Epidemiology of child pedestrian casualty rates: can we assume spatial independence?

Neighbourhood characteristics associated with child pedestrian fatalities in Johannesburg, South Africa

The present study investigated the relationship between neighbourhood characteristics and childhood pedestrian fatalities (2001-2010) in Johannesburg, South Africa. This cross-sectional study used negative binomial regression models. Results indicate that: areas with high concentrated disadvantage have elevated childhood pedestrian deaths, especially for those aged 5 to 9 years. Areas marked by residential mobility are associated with high pedestrian deaths among children 0 to 4 years. Black childhood pedestrian deaths are higher in areas marked by a high concentration of female-headed households. The analyses highlight the value of further exploring the effects of neighbourhood characteristics and suggest points of entry for interventions to reduce or prevent childhood pedestrian traffic mortality.

Community-based social determinants of three measures of mortality in Rhode Island cities and towns

Background

Efforts to understand and address the causes of place-based health disparities have focused primarily on understanding the social determinants of health on a large geographic level, such as the region, state, or county. However, there is a growing need to assess and understand how place-based characteristics at smaller geographic areas relate to of local place-based neighborhood characteristics on population health. Therefore, the objective of this study was to evaluate the magnitude of the associations between social determinants of health and life expectancy (LE) and related measures on the community level.

Methods

LE at birth (LE0), remaining LE at age 65 (LE65), and age-specific mortality rates (ASMR) were calculated from mortality data (2009–2011) collected by the Rhode Island Department of Health (RIDoH) using abridged life table methods for each RI city/town. The city/town-specific LE and ASMR were linked to data collected by the US Census, RIDoH, the Federal Bureau of Investigation, and other databases that include information about multiple social, environmental, and demographic determinants of health. Bivariate correlations between city/town-level LE0, LE65, and ASMR and social determinants: demographics, household composition, income and poverty, education, environment, food insecurity, crime, transportation, and rural-urban status were examined.

Results

LE0 (range: 75.9–83.3 years) was strongly associated with the percent of the population with a graduate/professional degree (r = 0.687, p <  0.001), violent crime rate (r = − 0.598, p <  0.001), and per capita income (r = 0.553, p <  0.001). Similar results were observed for ASMR: ASMR was associated with the percent of the population with a graduate/professional degree (r = − 0.596, p <  0.001), violent crime rate (r = 0.450, p = 0.005), and per capita income (r = − 0.533, p < 0.001). The associations between LE65 and social determinants were more attenuated. Of note, none of the measures (LE0, LE65, or ASMR) were associated with any of the race/ethnicity variables.

Conclusions

There are several important place-based characteristics associated with mortality (LE and ASMR) among RI cities/towns. Additionally, some communities had unexpectedly high LE and low ASMR, despite poor social indicators.

Is ethnic density associated with risk of child pedestrian injury? A comparison of inter-census changes in ethnic populations and injury rates

OBJECTIVES

Research on inequalities in child pedestrian injury risk has identified some puzzling trends: although, in general, living in more affluent areas protects children from injury, this is not true for those in some minority ethnic groups. This study aimed to identify whether 'group density' effects are associated with injury risk, and whether taking these into account alters the relationship between area deprivation and injury risk. 'Group density' effects exist when ethnic minorities living in an area with a higher proportion of people from a similar ethnic group enjoy better health than those who live in areas with a lower proportion, even though areas with dense minority ethnic populations can be relatively more materially disadvantaged.

DESIGN

This study utilised variation in minority ethnic densities in London between two census periods to identify any associations between group density and injury risk. Using police data on road traffic injury and population census data from 2001 to 2011, the numbers of 'White,' 'Asian' and 'Black' child pedestrian injuries in an area were modelled as a function of the percentage of the population in that area that are 'White,' 'Asian' and 'Black,' controlling for socio-economic disadvantage and characteristics of the road environment.

RESULTS

There was strong evidence (p < 0.001) of a negative association between 'Black' population density and 'Black' child pedestrian injury risk [incidence (of injury) rate ratios (IRR) 0.575, 95% CI 0.515-0.642]. There was weak evidence (p = 0.083) of a negative association between 'Asian' density and 'Asian' child pedestrian injury risk (IRR 0.901, 95% CI 0.801-1.014) and no evidence (p = 0.412) of an association between 'White' density and 'White' child pedestrian injury risk (IRR 1.075, 95% CI 0.904-1.279). When group density effects are taken into account, area deprivation is associated with injury risk of all ethnic groups.

CONCLUSIONS

Group density appears to protect 'Black' children living in London against pedestrian injury risk. These findings suggest that future research should focus on structural properties of societies to explain the relationships between minority ethnicity and risk.

Multilevel analysis in road safety research

Hierarchical structures in road safety data are receiving increasing attention in the literature and multilevel (ML) models are proposed for appropriately handling the resulting dependences among the observations. However, so far no empirical synthesis exists of the actual added value of ML modelling techniques as compared to other modelling approaches. This paper summarizes the statistical and conceptual background and motivations for multilevel analyses in road safety research. It then provides a review of several ML analyses applied to aggregate and disaggregate (accident) data. In each case, the relevance of ML modelling techniques is assessed by examining whether ML model formulations (i) allow improving the fit of the model to the data, (ii) allow identifying and explaining random variation at specific levels of the hierarchy considered, and (iii) yield different (more correct) conclusions than single-level model formulations with respect to the significance of the parameter estimates. The evidence reviewed offers different conclusions depending on whether the analysis concerns aggregate data or disaggregate data. In the first case, the application of ML analysis techniques appears straightforward and relevant. The studies based on disaggregate accident data, on the other hand, offer mixed findings: computational problems can be encountered, and ML applications are not systematically necessary. The general recommendation concerning disaggregate accident data is to proceed to a preliminary investigation of the necessity of ML analyses and of the additional information to be expected from their application.

Controlling for exposure changes the relationship between ethnicity, deprivation and injury: an observational study of child pedestrian injury rates in London

BACKGROUND

Research has suggested that inequalities in risk exposure may help explain identified ethnic inequalities in child pedestrian injury risk. However, addressing risk exposure in epidemiological research presents theoretical and methodological challenges. This article conceptualises the risk of child pedestrian injury as related to both exposure levels (the quantity of time children spend as pedestrians) and the probability of a hazard where that exposure takes place (the quality of the road environment).

OBJECTIVE

To investigate the sensitivity of results on ethnic inequalities in child pedestrian injury risk in London to control for exposure and hazard levels.

METHODS

Using police records of injury 2000-2009, we modelled the relationship between ethnicity, deprivation and child pedestrian injury rates in London using characteristics of the road environment to control for hazard levels and restricting the analysis to the time of the weekday morning commute (7.00-9.00 am), when most children must make a journey to school, to control for exposure levels.

RESULTS

Controlling for risk exposure in this way fundamentally changed the nature of the relationship between ethnicity, deprivation and child pedestrian injury. During the time of the morning commute to school, 'Black' children were found to have higher pedestrian injury rates in the least-deprived areas.

CONCLUSIONS

To inform effective strategies for reducing injury inequality, it is vital that exposure to risk is both acknowledged and considered.

The road most travelled: the geographic distribution of road traffic injuries in England

BACKGROUND

Both road safety campaigns and epidemiological research into social differences in road traffic injury risk often assume that road traffic injuries occur close to home. While previous work has examined distance from home to site of collision for child pedestrians in local areas, less is known about the geographic distribution of road traffic injuries from other modes. This study explores the distribution of the distance between home residence and collision site (crash distance) by mode of transport, geographic area, and social characteristics in England.

METHODS

Using 10 years of road casualty data collected by the police, we examined the distribution of crash distance by age, sex, injury severity, area deprivation, urban/rural status, year, day of week, and, in London only, ethnic group.

RESULTS

54% of pedestrians, 39% of cyclists, 17% of powered two-wheeler riders and 16% of car occupants were injured within 1 km of home. 82% of pedestrians, 83% of cyclists, 54% of powered two-wheeler and 53% of car occupants were injured within 5 km of home. We found some social and geographic differences in crash distance: for all transport modes injuries tended to occur closer to home in more deprived or urban areas; younger and older pedestrians and cyclists were also injured closer to home. Crash distance appears to have increased over time for pedestrian, cyclist and car occupant injuries, but has decreased over time for powered two-wheeler injuries.

CONCLUSIONS

Injuries from all travel modes tend to occur quite close to home, supporting assumptions made in epidemiological and road safety education literature. However, the trend for increasing crash distance and the social differences identified may have methodological implications for future epidemiological studies on social differences in injury risk.

Penetrating assaults in children: often non-fatal near-miss events with opportunities for prevention in the UK

INTRODUCTION

Media reports portray a growing problem of gun and stab assaults amongst UK children. Recent legislative changes aim to increase integration between services and protect children better. Child victims of gun or stab assaults are at increased risk of reinjury and are therefore vital targets for interventions shown to be effective at preventing violent injury. There is currently a paucity of data with which to inform public debate, guide policy and develop prevention strategies. We therefore aimed to provide contemporary data on the epidemiology and clinical outcomes for intentional gun and stab injuries in children, using a large UK city as a model environment and also to ascertain whether interventions to prevent violent injury are currently in routine use in a sample of UK urban paediatric EDs.

METHODS

A retrospective case series analysis was performed of children (<16 years) attending Emergency Departments (EDs) in a typical major UK city with high levels of deprivation. In addition, we undertook a qualitative survey of a sample of UK urban paediatric EDs regarding their use of violent injury prevention strategies in children.

RESULTS

Contrary to media reports and data from London, rates of gun and stab assault remained unchanged through the study (2003-2008). Although tragic fatal injury can occur, the majority of injuries were minor, with most children not requiring admission. Of those admitted, a minority needed surgery (mainly wound debridement and closure). Socioeconomically deprived, adolescent boys appear to be particularly at risk, with attacks at weekends and in public spaces beyond home and school being more common. Interventions to prevent violent reinjury are not currently employed in paediatric EDs in the 15 most populated urban areas of the UK.

CONCLUSIONS

Patient safety literature emphasises the need to identify near miss events. Media reports of tragic child deaths due to gunshot and stabbing are actually accompanied by large numbers of minor wounds that we should see as near miss events. Measures shown to reduce reinjury in these high-risk groups could now be pursued in the UK for patient safety and child protection purposes.

Traffic safety behaviour among young people in different residential settings: the use of seat belts, bicycle helmets, and reflectors by young people in Sweden

This study examines if, and how, the size of the community in which people live may contribute to explaining differences in traffic safety behaviour (self-reported behaviour regarding the use of seat belts, bicycle helmets and reflectors) among young people in Sweden. The study is based on a Swedish nationwide traffic safety survey with a net sample of 2854 respondents aged 16-25. Ordered logit regressions were performed, and place of residence is shown to have an impact on traffic safety behaviour. The results are presented and discussed in relation to risk exposure and traffic safety facilities in different settings. The implications of the study are considered, and the importance of investigating the way in which young people see traffic safety behaviour is emphasised.

Analyzing heterogeneous accident data from the perspective of accident occurrence

Clustering and classification approaches have been commonly applied in reducing the heterogeneity in accident data. As part of an effort to understand the features of the heterogeneity, this study assessed accident data from the perspective of accident occurrences. Using the rule-based classification method, rough set theory, rules were derived which consisted of indispensable factors to certain accident outcomes and reflected the process of accident occurrences. The occurring frequency of each derived rule was then adopted as the basis for grouping accidents for further analyses. Empirical results showed that rules with high occurring frequencies were largely related to drivers with high-risk characteristics. On the other hand, road facilities played a key role in rules with low-occurring frequencies. The distinctive features indicated the essential differences between the frequently repeated and the sparsely unique processes of accident occurrences. This suggests that the heterogeneity of accident data is not limited to one single factor, such as age, gender or area. Thus, the proposed approach, which takes the process of accident occurrences into consideration, can be a potential alternative to more comprehensively analyze the heterogeneity in accident data.