Sickness absence and disability pension after road traffic accidents, a nationwide register-based study comparing different road user groups with matched references

Background

Being injured in a road traffic accident may affect individuals' functional ability and in turn lead to sickness absence (SA) and disability pension (DP). Knowledge regarding long-term consequences in terms of SA and DP following a road traffic accident is lacking, especially comparing different groups of road users and compared to the general population. The aim was to estimate excess diagnosis-specific SA and DP among individuals of different road user groups injured in a road traffic accident compared to matched references without such injury.

Methods

A nationwide register-based study, including all working individuals aged 20-59 years and living in Sweden who in 2015 had in- or specialized outpatient healthcare after a new traffic-related injury (n = 20 177) and population-based matched references (matched on: sex, age, level of education, country of birth, living in cities) without any traffic-related injury during 2014-2015 (n = 100 885). Diagnosis-specific (injury and other diagnoses) SA and DP were assessed during 5 years: 1 year before and 4 years following the accident. Mean SA and DP net days/year for each road user group and mean differences of (excess) SA and DP net days/year compared with their matched references were calculated with independent t-tests with bootstrapped 95% confidence intervals (CIs).

Results

A third of all injured road users were bicyclists, 31% were car occupants, 16% were pedestrians (including fall accidents), and 19% were other and unspecified accidents. Pedestrians and other road users were the groups with the highest mean number of SA days during the first year following the accident (51 and 49 days/year respectively). The matched references had between 8 and 13 SA days/year throughout the study period. The excess SA days/year were elevated for all road user groups all five studied years. Excess SA due to injury diagnoses was 15-35 days/year during the first year following the accident. Excess SA due to diagnoses other than injuries were about eight days/year during the whole study period for pedestrians and car occupants and about zero for the bicyclists. The excess DP was low, although it increased every year after the accident for pedestrians and car occupants; for bicyclists no excess DP was seen.

Conclusion

Higher levels of SA due to injury diagnoses were seen among all road user groups during the first year after the accident compared to their references. Pedestrians and car occupants had more excess SA due to other diagnoses and more excess DP four years after the accident than bicyclists and other road users.

Swedish Olympic athletes report one injury insurance claim every second year: a 22-year insurance registry-based cohort study

PURPOSE

To describe injury incidence, time trends in injury incidence, and injury characteristics among Swedish Olympic athletes over 22 years based on insurance data, as a first step to inform injury preventive measures among Olympic athletes.

METHODS

The cohort comprised 762 elite athletes (54% males; age 26.5 ± 5.9 years) in 38 sports in the Swedish Olympic Committee support program 'Top and Talent' between 1999 and 2020, with total 3427 athlete-years included. Acute and gradual onset injuries were reported to the insurance registry by the athletes' medical staff.

RESULTS

A total of 1635 injuries in 468 athletes were registered. The overall injury incidence was 47.7 injuries/100 athlete-years (one injury per athlete every second year). An increasing trend in injury incidence was observed in the first decade 2001 to 2010 (annual change 6.0%, 95% CI 3.3-8.8%), while in the second decade 2011 to 2020 no change was evident (0.4%, 95% CI - 1.9 to 2.7%). Gymnastics, tennis, and athletics had the highest incidence (100.0, 99.3, and 93.4 injuries/100 athlete-years, respectively). Among sport categories, mixed and power sports had the highest incidence (72.8 and 69.5 injuries/100 athlete-years, respectively). Higher incidences were seen in the younger age groups (≤ 25 years) in mixed and skill sports. The injury incidence was comparable between male and female athletes, and summer and winter sports. Most injuries occurred in the lower limb, and specifically the knee (24%), foot/ankle (15%) and spine/pelvis (13%).

CONCLUSION

The results on injury patterns in different sports and age groups may guide preventive focus for health and performance teams working with Olympic athletes.

LEVEL OF EVIDENCE

II.

Fall and collision related injuries among pedestrians, sickness absence and associations with accident type and occupation

OBJECTIVES

This study explores pedestrian fall accidents and collisions with other road users in the Swedish road transport system, and sickness absence (SA) in relation to accident type, injury, and occupation. Further, it studies the associations between accident type, occupation, and duration of SA.

METHODS

Data from several national registers were used that included 15,359 working age pedestrians (20-64 years) receiving healthcare after a fall or collision throughout 2014-2016. Individual characteristics, accident type, injury, and occupation were presented and related to SA. Logistic regression was used to estimate odds ratios (OR), with 95% confidence intervals, for associations between accident type, occupation, and SA duration.

RESULTS

About 11,000 pedestrians (72%) were involved in fall accidents in the road traffic environment and well over 4,000 in collisions with another road user; 22% of all injured pedestrians had a new SA. The population had a higher proportion of women and individuals in older age groups (≥45). Of the falls, 31% were due to snow or ice, and these were associated with a higher OR for both short SA (<90 days) 1.76 (95% CI 1.56-1.98) and long SA (≥90 days) 1.81 (95% CI 1.51-2.18), compared to the group slipping, tripping, and stumbling. The working sectors health & social care, and construction had the highest ORs for SA. A higher OR was found for health & social care, short SA 1.58 (95% CI 1.38-1.81), long SA 1.79 (95% CI 1.45-2.20) and for construction, short SA 1.56 (95% CI 1.24-1.96), long SA 1.75 (95% CI 1.26-2.44), compared to the sector finance, communication, & cultural service.

CONCLUSIONS

The OR for having short and long SA was higher in falls due to snow or ice and differed between occupational sectors.

PRACTICAL IMPLICATIONS

This information contributes to the knowledge base for planning a safe road transport system for pedestrians.

Diagnosis-specific sickness absence among injured working-aged pedestrians: a sequence analysis

BACKGROUND

The knowledge about the long-term consequences in terms of sickness absence (SA) among pedestrians injured in a traffic-related accident, including falls, is scarce. Therefore, the aim was to explore diagnosis-specific patterns of SA during a four-year period and their association with different sociodemographic and occupational factors among all individuals of working ages who were injured as a pedestrian.

METHODS

A nationwide register-based study, including all individuals aged 20-59 and living in Sweden, who in 2014-2016 had in- or specialized outpatient healthcare after a new traffic-related accident as a pedestrian. Diagnosis-specific SA (> 14 days) was assessed weekly from one year before the accident up until three years after the accident. Sequence analysis was used to identify patterns (sequences) of SA, and cluster analysis to form clusters of individuals with similar sequences. Odds ratios (ORs) with 95% confidence intervals (CIs) for association of the different factors and cluster memberships were estimated by multinomial logistic regression.

RESULTS

In total, 11,432 pedestrians received healthcare due to a traffic-related accident. Eight clusters of SA patterns were identified. The largest cluster was characterized by no SA, three clusters had different SA patterns due to injury diagnoses (immediate, episodic, and later). One cluster had SA both due to injury and other diagnoses. Two clusters had SA due to other diagnoses (short-term and long-term) and one cluster mainly consisted of individuals with disability pension (DP). Compared to the cluster "No SA", all other clusters were associated with older age, no university education, having been hospitalized, and working in health and social care. The clusters "Immediate SA", "Episodic SA" and "Both SA due to injury and other diagnoses" were also associated with higher odds of pedestrians who sustained a fracture.

CONCLUSIONS

This nationwide study of the working-aged pedestrians observed diverging patterns of SA after their accident. The largest cluster of pedestrians had no SA, and the other seven clusters had different patterns of SA in terms of diagnosis (injury and other diagnoses) and timing of SA. Differences were found between all clusters regarding sociodemographic and occupational factors. This information can contribute to the understanding of long-term consequences of road traffic accidents.

Sickness absence and disability pension among injured working-aged pedestrians - a population-based Swedish register study

Background

The knowledge is scarce about sickness absence (SA) and disability pension (DP) among pedestrians injured in a traffic-related accident, including falls. Thus, the aim was to explore the frequencies of types of accidents and injuries and their association with SA and DP among working-aged individuals.

Methods

A nationwide register-based study, including all individuals aged 16-64 and living in Sweden, who in 2010 had in- or specialized outpatient healthcare after a new traffic-related accident as a pedestrian. Information on age, sex, sociodemographics, SA, DP, type of accident, injury type, and injured body region was used. Frequencies of pedestrians with no SA or DP, with ongoing SA or full-time DP already at the time of the accident, and with a new SA spell >14 days in connection to the accident were analyzed. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for new SA were estimated by logistic regression.

Results

In total, 5576 pedestrians received healthcare due to a traffic-related accident (of which 75% were falls, with half of the falls related to snow and ice). At the time of the accident, 7.5% were already on SA and 10.8% on full-time DP, while 20% started a new SA spell. The most common types of injuries were fractures (45%) and external injuries (30%). The body region most frequently injured was the lower leg, ankle, foot, and other (in total 26%). Older individuals had a higher OR for new SA compared with younger (OR 1.91; 95% CI 1.44-2.53, for ages: 45-54 vs. 25-34). The injury type with the highest OR for new SA, compared with the reference group external injuries, was fractures (9.58; 7.39-12.43). The injured body region with the highest OR for new SA, compared with the reference group head, face, and neck, was lower leg, ankle, foot, and other (4.52; 2.78-7.36).

Conclusions

In this explorative nationwide study of the working-aged pedestrians injured in traffic-related accidents including falls, one fifth started a new SA spell >14 days. Fractures, internal injuries, collisions with motor vehicle, and falls related to snow and ice had the strongest associations with new SA.

Electric scooters accidents: Analyses of two Swedish accident data sets

Since august 2018 electric scooters (e-scooters) are available in selected cities in Sweden, operated by several different operators. There is a growing concern regarding their safety as they grow in popularity. The aim with this study was to investigate injuries associated with e-scooters in Sweden and to identify accident characteristics. In addition, the aim was to observe how different data collection procedures and samples may influence the results. Two complementary data sets were used; insurance data including all reported injuries to Folksam Insurance Group during the period January 2019 to May 2020 and the Swedish Traffic Accident Data Acquisition database (STRADA), the national system for road traffic injury data collection, was used to study accident related to e-scooter use in the Stockholm city area between May and the end of August 2019. Most of the injuries associated with e-scooters occurred in single crashes, but in 13% of the accidents another road user was injured, either due to interactions with e-scooters or due to a parked e-scooter being a hazard. In both data sets more than half of the accidents occurred during weekends. In total 46% of all who had visited an emergency department the accident occurred during night-time (10 pm to 6 am). The overall large proportion of injuries to the head and face indicates the need for actions aimed to increase helmet use among e-scooter riders. Local authorities should take a wider responsibility since one third of all accidents primarily occurred due to lack of maintenance or that the rider hit a curb stone. In comparison to hospital data, insurance claims include riders with all types of injuries irrespectively what type of healthcare the rider was seeking. Hence, to better understand the consequences and to make the right decisions regarding countermeasures aimed to improve the safety of e-scooter riding, data from different data source are needed.

Sickness absence and disability pension among injured car occupants, and associations with injury and car safety factors: A prospective cohort study

OBJECTIVE

Knowledge regarding sickness absence (SA) and disability pension (DP) following a road traffic injury, is lacking. The aim of this study was to investigate SA and DP among injured car occupants before and after a crash, accounting for permanent medical impairment (PMI). Further, to explore associations between injured body region, car model year of introduction (MYI), and European New Car Assessment Programme (Euro NCAP) safety rating and number of SA/DP days in year two and four following the crash date.

METHODS

A longitudinal cohort study including 63,358 individuals injured when aged 17-62, in crashes occurring 2001-2013 and involving a car insured by the Folksam Insurance Group. Mean numbers of SA/DP net days per year were calculated, in total and by injury diagnosis category, for all, for those with SA or DP with the same diagnosis as the initial injury, and for those with and those without injuries resulting in PMI. Logistic regressions were performed to calculate odds ratios with 95% confidence intervals for having 90-180 or ≥181 combined SA/DP days, respectively, among those with injury diagnoses, in year two and four after the crash. Associations with injured body region, car model introduction year, and Euro NCAP star ratings, was investigated, with adjustments made for sociodemographics.

RESULTS

The mean number of SA/DP days/year was higher in the years following the crash (56-50 days) compared to the year prior (41). In year one and two the increase in days was mainly with SA due to injury diagnoses and musculoskeletal diagnoses, and in year three and four, with DP due to injury diagnoses, musculoskeletal diagnoses, and mental diagnoses, respectively. Individuals whose injuries resulted in PMI had more future SA/DP days compared to those without PMI. Individuals with injuries to the torso/back and with multiple injuries were more likely to have > 180 SA/DP days both year two (2.9 and 2.2 times, respectively) and year four (2.0 and 1.6 times), compared to individuals with head injuries. Injured occupants in Euro NCAP 2-3-star rated cars as well as in untested cars, were more likely to have > 180 days in year four (1.4 and 2.0 times, respectively), compared to 4-5 stars.

CONCLUSION

Higher levels of SA/DP remained throughout the four years following the crash, with substantial differences between those with PMI and those with no PMI. Low overall car safety level, injuries to the torso/back, and multiple injuries were associated with high SA/DP.

Overall health impacts of a potential increase in cycle commuting in Stockholm, Sweden

AIMS

To estimate the overall health impact of transferring commuting trips from car to bicycle.

METHODS

In this study registry information on the location of home and work for residents in Stockholm County was used to obtain the shortest travel route on a network of bicycle paths and roads. Current modes of travel to work were based on travel survey data. The relation between duration of cycling and distance cycled was established as a basis for selecting the number of individuals that normally would drive a car to work, but have a distance to work that they could bicycle within 30 minutes. The change in traffic flows was estimated by a transport model (LuTrans) and effects on road traffic injuries and fatalities were estimated by using national hospital injury data. Effects on air pollution concentrations were modelled using dispersion models.

RESULTS

Within the scenario, 111,000 commuters would shift from car to bicycle. On average the increased physical activity reduced the one-year mortality risk by 12% among the additional bicyclists. Including the number of years lost due to morbidity, the total number of disability adjusted life-years gained was 696. The amount of disability adjusted life-years gained in the general population due to reduced air pollution exposure was 471. The number of disability adjusted life-years lost by traffic injuries was 176. Also including air pollution effects among bicyclists, the net benefit was 939 disability adjusted life-years per year.

CONCLUSIONS

Large health benefits were estimated by transferring commuting by car to bicycle.

A New Assessment of Bicycle Helmets: The Brain Injury Mitigation Effects of New Technologies in Oblique Impacts

New helmet technologies have been developed to improve the mitigation of traumatic brain injury (TBI) in bicycle accidents. However, their effectiveness under oblique impacts, which produce more strains in the brain in comparison with vertical impacts adopted by helmet standards, is still unclear. Here we used a new method to assess the brain injury prevention effects of 27 bicycle helmets in oblique impacts, including helmets fitted with a friction-reducing layer (MIPS), a shearing pad (SPIN), a wavy cellular liner (WaveCel), an airbag helmet (Hövding) and a number of conventional helmets. We tested whether helmets fitted with the new technologies can provide better brain protection than conventional helmets. Each helmeted headform was dropped onto a 45° inclined anvil at 6.3 m/s at three locations, with each impact location producing a dominant head rotation about one anatomical axes of the head. A detailed computational model of TBI was used to determine strain distribution across the brain and in key anatomical regions, the corpus callosum and sulci. Our results show that, in comparison with conventional helmets, the majority of helmets incorporating new technologies significantly reduced peak rotational acceleration and velocity and maximal strain in corpus callosum and sulci. Only one helmet with MIPS significantly increased strain in the corpus collosum. The helmets fitted with MIPS and WaveCel were more effective in reducing strain in impacts producing sagittal rotations and a helmet fitted with SPIN in coronal rotations. The airbag helmet was effective in reducing brain strain in all impacts, however, peak rotational velocity and brain strain heavily depended on the analysis time. These results suggest that incorporating different impact locations in future oblique impact test methods and designing helmet technologies for the mitigation of head rotation in different planes are key to reducing brain injuries in bicycle accidents.

Sequence analysis of sickness absence and disability pension in the year before and the three years following a bicycle crash; a nationwide longitudinal cohort study of 6353 injured individuals

Background

Bicyclists are the road user group with the highest number of severe injuries in the EU, yet little is known about sickness absence (SA) and disability pension (DP) following such injuries.

Aims

To explore long-term patterns of SA and DP among injured bicyclists, and to identify characteristics associated with the specific patterns.

Methods

A longitudinal register-based study was conducted, including all 6353 individuals aged 18–59 years and living in Sweden in 2009, who in 2010 had incident in-patient or specialized out-patient healthcare after a bicycle crash. Information about sociodemographic factors, the injury, SA (SA spells > 14 days), and DP was obtained from nationwide registers. Weekly SA/DP states over 1 year before through 3 years after the crash date were used in sequence and cluster analyses. Multinomial logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for factors associated with each identified sequence cluster.

Results

Seven clusters were identified: “No SA or DP” (58.2% of the cohort), “Low SA or DP” (7.4%), “Immediate SA” (20.3%), “Episodic SA” (5.9%), “Long-term SA” (1.7%), “Ongoing part-time DP” (1.7%), and “Ongoing full-time DP” (4.8%). Compared to the cluster “No SA or DP”, all other clusters had higher ORs for women, and higher age. All clusters but “Low SA and DP” had higher ORs for inpatient healthcare. The cluster “Immediate SA” had a higher OR for: fractures (OR 4.3; CI 3.5–5.2), dislocation (2.8; 2.0–3.9), sprains and strains (2.0; 1.5–2.7), and internal injuries (3.0; 1.3–6.7) compared with external injuries. The cluster “Episodic SA” had higher ORs for: traumatic brain injury, not concussion (4.2; 1.1–16.1), spine and back (4.5; 2.2–9.5), torso (2.5; 1.4–4.3), upper extremities (2.9; 1.9–4.5), and lower extremities (3.5; 2.2–5.5) compared with injuries to the head, face, and neck (not traumatic brain injuries). The cluster “Long-term SA” had higher ORs for collisions with motor vehicles (1.9;1.1–3.2) and traumatic brain injury, not concussion (18.4;2.2–155.2).

Conclusion

Sequence analysis enabled exploration of the large heterogeneity of SA and DP following a bicycle crash. More knowledge is needed on how to prevent bicycle crashes and especially those crashes/injuries leading to long-term consequences.

Health status and quality of life among road users with permanent medical impairment several years after the crash

OBJECTIVE

Improvements in road infrastructure and vehicle safety have been achieved in many countries during the last decades. As the number of fatalities have dropped, the consequences of non-fatal injuries have been brought into focus. Therefore, the objective was to investigate self-reported health status and health-related quality of life several years after the crash for road-users that sustained injuries resulting in permanent medical impairment (PMI).

METHODS

A self-administered questionnaire using instruments to measure if health, health-related quality of life and physical activity had been affected by the crash, were used. The injured road-users were identified from insurance policy holders of the Folksam Insurance Group. The response rate was 29%, a total of 2078 responses were received from the 7174 road-users with PMI that received the questionnaire.

RESULTS

In total 85% were still suffering from the injuries several years after the crash (8-18 year after the crash). Furthermore, road-users with injuries to the spine were having highest pain intensity. Older road-users had poorer self-reported health status than younger road-users. Although, younger road-users had the greatest change in physical activity when comparing before and after the crash. Before the crash in total 63% were physically active while only 34% after the crash. The higher the PMI the higher it affected health several years after the crash.

CONCLUSIONS

The Swedish definition of serious injury, an injury leading to PMI, was found to correlate with self-reported health loss; 85% of the injured road-users reported that they still had remaining symptoms several years after the accident. The injured body region leading to PMI after an accident can vary from the body regions reported to cause long-term health loss. It was found that the higher the degree of PMI the higher the health loss. Sustaining a PMI regardless severity and injured body region has the same effects on general health for men and women. Sustaining a PMI will both lower the health-related quality of life and physical activity after the crash compared to before.

Characteristics of bicycle crashes among children and the effect of bicycle helmets

Objective: Focusing on children (0-17 years), this study aimed to investigate injury and accident characteristics for bicyclists and to evaluate the use and protective effect of bicycle helmets.Method: This nationwide Swedish study included children who had visited an emergency care center due to injuries from a bicycle crash. In order to investigate the causes of bicycle crashes, data from 2014 to 2016 were analyzed thoroughly (n = 7967). The causes of the crashes were analyzed and categorized, focusing on 3 subgroups: children 0-6, 7-12, and 13-17 years of age. To assess helmet effectiveness, the induced exposure approach was applied using data from 2006 to 2016 (n = 24,623). In order to control for crash severity, only bicyclists who had sustained at least one Abbreviated Injury Scale (AIS) 2+ injury (moderate injury or more severe) in body regions other than the head were included.Results: In 82% of the cases the children were injured in a single-bicycle crash, and the proportion decreased with age (0-6: 91%, 7-12: 84%, 13-17: 77%). Of AIS 2+ injuries, 8% were head injuries and 85% were injuries to the extremities (73% upper extremities and 13% lower extremities). Helmet use was relatively high up to the age of 10 (90%), after which it dropped. Helmets were much less frequently used by teenagers (14%), especially girls. Consistently, the share of head injuries increased as the children got older. Bicycle helmets were found to reduce all head injuries by 61% (95% confidence interval [CI], 10: +/- 10%) and AIS 2+ head injuries by 68% (95% CI, 12: +/- 12%). The effectiveness in reducing face injuries was lower (45% CI +/- 10% for all injuries and 54% CI +/- 32% for AIS2+ injuries).Conclusions: This study indicated that bicycle helmets effectively reduce injuries to the head and face. The results thus point to the need for actions aimed at increasing helmet use, especially among teenagers. Protective measures are necessary to further reduce injuries, especially to the upper extremities.

Sickness absence and disability pension sequences before and after a bicycle crash; a Swedish study

Background

In recent years, bicycle injuries have increased, yet little is known about impact of such injures on sickness absence (SA) and disability pension (DP). The aim was to explore the long-term patterns of SA and DP among injured bicyclists.

Methods

A longitudinal register-based study was conducted, including all individuals aged 18-59 years and living in Sweden, who in 2010 had incident in- or specialized out-patient healthcare for injuries sustained in a bicycle crash. Information about sociodemographics, the injury, SA, DP, and deaths were obtained from several nationwide registers. Weekly SA/DP data for four years: one year before and three years after the crash were used in sequence and cluster analyses. Multinomial logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for factors associated with each sequence cluster.

Results

Among all 6465 individuals injured in a bicycle crash 2010, five clusters were identified: No SA or DP (60.2%), Immediate SA (17.7%), Episodic SA (15.3%), Part-time DP (1.6%), and Full-time DP (5.2%). Compared to the cluster No SA or DP, all other clusters had high ORs for female sex, older age, living in small cities/villages, and inpatient care. Immediate SA also had high ORs for cyclists who sustained a fracture (OR 5.53; CI 4.47-6.83), dislocation (3.26; 2.29-4.65), sprains and strains (2.29; 1.68-3.10), and internal injuries (4.39; 1.95-9.90). Episodic SA had high ORs for other traumatic brain injury than concussion (6.27; 2.23-17.64) and injuries located in the spine and back (3.52; 2.12-5.86), torso (1.78; 1.29-2.45), upper extremities (1.95; 1.54-2.46), and lower extremities (1.85; 1.43-2.41).

Conclusions

Having SA in direct connection to the crash was associated with type of injury, in contrast to Episodic SA where the injured body region was of more importance, in particular other traumatic brain injuries and injuries to the spine and back.

Key messages

This nationwide study of new bicycle crashes found five clusters of sickness absence (SA) and disability pension (DP) sequences; No SA or DP, Immediate SA, Episodic SA, Part-time DP, and Full-time DP. The type of injury was more important for SA in direct connection to the crash, while the injured body region was of more importance for continued and repeated SA up to three years after the crash.

Bicycle crashes and sickness absence - a population-based Swedish register study of all individuals of working ages

BACKGROUND

In recent years, bicycle injuries have increased, yet little is known about the impact of such injures on sickness absence (SA) and disability pension (DP). The aim was to explore SA and DP among individuals of working ages injured in a bicycle crash.

METHOD

A nationwide register-based study, including all individuals aged 16-64 years and living in Sweden, who in 2010 had in- or specialized out-patient healthcare (including emergency units) after a bicycle crash. Information on age, sex, sociodemographics, SA, DP, crash type, injury type, and injured body region was used. We analyzed individuals with no SA or DP, with ongoing SA or full-time DP already at the time of the crash, and with new SA > 14 days in connection to the crash. Crude and adjusted odds ratios (OR) with 95% confidence intervals for new SA were estimated by logistic regression.

RESULTS

In total, 7643 individuals had healthcare due to a new bicycle crash (of which 85% were single-bicycle crashes). Among all, 10% were already on SA or full-time DP at the time of the crash, while 18% had a new SA spell. The most common types of injuries were external injuries (38%) and fractures (37%). The body region most frequently injured was the upper extremities (43%). Women had higher OR (1.40; 1.23-1.58) for new SA than men, as did older individuals compared with younger (OR 2.50; 2.02-3.09, for ages: 55-64 vs. 25-34). The injury types with the highest ORs for new SA, compared with the reference group external injuries was fractures (8.04; 6.62-9.77) and internal injuries (7.34; 3.67-14.66). Individuals with traumatic brain injury and injuries to the vertebral column and spinal cord had higher ORs for SA compared with other head, face, and neck injuries (2.72; 1.19-6.22 and 3.53; 2.24-5.55, respectively).

CONCLUSIONS

In this explorative nationwide study of new bicycle crashes among individuals of working ages, 18% had a new SA spell in connection to the crash while 10% were already on SA or DP. The ORs for new SA were higher among women, older individuals, and among individuals with a fracture.

Sickness absence, disability pension and permanent medical impairment among 64 000 injured car occupants of working ages: A two-year prospective cohort study

OBJECTIVE

There is a lack of knowledge regarding sickness absence (SA) and disability pension (DP) as consequences of road traffic injuries, and on the association between DP and permanent medical impairment (PMI). Therefore, the aim of this study was to investigate SA, DP, and PMI among injured passenger car occupants two years after a crash, and how they are associated, accounting for sociodemographics, crash-related factors, and previous SA/DP.

METHODS

This prospective cohort study included 64 007 injured car occupants aged 17-62 years at the time of a crash occurring in 2001-2013, involving a car insured at Folksam Insurance Group in Sweden. Information on sociodemographics, crash-related factors, SA (in SA spells >14 days) and DP status at inclusion and at two-year follow-up, and PMI assessed by the insurance company was used. PMI grades were categorized as 1-4, 5-9, 10-19, or >19%. Logistic regression was performed to calculate odds ratios (OR) with 95% confidence intervals (CI) for DP at follow-up and for PMI, respectively.

RESULTS

At the time of the crash 13% were already on SA or DP. At follow-up two years after the crash, 6% among those not already on SA/DP at the time of the crash were on SA and 2% on DP. Furthermore, 8% of the total cohort had a determined PMI. Among those not already on DP at the crash, 3% with no PMI had DP at follow-up. This proportion was higher the higher PMI grade. Among individuals without already ongoing DP at the crash date, 10% of those with a PMI 1-4 ha d DP, compared to 76% among PMI ≥ 20. Already ongoing SA at the time of the crash (OR = 39.16, 95% CI 34.89-43.95) and PMI grade (PMI ≥ 5 OR = 27.44, 95% CI 23.88-31.52, reference group PMI 0) were found to be associated with DP at two years after crash. The factor most strongly associated with PMI was the model year of the car. The older the car, the higher the risk of PMI (Model year ≤ 1990 OR = 3.36, 95% CI 2.67-4.23, reference group model year 2006-2010). An association with the same direction was also found between the model year of the car and DP at follow-up.

CONCLUSIONS

The association between PMI grade and DP status at follow-up among occupants not on DP at the crash date indicates that both could be used to measure long-term consequences of road traffic injury. In this cohort, already ongoing SA at the crash date was associated with DP at the two-year follow-up, emphasizing the importance of accounting for this factor in future research.

The potential of vehicle and road infrastructure interventions in fatal bicyclist accidents on Swedish roads-What can in-depth studies tell us?

Objective: The objective of this article is to describe the characteristics of fatal crashes with bicyclists on Swedish roads in rural and urban areas and to investigate the potential of bicycle helmets and different vehicle and road infrastructure interventions to prevent them. The study has a comprehensive approach to provide road authorities and vehicle manufacturers with recommendations for future priorities. Methods: The Swedish Transport Administration's (STA) in-depth database of fatal crashes was used for case-by-case analysis of fatal cycling accidents (2006-2016) on rural (n = 82) and urban (n = 102) roads. The database consists of information from the police, medical journals, autopsy reports, accident analyses performed by STA, and witness statements. The potential of helmet use and various vehicle and road infrastructure safety interventions was determined retrospectively for each case by analyzing the chain of events leading to the fatality. The potential of vehicle safety countermeasures was analyzed based on prognoses on their implementation rates in the Swedish vehicle fleet. Results: The most common accident scenario on rural roads was that the bicyclist was struck while cycling along the side of the road. On urban roads, the majority of accidents occurred in intersections. Most accidents involved a passenger car, but heavy trucks were also common, especially in urban areas. Most accidents occurred in daylight conditions (73%). Almost half (46%) of nonhelmeted bicyclists would have survived with a helmet. It was assessed that nearly 60% of the fatal accidents could be addressed by advanced vehicle safety technologies, especially autonomous emergency braking with the ability to detect bicyclists. With regard to interventions in the road infrastructure, separated paths for bicyclists and bicycle crossings with speed calming measures were found to have the greatest safety potential. Results indicated that 91% of fatally injured bicyclists could potentially be saved with known techniques. However, it will take a long time for such technologies to be widespread. Conclusions: The majority of fatally injured bicyclists studied could potentially be saved with known techniques. A speedy implementation of important vehicle safety systems is recommended. A fast introduction of effective interventions in the road infrastructure is also necessary, preferably with a plan for prioritization.

Modelling the effect on injuries and fatalities when changing mode of transport from car to bicycle

BACKGROUND

Several studies have estimated the health effects of active commuting, where a transport mode shift from car to bicycle reduces risk of mortality and morbidity. Previous studies mainly assess the negative aspects of bicycling by referring to fatalities or police reported injuries. However, most bicycle crashes are not reported by the police and therefore hospital reported data would cover a much higher rate of injuries from bicycle crashes. The aim of the present study was to estimate the effect on injuries and fatalities from traffic crashes when shifting mode of transport from car to bicycle by using hospital reported data.

METHODS

This present study models the change in number of injuries and fatalities due to a transport mode change using a given flow change from car to bicycle and current injury and fatality risk per distance for bicyclists and car occupants.

RESULTS

show that bicyclists have a much higher injury risk (29 times) and fatality risk (10 times) than car occupants. In a scenario where car occupants in Stockholm living close to their work place shifts transport mode to bicycling, injuries, fatalities and health loss expressed in Disability-Adjusted Life Years (DALY) were estimated to increase. The vast majority of the estimated DALY increase was caused by severe injuries and fatalities and it tends to fluctuate so that the number of severe crashes may exceed the estimation with a large margin.

CONCLUSION

Although the estimated increase of traffic crashes and DALY, a transport mode shift is seen as a way towards a more sustainable society. Thus, this present study highlights the need of strategic preventive measures in order to minimize the negative impacts from increased bicycling.

Differences in long-term medical consequences depending on impact direction involving passenger cars

OBJECTIVE

There is limited knowledge of the long-term medical consequences for occupants injured in car crashes in various impact directions. Thus, the objective was to evaluate whether injuries leading to permanent medical impairment differ depending on impact direction.

METHODS

In total, 36,743 injured occupants in car crashes that occurred between 1995 and 2011 were included. All initial injuries (n = 61,440) were classified according to the Abbreviated Injury Scale (AIS) 2005. Injured car occupants were followed for at least 3 years to assess permanent medical impairment. The data were divided into different groups according to impact direction and levels of permanent impairment. The risk of permanent medical impairment was established for different body regions and injury severity levels, according to AIS.

RESULTS

It was found that almost 12% of all car occupants sustained a permanent medical impairment. Given an injury, car occupants involved in rollover crashes had the highest overall risk to sustain a permanent medical impairment. Half of the head injuries leading to long-term consequences occurred in frontal impacts. Far-side occupants had almost the same risk as near-side occupants. Occupants who sustained a permanent medical impairment from cervical spine injuries had similar risk in all impact directions (13%) except from rollover (17%). However, these injuries occurred more often in rear crashes. Most of the injuries leading to long-term consequences were classified as minor injuries by AIS for all impact directions.

CONCLUSIONS

Studying crash data from a perspective of medical impairment is important to identify injuries that might not be prioritized only considering the AIS but might lead to lower quality of life for the occupant and also costs for society. These results can be used for road transport system strategies and for making priority decisions in vehicle design.

Risk of permanent medical impairment (RPMI) in car crashes correlated to age and gender

OBJECTIVE

As fatalities from car crashes decrease, focus on medical impairment following car crashes becomes more essential. This study assessed the risk of permanent medical impairment based on car occupant injuries. The aim was to study whether the risk of permanent medical impairment differs depending on age and gender.

METHODS

In total, 36,744 injured occupants in car crashes that occurred between 1995 and 2010 were included. All initial injuries (n = 61,440) were classified according to the Abbreviated Injury Scale (AIS) 2005. If a car occupant still had residual symptoms 3 years after a crash, the case was classed as a permanent medical impairment. In total, 5,144 injuries led to permanent medical impairment. The data were divided into different groups according to age and gender as well as levels of permanent impairment. The risk of permanent medical impairment was established for different body regions and injury severity levels, according to the AIS.

RESULTS

The cervical spine was the body region that had the highest number of diagnoses, and occupants who sustained injuries to the upper and lower extremities had the highest risk of medical impairment for both genders. Females aged 60 and above had a higher risk of permanent medical impairment from fractures in the extremities compared to males in the same age group and younger females. Females aged 44 or younger had a higher risk of permanent medical impairment from whiplash-associated disorders (WAD) than males in the same age group. Minor and moderate injuries (AIS 1-2) had a higher risk of permanent medical impairment among older car occupants compared to younger ones.

CONCLUSIONS

Differences in long-term outcome were dependent on both gender and age. Differences between age groups were generally greater than between genders. The vast majority of permanent medical impairments resulted from diagnoses with a low risk of fatality. The results emphasize the impact of age and gender in long-term consequences from car crashes. They could be used when designing safety technology in cars as well as to improve health care by contributing to better allocation of rehabilitation resources following trauma.

A one year pay-as-you-speed trial with economic incentives for not speeding

OBJECTIVE

The objective was to identify whether it was possible to change driver behavior by economic incentives and thereby reduce crash risk. Furthermore, the objective was to evaluate the participants' attitudes toward the pay-as-you-speed (PAYS) concept.

METHODS

A one-year PAYS trial with economic incentives for keeping speed limits using intelligent speed assistance (ISA) was conducted in Sweden during 2011-2012. The full incentive was a 30 percent discount off the insurance premium. The participants were private insurance customers and were randomized into a test group (initial n = 152, final n = 128) and a control group (initial n = 98, final n = 68). When driving, the drivers in the test group were informed and warned visually when the speed limit was exceeded. They could also follow their driving results on a personal website. The control group was not given any feedback at all. To reflect the impact of the PAYS concept the proportion of distance driven above the speed limit was compared between the 2 groups.

RESULTS

The introduction of a PAYS concept shows that the test group significantly reduced the proportion of distance driven above the speed limit. The proportion of driving at a speed exceeding 5 km/h over the speed limit was 6 percent for the test group and 14 percent for the control group. It also showed that the effect was higher the higher the violation of speed. The result remained constant over time.

CONCLUSIONS

It was shown that a PAYS concept is an effective way to reduce speed violations. Hence, it has the possibility to reduce crash severity and thereby to save lives. This could be an important step toward a safer road transport system. The majority of the participants were in favor of the concept, which indicates the potential of a new insurance product in the future.

Long-term medical consequences for child occupants 0 to 12 years injured in car crashes

OBJECTIVE

There is limited knowledge of the long-term medical consequences for children injured in car crashes. Thus, in the event of injury, the aim of the study was to specify patterns and risks of injuries resulting in permanent medical impairment of children (0-12 years) for different body regions and injury severity levels, according to Abbreviated Injury Scale (AIS). The aim was also to compare the impairment outcome with adults.

METHODS

Data were obtained from the Folksam insurance company, including reported car crashes from 1998 to 2010 with at least one injured child 0-12 years of age. In all, 2619 injured children with 3704 reported medical diagnoses were identified. All injuries were classified according to the AIS 2005 revision. If the child had not recovered within 1 year postinjury an assessment of permanent medical impairment (PMI) was made by one or several medical specialists.

RESULTS

In all, 55 children sustained 59 injuries resulting in PMI of which 75 percent were at AIS 1 or AIS 2. The head and cervical spine were the body regions sustaining the most injuries resulting in PMI. Sixty-eight percent of all injuries resulting in PMI were AIS 1 injuries to the cervical spine, with the majority occurring in frontal or rear impacts. Given an injury to the cervical spine, the risk of injuries resulting in PMI was 3 percent, and older children (≥6 years) had a significantly higher risk (3% versus 1%) than younger children. The head was the second most commonly injured body region with injuries resulting in PMI (12/59), which were predominantly AIS 2+. In addition, mild traumatic brain injuries at AIS 1 were found to lead to PMI. Whereas for children the injuries leading to PMI were primarily limited to the head and cervical spine, adults sustained injuries that led to PMI from a more diverse distribution of body regions.

CONCLUSION

The pattern of injuries resulting in permanent medical impairment is different for children and adults; therefore, safety priorities for children need to be based on child data. The majority of those injuries leading to PMI were at lower AIS levels. Furthermore, AIS 1 cervical spine and AIS 1+ head injuries should be given priority concerning mitigation of long-term consequences for children.

Injury risk functions in frontal impacts using data from crash pulse recorders

Knowledge of how crash severity influences injury risk in car crashes is essential in order to create a safe road transport system. Analyses of real-world crashes increase the ability to obtain such knowledge.The aim of this study was to present injury risk functions based on real-world frontal crashes where crash severity was measured with on-board crash pulse recorders.Results from 489 frontal car crashes (26 models of four car makes) with recorded acceleration-time history were analysed. Injury risk functions for restrained front seat occupants were generated for maximum AIS value of two or greater (MAIS2+) using multiple logistic regression. Analytical as well as empirical injury risk was plotted for several crash severity parameters; change of velocity, mean acceleration and peak acceleration. In addition to crash severity, the influence of occupant age and gender was investigated.A strong dependence between injury risk and crash severity was found. The risk curves reflect that small changes in crash severity may have a considerable influence on the risk of injury. Mean acceleration, followed by change of velocity, was found to be the single variable that best explained the risk of being injured (MAIS2+) in a crash. Furthermore, all three crash severity parameters were found to predict injury better than age and gender. However, age was an important factor. The very best model describing MAIS2+ injury risk included delta V supplemented by an interaction term of peak acceleration and age.

Census study of fatal car-to-car intersection crashes in Sweden involving modern vehicles

OBJECTIVE

Intersections are challenging for many road users. According to US, European, and global statistics, intersection-related crashes with fatal outcome represent approximately 20 percent of all traffic fatalities. The aim of this study was to use Swedish data to investigate and characterize fatal car-to-car intersection crashes for modern cars equipped with frontal and side air bags.

METHOD

The Swedish Transport Administration (STA) national database on fatal crashes was searched to find vehicle-to-vehicle intersection crashes involving modern cars that occurred between 2003 and 2009 that resulted in fatal injuries for at least one of the involved passengers. From all intersection crashes, the car-to-car crashes from the sample were analyzed at an occupant level. Occupant location in the target vehicle with respect to impact direction as well as AIS3+ injuries to body regions was examined for the total car-to-car sample. Crashes involving a target vehicle equipped with front and side air bags were then selected for an in-depth study.

RESULTS

In the STA database, 39 vehicle-to-vehicle crashes matched the search criteria. Of 39 crashes, 17 involved a heavy goods vehicle (HGV) as the striking vehicle, and 17 were car-to-car crashes. All car-to-car crashes were side impacts, occurring at rural intersections, involving 20 (12 female and 8 male) fatally injured occupants, 15 of whom were 61 years or older and classified as senior occupants. A majority of fatally injured occupants sustained combined AIS3+ injuries to more than one body region.

CONCLUSIONS

All modern car-to-car crashes with a fatal outcome occurring at Swedish intersections from 2003 to 2009 were side impacts. The crashes were characterized by a senior front seat driver, traveling with a front seat passenger, hit on the left side at approximately 70 km/h. In this study all fatal crashes occurred at severities beyond those currently evaluated in side impact rating procedures but were within survivable limits for a non-senior occupant in a majority of cases.

Literature review of pedestrian fatality risk as a function of car impact speed

The aim of this review was to evaluate all studies of pedestrian fatality risk as a function of car impact speed. Relevant papers were primarily investigated with respect to data sampling procedures and methods for statistical analysis. It was uniformly reported that fatality risk increased monotonically with car impact speed. However, the absolute risk estimates varied considerably. Without exceptions, papers written before 2000 were based on direct analyses of data that had a large bias towards severe and fatal injuries. The consequence was to overestimate the fatality risks. We also found more recent research based on less biased data or adjusted for bias. While still showing a steep increase of risk with impact speed, these later papers provided substantially lower risk estimates than had been previously reported.

The properties of Safety Performance Indicators in target setting, projections and safety design of the road transport system

Road traffic Safety Performance Indicators (SPIs) are becoming increasingly used as an instrument for the planning and monitoring of safety progress. SPIs form an intermediate step between actions and final outcome in terms of casualties in road crashes. It is understood that SPIs are closely related to outcome; and that it is also possible to use them in calculations and predictions of both actions and final outcome. In the present study, it was found that some of the properties assigned to SPIs could be questioned. An assumption of linearity between SPIs and final outcome was partly rejected. It was also found that 100% fulfillment of a set of SPIs could lead to very low mortality, demonstrating the importance of handling SPIs simultaneously.

Use of car crashes resulting in fatal and serious injuries to analyze a safe road transport system model and to identify system weaknesses

OBJECTIVE

The objective of this study was to evaluate a model for a safe road transport system, based on some safety performance indicators regarding the road user, the vehicle, and the road, by using crashes with fatally and seriously injured car occupants. The study also aimed to evaluate whether the model could be used to identify system weaknesses and components (road user, vehicles, and road) where improvements would yield the highest potential for further reductions in serious injuries.

METHODS

Real-life car crashes with serious injury outcomes (Maximum Abbreviated Injury Scale 2+) were classified according to the vehicle's safety rating by Euro NCAP (European New Car Assessment Programme) and whether the vehicle was fitted with ESC (Electronic Stability Control). For each crash, the road was also classified according to EuroRAP (European Road Assessment Programme) criteria, and human behavior in terms of speeding, seat belt use, and driving under the influence of alcohol/drugs. Each crash was compared and classified according to the model criteria. Crashes where the safety criteria were not met in more than one of the 3 components were reclassified to identify whether all the components were correlated to the injury outcome. In-depth crash injury data collected by the UK On The Spot (OTS) accident investigation project was used in this study. All crashes in the OTS database occurring between 2000 and 2005 with a car occupant with injury rated MAIS2+ were included, for a total of 101 crashes with 120 occupants.

RESULTS

It was possible to classify 90 percent of the crashes according to the model. Eighty-six percent of the occupants were injured when more than one of the 3 components were noncompliant with the safety criteria. These cases were reclassified to identify whether all of the components were correlated to the injury outcome. In 39 of the total 108 cases, at least two components were still seen to interact. The remaining cases were only related to one of the safety criteria, namely, the road user (26), the vehicle (19), and the road (24). The criteria for the road and the vehicle did not address multiple event crashes, rear-end crashes, hitting stationary/parked vehicles, or trailers.

CONCLUSIONS

The model for a safe road transport system was found useful to classify fatal and serious road vehicle crashes. It was possible to classify 90 percent of the crashes according to the safety road transport model. For all these cases it was possible to identify weaknesses and parts of the road transport system with the highest potential to prevent fatal and serious injuries. Injury outcomes were mostly related to an interaction between the 3 components: the road, the vehicle, and the road user.

Evaluation of safety ratings of roads based on frontal crashes with known crash pulse and injury outcome

OBJECTIVE

The objective in this study, using data from crashed cars fitted with on-board crash pulse recorders, was to present differences in average crash severity, distribution of crash severity, and injury outcomes, based on an independent safety rating of roads, also taking road type and speed limit into consideration. Furthermore, the objective was to evaluate differences in injury risk, based on the distribution of crash severity.

METHODS

The investigation included both frontal two-vehicle crashes and single-vehicle crashes with known injury outcome. In total, 209 real-world crashes involving cars fitted with crash pulse recorders were included. For all crashes, average mean acceleration and change of velocity of the vehicle acceleration pulse were measured and calculated. All crash spots were classified according to an independent road safety rating program (European Road Assessment Programme Road Protection Score), where the safety quality of roads is rated in relation to posted speed limits. The crash severity and injury outcome in crashes that occurred on roads with good safety ratings were compared with crashes on roads with poor safety ratings. The data were also divided into subcategories according to posted speed limit and road type, to evaluate whether there was a difference in crash severity and injury outcome within the categories.

RESULTS AND CONCLUSIONS

In total, crash severity was statistically significantly lower in crashes occurring on roads with good safety ratings than in crashes occurring on roads with poor safety ratings. It was found that crash severity and injury risk were lower on roads with good safety ratings with a speed limit of above 90 km/h compared with roads with poor safety ratings, irrespective of speed limit. On the other hand, crash severity was higher on roads with good safety ratings with speed limit of 70 km/h than on roads with poor safety ratings with the same speed limit. Though it was found that a higher speed limit resulted in higher crash severity on roads with poor safety ratings, the opposite was found on roads with good safety ratings. The main reason for this was that lanes for traffic traveling in opposite directions were more often separated at higher speeds on roads with good safety ratings. On divided roads with good safety ratings, there were no crashes resulting in crash severity above the level corresponding to a 10 percent risk of sustaining serious or fatal injury. This indicates that one of the most important safety measures is divided roads.

Use of fatal real-life crashes to analyze a safe road transport system model, including the road user, the vehicle, and the road

OBJECTIVE

To evaluate if the Swedish Road Administration (SRA) model for a safe road transport system, which includes the interaction between the road user, the vehicle, and the road, could be used to classify fatal car crashes according to some safety indicators. Also, to present a development of the model to better identify system weakness.

METHODS

Real-life crashes with a fatal outcome were classified according to the vehicle's safety rating by Euro NCAP (European Road Assessment Programme) and fitment of ESC (Electronic Stability Control). For each crash, the road was also classified according to EuroRAP (European Road Assessment Programme) criteria, and human behavior in terms of speeding, seat belt use, and driving under the influence of alcohol. Each crash was compared with the model criteria, to identify components that might have contributed to fatal outcome. All fatal crashes where a car occupant was killed that occurred in Sweden during 2004 were included: in all, 215 crashes with 248 fatalities. The data were collected from the in-depth fatal crash data of the Swedish Road Administration (SRA).

RESULTS

It was possible to classify 93% of the fatal car crashes according to the SRA model. A number of shortcomings in the criteria were identified since the model did not address rear-end or animal collisions or collisions with stationary/parked vehicles or trailers (18 out of 248 cases). Using the further developed model, it was possible to identify that most of the crashes occurred when two or all three components interacted (in 85 of the total 230 cases). Noncompliance with safety criteria for the road user, the vehicle, and the road led to fatal outcome in 43, 27, and 75 cases, respectively.

CONCLUSIONS

The SRA model was found to be useful for classifying fatal crashes but needs to be further developed to identify how the components interact and thereby identify weaknesses in the road traffic system. This developed model might be a tool to systematically identify which of the components are linked to fatal outcome. In the presented study, fatal outcomes were mostly related to an interaction between the three components: the road, the vehicle, and the road user. Of the three components, the road was the one that was most often linked to a fatal outcome.