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Background and aims Bicycling may be less appealing in parts of the world where cycling is less safe. Differences between jurisdictions suggest route design is key to improving safety and increasing ridership. Previous studies faced difficulties in effectively assessing denominators for risk calculations and controlling confounding. This paper describes the advantages of the case-crossover design of the Bicyclists' Injuries and the Cycling Environment study to address these challenges to observational studies of cycling safety. Methods Injured cyclists were recruited from the emergency departments of five hospitals in Vancouver and Toronto, Canada. In 18 months, 690 participants were successfully recruited and interviewed. Each participant was interviewed to map the route of their injury trip, identify the injury site and select two control sites at random from the same route. Infrastructural characteristics at each study site were scored by site observers who were blinded as to whether sites were crash or comparison sites. Analyses will compare infrastructural variables between case and control sites with conditional logistic regression. Discussion This study presents a novel application of the case-crossover design to the evaluation of relationships between infrastructure and cycling safety while controlling confounders and exposure to risk. It is hoped that the value of this method and the efficiency of the recruitment process will encourage replication in other locations, to expand the range of cycling infrastructure compared and to facilitate evidence-based cycling infrastructure choices that can make cycling safer and more appealing. [ABSTRACT FROM AUTHOR]

In this paper some methodological problems particularly relevant to case-control studies of injury are illustrated by reference to previous childhood injury case-control studies. In contrast to studies of disease, where 'person time' constitutes the observational experience of interest, in injury studies person time engaged in a particular activity is often more appropriate. The implications for the definition of the study base are discussed. The potential for hospital admission bias in injury case-control studies is considered along with potential strategies for avoiding it. The importance of errors in exposure measurement, including those arising from inappropriate induction time assumptions, are illustrated. Finally, the potential for bias resulting from the combination of etiologically unrelated injury outcomes into a single outcome measure is illustrated and discussed. [ABSTRACT FROM AUTHOR]

Background Childhood falls are an important global public health problem, but there is lack of evidence about their prevention. Falls on one level result in considerable morbidity and they are costly to health services. Objective To estimate ORs for falls on one level in children aged 0-4 years for a range of safety behaviours, safety equipment use and home hazards. Design, setting and participants Multicentre case-control study at hospitals, minor injury units and general practices in and around four UK study centres. Participants included 582 children less than 5 years of age with a medically attended fall injury occurring at home and 2460 controls matched on age, sex, calendar time and study centre. Main outcome measure Fall on one level. Results Cases' most common injuries were bangs on the head (52%), cuts or grazes not needing stitches (29%) or cuts or grazes needing stitches (17%). Comparing cases to community controls in the adjusted analyses, significant findings were observed for only two exposures. Injured children were significantly less likely to live in a household without furniture corner covers (adjusted OR (AOR) 0.72, 95% CI 0.55 to 0.95), or without rugs and carpets firmly fixed to the floor (AOR 0.76, 95% CI 0.59 to 0.98). Conclusions We did not find any safety practices, use of safety equipment or home hazards associated with a reduced risk of fall on one level. Our findings do not provide evidence to support changes to current injury prevention practice. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether the occupants in vehicles with better safety ratings according to EuroNCAP sustain fewer fatal and severe injuries than occupants in vehicles with worse experimental safety ratings when in frontal crashes. Design: Caseecontrol study. Setting: A representative sample of crashes in Britain from 1996 to 2008 as gathered in the Cooperative Crash Injury Study (CCIS) database under the auspices of the UK Department of Transportation and augmented with EuroNCAP experimental ratings for each crashed vehicle. Subjects: Drivers and front seat passengers while occupants of vehicles for which EuroNCAP test results were available and who met inclusion criteria meant to select those in crashes similar to those in the frontal experimental setting. Main outcome measures: Fatality and severe MAIS3+ injuries to the head, thorax, pelvis and lower extremities. Results: The multivariate Poisson regression models on the 1259 cases who sustained crash conditions most similar to the experimental ones showed no statistically significant effect on either mortality or MAIS3+ injury in real-world crashes when travelling in cars with better safety ratings. For example, when compared to a driver in a vehicle rated as safest for head injuries MAIS3+ in frontal crashes, drivers in vehicles rated yellow or orange presented adjusted ORs of 0.6 (0.2 to 1.7) and 0.8 (0.3 to 2.1), respectively. Conclusions: No statistically significant relationships between the EuroNCAP safety scores and real-world death or severe injury outcomes were found, suggesting the need to review biomechanical criteria chosen to set cut-off points for the rating system. [ABSTRACT FROM AUTHOR]

Objective Assess the association between caregiver supervision and acute unintentional injury in young children; evaluate whether lower levels of supervision result in more severe injury. Methods A case cross-over study was conducted. Parents of children aged ≤4 years whose injuries required emergency department (ED sample) treatment or admission to the hospital (inpatient sample) were interviewed. Information on supervision (3 dimensions: proximity, attention, continuity) at the time of injury and 1 h before the injury (control time) was collected. An overall supervision score was created; a higher score indicates closer supervision. Hospital admission served as a proxy for injury severity. ORs and 95% CIs were calculated. Results Interviews were completed by 222 participants; 50 (23%) were in the inpatient sample. For each supervision dimension the inpatient sample had higher odds of injury, indicating effect modification requiring separate analyses for inpatient and ED samples. For both samples, proximity ‘beyond reach' was associated with the highest odds of injury; compared with 1 h before injury, children were more likely to be beyond reach of their caregiver at the time of injury (inpatient sample: OR 11.5, 95% CI 2.7 to 48.8; ED sample: OR 2.9, 95% CI 1.8 to 4.9). Children with lower supervision scores had the greatest odds of injury (inpatient sample: OR 8.0, 95% CI 2.4 to 26.6; ED sample: OR 3.3, 95% CI 1.9 to 5.6). Conclusions Lower levels of adult supervision are associated with higher odds of more severe injury in young children. Proximity is the most important supervision dimension for reducing injury risk. [ABSTRACT FROM AUTHOR]

Objective. To determine the risk factors for serious injury to bicyclists, aside from helmet use. Design. Prospective case-control study. Setting. Seven Seattle area hospital emergency departments and two county medical examiner’s offices. Patients. Individuals treated in the emergency department or dying from bicycle related injuries. Measurements. Information collected from injured bicyclists or their parents by questionnaire on circumstances of the crash; abstract of medical records for injury data. Serious injury defined as an injury severity score>8. Analysis. Odd ratios computed using the maximum likelihood method, and adjusted using unconditional logistic regression. Results.There were 3854 injured cyclists in the three year period; 3390 (88%) completed questionnaires were returned. 51% wore helmets at the time of crash. Only 22.3% of patients had head injuries and 34% had facial injuries. Risk of serious injury was increased by collision with a motor vehicle (odds ratio (OR)=4.6), self reported speed >15 mph (OR=1.2), young age (<6 years), and age >39 years (OR=2.1 and 2.2 respectively, compared with adults 20-39 years). Risk for serious injury was not affected by helmet use (OR=0.9). Risk of neck injury was increased in those struck by motor vehicles (OR=4.0), hospitalized for any injury (OR=2.0), and those who died (OR=15.1), but neck injury was not affected by helmet use. Conclusions. Prevention of serious bicycle injuries cannot be accomplished through helmet use alone, and may require separation of cyclists from motor vehicles, and delaying cycling until children are developmentally ready. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether the Victorian mandatory personal flotation device wearing regulations that came into effect on 1 December 2005 reduced drowning deaths among recreational boaters in Victoria, Australia. Design: A retrospective population-based ‘before and after’ study using Victorian coronial data on drowning deaths of occupants of recreational vessels operating in Victorian waters. Methods: The annual numbers of deaths in the 5 years after the transition year of the regulations (2005) was compared with the annual numbers of deaths in the 6 years prior to the transition year, using the Mann- Whitney U test. Results: There were 59 recreational boating drowning deaths in the 6-year preintervention period (1 December 1998 to 30 November 2004) compared with 16 in the 5-year postintervention period (1 December 2005 to 30 November 2010). The analysis showed a significant decrease in drowning deaths among all recreational boaters (U=30.0, p=0.01) and among these strata: vessel occupants aged 0–29 years (U=28.0, p=0.02) and 30–59 years (U=27.5, p=0.02), vessel occupants engaged in pleasure cruising (U=29.0, p=0.01) and in ‘other’ boating activities (U=25.0, p=0.04), boaters on small powerboats ≤4.8 m in length (U=29.5; p=0.01), boaters on motorised (U=29.5; p=0.01) and sail-powered vessels (U=26.0; p=0.04), and occupants of vessels operating in inland waterways (U=30.0; p=0.01). Conclusions: These findings provide further support for the adoption of a regulatory approach to personal flotation device wearing to reduce drowning among recreational boaters. [ABSTRACT FROM AUTHOR]

Background: Scalds are one of the most common forms of thermal injury in young children worldwide. Childhood scald injuries, which mostly occur in the home, result in substantial health service use and considerable morbidity and mortality. There is little research on effective interventions to prevent scald injuries in young children. Objectives: To determine the relationship between a range of modifiable risk factors for medically attended scalds in children under the age of 5 years. Design: A multicentre case-control study in UK hospitals and minor injury units with parallel home observation to validate parental reported exposures. Cases will be 0–4 years old with a medically attended scald injury which occurred in their home or garden, matched on gender and age with community controls. An additional control group will comprise unmatched hospital controls drawn from children aged 0–4 years attending the same hospitals and minor injury units for other types of injury. Conditional logistic regression will be used for the analysis of cases and matched controls, and unconditional logistic regression for the analysis of cases and unmatched controls to estimate ORs and 95% CI, adjusted and unadjusted for confounding variables. Main exposure measures: Use of safety equipment and safety practices for scald prevention and scald hazards. Discussion: This large case-control study will investigate modifiable risk factors for scalds injuries, adjust for potential confounders and validate measures of exposure. Its findings will enhance the evidence base for prevention of scalds injuries in young children. [ABSTRACT FROM AUTHOR]

Background: Childhood unintentional and suspected poisonings are a serious public health problem. Evidence from systematic reviews demonstrates that home safety education in combination with safety equipment provision increases the safe storage of medicines and other products. There is lack of evidence that poisoning prevention practices reduce poisoning rates. Objectives: To estimate ORs for medically attended poisonings in children aged 0–4 years for items of safety equipment, home hazards and parental safety practices aimed at preventing poisoning, and to explore differential effects by child and family factors. Design: Multicentre case-control study in UK hospitals with validation of parent-reported exposures using home observations. Cases are aged 0–4 years with a medically attended poisoning occurring at home, matched on age and sex with community controls. Children attending hospital for other types of injury will serve as unmatched hospital controls. Matched analyses will use conditional logistic regression; unmatched analyses will use unconditional logistic regression to adjust for confounding variables. The study requires 266 poisoning cases and 1064 matched controls to detect an OR of 0.64 for safe storage of medicinal products and of 0.65 for non-medicinal products, with 80% power, a 5% significance level and a correlation between exposures in cases and controls of 0.1. Main outcome measures: Unintentional childhood poisoning. Discussion: This will be the largest study to date exploring modifiable risk factors for poisoning in young children. Findings will inform: policy makers developing poison prevention strategies, practitioners delivering poison prevention interventions, parents to reduce the risk of poisoning in their homes. [ABSTRACT FROM AUTHOR]

Objective: To measure the validity of safety behaviours, safety equipment use and hazards reported on a questionnaire by parents/carers with children aged under 5 years participating in a series of home safety case-control studies. Methods: The questionnaire measured safety behaviours, safety equipment use and hazards being used as exposures in five case-control studies. Responses to questions were compared with observations made during a home visit. The researchers making observations were blind to questionnaire responses. Results: In total, 162 families participated in the study. Overall agreement between reported and observed values of the safety practices ranged from 48.5% to 97.3%. Only 3 safety practices (stair gate at the top of stairs, stair gate at the bottom of stairs, stairs are carpeted) had substantial agreement based on the κ statistic (k=0.65, 0.72, 0.74, respectively). Sensitivity was high (≥70%) for 19 of the 30 safety practices, and specificity was high (≥70%) for 20 of the 30 practices. Overall for 24 safety practices, a higher proportion of respondents over-reported than under-reported safe practice (negative predictive value>positive predictive value). For six safety practices, a higher proportion of respondents under-reported than over-reported safe practice (negative predictive value

Objective This study investigated the relationship between the number of different medications dispensed (NDMD) to senior drivers and the risk of injurious road traffic crashes (RTCs). Design A matched case-control study with data from various population-based national registers was conducted. Cases were drivers aged 50-80 years involved in a crash in Sweden between 2005 and 2009. Only the first non-alcohol-related RTC was studied. Controls were residents with a valid license who did not crash. Four controls were matched by sex, age (year and month of birth), and place of residence. Exposure to NDMD prior to the crash date was assessed using four time periods: 1-8, 1-15, 1-30 and 1-90 days. Conditional logistic regression was used and analyses adjusted for civil status, occupation and dispensation of medications affecting the cardiovascular or nervous systems (C/N). Results ORs (95% CI) increased progressively with the NDMD. For 1-8 days the OR ranged from 1.15 (1.10 to 1.20) for 1-2 medications to 1.27 (1.13 to 1.42) for five or more medications. The magnitude of the effect declined gradually with longer exposure periods, but remained when five or more medications were used. Adjusting for C/N medications resulted in slightly higher effects; for 1-8 days it ranged from 1.16 (1.10 to 1.23) for 1-2 medications to 1.35 (1.17 to 1.56) for five or more, with similar trends by exposure period. The highest effects were seen for single crashes and for drivers aged 66-80 years. Conclusions The NDMD was linked to the likelihood of a senior driver being involved in an injurious RTC. The strength of the association steadily increased with increased NDMD, especially when medications were taken closer to the index date, or when more than five medications were dispensed. [ABSTRACT FROM AUTHOR]

Objectives Many colleges assess criminal histories during the admissions process, in part, to address violence on campus. This study sought to examine the utility of screening as a means of reducing violence. Methods Using cohort and case-control analyses, we identified college misconduct through college records and self-reports on a confidential survey of graduating seniors, and examined precollege behaviour as indicated on admissions records, a survey and criminal background checks. Results One hundred and twenty students met our case definition of college misconduct, with an estimated OR of 5.28 (95% CI 1.92 to 14.48) associated with precollege misconduct revealed on the college application. However, only 3.3% (95% CI 1.0% to 8.0%) of college seniors engaging in college misconduct had reported precollege criminal behaviours on their applications and 8.5% (95% CI 2.4% to 20.4%) of applicants with a criminal history engaged in misconduct during college. Discussion Though precollege behaviour is a risk factor for college misconduct, screening questions on the application are not adequate to detect which students will engage in college misconduct. This pilot work would benefit from replication to determine the utility of criminal background investigations as part of admissions. [ABSTRACT FROM AUTHOR]

Background This study examined the impact of transportation infrastructure at intersection and nonintersection 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. [ABSTRACT FROM AUTHOR]

Background It is globally reported that young children are at a higher risk of burns but little is known about the individual risk factors. This study was undertaken in 2008 to investigate factors associated with burn injuries in children aged 0-5 years. Methods This was a case-control study with cases recruited prospectively from children attending hospital for a new burn injury and controls recruited from children admitted for other conditions. Results A total of 248 cases and 248 controls were recruited. Cases included scalds (79%), contact burns (17%) and flame injuries (4%). Burns were most commonly caused by tea utensils (42%) and kerosene stoves (36%). Multivariable analyses found that a poor living standard (OR 5.4, 95% CI 2.6 to 11.7), having a child with a higher activity score (OR 5.3, 95% CI 3.4 to 8.5), having a history of burns in other family members (OR 2.8, 95% CI 1.5 to 5.2) and a higher number of home hazards (OR for a one unit increase in hazards score 1.32, 95% CI 1.02 to 1.70) were all associated with a significant increase in the odds of a burn injury. The presence of a second carer (OR 0.42, 95% CI 0.2 to 0.7) and having disability (OR 0.14, 95% CI 0.03 to 0.6) were protective factors. Conclusions This information about risk factors for burn injuries can be used to target preventive interventions towards families at the greatest risk of injury. [ABSTRACT FROM AUTHOR]

BACKGROUND: Unintentional falls from windows are an important cause of paediatric morbidity. There have been no controlled studies to identify modifiable environmental risk factors for window falls in young children. The authors have piloted a case–control study to test procedures for case identification, subject enrolment, and environmental data collection. METHODS: Case windows were identified when a child 0–9 years old presented for care after a fall from that window. Control windows were identified (1) from the child's home and (2) from the home of an age- and gender-matched child seeking care for an injury diagnosis not related to a window fall. Study staff visited enrolled homes to collect window measurements and conduct window screen performance tests. RESULTS: The authors enrolled and collected data on 18 case windows, 18 in-home controls, and 14 matched community controls. Six potential community controls were contacted for every one enrolled. Families who completed the home visit viewed study procedures positively. Case windows were more likely than community controls to be horizontal sliders (100% vs 50%), to have deeper sills (6.28 vs 4.31 inches), to be higher above the exterior surface (183 vs 82 inches), and to have screens that failed below a threshold derived from the static pressure of a 3-year-old leaning against the mesh (60.0% vs 16.7%). Case windows varied very little from in-home controls. DISCUSSION: Case–control methodology can be used to study risk factors for paediatric falls from windows. Recruitment of community controls is challenging but essential, because in-home controls tend to be over-matched on important variables. A home visit allows direct measurement of window type, height, sill depth, and screen performance. These variables should all be investigated in subsequent, larger studies covering major housing markets. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explore the effects of working conditions of private-bus drivers on bus crashes in Kandy district, Sri Lanka. METHODS: A case–control study was carried out from August to September 2006. All private-bus drivers registered in Kandy district and involved in crashes reported to the police between November 2005 and April 2006 (n = 63) were selected as cases. Two control groups were included: private-bus drivers working on the same routes as the case drivers (n = 90) and private-bus drivers selected randomly from other routes of the district (n = 111). Data were collected using an anonymous self-administered questionnaire. Associations between working conditions and crashes were analysed using logistic regression. RESULTS: A strong association was observed between drivers’ disagreements about working hours and bus crashes (matched controls, adjusted odds ratio (AOR) 5.98, 95% CI 1.02 to 34.90; unmatched controls, AOR 18.74, 95% CI 2.00 to 175.84). A significant association was also observed between low salaries (

Objectives-To examine the association between sensory deficit and the risk of child pedestrian-motor vehicle collisions. Setting-The Auckland region of New Zealand. Methods-A community based case-control study was conducted. Cases (n= 190) were all children (<15 years) killed or hospitalised as a result of a pedestrian injury occurring on a public road between 1 January 1992 and 1 March 1994. Controls (n = 479) were a random sample of the child population. Results-The risk of pedestrian injury for children whose parents reported abnormal vision was over four times that of children with reported normal vision (odds ratio = 4.25,95% confidence interval 1-68 to 10-8). The risk of injury for children whose parents reported abnormal hearing was close to twice that ofchildren with reported normal hearing (odds ratio = 1-73, 95% confidence interval 0-83 to 3-61). Conclusions-Children with sensory deficits constitute a high risk group for pedestrian injuries. Paediatricians caring for children with sensory impairments should be aware of this increased risk. [ABSTRACT FROM AUTHOR]

Objective To provide an overview of the two-stage case-control study design and its potential application to ED injury surveillance data and to apply this approach to published ED data on the relation between brain injury and bicycle helmet use. Methods Relevant background is presented on injury aetiology and case-control methodology with extension to the two-stage case-control design in the context of ED injury surveillance. The design is then applied to data from a published case-control study of the relation between brain injury and bicycle helmet use with motor vehicle involvement considered as a potential confounder. Taking into account the additional sampling at the second stage, the adjusted and corrected odds ratio and 95% confidence interval for the brain injury-helmet use relation is presented and compared with the estimate from the entire original dataset. Contexts where the two-stage case-control study design might be most appropriately applied to ED injury surveillance data are suggested. Results The adjusted odds ratio for the relation between brain injury and bicycle helmet use based on all data (n=2833) from the original study was 0.34 (95% CI 0.25 to 0.46) compared with an estimate from a two-stage case-control design of 0.35 (95% CI 0.25 to 0.48) using only a fraction of the original subjects (n=480). Conclusion Application of the two-stage case-control study design to ED injury surveillance data has the potential to dramatically reduce study time and resource costs with acceptable losses in statistical efficiency. [ABSTRACT FROM AUTHOR]