Who is in the near market for bicycle sharing? Identifying current, potential, and unlikely users of a public bicycle share program in Vancouver, Canada.

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.

Bike Score®: Associations between urban bikeability and cycling behavior in 24 cities.

BACKGROUND: There is growing interest in designing cities that support not only walking, but also cycling. Bike Score® is a metric capturing environmental characteristics associated with cycling that is now available for over 160 US and Canadian cities. Our aim was to determine if Bike Score was associated with between and within-city variability in cycling behavior. METHODS: We used linear regression to model associations between Bike Score and journey to work cycling mode share (US: American Community Survey, 2013 or 2012 5-year estimates; Canada: 2011 National Household Survey) for 5664 census tracts in 24 US and Canadian cities. RESULTS: At the city level, the correlation between mean Bike Score and mean journey to work cycling mode share was moderate (r = 0.52). At the census tract level, the correlation was 0.35; a ten-unit increase in Bike Score was associated with a 0.5% (95% CI: 0.5 to 0.6) increase in the proportion of population cycling to work, a meaningful difference given the low modal shares (mean = 1.9%) in many North American cities. Census tracts with the highest Bike Scores (>90 to 100) had mode shares 4.0 higher (ß = 4.0, 95% CI: 2.9 to 5.0) than the lowest Bike Score areas (0-25). City specific analyses indicated between-city variability in associations, with regression estimates between Bike Score and mode share ranging from 0.2 to 3.5%. CONCLUSIONS: The Bike Score metric was associated bicycle mode share between and within cities, suggesting its utility for planning bicycle infrastructure.

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.

Antineoplastic drug contamination in the urine of Canadian healthcare workers.

PURPOSE: The purpose of this study was to quantify the urine concentration of non-metabolized cyclophosphamide (CP), a commonly administered antineoplastic drug, among potentially exposed Canadian healthcare workers and to identify factors associated with the drug concentration levels. METHODS: Participants were asked to provide two sets of 24-h urine samples (at two different sampling events), and the level of CP was quantified using high-performance liquid chromatography-tandem mass spectrometry. In addition to demographic information, participants were surveyed regarding their frequency of handling of antineoplastic drugs, safe drug handling training, and known contact with CP on their work shift. Descriptive and inferential statistical analyses were performed. A backward stepwise linear mixed effect model was conducted to identify the factors associated with urine concentration levels. RESULTS: We collected 201 urine samples, and 55 % (n = 111) had levels greater than the LOD of 0.05 ng/mL. The mean urinary CP concentration was 0.156 ng/mL, the geometric mean was 0.067 ng/mL, the geometric standard deviation was 3.18, the 75th percentile was 0.129 ng/mL, and the range was

Health Care Workers' Knowledge, Perceptions, and Behaviors Regarding Antineoplastic Drugs: Survey From British Columbia, Canada.

Although nurses are knowledgeable regarding the risk of exposure to antineoplastic drugs, they often do not adhere with safe work practices. However, the knowledge, perceptions, and behavior of other health care job categories at risk of exposure has yet to be determined. This study aimed to survey a range of health care workers from British Columbia, Canada about their knowledge, perceptions, and behaviors regarding antineoplastic drugs. A self-administered questionnaire was sent to participants querying the degree of contact with antineoplastics, knowledge of risks associated with antineoplastics, perceptions of personal risk, previous training with respect to antineoplastics, and safe work practices. Subjects were recruited from health care facilities in and around Vancouver. Fisher's exact tests were performed to ascertain whether there were differences in responses between job categories. We received responses from 120 participants representing seven different job categories. Pharmacists, pharmacy technicians, and nurses were more knowledgeable regarding risks than other job categories examined (statistically significant difference). Although 80% of respondents were not afraid of working with or near antineoplastics, there were concerns about the suitability of current control measures and practices employed by co-workers. Only half of respondents felt confident that they could handle all situations where there was a potential for exposure. Only one of the perception questions, self-perceived risk of exposure to antineoplastic drugs, differed significantly between job categories. Not all respondents always wore gloves when directly handling antineoplastic drugs. Further, hand hygiene was not regularly practiced after glove usage or after being in an area where antineoplastic drugs are handled. The majority of responses to questions related to safe work practices differed significantly between job categories. Our results suggest that knowledge regarding risks associated with antineoplastic drugs can be improved, especially among job categories that are not tasked with drug preparation or drug administration. There is also a gap between knowledge and compliance with glove usage and hand hygiene.Training is also recommended to improve health care workers' perceptions of the risks associated with antineoplastic drugs.

Antineoplastic drug contamination on the hands of employees working throughout the hospital medication system.

We previously reported that antineoplastic drug contamination is found on various work surfaces situated throughout the hospital medication system (process flow of drug within a facility from initial delivery to waste disposal). The presence of drug residual on surfaces suggests that healthcare workers involved in some capacity with the system may be exposed through dermal contact. The purpose of this paper was to determine the dermal contamination levels of healthcare employees working throughout a hospital and to identify factors that may influence dermal contamination. We selected participants from six hospitals and wiped the front and back of workers' hands. Wipe samples were analyzed for cyclophosphamide (CP), a commonly used antineoplastic drug, using high-performance liquid chromatography-tandem mass spectrometry. Participants were asked about their frequency of handling antineoplastic drugs, known contact with CP on their work shift, gender, job title, and safe drug handling training. In addition, participants were surveyed regarding their glove usage and hand washing practices prior to wipe sample collection. We collected a total of 225 wipe samples. Only 20% (N = 44) were above the limit of detection (LOD) of 0.36ng per wipe. The average concentration was 0.36ng per wipe, the geometric mean < LOD, the geometric standard deviation 1.98, and the range < LOD to 22.8ng per wipe. Hospital employees were classified into eight different job categories and all categories had some dermal contamination levels in excess of the LOD. The job category with the highest proportion of samples greater than the LOD were those workers in the drug administration unit who were not responsible for drug administration (volunteer, oncologist, ward aide, dietician). Of note, the highest recorded concentration was from a worker who had no known contact with CP on their work shift. Our results suggest that a broader range of healthcare workers than previously believed, including those that do not directly handle or administer the drugs (e.g. unit clerks, ward aides, dieticians, and shipper/receivers), are at risk of exposure to antineoplastic drugs. A review of control measures to minimize antineoplastic drug exposure that encompasses a wide array of healthcare workers involved with the hospital medication system is recommended.

Evaluating the impact of environmental interventions across 2 countries: the International Bikeshare Impacts on Cycling and Collisions Study (IBICCS) Study protocol.

BACKGROUND: Few international studies examine public bicycle share programs (PBSP) health impacts. We describe the protocol for the International Bikeshare Impacts on Cycling and Collisions Study (IBICCS). METHODS: A quasi-experimental non-equivalent groups design was used. Intervention cities (Montreal, Toronto, Boston, New York and Vancouver) were matched to control cities (Chicago, Detroit, and Philadelphia) on total population, population density, cycling rates, and average yearly temperature. The study used three repeated, cross-sectional surveys in intervention and control cities in Fall 2012 (baseline), 2013 (year 1), and 2014 (year 2). A non-probabilistic online panel survey with a sampling frame of individuals residing in and around areas where PBSP are/would be implemented was used. A total of 12,000 respondents will be sampled. In each of the 8 cities 1000 respondents will be sampled with an additional 4000 respondents sampled based on the total population of the city. Survey questions include measures of self-rated health, and self-reported height and weight, knowledge and experience using PBSP, physical activity, bicycle helmet use and history of collisions and injuries while cycling, socio-demographic questions, and home/workplace locations. Respondents could complete questionnaires in English, French, and Spanish. Two weights will be applied to the data: inverse probability of selection and post-stratification on age and sex.A triple difference analysis will be used. This approach includes in the models, time, exposure, and treatment group, and interaction terms between these variables to estimate changes across time, between exposure groups and between cities. DISCUSSION: There are scientific and practical challenges in evaluating PBSP. Methodological challenges included: appropriate sample recruitment, exchangeability of treatment and control groups, controlling unmeasured confounding, and specifying exposure. Practical challenges arise in the evaluation of environmental interventions such as a PBSP: one of the companies involved filed for bankruptcy, a Hurricane devastated New York City, and one PBSP was not implemented. Overall, this protocol provides methodological and practical guidance for researchers wanting to study PBSP impacts on health.

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.

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.

Head injuries and Parkinson's disease in a case-control study.

BACKGROUND: Head injury is a hypothesised risk factor for Parkinson's disease, but there is a knowledge gap concerning the potential effect of injury circumstances (eg, work-related injuries) on risk. The objective of this study is to address this gap while addressing issues of recall bias and potential for reverse causation by prediagnosis symptoms. METHODS: We conducted a population based case-control study of Parkinson's disease in British Columbia, Canada (403 cases, 405 controls). Interviews queried injury history; whether injuries occurred at work, in a motor vehicle accident or during sports. Participants were also asked to report their suspicions about the causes of Parkinson's disease to provide an indicator of potential recall bias. Associations were estimated with logistic regression, adjusted for age, sex and smoking history. RESULTS: Associations were strongest for injuries involving concussion (OR: 2.08, 95% CI 1.30 to 3.33) and unconsciousness (OR: 2.64, 95% CI 1.39 to 5.03). Effects remained for injuries that occurred long before diagnosis and after adjustment for suspicion of head injury as a cause of Parkinson's disease. Injuries that occurred at work were consistently associated with stronger ORs, although small numbers meant that estimates were not statistically significant. CONCLUSIONS: This study adds to the body of literature suggesting a link between head injury and Parkinson's disease and indicates further scrutiny of workplace incurred head injuries is warranted.

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.

Antineoplastic drug contamination of surfaces throughout the hospital medication system in Canadian hospitals.

We previously reported that there is a potential for antineoplastic drug contamination throughout the hospital medication system (process flow of drug within a facility from delivery to waste disposal) due to the various surfaces contacted by health care workers. This article describes the contamination of these frequently contacted surfaces as well as identifies factors that may be associated with surface contamination. Surfaces which health care workers frequently contact were wiped and the concentration of cyclophosphamide (CP) was determined using high-performance liquid chromatography-tandem mass spectrometry. Descriptive and inferential statistical analyses were performed. A backward stepwise multiple linear regression was conducted to identify determinants associated with surface contamination. Overall, 229 surfaces were sampled, most on two occasions, for a total of 438 surface wipes. The mean CP concentration was 0.201 ng/cm(2), the geometric mean 0.019 ng/cm(2), and the geometric standard deviation 2.54, with a range of less than detection (LOD) to 26.1 ng/cm(2). (Method LOD was 0.356 ng/wipe; factoring in the surface area of the wiped surface, results in a sample LOD ranging from 0.00 to 0.049 ng/cm(2)). Our study found that frequently contacted surfaces at every stage of the hospital medication system had measureable levels of antineoplastic drug contamination. Two factors were statistically significant with respect to their association with surface contamination: (1) the stage of the hospital medication system, and (2) the number of job categories responsible for drug transport. The drug preparation stage had the highest average contamination. Those hospitals that had two or more drug transport job categories had higher levels of surface contamination. Neither the reported handling of CP prior to wipe sampling nor the cleaning of surfaces appeared to be associated with contamination.

Anthropometry-corrected exposure modeling as a method to improve trunk posture assessment with a single inclinometer.

Measuring trunk posture in the workplace commonly involves subjective observation or self-report methods or the use of costly and time-consuming motion analysis systems (current gold standard). This work compared trunk inclination measurements using a simple data-logging inclinometer with trunk flexion measurements using a motion analysis system, and evaluated adding measures of subject anthropometry to exposure prediction models to improve the agreement between the two methods. Simulated lifting tasks (n=36) were performed by eight participants, and trunk postures were simultaneously measured with each method. There were significant differences between the two methods, with the inclinometer initially explaining 47% of the variance in the motion analysis measurements. However, adding one key anthropometric parameter (lower arm length) to the inclinometer-based trunk flexion prediction model reduced the differences between the two systems and accounted for 79% of the motion analysis method's variance. Although caution must be applied when generalizing lower-arm length as a correction factor, the overall strategy of anthropometric modeling is a novel contribution. In this lifting-based study, by accounting for subject anthropometry, a single, simple data-logging inclinometer shows promise for trunk posture measurement and may have utility in larger-scale field studies where similar types of tasks are performed.

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.

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).

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.

Recruitment of healthy first-trimester pregnant women: lessons from the Chemicals, Health & Pregnancy study (CHirP).

To describe and evaluate recruitment techniques used to enroll 152 healthy pregnant women fewer than 15 weeks gestation into a prospective study of environmental chemical exposure during pregnancy. Posters, a website, online and print advertising, recruitment emails, media coverage, recruitment from clinic waiting rooms, networking within the pregnancy community and presenting a study booth at baby "trade shows" were used to advertise the study. Participants had to meet a strict set of eligibility criteria, and were asked to donate two-second-trimester blood samples, complete two questionnaires, have samples of air, dust, lint and tap water collected from their homes, and donate a cord blood sample at delivery. Over 17 months, 171 women enrolled (49% of initial contacts, and 99% of all eligible women) and 152 women completed the study (89% retention). Total recruitment costs were approximately $400 Cdn per final participant. Posters, study booth presentations and online advertising generated the most inquiries about the study. Word of mouth, referral from another study and direct email were the most cost-effective strategies. Not surprisingly, the recruited study population was less ethnically diverse, more affluent and more educated than the background population of pregnant women in Vancouver. A combination of passive and active recruitment techniques were successful for recruiting healthy women in roughly the first trimester of pregnancy (<15 weeks gestation). While a convenience sample of women is suitable for our study questions, additional strategies may be required to recruit a more representative pregnant population in future studies.

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.

Wood dust exposure and risk of lung cancer.

OBJECTIVES: Despite the compelling association between wood dust and sinonasal cancer, there has been little systematic and rigorous study of the relationship between wood dust and lung cancer. We investigated whether a history of wood dust exposure through occupational and hobby-related activities was associated with increased lung cancer risk. METHODS: We conducted a population-based case-control study, with 440 cases and 845 age-matched controls. Using detailed work and personal histories, quantitative estimates of cumulative exposure to wood dust (thought to be primarily from softwood) were calculated for each participant. Using unconditional logistic regression adjusted for age and smoking status, risk of lung cancer was examined in relation to employment in wood-related occupations, working with wood as a hobby, as well as cumulative wood dust exposure that took into account both occupational and hobby-related sources. RESULTS: While we observed an increased risk of lung cancer associated with working in a sawmill (OR=1.5; 95% CI: 1.1, 2.1), we found no evidence of increased risks with other occupations, working with wood as a hobby or with estimated cumulative exposure to wood dust. Contrary to our hypothesis, we observed modest decreased risks with exposure to wood dust, although no dose-response relationship was apparent. CONCLUSIONS: This study provided somewhat reassuring evidence that softwood dust does not increase the risk of lung cancer, but future studies should evaluate exposure to hardwood dusts. Suggestive evidence for an inverse association may be attributable to the presence of endotoxin in the wood dust, but the lack of a dose-response relationship suggests a non-causal relationship.