is inadequate, and that linkage with other health service data is essential.

Risk Factors and Inequities in Transportation Injury and Mortality in the Canadian Census Health and Environment Cohorts (CanCHECs)

BACKGROUND

Road traffic injury contributes substantially to morbidity and mortality. Canada stands out among developed countries in not conducting a national household travel survey, leading to a dearth of national transportation mode data and risk calculations that have appropriate denominators. Since traffic injuries are specific to the mode of travel used, these risk calculations should consider travel mode.

METHODS

Census data on mode of commute is one of the few sources of these data for persons aged 15 and over. This study leveraged a national data linkage cohort, the Canadian Census Health and Environment Cohorts, that connects census sociodemographic and commute mode data with records of deaths and hospitalizations, enabling assessment of road traffic injury associations by indicators of mode of travel (commuter mode). We examined longitudinal (1996-2019) bicyclist, pedestrian, and motor vehicle occupant injury and fatality risk in the Canadian Census Health and Environment Cohorts by commuter mode and sociodemographic characteristics using Cox proportional hazards models within the working adult population.

RESULTS

We estimated positive associations between commute mode and same mode injury and fatality, particularly for bicycle commuters (hazard ratios for bicycling injury was 9.1 and for bicycling fatality was 11). Low-income populations and Indigenous people had increased injury risk across all modes.

CONCLUSIONS

This study shows inequities in transportation injury risk in Canada and underscores the importance of adjusting for mode of travel when examining differences between population groups.

Traditional activities and general and mental health of adult Indigenous peoples living off-reserve in Canada

Introduction

We examined associations between traditional Indigenous activities and self-perceived general and mental health in adult Indigenous persons living off-reserve in Canada using the 2012 and 2017 Aboriginal Peoples Surveys (APS), the two most recent datasets. We utilized four traditional Indigenous activities including hunting, making clothes or footwear, making arts or crafts, and gathering wild plants to investigate these self-reported data.

Methods

Data from 9,430 and 12,598 respondents from the 2012 and 2017 APS, respectively, who responded to 15 questions concerning traditional activities were assessed using multivariable logistic regression to produce odds ratios (OR) and 95% confidence intervals (CI). Covariates included age, sex, education-level, income-level, Indigenous identity, residential school connection, ability to speak an Indigenous language, smoking status, and alcohol consumption frequency.

Results

Using the 2012 APS, clothes-making was associated with poor self-reported general (OR = 1.50, 95%CI: 1.12-1.99) and mental (OR = 1.59, 95%CI: 1.14-2.21) health. Hunting was associated with good mental health (OR = 0.71 95%CI: 0.56-0.93). Similarly, 2017 analyses found clothes-making associated with poor general health (OR = 1.25, 95%CI: 1.01-1.54), and hunting associated with good general (OR = 0.76, 95%CI: 0.64-0.89) and mental (OR = 0.69, 95%CI: 0.58-0.81) health. Artmaking was associated with poor general (OR = 1.37, 95%CI: 1.17-1.60) and mental (OR = 1.85, 95%CI: 1.58-2.17) health.

Conclusion

Hunting had protective relationships with mental and general health, which may reflect benefits of participation or engagement of healthier individuals in this activity. Clothes-making and artmaking were associated with poor general and poor mental health, possibly representing reverse causation as these activities are often undertaken therapeutically. These findings have implications for future research, programs and policies concerning Indigenous health.

Radon exposure and risk of neurodegenerative diseases among male miners in Ontario, Canada: A cohort study

BACKGROUND

Environmental radon has been examined as a risk factor for neurodegenerative diseases in a small number of previous studies, but the findings have been inconsistent. This study aims to investigate the association between occupational radon exposure and neurodegenerative disease in a cohort of male miners with work experience in multiple ore types in Ontario, Canada.

METHODS

Radon exposure (1915-1988) was assessed using two job-exposure matrices (JEM) constructed from using historical records for 34,536 Ontario male miners. Neurodegenerative outcomes were ascertained between 1992 and 2018. Poisson regression models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between cumulative radon exposure in working level months (WLM) and each neurodegenerative outcome.

RESULTS

Levels of cumulative radon exposure showed variability among cohort members with a mean of 7.5 WLM (standard deviation 24.4). Miners in uranium mines or underground jobs had higher levels and more variability in exposure than workers in non-uranium work or surface jobs. Compared to the reference group (radon < 1 WLM), increased rates of Alzheimer's (RR 1.23, 95% CI 1.05-1.45) and Parkinson's disease (RR 1.43, 95% CI 1.08-1.89) were observed among workers with >1-5 WLM and >5-10 WLM, respectively, but not among higher exposed workers (>10 WLM).

CONCLUSION

This study did not observe a positive monotonic dose-response relationship between cumulative radon exposure and Alzheimer's or Parkinson's disease in Ontario mining workers. There was no association observed with motor neuron disease.

Biogeographical survey of soil microbiomes across sub-Saharan Africa: structure, drivers, and predicted climate-driven changes

BACKGROUND

Top-soil microbiomes make a vital contribution to the Earth's ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents.

RESULTS

The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa's top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation.

CONCLUSION

This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change. Video Abstract.

The Association Between Child Marriage and Domestic Violence in Afghanistan

Child marriage and intimate partner violence have been globally recognized as human rights violations. Both indicators can derail an individual's future and have various public health implications. Previous studies have shown an association between child marriage and domestic violence in low- and middle-income countries; however, data in Afghanistan are not known. This study aimed to assess the association between child marriage and domestic violence in Afghanistan. We used nationally representative data collected by the Demographic and Health Surveys to conduct logistic regression analyses. Child marriage was separated into three categories: very early marriage (<15 years), early marriage (15-17 years), and adult marriage (≥18 years). Domestic violence was the response variable and was assessed as any violence, physical violence, emotional violence, and sexual violence. Of the sample (N = 21,324), 15% of the respondents were married before the age of 15; 35% were married between the ages of 15 and 17; and 50% were married as adults. After adjusting for current age, place of residence, and socioeconomic status, the odds of sexual violence were 22% higher among women who married before age 15 compared with those married as adults (OR = 1.22, 95% CI = [1.05, 1.40], p = .005). However, the odds of reporting any violence, physical violence, and emotional violence among those who married as children did not differ compared with those who married as adults. This may be due to a shift in traditional norms or underreporting in Afghanistan. This study adds to the body of research on child marriage and intimate partner violence, and specifically provides novel information on this association in Afghanistan.

Evaluating cone-beam CT in the diagnosis of suspected scaphoid fractures in the emergency department: preliminary findings

OBJECTIVES

Scaphoid fractures are challenging to accurately diagnose with delayed and missed diagnoses risking poor patient outcomes. Cone beam CT (CBCT) is an emerging technology facilitating alternative access to multi-planar imaging. The aim of this study was to evaluate the use of early CBCT in the diagnosis of suspected scaphoid fractures presenting via the Emergency Department (ED).

METHODS

In this single centre the imaging pathway was adapted to include early CBCT in adult patients with a persisting high index of clinical suspicion for scaphoid fracture despite normal radiographs. Evaluation of referrals between September 2019 and February 2020 was undertaken. Statistical analysis and temporal pathway metrics were assessed including interrater agreement for CBCT and radiography examinations.

RESULTS

Over the six-month timeframe 100 CBCT wrist scans were performed on 99 adult patients. 94% of CBCT scans were performed within 1 day of referral. 25% of scans demonstrated acute injuries including 12 radius, 6 trapezium and 2 scaphoid fractures. For fracture, CBCT had a sensitivity of 96.2% and specificity of 100%. There was a highly significant difference in interobserver variation between fracture detection on CBCT and radiographs.

CONCLUSION

CBCT heralds the potential for early accurate diagnosis of radiocarpal fractures, at lower cost, shortening clinical pathways and reducing clinical risk in the ED.

Metabolic health measurements of shift workers in a national cross-sectional study: Results from the Canadian Health Measures Survey

BACKGROUND

Shift work exposure may be a concern for a range of health effects, including metabolic health outcomes such as insulin resistance, high body weight, and abdominal obesity.

METHODS

We analyzed shift work and indicators of metabolic health (overweight/obesity defined by body mass index, self-reported changes in body mass index (BMI) in previous 1 and 10 years, waist circumference, waist-to-hip ratio, and insulin resistance assessed by the homeostasis model assessment 2 (HOMA-2-IR)) in the cross-sectional Canadian Health Measures Survey (CHMS). We analyzed descriptive characteristics of shift workers (regular night, evening, and rotating shift) and used multivariable linear regression to examine the association between two definitions of shift work exposure and measures of metabolic health, adjusted for age, sex, daily energy expenditure, sleep, and poor dietary quality.

RESULTS

5470 anthropometry (2637 fasting) participants in CHMS Cycles 1 and 2 were included, of whom 16.5% worked regular evening, night, or rotating shifts. Shift workers were younger and slept longer hours than non-shift workers. Bivariate associations showed inverse relationships between shift work and BMI, waist circumference, waist-to-hip ratio, and HOMA-2-IR. In adjusted analyses, BMI was inversely related to shift work, and other metabolic health outcomes showed no significant associations.

CONCLUSIONS

Healthy worker effects (including self-selection of exposure) could explain inverse relationships, particularly as the cross-sectional design only allowed assessment of current exposure. Key strengths include the population-based design and measurement of metabolic health indicators. Results underscore the importance of consideration of the health of shift workers following departure from the exposed population.

COVID-19 Experiences, PPE, and Health Concerns in Toronto, Canada Bicycle Delivery Workers: Cross-sectional Pilot Survey

OBJECTIVES

To pilot recruitment methods for bicycle delivery workers in Toronto, Canada and to assess workers' experiences with COVID-19 and personal protective equipment (PPE).

METHODS

This was a cross-sectional study. An online survey was deployed and advertised via social media with both paid and free postings in July and August of 2020. An incentive draw was used to motivate participation. These analyses summarized descriptive statistics of the sample and variables relevant to COVID-19.

RESULTS

Complete responses were received from 35 participants. No participants reported a diagnosis of COVID-19, however four participants indicated experiencing symptoms. Most participants reported they used PPE, especially masks and/or respirators (97.1%) and 71.4% of participants indicated their employer provided them with PPE (masks or gloves). Participants expressed concern about precarious work and uncertainty about their own COVID-19 exposure risk.

CONCLUSIONS

Bicycle delivery workers are a precarious working population that may be difficult to reach for research recruitment purposes. Given their essential role in deliveries during the COVID-19 pandemic, further work is needed to characterize exposures and risks in this population.

Age Differences in Work-Disability Duration Across Canada: Examining Variations by Follow-Up Time and Context

Purpose This study aimed to understand age differences in wage-replacement duration by focusing on variations in the relationship across different periods of follow-up time. Methods We used administrative claims data provided by six workers' compensation systems in Canada. Included were time-loss claims for workers aged 15-80 years with a work-related injury/illness during the 2011 to 2015 period (N = 751,679 claims). Data were coded for comparability across cohorts. Survival analysis examined age-related differences in the hazard of transitioning off (versus remaining on) disability benefits, allowing for relaxed proportionality constraints on the hazard rates over time. Differences were examined on the absolute (hazard difference) and relative (hazard ratios [HR]) scales. Results Older age groups had a lower likelihood of transitioning off wage-replacement benefits compared to younger age groups in the overall models (e.g., 55-64 vs. 15-24 years: HR 0.62). However, absolute and relative differences in age-specific hazard rates varied as a function of follow-up time. The greatest age-related differences were observed at earlier event times and were attenuated towards a null difference across later follow-up event times. Conclusions Our study provides new insight into the workplace injury/illness claim and recovery processes and suggests that older age is not always strongly associated with worse disability duration outcomes. The use of data from multiple jurisdictions lends external validity to our findings and demonstrates the utility of using cross-jurisdictional data extracts. Future work should examine the social and contextual determinants that operate during various recovery phases, and how these factors interact with age.

Trends in participation rates in case–control studies of occupational risk factors 1991–2017

Objective

Declining participation has been observed in previous epidemiological studies, could occupational risk factor epidemiology be particularly vulnerable to this trend? The objective of this study was to assess trends of participation rates in occupational case-control studies.

Methods

Five prominent occupational and epidemiological journals were pre-selected and all articles published between 1991 and 2017 were screened for case-control studies of occupational risk factors for chronic disease outcomes. The primary independent variable was median year of data collection, while the primary outcome variable was reported participation rate. We conducted linear regression, adjusting for study characteristics that included study gender mix, location of recruitment, disease outcome, and data collection method.

Results

A total of 180 studies published in the five journals were included in the final analysis. The mean participation was higher for cases (78.9%) than for controls (71.5%). In linear regression, a significant trend of decreasing participation was observed for both cases with a percent change of −0.50 per year (95% CI −0.75 to −0.25) for cases and a percent change of −0.95 per year (95% CI −1.23 to −0.67) for controls. After adjustment for study gender mix, location, disease outcome, and data collection method, the trend remained statistically significant for both case and control groups.

Conclusion

Declining participation rates in case-control studies of occupational risk factors may reflect an overall decline of participation in population-based samples. Lower participation rates introduce the potential for bias and may deter future population-based studies of occupational risk factors.

Use of a Canadian Population-Based Surveillance Cohort to Test Relationships Between Shift Work and Breast, Ovarian, and Prostate Cancer

OBJECTIVES

Shift work with circadian disruption is a suspected human carcinogen. Additional population-representative human studies are needed and large population-based linkage cohorts have been explored as an option for surveillance shift work and cancer risk. This study uses a surveillance linkage cohort and job-exposure matrix to test relationships.

METHODS

We estimated associations between shift work and breast, ovarian, and prostate cancer using the population-based Canadian Census Health and Environment Cohort (CanCHEC), linking the 1991 Canadian census to national cancer registry and mortality databases. Prevalence estimates from population labour survey data were used to estimate and assign probability of night, rotating, or evening shifts by occupation and industry. Cohort members were assigned to high (>50%), medium (>25 to 50%), low (>5 to 25%), or no (<5%) probability of exposure categories. Cox proportional hazards modelling was used to estimate associations between shift work exposure and incidence of prostate cancer in men and ovarian and breast cancer in women.

RESULTS

The cohort included 1 098 935 men and 939 520 women. Hazard ratios (HRs) indicated null or inverse relationships comparing high probability to no exposure for prostate cancer: HR = 0.96, 95% confidence interval (CI) = 0.91-1.02; breast cancer: HR = 0.94, 95% CI = 0.90-0.99; and ovarian cancer: HR = 0.99, 95% CI = 0.87-1.13.

CONCLUSIONS

This study showed inverse and null associations between shift work exposure and incidence of prostate, breast, or ovarian cancer. However, we explore limitations of a surveillance cohort, including a possible healthy worker survivor effect and the possibility that this relationship may require the nuanced exposure detail in primary collection studies to be measurable.

Magnetic Stimulus Responsive DDS Based on Chitosan Microbeads Embedded with Magnetic Nanoparticles

In this paper, we have presented a novel Drug Delivery Substrate (DDS) that that is responsive to external stimuli of high-frequency alternating magnetic fields. The DDS is constituted of chitosan crosslinked with PEGDMA (polyethylene glycol dimethacrylate), loaded with Fe₃O₄ magnetic nanoparticles and vancomycin. In another experiment, a 19-hour elution was observed where three magnetic stimuli of 25 mT, 109.9 kHz were given for 60 min to the test samples. The stimuli were separated by several hours. After excitation span, it was observed that the stimulated samples released a significantly higher amount of vancomycin by as much as 21% compared to non-stimulated samples. In another study, preliminary results showing the effect of different PEGDMA chain lengths have been discussed. These results show evidence of a smart, controllable DDS that allows modulation of its normal passive antibiotic elution by applying external stimuli per personalized needs.

The impact of night shift work on breast cancer: Results from the Burden of Occupational Cancer in Canada Study

BACKGROUND

We estimated the proportion and number of female breast cancer cases in Canada attributable to night shift work, a probable cause of breast cancer.

METHODS

Levin's equation was used to calculate population attributable fractions (PAFs) among Canadian women who ever worked night/rotating shifts from 1961 to 2000, accounting for labor turnover and survival to the year 2011. The calculated PAFs were applied to 2011 Canadian breast cancer incidence statistics to obtain the number of attributable cases.

RESULTS

Approximately 1.5 million women ever worked night/rotating shifts during 1961-2000 and survived to 2011. The PAFs ranged from 2.0% (95% confidence interval [CI]: 1.4-6.2) to 5.2% (95% CI: 3.7-13.6), and 470 to 1200 incident breast cancer cases in 2011 were likely due to shift work, of which 38% would have been diagnosed among women in health-related occupations.

CONCLUSIONS

More research is needed to increase the certainty of this association, but current evidence supports workplace-based prevention.

Surveillance of cancer risks for firefighters, police, and armed forces among men in a Canadian census cohort

BACKGROUND

Firefighters, police, and armed services may be exposed to hazards such as combustion by-products and shift work.

METHODS

The CanCHEC cohort linked 1991 census data to the Canadian cancer registry for follow up. Cox proportional hazards modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) to estimate risks for firefighter, police, or armed forces compared to workers in other occupations.

RESULTS

The cohort of 1 108 410 men included 4535 firefighters, 10 055 police, and 9165 armed forces. For firefighters, elevated risks were noted for Hodgkin's lymphoma (HR: 2.89, 95%CI: 1.29-6.46), melanoma (HR: 1.67, 95%CI: 1.17-2.37), and prostate cancer (HR: 1.18, 95%CI: 1.01-1.37). Police had elevated risks for melanoma (HR:1.69, 95%CI: 1.32-2.16) and prostate cancer (HR:1.28, 95%CI: 1.14-1.42). No significant associations were found for armed forces workers.

CONCLUSIONS

Canadian firefighters, police, and armed services, may be at an increased risk of developing certain cancers. Results suggested that a healthy worker effect may influence risk estimates.

Assistant radiographer practitioners: Creating capacity or challenging professional boundaries?

INTRODUCTION

Over the last 2 decades the assistant radiographer practitioner (ARP) role has been introduced into NHS diagnostic imaging departments as a strategy to expand the workforce and create capacity. This skill mix initiative has not been implemented in a standardised way and there is limited knowledge of the current role scope within general radiography (X-Ray).

METHOD

An electronic survey of ARPs working within UK diagnostic imaging departments was conducted. Both open and closed questions sought information regarding basic demographic data (age category; gender; geographic region), scope of practice (patient groups; anatomical regions; imaging outside of the diagnostic imaging department), limitations placed on practice, supervision and additional roles.

RESULTS

A total of 108 responses, including 13 trainees, were received. Most sites employ three or less ARPs in general radiography (n = 43/66; 65.2%), although 11 sites have five (range 1-15). The majority undertake imaging of both adults and children (n = 85/108; 78.7%), although limitations on age were described. Their scope of practice covers a broad anatomical range and included some non-ambulant patients. The level of supervision varied with some sites empowering ARPs to check the referral prior to examination (n = 25) or images post acquisition (n = 32) (both n = 20/66; χ² = 16.003; 1df; p = 0.000).

CONCLUSION

ARPs are helping to maintain capacity in imaging departments but we suggest there is further scope for expansion. The practice described by the post holders suggests that many are working beyond the scope envisaged by the radiography professional body.

Cancer Risks among Welders and Occasional Welders in a National Population-Based Cohort Study: Canadian Census Health and Environmental Cohort

BACKGROUND

Welders are exposed to many known and suspected carcinogens. An excess lung cancer risk among welders is well established, but whether this is attributable to welding fumes is unclear. Excess risks of other cancers have been suggested, but not established. We investigated welding cancer risks in the population-based Canadian Census Health and Environmental Cohort.

METHODS

Among 1.1 million male workers, 12,845 welders were identified using Standard Occupational Classification codes and followed through retrospective linkage of 1991 Canadian Long Form Census and Canadian Cancer Registry (1992-2010) records. Hazard ratios (HRs) were calculated using Cox proportional hazards models based on estimated risks of lung cancer, mesothelioma, and nasal, brain, stomach, kidney, and bladder cancers, and ocular melanoma. Lung cancer histological subtypes and risks by industry group and for occasional welders were examined. Some analyses restricted comparisons to blue-collar workers to minimize effects of potential confounders.

RESULTS

Among welders, elevated risks were observed for lung cancer [HR: 1.16, 95% confidence interval (CI): 1.03-1.31], mesothelioma (HR: 1.78, 95% CI: 1.01-3.18), bladder cancer (HR: 1.40, 95% CI: 1.15-1.70), and kidney cancer (HR: 1.30, 95% CI: 1.01-1.67). When restricted to blue-collar workers, lung cancer and mesothelioma risks were attenuated, while bladder and kidney cancer risks increased.

CONCLUSION

Excess risks of lung cancer and mesothelioma may be partly attributable to factors including smoking and asbestos. Welding-specific exposures may increase bladder and kidney cancer risks, and particular sources of exposure should be investigated. Studies that are able to disentangle welding effects from smoking and asbestos exposure are needed.

Occupational variation in incidence of bladder cancer: a comparison of population-representative cohorts from Nordic countries and Canada

OBJECTIVES

The objective of this study was to compare occupational variation of the risk of bladder cancer in the Nordic countries and Canada.

METHODS

In the Nordic Occupational Cancer study (NOCCA), 73 653 bladder cancer cases were observed during follow-up of 141.6 million person-years. In the Canadian Census Health and Environment Cohort (CanCHEC), 8170 cases were observed during the follow-up of 36.7 million person-years. Standardised incidence ratios with 95% CI were estimated for 53 occupations in the NOCCA cohort and HR with 95% CIs were estimated for 42 occupations in the CanCHEC.

RESULTS

Elevated risks of bladder cancer were observed among hairdressers, printers, sales workers, plumbers, painters, miners and laundry workers. Teachers and agricultural workers had reduced risk of bladder cancer in both cohorts. Chimney-sweeps, tobacco workers and waiters had about 1.5-fold risk in the Nordic countries; no risk estimates for these categories were given from the CanCHEC cohort.

CONCLUSION

We observed different occupational patterns in risk of bladder cancer in Nordic countries and Canada. The only occupation with similarly increased risk was observed among sales workers. Differences in smoking across occupational groups may explain some, but not all, of this variation.

Cancer risks in a population-based study of 70,570 agricultural workers: results from the Canadian census health and Environment cohort (CanCHEC)

BACKGROUND

Agricultural workers may be exposed to potential carcinogens including pesticides, sensitizing agents and solar radiation. Previous studies indicate increased risks of hematopoietic cancers and decreased risks at other sites, possibly due to differences in lifestyle or risk behaviours. We present findings from CanCHEC (Canadian Census Health and Environment Cohort), the largest national population-based cohort of agricultural workers.

METHODS

Statistics Canada created the cohort using deterministic and probabilistic linkage of the 1991 Canadian Long Form Census to National Cancer Registry records for 1992-2010. Self-reported occupations were coded using the Standard Occupational Classification (1991) system. Analyses were restricted to employed persons aged 25-74 years at baseline (N = 2,051,315), with follow-up until December 31, 2010. Hazard ratios (HR) and 95% confidence intervals (CI) were modeled using Cox proportional hazards for all workers in agricultural occupations (n = 70,570; 70.8% male), stratified by sex, and adjusted for age at cohort entry, province of residence, and highest level of education.

RESULTS

A total of 9515 incident cancer cases (7295 in males) occurred in agricultural workers. Among men, increased risks were observed for non-Hodgkin lymphoma (HR = 1.10, 95% CI = 1.00-1.21), prostate (HR = 1.11, 95% CI = 1.06-1.16), melanoma (HR = 1.15, 95% CI = 1.02-1.31), and lip cancer (HR = 2.14, 95% CI = 1.70-2.70). Decreased risks in males were observed for lung, larynx, and liver cancers. Among female agricultural workers there was an increased risk of pancreatic cancer (HR = 1.36, 95% CI = 1.07-1.72). Increased risks of melanoma (HR = 1.79, 95% CI = 1.17-2.73), leukemia (HR = 2.01, 95% CI = 1.24-3.25) and multiple myeloma (HR = 2.25, 95% CI = 1.16-4.37) were observed in a subset of female crop farmers.

CONCLUSIONS

Exposure to pesticides may have contributed to increased risks of hematopoietic cancers, while increased risks of lip cancer and melanoma may be attributed to sun exposure. The array of decreased risks suggests reduced smoking and alcohol consumption in this occupational group compared to the general population.

Bicycling crashes on streetcar (tram) or train tracks: mixed methods to identify prevention measures

BACKGROUND

Streetcar or train tracks in urban areas are difficult for bicyclists to negotiate and are a cause of crashes and injuries. This study used mixed methods to identify measures to prevent such crashes, by examining track-related crashes that resulted in injuries to cyclists, and obtaining information from the local transit agency and bike shops.

METHODS

We compared personal, trip, and route infrastructure characteristics of 87 crashes directly involving streetcar or train tracks to 189 crashes in other circumstances in Toronto, Canada. We complemented this with engineering information about the rail systems, interviews of personnel at seven bike shops about advice they provide to customers, and width measurements of tires on commonly sold bikes.

RESULTS

In our study, 32 % of injured cyclists had crashes that directly involved tracks. The vast majority resulted from the bike tire being caught in the rail flangeway (gap in the road surface alongside rails), often when cyclists made unplanned maneuvers to avoid a collision. Track crashes were more common on major city streets with parked cars and no bike infrastructure, with left turns at intersections, with hybrid, racing and city bikes, among less experienced and less frequent bicyclists, and among women. Commonly sold bikes typically had tire widths narrower than the smallest track flangeways. There were no track crashes in route sections where streetcars and trains had dedicated rights of way.

CONCLUSIONS

Given our results, prevention efforts might be directed at individual knowledge, bicycle tires, or route design, but their potential for success is likely to differ. Although it may be possible to reach a broader audience with continued advice about how to avoid track crashes, the persistence and frequency of these crashes and their unpredictable circumstances indicates that other solutions are needed. Using tires wider than streetcar or train flangeways could prevent some crashes, though there are other considerations that lead many cyclists to have narrower tires. To prevent the majority of track-involved injuries, route design measures including dedicated rail rights of way, cycle tracks (physically separated bike lanes), and protected intersections would be the best strategy.

Shift Work and Obesity among Canadian Women: A Cross-Sectional Study Using a Novel Exposure Assessment Tool

Background/Objectives

It has been suggested that the association between shift work and chronic disease is mediated by an increase in obesity. However, investigations of the relationship between shift work and obesity reveal mixed findings. Using a recently developed exposure assessment tool, this study examined the association between shift work and obesity among Canadian women from two studies: a cohort of university alumni, and a population-based study.

Methods

Self-administered questionnaire data were used from healthy, currently employed females in a population-based study, the Ontario Women’s Diet and Health case-control study (n = 1611 controls), and from a subset of a of university alumni from the Canadian Study of Diet, Lifestyle, and Health (n = 1097) cohort study. Overweight was defined as BMI≥25 to <30, and obesity as BMI≥30. Reported occupation was converted to occupational codes and linked to a probability of shift work value derived from Survey of Labour and Income Dynamics data. Regular evenings, nights, or rotating work comprised shift work. Polytomous logistic regression estimated the association between probability of shift work, categorized as near nil, low, medium, and high probability of shift work, on overweight and obesity, controlling for detected confounders.

Results

In the population-based sample, high probability of shift work was associated with obesity (reference = near nil probability of shift work, OR: 1.88, 95% CI: 1.01–3.51, p = 0.047). In the alumni cohort, no significant association was detected between shift work and overweight or obesity.

Conclusions

As these analyses found a positive association between high probability of shift work exposure and obesity in a population-based sample, but not in an alumni cohort, it is suggested that the relationship between shift work and obesity is complex, and may be particularly susceptible to occupational and education-related factors within a given population.

Severity of urban cycling injuries and the relationship with personal, trip, route and crash characteristics: analyses using four severity metrics

OBJECTIVE

To examine the relationship between cycling injury severity and personal, trip, route and crash characteristics.

METHODS

Data from a previous study of injury risk, conducted in Toronto and Vancouver, Canada, were used to classify injury severity using four metrics: (1) did not continue trip by bike; (2) transported to hospital by ambulance; (3) admitted to hospital; and (4) Canadian Triage and Acuity Scale (CTAS). Multiple logistic regression was used to examine associations with personal, trip, route and crash characteristics.

RESULTS

Of 683 adults injured while cycling, 528 did not continue their trip by bike, 251 were transported by ambulance and 60 were admitted to hospital for further treatment. Treatment urgencies included 75 as CTAS=1 or 2 (most medically urgent), 284 as CTAS=3, and 320 as CTAS=4 or 5 (least medically urgent). Older age and collision with a motor vehicle were consistently associated with increased severity in all four metrics and statistically significant in three each (both variables with ambulance transport and CTAS; age with hospital admission; and motor vehicle collision with did not continue by bike). Other factors were consistently associated with more severe injuries, but statistically significant in one metric each: downhill grades; higher motor vehicle speeds; sidewalks (these significant for ambulance transport); multiuse paths and local streets (both significant for hospital admission).

CONCLUSIONS

In two of Canada's largest cities, about one-third of the bicycle crashes were collisions with motor vehicles and the resulting injuries were more severe than in other crash circumstances, underscoring the importance of separating cyclists from motor vehicle traffic. Our results also suggest that bicycling injury severity and injury risk would be reduced on facilities that minimise slopes, have lower vehicle speeds, and that are designed for bicycling rather than shared with pedestrians.

Bicycling crash circumstances vary by route type: a cross-sectional analysis

Background

Widely varying crash circumstances have been reported for bicycling injuries, likely because of differing bicycling populations and environments. We used data from the Bicyclists’ Injuries and the Cycling Environment Study in Vancouver and Toronto, Canada, to describe the crash circumstances of people injured while cycling for utilitarian and leisure purposes. We examined the association of crash circumstances with route type.

Methods

Adult cyclists injured and treated in a hospital emergency department described their crash circumstances. These were classified into major categories (collision vs. fall, motor vehicle involved vs. not) and subcategories. The distribution of circumstances was tallied for each of 14 route types defined in an earlier analysis. Ratios of observed vs. expected were tallied for each circumstance and route type combination.

Results

Of 690 crashes, 683 could be characterized for this analysis. Most (74%) were collisions. Collisions included those with motor vehicles (34%), streetcar (tram) or train tracks (14%), other surface features (10%), infrastructure (10%), and pedestrians, cyclists, or animals (6%). The remainder of the crashes were falls (26%), many as a result of collision avoidance manoeuvres. Motor vehicles were involved directly or indirectly with 48% of crashes. Crash circumstances were distributed differently by route type, for example, collisions with motor vehicles, including “doorings”, were overrepresented on major streets with parked cars. Collisions involving streetcar tracks were overrepresented on major streets. Collisions involving infrastructure (curbs, posts, bollards, street furniture) were overrepresented on multiuse paths and bike paths.

Conclusions

These data supplement our previous analyses of relative risks by route type by indicating the types of crashes that occur on each route type. This information can guide municipal engineers and planners towards improvements that would make cycling safer.

Prostate cancer and occupational exposure to whole-body vibration in a national population-based cohort study

BACKGROUND

Following preliminary evidence from observational studies, we test the potential relationship between whole-body vibration (WBV) and prostate cancer in a cohort study.

METHODS

WBV exposure was assigned based on occupation in 1991 and 1,107,700 participants were followed for incident prostate cancer until the end of 2003. Adjusted hazard rate ratios (HRs) were calculated using Cox proportional hazards modeling.

RESULTS

17,922 incident prostate cancer cases were observed. WBV-exposed men in Natural and Applied Sciences Occupations had a 37% elevated risk of prostate cancer (95% CI 1.09-1.72) and WBV-exposed men in Trades, Transport, and Equipment Operators Occupations had a 9% reduced risk (95% CI 0.86-0.97). Independent of WBV exposure, small but significant differences in risk were seen for several occupational categories.

CONCLUSIONS

We found no consistent relationship between WBV and prostate cancer. Further research could focus on other exposures or specific occupations in the studied categories to determine what may be contributing to the observed differences in prostate cancer risk.

Parkinson's disease and occupation: differences in associations by case identification method suggest referral bias

METHODS

We used a population-based sample of 403 Parkinson's disease cases and 405 controls to examine risks by occupation. Results were compared to a previous clinic-based analysis.

RESULTS

With censoring of jobs held within 10 years of diagnosis, the following had significantly or strongly increased risks: social science, law and library jobs (OR = 1.8); farming and horticulture jobs (OR = 2.0); gas station jobs (OR = 2.6); and welders (OR = 3.0). The following had significantly decreased risks: management and administration jobs (OR = 0.70); and other health care jobs (OR = 0.44).

CONCLUSIONS

These results were consistent with other findings for social science and farming occupations. Risks for teaching, medicine and health occupations were not elevated, unlike our previous clinic-based study. This underscores the value of population-based over clinic-based samples. Occupational studies may be particularly susceptible to referral bias because social networks may spread preferentially via jobs.

Evaluation of impact of shale gas operations in the Barnett Shale region on volatile organic compounds in air and potential human health risks

Shale gas exploration and production (E&P) has experienced substantial growth across the U.S. over the last decade. The Barnett Shale, in north-central Texas, contains one of the largest, most active onshore gas fields in North America, stretching across 5000 square miles and having an estimated 15,870 producing wells as of 2011. Given that these operations may occur in relatively close proximity to populated/urban areas, concerns have been expressed about potential impacts on human health. In response to these concerns, the Texas Commission on Environmental Quality established an extensive air monitoring network in the region. This network provides a unique data set for evaluating the potential impact of shale gas E&P activities on human health. As such, the objective of this study was to evaluate community-wide exposures to volatile organic compounds (VOCs) in the Barnett Shale region. In this current study, more than 4.6 million data points (representing data from seven monitors at six locations, up to 105 VOCs/monitor, and periods of record dating back to 2000) were evaluated. Measured air concentrations were compared to federal and state health-based air comparison values (HBACVs) to assess potential acute and chronic health effects. None of the measured VOC concentrations exceeded applicable acute HBACVs. Only one chemical (1,2-dibromoethane) exceeded its applicable chronic HBACV, but it is not known to be associated with shale gas production activities. Annual average concentrations were also evaluated in deterministic and probabilistic risk assessments and all risks/hazards were below levels of concern. The analyses demonstrate that, for the extensive number of VOCs measured, shale gas production activities have not resulted in community-wide exposures to those VOCs at levels that would pose a health concern. With the high density of active wells in this region, these findings may be useful for understanding potential health risks in other shale play regions.

Central sleep-disordered breathing and the effects of oxygen therapy in infants with Prader-Willi syndrome

OBJECTIVES

To describe breathing patterns in infants with Prader-Willi Syndrome (PWS), as well as the effects of supplemental oxygen (O2) on breathing patterns. Children with PWS commonly have sleep-disordered breathing, including hypersomnolence and obstructive sleep apnoea, as well as central sleep breathing abnormalities that are present from infancy.

DESIGN

Retrospective cohort study.

PATIENTS

Infants with a diagnosis of PWS.

SETTING

Tertiary children's hospital.

INTERVENTIONS

Infants with PWS underwent full polysomnography, and in those with frequent desaturations associated with central events, supplemental O2 during sleep was started and followed with regular split-night studies (periods in both air and O2).

RESULTS

Thirty split-night studies on 10 infants (8 female) aged 0.06-1.79 (median 0.68, IQR 0.45, 1.07) years were undertaken. At baseline (ie, air), children with PWS had a median (IQR) central apnoea index (CAI) of 4.7 (1.9, 10.6) per hour, with accompanying falls in oxygen saturation (SpO2). O2 therapy led to statistically significant reductions in CAI to 2.5/hour (p=0.002), as well as a reduced central event index (CEI) and improved SpO2. No change in the number of obstructive events was noted. Central events were more prevalent in rapid-eye movement/active sleep.

CONCLUSIONS

It is concluded that infants with PWS may have central sleep-disordered breathing, which, in some children, may cause frequent desaturations. Improvements in CAI and CEI as well as oxygenation were noted with O2 therapy. Longitudinal work with this patient group would help to establish the timing of onset of obstructive symptoms.

Comparing the effects of infrastructure on bicycling injury at intersections and non-intersections using a case-crossover design

Background

This study examined the impact of transportation infrastructure at intersection and non-intersection locations on bicycling injury risk.

Methods

In Vancouver and Toronto, we studied adult cyclists who were injured and treated at a hospital emergency department. A case–crossover design compared the infrastructure of injury and control sites within each injured bicyclist's route. Intersection injury sites (N=210) were compared to randomly selected intersection control sites (N=272). Non-intersection injury sites (N=478) were compared to randomly selected non-intersection control sites (N=801).

Results

At intersections, the types of routes meeting and the intersection design influenced safety. Intersections of two local streets (no demarcated traffic lanes) had approximately one-fifth the risk (adjusted OR 0.19, 95% CI 0.05 to 0.66) of intersections of two major streets (more than two traffic lanes). Motor vehicle speeds less than 30 km/h also reduced risk (adjusted OR 0.52, 95% CI 0.29 to 0.92). Traffic circles (small roundabouts) on local streets increased the risk of these otherwise safe intersections (adjusted OR 7.98, 95% CI 1.79 to 35.6). At non-intersection locations, very low risks were found for cycle tracks (bike lanes physically separated from motor vehicle traffic; adjusted OR 0.05, 95% CI 0.01 to 0.59) and local streets with diverters that reduce motor vehicle traffic (adjusted OR 0.04, 95% CI 0.003 to 0.60). Downhill grades increased risks at both intersections and non-intersections.

Conclusions

These results provide guidance for transportation planners and engineers: at local street intersections, traditional stops are safer than traffic circles, and at non-intersections, cycle tracks alongside major streets and traffic diversion from local streets are safer than no bicycle infrastructure.

Pumpers, skypers, surfers and texters: technology to improve the management of diabetes in teenagers

A variety of innovative technologies are available to assist with the management of diabetes in teenagers. Technologies include devices that assist with the direct day-to-day management of diabetes including insulin pumps and continuous glucose monitors. These devices are being used more and more with teenagers as a means of improving treatment adherence and glycaemic control. In addition, telehealth is being used to deliver care and support around diabetes management issues for teens with diabetes. Telehealth used in diabetes care for teens includes cell phones and video-conferencing. The goal of this telehealth technology is to support health behaviours and implement behavioural change strategies in a way that is more integrated into the everyday lives of patients and even in the context in which the behaviours occur in 'real time'. Finally, information and support via the Internet are gaining acceptance and use among teens with diabetes as an effective means of strategies for improved diabetes self-care. All three of these broad uses of technology in diabetes in teens represent flexible, innovative, and accessible approaches to improving both diabetes management and glycaemic control in this 'at risk' population.

Route infrastructure and the risk of injuries to bicyclists: a case-crossover study

OBJECTIVES

We compared cycling injury risks of 14 route types and other route infrastructure features.

METHODS

We recruited 690 city residents injured while cycling in Toronto or Vancouver, Canada. A case-crossover design compared route infrastructure at each injury site to that of a randomly selected control site from the same trip.

RESULTS

Of 14 route types, cycle tracks had the lowest risk (adjusted odds ratio [OR] = 0.11; 95% confidence interval [CI] = 0.02, 0.54), about one ninth the risk of the reference: major streets with parked cars and no bike infrastructure. Risks on major streets were lower without parked cars (adjusted OR = 0.63; 95% CI = 0.41, 0.96) and with bike lanes (adjusted OR = 0.54; 95% CI = 0.29, 1.01). Local streets also had lower risks (adjusted OR = 0.51; 95% CI = 0.31, 0.84). Other infrastructure characteristics were associated with increased risks: streetcar or train tracks (adjusted OR = 3.0; 95% CI = 1.8, 5.1), downhill grades (adjusted OR = 2.3; 95% CI = 1.7, 3.1), and construction (adjusted OR = 1.9; 95% CI = 1.3, 2.9).

CONCLUSIONS

The lower risks on quiet streets and with bike-specific infrastructure along busy streets support the route-design approach used in many northern European countries. Transportation infrastructure with lower bicycling injury risks merits public health support to reduce injuries and promote cycling.

Personal and trip characteristics associated with safety equipment use by injured adult bicyclists: a cross-sectional study

BACKGROUND

The aim of this study was to estimate use of helmets, lights, and visible clothing among cyclists and to examine trip and personal characteristics associated with their use.

METHODS

Using data from a study of transportation infrastructure and injuries to 690 adult cyclists in Toronto and Vancouver, Canada, we examined the proportion who used bike lights, conspicuous clothing on the torso, and helmets on their injury trip. Multiple logistic regression was used to examine associations between personal and trip characteristics and each type of safety equipment.

RESULTS

Bike lights were the least frequently used (20% of all trips) although they were used on 77% of trips at night. Conspicuous clothing (white, yellow, orange, red) was worn on 33% of trips. Helmets were used on 69% of trips, 76% in Vancouver where adult helmet use is required by law and 59% in Toronto where it is not. Factors positively associated with bike light use included night, dawn and dusk trips, poor weather conditions, weekday trips, male sex, and helmet use. Factors positively associated with conspicuous clothing use included good weather conditions, older age, and more frequent cycling. Factors positively associated with helmet use included bike light use, longer trip distances, hybrid bike type, not using alcohol in the 6 hours prior to the trip, female sex, older age, higher income, and higher education.

CONCLUSIONS

In two of Canada's largest cities, helmets were the most widely used safety equipment. Measures to increase use of visibility aids on both daytime and night-time cycling trips may help prevent crashes.

Physiologically based pharmacokinetic model for rats and mice orally exposed to chromium

A multi-compartment physiologically based pharmacokinetic (PBPK) model was developed to describe the behavior of Cr(III) and Cr(VI) in rats and mice following long-term oral exposure. Model compartments were included for GI lumen, oral mucosa, forestomach/stomach, small intestinal mucosa (duodenum, jejunum, ileum), blood, liver, kidney, bone, and a combined compartment for remaining tissues. Data from ex vivo Cr(VI) reduction studies were used to characterize reduction of Cr(VI) in fed rodent stomach fluid as a second-order, pH-dependent process. For model development, tissue time-course data for total chromium were collected from rats and mice exposed to Cr(VI) in drinking water for 90 days at six concentrations ranging from 0.1 to 180 mg Cr(VI)/L. These data were used to supplement the tissue time-course data collected in other studies with oral administration of Cr(III) and Cr(VI), including that from recent NTP chronic bioassays. Clear species differences were identified for chromium delivery to the target tissue (small intestines), with higher concentrations achieved in mice than in rats, consistent with small intestinal tumor formation, which was observed upon chronic exposures in mice but not in rats. Erythrocyte:plasma chromium ratios suggest that Cr(VI) entered portal circulation at drinking water concentrations equal to and greater than 60 mg/L in rodents. Species differences are described for distribution of chromium to the liver and kidney, with liver:kidney ratios higher in mice than in rats. Overall, the PBPK model provides a good description of chromium toxicokinetics, with model predictions for tissue chromium within a factor of 3 for greater than 80% of measurements evaluated. The tissue data and PBPK model predictions indicate a concentration gradient in the small intestines (duodenum > jejunum > ileum), which will be useful for assessing the tumor response gradient observed in mouse small intestines in terms of target tissue dose. The rodent PBPK model presented here, when used in conjunction with a human PBPK model for Cr(VI), should provide a more robust characterization of species differences in toxicokinetic factors for assessing the potential risks associated with low-dose exposures of Cr(VI) in human populations.

Occupational exposure to whole-body vibration and Parkinson's disease: results from a population-based case-control study

Mechanical stress producing head injury is associated with Parkinson's disease, suggesting that relations with other physical hazards such as whole-body vibration (WBV) should be tested. In this study, the authors evaluated the relation between occupational exposure to WBV and Parkinson's disease. A population-based case-control study with 403 cases and 405 controls was conducted in British Columbia, Canada, between 2001 and 2008. From detailed occupational histories and published measurements, metrics of occupational WBV exposure were constructed and tested for associations with Parkinson's disease using logistic regression and adjusting for age and sex first, and then also for smoking and history of head injury. While ever being occupationally exposed to WBV was inversely associated with Parkinson's disease (odds ratio = 0.67, 95% confidence interval: 0.48, 0.94), higher intensities had consistently elevated odds ratios, with a statistically significant effect being noted for intermediate intensities when exposures were restricted to the 10 years or more prior to diagnosis. Possible mechanisms of an inverse relation between low levels of WBV exposure and Parkinson's disease could include direct protective effects or correlation with other protective effects such as exercise. Higher intensities of WBV could result in micro-injury, leading to vascular or inflammatory pathology in susceptible neurons.

Safe cycling: how do risk perceptions compare with observed risk?

OBJECTIVE

Safety concerns deter cycling. The Bicyclists' Injuries and the Cycling Environment (BICE) study quantified the injury risk associated with 14 route types, from off-road paths to major streets. However, when it comes to injury risk, there may be discordance between empirical evidence and perceptions. If so, even if protective infrastructure is built people may not feel safe enough to cycle. This paper reports on the relationship between perceived and observed injury risk.

METHODS

The BICE study is a case-crossover study that recruited 690 injured adult cyclists who visited emergency departments in Toronto and Vancouver. Observed risk was calculated by comparing route types at the injury sites with those at randomly selected control sites along the same route. The perceived risk was the mean response of study participants to the question "How safe do you think this site was for cyclists on that trip?", with responses scored from +1 (very safe) to -1 (very dangerous). Perceived risk scores were only calculated for non-injury control sites, to reduce bias by the injury event.

RESULTS

The route type with the greatest perceived risk was major streets with shared lanes and no parked cars (mean score = -0.21, 95% confidence interval [CI]: -0.54-0.11), followed by major streets without bicycle infrastructure (-0.07, CI -0.14-0.00). The safest perceived routes were paved multi-use paths (0.66, CI 0.43-0.89), residential streets (0.44, CI 0.37-0.51), bike paths (0.42, CI 0.25-0.60) and residential streets marked as bike routes with traffic calming (0.41, CI 0.32-0.51). Most route types that were perceived as higher risk were found to be so in our injury study; similarly, most route types perceived as safer were also found to be so. Discrepancies were observed for cycle tracks (perceived as less safe than observed) and for multiuse paths (perceived as safer than observed).

CONCLUSIONS

Route choices and decisions to cycle are affected by perceptions of safety, and we found that perceptions usually corresponded with observed safety. However, perceptions about certain separated route types did not align well. Education programs and social media may be ways to ensure that public perceptions of route safety reflect the evidence.

Association of Parkinson's disease with infections and occupational exposure to possible vectors

The ultimate causes of idiopathic Parkinson's disease (PD) are not fully known, but environmental and occupational causes are suspected. Postencephalitic parkinsonism has been linked to influenza, and other viral infections have also been suspected to relate to PD. We estimated the relationship between PD and both infections and possible vectors of infection (i.e., animal and human) in a population-based, case-control study in British Columbia, Canada. We recruited 403 cases detected by their use of antiparkinsonian medications and 405 controls from the registrants of the provincial universal health insurance plan. Severe influenza was associated with PD (odds ratio [OR]: 2.01; 95% confidence interval [CI]: 1.16-3.48), although this effect was attenuated when reports were restricted to those occurring 10 or more years before diagnosis. Childhood illnesses were inversely associated with PD, particularly red measles (OR: 0.65; 95% CI: 0.48-0.90). Several animal exposures were associated with PD, with statistically significant effects for cats (OR: 2.06; 95% CI: 1.09-3.92) and cattle (OR: 2.23; 95% CI: 1.22-4.09). Influenza infection may be associated with PD. The inverse relationships with childhood infections may suggest an increased risk with subclinical or asymptomatic childhood infections. Occupational exposure to animals may increase risk through transmission of infections or may indicate exposure to another agent of interest (e.g., bacterial endotoxin).

Contrast ureteropyelography in theatre: standardised flowchart reporting

INTRODUCTION

Urologists perform retrograde contrast studies of the ureters and pelvicalyceal systems in the operating theatre, both for diagnostic purposes and to guide instrumentation. We describe the development of a set of guidelines that aim to standardise the diagnostic quality of these studies and to reduce radiation dose to the patient and theatre staff. The guidelines incorporate a reporting template that allows a urologist's written report to be made available on the picture archiving and com- munication system (PACS) for subsequent multidisciplinary review.

METHODS

Three cycles of audit were conducted to assess the implementation of the guidelines. An independent reviewer rated image quality and screening times. During the audit cycle, the presentation of the guidelines was honed. The end prod- uct is a flowchart and reporting template for use by urologists in the operating theatre.

RESULTS

Phase 1 of the audit included 63 studies, phase 2 included 42 studies and phase 3 included 46 studies. The results demonstrate significant improvements in the number of good quality studies and in the recording of control, contrast and post-procedure images. The mean screening time decreased from 5.0 minutes in phase 1 to 3.2 minutes in phase 3. In phase 3, when in-theatre reporting of the studies by the urologist was added, the handwritten report was scanned in and made available on PACS in 43 of 46 cases (93%). CONCLUSIONS Introduction of guidelines improved retrograde contrast study quality and reduced screening times. A system has been developed to store appropriate pictures and a urologist's report of the study on PACS.

Retrospective assessment of occupational exposure to whole-body vibration for a case-control study

Occupational whole-body vibration is often studied as a risk factor for conditions that may arise soon after exposure, but only rarely have studies examined associations with conditions arising long after occupational exposure has ceased. We aimed to develop a method of constructing previous occupational whole-body vibration exposure metrics from self-reported data collected for a case-control study of Parkinson's disease. A detailed job history and exposure interview was administered to 808 residents of British Columbia, Canada (403 people with Parkinson's disease and 405 healthy controls). Participants were prompted to report exposure to whole-body vibrating equipment. We limited the data to exposure reports deemed to be above background exposures and used the whole-body vibration literature (typically reporting on seated vector sum measurements) to assign intensity (acceleration) values to each type of equipment reported. We created four metrics of exposure (duration of exposure, most intense equipment exposure, and two dose metrics combining duration and intensity) and examined their distributions and correlations. We tested the role of age and gender in predicting whole-body vibration exposure. Thirty-six percent of participants had at least one previous occupational exposure to whole-body vibrating equipment. Because less than half of participants reported exposure, all continuous metrics exhibited positively skewed distributions, although the distribution of most intense equipment exposure was more symmetrically distributed among the exposed. The arithmetic mean of duration of exposure among those exposed was 14.0 (standard deviation, SD: 14.2) work years, while the geometric mean was 6.8 (geometric SD, GSD: 4.5). The intensity of the most intense equipment exposure (among the exposed) had an arithmetic mean of 0.9 (SD: 0.3) m·s(-2) and a geometric mean of 0.8 (GSD: 1.4). Male gender and older age were both associated with exposure, although the effect of age was attenuated after adjustment for gender. The methods developed allowed us to create continuous metrics of whole-body vibration retrospectively, displaying useful variance for epidemiologic studies.

Bmp2 is required for odontoblast differentiation and pulp vasculogenesis

Using the Bmp2 floxed/3.6Col1a1-Cre (Bmp2-cKO(od)) mouse model, we have observed severe defects in odontogenesis and dentin formation with the removal of the Bmp2 gene in early-polarizing odontoblasts. The odontoblasts in the Bmp2-cKO(od) do not mature properly and fail to form proper dentin with normal dentinal tubules and activate terminal differentiation, as reflected by decreased Osterix, Col1a1, and Dspp expression. There is less dentin, and the dentin is hypomineralized and patchy. We also describe an indirect effect of the Bmp2 gene in odontoblasts on formation of the vascular bed and associated pericytes in the pulp. This vascular niche and numbers of CD146+ pericytes are likely controlled by odontogenic and Bmp2-dependent VegfA production in odontoblasts. The complex roles of Bmp2, postulated to be both direct and indirect, lead to permanent defects in the teeth throughout life, and result in teeth with low quantities of dentin and dentin of poor quality.

Invited commentary: Evaluating epidemiologic research methods--the importance of response rate calculation

Epidemiologic research that uses administrative records (rather than registries or clinical surveys) to identify cases for study has been increasingly restricted because of concerns about privacy, making unbiased population-based research less practicable. In their article, Nattinger et al. (Am J Epidemiol. 2010;172(6):637-644) present a method for using administrative data to contact participants that has been well received. However, the methods employed for calculating and reporting response rates require further consideration, particularly the classification of untraceable cases as ineligible. Depending on whether response rates are used to evaluate the potential for bias to influence study results or to evaluate the acceptability of the method of contact, different fractions may be considered. To improve the future study of epidemiologic research methods, a consensus on the calculation and reporting of study response rates should be sought.

Public opinions about participating in health research

OBJECTIVES

Privacy legislation has limited options for recruiting subjects to health studies. Policy changes are motivated by assumptions about public attitudes towards participation, yet surveys of attitudes have rarely been done. We investigated public willingness to participate in health research and how willingness was affected by various factors.

METHODS

A survey of adults randomly selected from the telephone directory was conducted in British Columbia, Canada. Mailed self-administered questionnaires asked about willingness to participate in health research and the influence on willingness of the method of subject selection, the organization making the contact, and other factors.

RESULTS

There were 1,477 respondents (58% of eligible); 85% were willing to participate in health research at least sometimes. The organization making the contact influenced comfort about participation: 10% of respondents felt uncomfortable if contacted by a university, 12% if by a hospital, 26% if by government, and 55% if by private research firms. Factors most positively influencing choice to participate were future health benefits to society (87%) and oneself (87%), and receiving a copy of the study results (81%).

CONCLUSIONS

Participation in health research appears to be viewed favourably by members of the public, and participation may be highest when university or hospital-based researchers are able to contact subjects directly using information from government databases.

Reduction of a large fish tissue analyte database: identifying and assessing data specific to a remediation site for risk assessment application

The Lower Passaic River (LPR) is one of the most heavily industrialized waterways in the US with both historical and continuing discharges of chemicals from point and non-point sources. Significant efforts have been initiated on behalf of public, private, and regulatory entities to restore this degraded urban river. Considerable attention has been devoted to characterizing environmental media with respect to human and ecological risk. As part of these efforts, a wealth of environmental data have been collected and analyzed for a variety of metals, pesticides, organic compounds, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins/furans (PCDD/Fs), and dioxin-like compounds. The objectives of the study described in this paper were two-fold: (1) to generate LPR-specific data for use in human health risk assessment by characterizing concentrations of contaminants in LPR fish tissue samples based on publicly available data using a methodical and transparent approach, and (2) using the resulting data, to calculate the contaminant concentrations in a "Representative Fish," which is a representation of proportional fish tissue concentrations calculated based upon consumption patterns of LPR anglers. The data reduction, processing, and analyses described provide a representative dataset for the conduct of a human health assessment associated with fish consumption from the LPR.

New roles and mechanism of action of BMP4 in postnatal tooth cytodifferentiation

During the phase of overt tooth cytodifferentiation that occurs after birth in the mouse and using the 3.6Collagen1a-Cre and the BMP4 floxed and BMP4 knockout mice, the BMP4 gene was deleted in early collagen producing odontoblasts around postnatal day 1. BMP4 expression was reduced over 90% in alveolar osteoblasts and odontoblasts. There was decreased rate of predentin to dentin formation and decreased mature odontoblast differentiation reflected in reduced DMP1 expression and proper dentinal tubule formation, as well as reduced Collagen type I and Osteocalcin expression. We observed mutant dysmorphogenic odontoblasts that failed to properly elongate and differentiate. The consequence of this failed differentiation process leads to permanent loss of dentin thickness, apparent enlarged pulp chambers in the molars and reduced bone supporting the tooth structures in mice as old as 10-12 months. Deletion of the BMP4 gene in odontoblasts also indirectly disrupted the process of enamel formation that persisted throughout life. The mechanism for this altered differentiation program in the absence of the BMP4 gene in odontoblasts is from decreased BMP signaling, and decreased expression of three key transcription factors, Dlx3, Dlx5, and Osterix. BMP signaling, as well as Dlx3 and Amelogenin expression, is also indirectly reduced in the ameloblasts of the odontoblast BMP4 cKO mice. This supports a key paracrine or endocrine postnatal role of odontoblast derived BMP4 on the proper amelogenesis and formation of the enamel.

Assessment of human health risks posed by consumption of fish from the Lower Passaic River, New Jersey

The Lower Passaic River (LPR) in New Jersey has been impacted by variety of human activities over the course of the last two centuries. In this risk assessment, we assessed potential human health risks associated with consumption of fish from the LPR, the human exposure pathway of greatest concern when addressing contaminated sediments. Our risk assessment incorporates fish consumption information gathered during a year-long, intercept-style creel angler survey and representative fish tissue concentrations for 156 chemicals of potential concern (COPCs) obtained from USEPA's public database (OurPassaic website: http://www.ourpassaic.org/projectsites/premis_public/index.cfm?fuseaction=contaminants). Due to the large number of COPCs investigated, this risk assessment was divided into two phases: (1) identification of COPCs that contribute to the majority of overall excess cancer risk and hazard estimates using deterministic and probabilistic methods, and (2) probabilistic characterization of risk using distributions of chemical concentration and cooking loss for those compounds identified in Phase 1. Phase 1 relied on point estimates of COPC concentrations and demonstrated that PCDD/Fs and PCBs (dioxin-like and non-dioxin-like) are the greatest contributors to cancer risk, while non-dioxin-like PCBs are the primary contributors to non-cancer hazard estimates. Total excess cancer risks for adult and child and receptors estimated in Phase 1 were within USEPA's acceptable excess cancer risk range, with the exception of RME child (3.0 x 10(-4) and 1.3 x 10(-4) for deterministic and probabilistic approaches, respectively). Phase 2 focused on PCDD, PCDF, and PCBs and used distributions of chemical concentrations in fish. The results showed that all excess cancer risk estimates were within the acceptable risk range, although non-cancer hazard estimates for PCBs slightly exceeded a Hazard Index of 1. This HHRA of LPR fish ingestion represents the most comprehensive evaluation conducted to date, and demonstrates that measured concentrations of COPCs are not likely to pose a health risk to people who currently consume fish from the LPR.

Influences of reduced expression of maternal bone morphogenetic protein 2 on mouse embryonic development

Bone morphogenetic protein 2 (BMP2) was originally found by its osteoinductive ability, and recent genetic analyses have revealed that it plays critical roles during early embryogenesis, cardiogenesis, decidualization as well as skeletogenesis. In the course of evaluation of the conditional allele for Bmp2, we found that the presence of a neo cassette, a selection marker needed for gene targeting events in embryonic stem cells, in the 3' untranslated region of exon 3 of Bmp2, reduced the expression levels of Bmp2 both in embryonic and maternal mouse tissues. Some of the embryos that were genotyped as transheterozygous for the floxed allele with the neo cassette over the conventional null allele (fn/-) showed a lethal phenotype including defects in cephalic neural tube closure and ventral abdominal wall closure. The number of embryos exhibiting these abnormalities was increased when, due to different genotypes, expression levels of Bmp2 in maternal tissues were lower. These results suggest that the expression levels of Bmp2 in both embryonic and maternal tissues influence the normal neural tube closure and body wall closure with different thresholds.

Risk of gastrointestinal disease associated with exposure to pathogens in the sediments of the Lower Passaic River

High levels of pathogenic microorganisms have been documented previously in waters of the Lower Passaic River in northern New Jersey. The purpose of this study was to characterize the microbial contamination of river sediments near combined sewer overflows (CSOs), a known source of pathogens. Concentrations of fecal coliform, total coliform, fecal Streptococcus, fecal Enterococcus, Pseudomonas aeruginosa, Staphylococcus aureus, Giardia lamblia, and Cryptosporidium parvum organisms were measured in 16 samples from three mudflat locations along the Lower Passaic River, as well as from an upstream location. Selected samples were also analyzed for antibiotic resistance. All of the samples contained high concentrations of total coliform, fecal coliform, fecal Streptococcus, and fecal Enterococcus organisms. Analysis of isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli from several samples indicated that each strain was resistant to at least one antibiotic typically used in clinical settings. Eight of 16 samples contained Giardia, and one sample contained Cryptosporidium. With these sampling data, a quantitative microbial risk assessment was conducted to evaluate the probability of infection or illness resulting from incidental ingestion of contaminated sediments over a 1-year period. Three potential exposure scenarios were considered: visitor, recreator, and homeless person. Single-event risk was first evaluated for the three individual exposure scenarios; overall risk was then determined over a 1-year period using Monte Carlo techniques to characterize uncertainty. For fecal Streptococcus and Enterococcus, annualized risk estimates for gastrointestinal illness ranged from approximately 0.42 to 0.53 for recreators, 0.07 to 0.10 for visitors, and 0.62 to 0.72 for homeless individuals across the three sampling locations. Annualized risk of Giardia infection ranged from 0.14 to 0.64 for recreators, 0.01 to 0.1 for visitors, and 0.30 to 0.87 for homeless individuals, across all locations where detected. Cryptosporidium was detected at one location, and the corresponding annualized risk of infection was 0.32, 0.05, and 0.51 for recreators, visitors, and homeless individuals, respectively. This risk assessment suggests that pathogen-contaminated sediments near areas of CSO discharge in the Lower Passaic River could pose a health risk to individuals coming into contact with sediments in the mudflat areas.