Journal of Forensic and Legal Medicine 34 (2015) 99e103
Contents lists available at ScienceDirect
Journal of Forensic and Legal Medicine j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j fl m
Original communication
Injury patterns and features of cycling fatalities in South Australia Kelly Olds a, b, Roger W. Byard a, b, Neil E.I. Langlois a, b, * a b
School of Medical Sciences, The University of Adelaide, Frome Road, Australia Forensic Science SA, Adelaide, SA 5005, Australia
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 February 2015 Received in revised form 6 May 2015 Accepted 30 May 2015 Available online 9 June 2015
There has been an increase in cycling in Australia. This means that more cyclists are at risk of injuries, which account for a proportion of transport-related fatalities. In this study, all cyclist fatalities from 2002 to 2013 in South Australia where post-mortem examinations were performed were investigated. There were 42 deaths representing 3% of the total road fatalities over the same time. Of this total number of cases, 13 deaths (31%) involved collapse (mostly natural causes from an underlying medical condition) and 29 (69%) resulted from trauma. There were no cases of hyperthermia. Of the decedents 95% were male, and the mean age at death was 47 years. Fatal incidents were more likely to occur during April and November, and on a Monday. However, statistical analysis was not possible due to the small number of cases. Fatalities (traumatic and collapse) predominantly occurred whilst the cyclist was riding (86%). The majority of riding fatalities were as a result of collision with vehicles (81%). Drugs (including alcohol) were detected in two (15%) of the 13 cases of the collapses, and in seven (26%) of the 27 trauma cases tested. In trauma cases, death was most often due to multiple injuries. The most frequent area for injury was the head (found in 90% of traumatic deaths). Despite the increasing numbers of cyclists on South Australian roads over the last decade, death rates have trended downwards suggesting that road safety campaigns and the provision of more dedicated bicycle lanes have had a positive outcome. © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
Keywords: Cyclist Injury Fatalities Head trauma Road traffic
1. Introduction In recent years, there have been an increasing number of bicyclists in Australia. In South Australia, a state with approximately 1.7 million people,1 the number of cyclists on an average weekday has almost doubled, with 4821 in 2004 compared to 9569 in 2014.2 The number of cyclists over the course of this period showed an average annual increase of 10%.2 Whilst the number of cyclists on South Australian roads has increased in the last decade, the incidence of cyclist fatalities has decreased (from 0.1% in 2004 to 0.04% in 2014), indicating improved safety for this group of road users.3 The increasing trend in cycling has been observed particularly in those aged 15 years and above.4 Whilst this increase is positive, illustrating that many Australians are trying to be more active, it has also resulted in a larger group of cyclists at risk of transportrelated injuries.5 Cyclists in Australia still account for one in seven traffic incidents resulting in serious injuries, and about one in 40 events where injuries sustained on the road are fatal.6 Whilst cyclists comprise a significant subgroup of serious and lethal
transport-related injury in Australia, there has been a relative lack of studies performed in this area. This study was undertaken to examine the fatal injuries that were incurred by cyclists in South Australia from 2002 to 2013, in order to highlight common findings at post-mortem examination. 2. Materials and methods Forensic Science South Australia performs all post-mortem examinations for the state of South Australia. All cyclist fatalities in South Australia, where a post-mortem examination was performed between 1 January 2002 and 31 December 2013, were included in this study. Data for all fatalities were collected from medico-legal autopsy reports. Cyclist fatalities were defined as those involving the death of a cyclist either riding or in close temporal proximity to riding a bicycle. Data were then analysed in terms of the day/month/year, the circumstances and causes of death, and the distribution of the injuries (if present). 3. Results
* Corresponding author. Forensic Science SA, 21 Divett Place, Adelaide, SA 5000, Australia. E-mail address: [email protected] (N.E.I. Langlois).
The number of cyclist fatalities that occurred during the period of 2002e2013 in South Australia was 42; of these 40 were
http://dx.doi.org/10.1016/j.jflm.2015.05.018 1752-928X/© 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
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K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
Fig. 1. Age distribution of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
males (95%). The average age at death was 47 years. Of this total number of cases 13 deaths (31%) involved collapse from an underlying medical condition and 29 (69%) resulted from trauma. The 29 deaths due to trauma represented 2% of the total road fatalities over the same time.7,8 There were no cases of hyperthermia. The age range of the deaths due to an underlying medical condition was 33e75 years, with an average of 55 years; for the trauma deaths, the distribution was broader and more normally distributed than the collapse deaths, ranging from 5 to 80 years, with a mean age of 43 years (Fig. 1).
instance of both collapse and trauma cases over the study period. 3.2. Month April and November were the months that had the highest incidence of fatalities, with 6 and 5 cases respectively, compared to the average number of cases per month of 3.5 (Fig. 3). There appeared to be less deaths in the antipodeans' winter months with a higher proportion of collapse deaths compared to spring and autumn.
3.1. Year 3.3. Day Over the twelve-year period the number of cases annually ranged from two to six. The highest number of incidents was in 2010, with seven cases, compared to an average of 3.5 cases per year (Fig. 2). Trendline analysis showed a decrease in the
Monday was the day of the week in which the most cases occurred.9 Saturday had the second-most cases recorded, with 8. There were 7 cases that occurred on a Wednesday. Thursday4
Fig. 2. Yearly incidence of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
101
Fig. 3. Monthly incidence of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
Friday4 and Sunday,5 were the days where the lowest cyclist fatalities were observed (Fig. 4). 3.4. Circumstances surrounding death Of the cyclist deaths that occurred from 2002 to 2013, 6 incidents (14%) occurred with the cyclist off of their bicycle and 36 (86%) occurred whilst the cyclist was riding. Death in all cases whilst riding was attributed to either vehicle collision or collapse. Of these riding cases, there were 29 cases (81%) involving vehicle collision and seven (19%) due to a medical condition. Deaths that occurred whilst the cyclist was off of their bicycle all involved a collapse. There were no cases of hyperthermia despite recent significant heat waves. 3.5. Toxicology Toxicology was performed in four of the 13 cases of collapse, and 27 of the 29 trauma cases. Drugs were detected in two (15%) of the
13 collapses. One had a dothiepin level of 10 mg/L and the other had a blood alcohol concentration of 0.062 percent and 0.27 mg of methadone with cannabinoids detected. Of the 27 toxicological analyses performed on trauma cases, drugs (including alcohol) were detected in seven (26%). Of these, the findings would be regarded as unlikely to be contributory to the incident in six cases, but the identification of a blood alcohol concentration of 0.1532 percent in a peripheral blood sample could be regarded as relevant to the incident. 3.6. Cause of death The principle causes of traumatic death were multiple injuries (38%) and head injuries (24%) (Table 1). Other causes of death recorded were injuries to the chest and neck (Table 1). In one case the cause of death was given as unascertained due to severe body disruption and loss of tissue that precluded the ability to be definite about the cause of death as it was not possible to exclude that a
Fig. 4. Day on which cyclist fatalities occurred in South Australia, over the period of 2002e2013, split for collapse and trauma deaths.
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contributing factors such as alcohol or drugs. Cycling deaths encompass all of these factors. Between the years 2002 and 2013, 42 cyclist deaths occurred in South Australia. Of these deaths 29 were due to trauma. The number of incidents that occurred varied each year between two and six cases. In 2010, the highest number of fatalities was recorded, with ten cyclist deaths. The annual numbers are too small to permit for statistical analysis other than a trendline analysis on the incidence of events over the study period. The number of cyclists in South Australia has roughly doubled over the study period2; however, the trendline analysis indicates that the number of cyclist fatalities has decreased from 2002 to 2013, thus there has been a decrease in the overall incidence of deaths. Data shows that the overall number of road fatalities has similarly decreased over the same period, suggesting that implemented road safety policies have been effective. Decedents were predominantly male, a finding that is consistent with previous literature.10e13 Many cases documented were of males that were middle-aged, which is a commonly observed age group where these incidents occur.10,11,13 In a Victorian study most cyclist deaths were found to be males over 35 years of age.10 This appears at odds with increased risk taking in male adolescents,14 but may have been influenced by lack of experience or worse physical condition in the older males. The age may also have been elevated by deaths due to underlying cardiovascular disease, as the cases of collapse had an average age at death of 55 years, compared to the cases of traumatic deaths that had a mean age of 43. The highest incidence of deaths occurring on Monday was unexpected as it was anticipated that the majority of cases would occur on the weekend given the larger numbers of recreational cyclists. Other studies have, however, found more cyclist fatalities occurring on weekdays.11,13 The reasons for this are not apparent but suggestions for this include high numbers of traffic or increased number of cyclists on a Monday; however, data is not available to confirm or refute this. Post-weekend impairment could also be postulated. Increases in bicycle-related deaths were observed in both April and November. Previous studies have noted increases during nonwinter months, presumably reflecting the increase in recreational cycling in warmer months.13,15,16 It was found the majority of fatalities in Northern Sweden to occur during summer and autumn, with the most cases in June and August.13 Others also found autumn to have the highest number of cyclist deaths.16 The current study did not attempt to correlate deaths with vacation periods17 given the relatively low numbers. Despite the association of physical exertion with hyperthermic deaths18 and the increase in death rates in South Australia during heat waves,19 no deaths occurred that could be attributed to heat-related factors. Fatal incidents that occurred whilst riding were predominantly due to collisions with motor vehicles, an event that is frequently reported in the literature available on cyclist mortality.10,12,13 Separating cyclists from motor vehicles on roads could potentially
Table 1 Causes of death documented for cyclist fatalities due to trauma in South Australia, from 2002 to 2013. Traumatic deaths
Cases
Percentagea
Chest injuries Head injury Multiple injuries Neck injury Unascertained
1 10 16 1 1
3 35 55 3 3
a
Rounded to nearest integer value.
Table 2 Causes of natural deaths documented for cyclist fatalities in South Australia, from 2002 to 2013. Percentagea
Natural deaths
Cases
Anomalous coronary artery ostia Arrhythmogenic Right Ventricular Cardiomyopathy Aspiration of gastric contents Ischaemic heart disease Valvular heart disease
1 1
8 8
1 9 1
8 69 8
a
Rounded to nearest integer value.
natural event has caused a fall from the bike into the traffic (Table 1). Of the collapse deaths, ischaemic heart disease was the most common cause, found in 69 percent9 of cases (Table 2). Singular cases of valvular heart disease, anomalous coronary artery ostia, arrhythmogenic right ventricular cardiomyopathy (ARVC) were also documented. There was one case of aspiration of gastric contents (possibly related to the presence of drugs and alcohol). 3.7. Injury distribution The head was the most frequently injured body region in cyclist deaths due to trauma, occurring in 90% of all cases (Table 3). Injuries were also commonly documented to the chest (83%), abdomen (62%) and pelvis (55%) (Table 3). The neck was injured in 28 percent of cases. Severe injuries of the upper (24%) and lower limb (17%) were found to be less frequent (Table 3). 4. Discussion Fatalities may be related to many sports or physical activities at any age. There are two major categories which include deaths due to trauma directly related to the activity, or fatalities from an exacerbation of an underlying medical condition, which may not have been previously identified.9 Among the purposes of forensic examinations is ascertainment as to whether natural diseases either caused or contributed to the death, in addition to documentation of the nature and extent of injuries, determination of the cause, mechanism and manner of death, and evaluation of possible
Table 3 Distribution of injuries for traumatic cyclist deaths in South Australia, from 2002 to 2013. Region
Case 1
2
3
4
5
6
7
8
9
10
11
12
13
Head Neck Chest Abdo Pelvis Upper limb Lower limb
X
X
X
X
X X X X X
X
X
X
X
X
X X X X X X
X
X
X X X
X X X
X X
X
X X X
X X X
X X X X
X X
X
X
X X
X X X
14 X X X X
15
16
17
18
19
20
21
X
X
X
X X X
X X X X X X
X X X X X
X
X X
X X X
X
X
X
22
X X
23
24
25
X X X
X X X X X
X
X X
26
X X X
27
28
29
Total
%
X
X
X
X X
X X
26 8 24 18 16 7
90 28 83 62 55 24
5
17
X
K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
reduce the number of these fatalities that occur and the increase in bicycle only lanes in recent years in South Australia may have been responsible for the stability in numbers of deaths despite increase road usage by cyclists. It was not possible to get any meaningful information on the level of experience of the cyclists involved in fatal crashes compared to those who were not, or on weather conditions and traffic density for particular incidents. The dothiepin level of 10 mg/L, found in one of the collapse cases can be regarded as potentially toxic,20 and its presence may have been a factor in the collapse but post-mortem redistribution21 was considered more likely. In the case with alcohol, methadone and cannabinoids, the presence of drugs and alcohol were considered a possible cause of vomiting and subsequent aspiration. The blood alcohol concentration of 0.15% in one of the trauma cases could have impaired the psychomotor skills needed for cycling.22 Injury patterns from motor vehicle related incidents vary depending on the nature of the crash, and the position and age of the decedent.23,24 Head injury alone often accounts for many of these fatalities10,11,13,16,25; Depreitere and colleagues in 2006 reported head injury as the primary cause of death in 69e93 percent of cases.25 However, most fatalities in this study (55%) were attributed to multiple injuries. Death due to multiple injuries in some cases occurred in the context of extensive disruption of all body cavities and major damage to all organs. This is particularly so if cyclists are dragged for some distance under large vehicles such as trucks.26 In one case in this series the disruption was severe and associated with loss of tissue that prevented the exclusion of natural disease having caused a collapse onto the road with subsequent multiple vehicle impacts and the pathologist gave the cause of death as unascertained; nonetheless, it is likely that death was a result of multiple injuries resulting from trauma (hence its inclusion in the traumatic group deaths). Many studies do not include cyclist deaths due to natural causes, and thus it is difficult to compare findings from this study on deaths due to natural causes. In this study, the head was found to be the most frequently injured region despite compulsory wearing of bicycle helmets in South Australia. Others have also reported that 46% of their cases had head injuries only.12 Injuries to the chest and abdomen were the next most commonly observed sites of injury in the current study. Upper and lower limbs are less frequently recorded sites for severe injuries. 5. Conclusion The present study investigated 42 cyclist fatalities that occurred in South Australia over the period 2002e2013. Deaths often involved severe multiorgan injuries, reflecting the relatively unprotected and exposed nature of cyclists on roads. Although there has been an apparent marked increase in numbers of cyclists on suburban and country roads in recent years, relatively static death rates would be supportive of a positive effect from information promulgated through road safety campaigns and the provision of dedicated bicycle lanes.
Conflict of interest None declared. Funding None declared.
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Ethical approval Forensic Science South Australia.
References 1. Australian Bureau of Statistics. Australian Demographic Statistics [Internet]. ABS cat. no. 3101.0: Available from: http://www.ausstats.abs.gov.au/Ausstats/ subscriber.nsf/0/4BFD619814CF9F8FCA257E1300775C68/$File/31010_sep 2014. pdf; 2014 [cited 27.04.15]. 2. Government of South Australia. Cycling facts: Government of South Australia. Available from: https://http://www.sa.gov.au/topics/transport-travel-andmotoring/cycling/cycling-facts; 2014 [updated 28.11.14; cited 05.02.15]. 3. Government of South Australia. Road fatalities and serious injuries in South Australia. Available from: http://dpti.sa.gov.au/__data/assets/pdf_file/0017/ 154232/DOCS_AND_FILES-9144119-v11-End_of_year_stats_2014_-_media.pdf; 2014 [cited 05.02.15]. 4. The Australian National Cycling Strategy 2005e2010[Internet]. Pub. no. AP-C8505. Available from: Austroads 2005. https://http://www.onlinepublications. austroads.com.au/items/AP-C85-05 [cited 05.02.15]. 5. Chong S, Poulos R, Olivier J, Watson WL, Grzebieta R. Relative injury severity among vulnerable non-motorised road users: comparative analysis of injury arising from bicycleemotor vehicle and bicycleepedestrian collisions. Accid Anal Prev 2010;42(1):290e6. 6. Garrard J, Greaves S, Ellison A. Cycling injuries in Australia: road safety's blind spot? J Australas Coll Road Saf 2010;21(3):37. 7. Government of South Australia. South Australia's Road Safety Strategy 2020 [Internet]. Available from: http://www.towardszerotogether.sa.gov.au/__data/ assets/pdf_file/0020/82163/South_Australias_Road_Safety_Strategy_to_2020.pdf; 2011 [cited 27.04.15]. 8. South Australia Police. Traffic statistics [Internet]. Available from: https://http:// www.police.sa.gov.au/about-us/traffic-statistics; 2014 [updated 28.08.14; cited 05.02.15]. 9. Byard RW, James RA, Gilbert JD. Childhood sporting deaths. Am J Forensic Med Pathol 2002;23(4):364e7. 10. Sikic M, Mikocka-Walus AA, Gabbe BJ, McDermott FT, Cameron PA. Bicycling injuries and mortality in Victoria, 2001-2006. Med J Aust 2009;190(7):353e6. 11. Bener A, Rahman YSA, Mitra B. Incidence and severity of head and neck injuries in victims of road traffic crashes: In an economically developed country. Int Emerg Nurs 2009;17(1):52e9. 12. Nicaj L, Stayton C, Mandel-Ricci J, McCarthy P, Grasso K, Woloch D, et al. Bicyclist fatalities in New York City: 1996e2005. Traffic Inj Prev 2009;10(2): 157e61. € o € m M, Eriksson A. Single-vehicle crashes and alcohol: a retrospective study 13. Ostr of passenger car fatalities in northern Sweden. Accid Anal Prev 1993;25(2): 171e6. 14. Byard RW. Accidental childhood death and the role of the pathologist. Pediatr Dev Pathol 2000;3(5):405e18. lot B, Laumon B. The injury epidemiology of cyclists 15. Amoros E, Chiron M, The based on a road trauma registry. BMC Public Health 2011;11(1):653. 16. Eilert-Petersson E, Schelp L. An epidemiological study of bicycle-related injuries. Accid Anal Prev 1997;29(3):363e72. 17. Rosenfeld H, Byard RW. Temporal trends in vehicle fatalities on South Australian roads: an analysis of the holiday road toll. Aust J Forensic Sci 2012;44(3):295e8. 18. Green H, Gilbert J, James R, Byard RW. An analysis of factors contributing to a series of deaths caused by exposure to high environmental temperatures. Am J Forensic Med Pathol 2001;22(2):196e9. 19. Langlois N, Herbst J, Mason K, Nairn J, Byard RW. Using the Excess Heat Factor (EHF) to predict the risk of heat related deaths. J Forensic Leg Med 2013;20(5): 408e11. 20. Keller T, Schneider A, Tutsch-Bauer E. Fatal intoxication due to dothiepin. Forensic Sci Int 2000;109(2):159e66. 21. Pounder DJ, Hartley AK, Watmough PJ. Postmortem redistribution and degradation of dothiepin human case studies and an animal model. Am J Forensic Med Pathol 1994;15(3):231e5. 22. Li G, Baker SP, Smialek JE, Soderstrom CA. Use of alcohol as a risk factor for bicycling injury. JAMA 2001;285(7):893e6. 23. Turk EE, Tsang Y-W, Champaneri A, Pueschel K, Byard RW. Cardiac injuries in car occupants in fatal motor vehicle collisionsean autopsy-based study. J Forensic Leg Med 2010;17(6):339e43. 24. Byard RW, Green H, James RA, Gilbert JD. Pathologic features of childhood pedestrian fatalities. Am J Forensic Med Pathol 2000;21(2):101e6. 25. Depreitere B, Van Lierde C, Maene S, Plets C, Vander Sloten J, Van Audekercke R, et al. Bicycle-related head injury: a study of 86 cases. Accid Anal Prev 2004;36(4):561e7. 26. Prahlow JA, Byard RW. Atlas of forensic pathology: for police, forensic scientists, attorneys, and death investigators. Springer Science & Business Media; 2011.
Contents lists available at ScienceDirect
Journal of Forensic and Legal Medicine j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j fl m
Original communication
Injury patterns and features of cycling fatalities in South Australia Kelly Olds a, b, Roger W. Byard a, b, Neil E.I. Langlois a, b, * a b
School of Medical Sciences, The University of Adelaide, Frome Road, Australia Forensic Science SA, Adelaide, SA 5005, Australia
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 February 2015 Received in revised form 6 May 2015 Accepted 30 May 2015 Available online 9 June 2015
There has been an increase in cycling in Australia. This means that more cyclists are at risk of injuries, which account for a proportion of transport-related fatalities. In this study, all cyclist fatalities from 2002 to 2013 in South Australia where post-mortem examinations were performed were investigated. There were 42 deaths representing 3% of the total road fatalities over the same time. Of this total number of cases, 13 deaths (31%) involved collapse (mostly natural causes from an underlying medical condition) and 29 (69%) resulted from trauma. There were no cases of hyperthermia. Of the decedents 95% were male, and the mean age at death was 47 years. Fatal incidents were more likely to occur during April and November, and on a Monday. However, statistical analysis was not possible due to the small number of cases. Fatalities (traumatic and collapse) predominantly occurred whilst the cyclist was riding (86%). The majority of riding fatalities were as a result of collision with vehicles (81%). Drugs (including alcohol) were detected in two (15%) of the 13 cases of the collapses, and in seven (26%) of the 27 trauma cases tested. In trauma cases, death was most often due to multiple injuries. The most frequent area for injury was the head (found in 90% of traumatic deaths). Despite the increasing numbers of cyclists on South Australian roads over the last decade, death rates have trended downwards suggesting that road safety campaigns and the provision of more dedicated bicycle lanes have had a positive outcome. © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
Keywords: Cyclist Injury Fatalities Head trauma Road traffic
1. Introduction In recent years, there have been an increasing number of bicyclists in Australia. In South Australia, a state with approximately 1.7 million people,1 the number of cyclists on an average weekday has almost doubled, with 4821 in 2004 compared to 9569 in 2014.2 The number of cyclists over the course of this period showed an average annual increase of 10%.2 Whilst the number of cyclists on South Australian roads has increased in the last decade, the incidence of cyclist fatalities has decreased (from 0.1% in 2004 to 0.04% in 2014), indicating improved safety for this group of road users.3 The increasing trend in cycling has been observed particularly in those aged 15 years and above.4 Whilst this increase is positive, illustrating that many Australians are trying to be more active, it has also resulted in a larger group of cyclists at risk of transportrelated injuries.5 Cyclists in Australia still account for one in seven traffic incidents resulting in serious injuries, and about one in 40 events where injuries sustained on the road are fatal.6 Whilst cyclists comprise a significant subgroup of serious and lethal
transport-related injury in Australia, there has been a relative lack of studies performed in this area. This study was undertaken to examine the fatal injuries that were incurred by cyclists in South Australia from 2002 to 2013, in order to highlight common findings at post-mortem examination. 2. Materials and methods Forensic Science South Australia performs all post-mortem examinations for the state of South Australia. All cyclist fatalities in South Australia, where a post-mortem examination was performed between 1 January 2002 and 31 December 2013, were included in this study. Data for all fatalities were collected from medico-legal autopsy reports. Cyclist fatalities were defined as those involving the death of a cyclist either riding or in close temporal proximity to riding a bicycle. Data were then analysed in terms of the day/month/year, the circumstances and causes of death, and the distribution of the injuries (if present). 3. Results
* Corresponding author. Forensic Science SA, 21 Divett Place, Adelaide, SA 5000, Australia. E-mail address: [email protected] (N.E.I. Langlois).
The number of cyclist fatalities that occurred during the period of 2002e2013 in South Australia was 42; of these 40 were
http://dx.doi.org/10.1016/j.jflm.2015.05.018 1752-928X/© 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
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K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
Fig. 1. Age distribution of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
males (95%). The average age at death was 47 years. Of this total number of cases 13 deaths (31%) involved collapse from an underlying medical condition and 29 (69%) resulted from trauma. The 29 deaths due to trauma represented 2% of the total road fatalities over the same time.7,8 There were no cases of hyperthermia. The age range of the deaths due to an underlying medical condition was 33e75 years, with an average of 55 years; for the trauma deaths, the distribution was broader and more normally distributed than the collapse deaths, ranging from 5 to 80 years, with a mean age of 43 years (Fig. 1).
instance of both collapse and trauma cases over the study period. 3.2. Month April and November were the months that had the highest incidence of fatalities, with 6 and 5 cases respectively, compared to the average number of cases per month of 3.5 (Fig. 3). There appeared to be less deaths in the antipodeans' winter months with a higher proportion of collapse deaths compared to spring and autumn.
3.1. Year 3.3. Day Over the twelve-year period the number of cases annually ranged from two to six. The highest number of incidents was in 2010, with seven cases, compared to an average of 3.5 cases per year (Fig. 2). Trendline analysis showed a decrease in the
Monday was the day of the week in which the most cases occurred.9 Saturday had the second-most cases recorded, with 8. There were 7 cases that occurred on a Wednesday. Thursday4
Fig. 2. Yearly incidence of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
101
Fig. 3. Monthly incidence of cyclist fatalities in South Australia over the period of 2002e2013, split for collapse and trauma deaths.
Friday4 and Sunday,5 were the days where the lowest cyclist fatalities were observed (Fig. 4). 3.4. Circumstances surrounding death Of the cyclist deaths that occurred from 2002 to 2013, 6 incidents (14%) occurred with the cyclist off of their bicycle and 36 (86%) occurred whilst the cyclist was riding. Death in all cases whilst riding was attributed to either vehicle collision or collapse. Of these riding cases, there were 29 cases (81%) involving vehicle collision and seven (19%) due to a medical condition. Deaths that occurred whilst the cyclist was off of their bicycle all involved a collapse. There were no cases of hyperthermia despite recent significant heat waves. 3.5. Toxicology Toxicology was performed in four of the 13 cases of collapse, and 27 of the 29 trauma cases. Drugs were detected in two (15%) of the
13 collapses. One had a dothiepin level of 10 mg/L and the other had a blood alcohol concentration of 0.062 percent and 0.27 mg of methadone with cannabinoids detected. Of the 27 toxicological analyses performed on trauma cases, drugs (including alcohol) were detected in seven (26%). Of these, the findings would be regarded as unlikely to be contributory to the incident in six cases, but the identification of a blood alcohol concentration of 0.1532 percent in a peripheral blood sample could be regarded as relevant to the incident. 3.6. Cause of death The principle causes of traumatic death were multiple injuries (38%) and head injuries (24%) (Table 1). Other causes of death recorded were injuries to the chest and neck (Table 1). In one case the cause of death was given as unascertained due to severe body disruption and loss of tissue that precluded the ability to be definite about the cause of death as it was not possible to exclude that a
Fig. 4. Day on which cyclist fatalities occurred in South Australia, over the period of 2002e2013, split for collapse and trauma deaths.
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K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
contributing factors such as alcohol or drugs. Cycling deaths encompass all of these factors. Between the years 2002 and 2013, 42 cyclist deaths occurred in South Australia. Of these deaths 29 were due to trauma. The number of incidents that occurred varied each year between two and six cases. In 2010, the highest number of fatalities was recorded, with ten cyclist deaths. The annual numbers are too small to permit for statistical analysis other than a trendline analysis on the incidence of events over the study period. The number of cyclists in South Australia has roughly doubled over the study period2; however, the trendline analysis indicates that the number of cyclist fatalities has decreased from 2002 to 2013, thus there has been a decrease in the overall incidence of deaths. Data shows that the overall number of road fatalities has similarly decreased over the same period, suggesting that implemented road safety policies have been effective. Decedents were predominantly male, a finding that is consistent with previous literature.10e13 Many cases documented were of males that were middle-aged, which is a commonly observed age group where these incidents occur.10,11,13 In a Victorian study most cyclist deaths were found to be males over 35 years of age.10 This appears at odds with increased risk taking in male adolescents,14 but may have been influenced by lack of experience or worse physical condition in the older males. The age may also have been elevated by deaths due to underlying cardiovascular disease, as the cases of collapse had an average age at death of 55 years, compared to the cases of traumatic deaths that had a mean age of 43. The highest incidence of deaths occurring on Monday was unexpected as it was anticipated that the majority of cases would occur on the weekend given the larger numbers of recreational cyclists. Other studies have, however, found more cyclist fatalities occurring on weekdays.11,13 The reasons for this are not apparent but suggestions for this include high numbers of traffic or increased number of cyclists on a Monday; however, data is not available to confirm or refute this. Post-weekend impairment could also be postulated. Increases in bicycle-related deaths were observed in both April and November. Previous studies have noted increases during nonwinter months, presumably reflecting the increase in recreational cycling in warmer months.13,15,16 It was found the majority of fatalities in Northern Sweden to occur during summer and autumn, with the most cases in June and August.13 Others also found autumn to have the highest number of cyclist deaths.16 The current study did not attempt to correlate deaths with vacation periods17 given the relatively low numbers. Despite the association of physical exertion with hyperthermic deaths18 and the increase in death rates in South Australia during heat waves,19 no deaths occurred that could be attributed to heat-related factors. Fatal incidents that occurred whilst riding were predominantly due to collisions with motor vehicles, an event that is frequently reported in the literature available on cyclist mortality.10,12,13 Separating cyclists from motor vehicles on roads could potentially
Table 1 Causes of death documented for cyclist fatalities due to trauma in South Australia, from 2002 to 2013. Traumatic deaths
Cases
Percentagea
Chest injuries Head injury Multiple injuries Neck injury Unascertained
1 10 16 1 1
3 35 55 3 3
a
Rounded to nearest integer value.
Table 2 Causes of natural deaths documented for cyclist fatalities in South Australia, from 2002 to 2013. Percentagea
Natural deaths
Cases
Anomalous coronary artery ostia Arrhythmogenic Right Ventricular Cardiomyopathy Aspiration of gastric contents Ischaemic heart disease Valvular heart disease
1 1
8 8
1 9 1
8 69 8
a
Rounded to nearest integer value.
natural event has caused a fall from the bike into the traffic (Table 1). Of the collapse deaths, ischaemic heart disease was the most common cause, found in 69 percent9 of cases (Table 2). Singular cases of valvular heart disease, anomalous coronary artery ostia, arrhythmogenic right ventricular cardiomyopathy (ARVC) were also documented. There was one case of aspiration of gastric contents (possibly related to the presence of drugs and alcohol). 3.7. Injury distribution The head was the most frequently injured body region in cyclist deaths due to trauma, occurring in 90% of all cases (Table 3). Injuries were also commonly documented to the chest (83%), abdomen (62%) and pelvis (55%) (Table 3). The neck was injured in 28 percent of cases. Severe injuries of the upper (24%) and lower limb (17%) were found to be less frequent (Table 3). 4. Discussion Fatalities may be related to many sports or physical activities at any age. There are two major categories which include deaths due to trauma directly related to the activity, or fatalities from an exacerbation of an underlying medical condition, which may not have been previously identified.9 Among the purposes of forensic examinations is ascertainment as to whether natural diseases either caused or contributed to the death, in addition to documentation of the nature and extent of injuries, determination of the cause, mechanism and manner of death, and evaluation of possible
Table 3 Distribution of injuries for traumatic cyclist deaths in South Australia, from 2002 to 2013. Region
Case 1
2
3
4
5
6
7
8
9
10
11
12
13
Head Neck Chest Abdo Pelvis Upper limb Lower limb
X
X
X
X
X X X X X
X
X
X
X
X
X X X X X X
X
X
X X X
X X X
X X
X
X X X
X X X
X X X X
X X
X
X
X X
X X X
14 X X X X
15
16
17
18
19
20
21
X
X
X
X X X
X X X X X X
X X X X X
X
X X
X X X
X
X
X
22
X X
23
24
25
X X X
X X X X X
X
X X
26
X X X
27
28
29
Total
%
X
X
X
X X
X X
26 8 24 18 16 7
90 28 83 62 55 24
5
17
X
K. Olds et al. / Journal of Forensic and Legal Medicine 34 (2015) 99e103
reduce the number of these fatalities that occur and the increase in bicycle only lanes in recent years in South Australia may have been responsible for the stability in numbers of deaths despite increase road usage by cyclists. It was not possible to get any meaningful information on the level of experience of the cyclists involved in fatal crashes compared to those who were not, or on weather conditions and traffic density for particular incidents. The dothiepin level of 10 mg/L, found in one of the collapse cases can be regarded as potentially toxic,20 and its presence may have been a factor in the collapse but post-mortem redistribution21 was considered more likely. In the case with alcohol, methadone and cannabinoids, the presence of drugs and alcohol were considered a possible cause of vomiting and subsequent aspiration. The blood alcohol concentration of 0.15% in one of the trauma cases could have impaired the psychomotor skills needed for cycling.22 Injury patterns from motor vehicle related incidents vary depending on the nature of the crash, and the position and age of the decedent.23,24 Head injury alone often accounts for many of these fatalities10,11,13,16,25; Depreitere and colleagues in 2006 reported head injury as the primary cause of death in 69e93 percent of cases.25 However, most fatalities in this study (55%) were attributed to multiple injuries. Death due to multiple injuries in some cases occurred in the context of extensive disruption of all body cavities and major damage to all organs. This is particularly so if cyclists are dragged for some distance under large vehicles such as trucks.26 In one case in this series the disruption was severe and associated with loss of tissue that prevented the exclusion of natural disease having caused a collapse onto the road with subsequent multiple vehicle impacts and the pathologist gave the cause of death as unascertained; nonetheless, it is likely that death was a result of multiple injuries resulting from trauma (hence its inclusion in the traumatic group deaths). Many studies do not include cyclist deaths due to natural causes, and thus it is difficult to compare findings from this study on deaths due to natural causes. In this study, the head was found to be the most frequently injured region despite compulsory wearing of bicycle helmets in South Australia. Others have also reported that 46% of their cases had head injuries only.12 Injuries to the chest and abdomen were the next most commonly observed sites of injury in the current study. Upper and lower limbs are less frequently recorded sites for severe injuries. 5. Conclusion The present study investigated 42 cyclist fatalities that occurred in South Australia over the period 2002e2013. Deaths often involved severe multiorgan injuries, reflecting the relatively unprotected and exposed nature of cyclists on roads. Although there has been an apparent marked increase in numbers of cyclists on suburban and country roads in recent years, relatively static death rates would be supportive of a positive effect from information promulgated through road safety campaigns and the provision of dedicated bicycle lanes.
Conflict of interest None declared. Funding None declared.
103
Ethical approval Forensic Science South Australia.
References 1. Australian Bureau of Statistics. Australian Demographic Statistics [Internet]. ABS cat. no. 3101.0: Available from: http://www.ausstats.abs.gov.au/Ausstats/ subscriber.nsf/0/4BFD619814CF9F8FCA257E1300775C68/$File/31010_sep 2014. pdf; 2014 [cited 27.04.15]. 2. Government of South Australia. Cycling facts: Government of South Australia. Available from: https://http://www.sa.gov.au/topics/transport-travel-andmotoring/cycling/cycling-facts; 2014 [updated 28.11.14; cited 05.02.15]. 3. Government of South Australia. Road fatalities and serious injuries in South Australia. Available from: http://dpti.sa.gov.au/__data/assets/pdf_file/0017/ 154232/DOCS_AND_FILES-9144119-v11-End_of_year_stats_2014_-_media.pdf; 2014 [cited 05.02.15]. 4. The Australian National Cycling Strategy 2005e2010[Internet]. Pub. no. AP-C8505. Available from: Austroads 2005. https://http://www.onlinepublications. austroads.com.au/items/AP-C85-05 [cited 05.02.15]. 5. Chong S, Poulos R, Olivier J, Watson WL, Grzebieta R. Relative injury severity among vulnerable non-motorised road users: comparative analysis of injury arising from bicycleemotor vehicle and bicycleepedestrian collisions. Accid Anal Prev 2010;42(1):290e6. 6. Garrard J, Greaves S, Ellison A. Cycling injuries in Australia: road safety's blind spot? J Australas Coll Road Saf 2010;21(3):37. 7. Government of South Australia. South Australia's Road Safety Strategy 2020 [Internet]. Available from: http://www.towardszerotogether.sa.gov.au/__data/ assets/pdf_file/0020/82163/South_Australias_Road_Safety_Strategy_to_2020.pdf; 2011 [cited 27.04.15]. 8. South Australia Police. Traffic statistics [Internet]. Available from: https://http:// www.police.sa.gov.au/about-us/traffic-statistics; 2014 [updated 28.08.14; cited 05.02.15]. 9. Byard RW, James RA, Gilbert JD. Childhood sporting deaths. Am J Forensic Med Pathol 2002;23(4):364e7. 10. Sikic M, Mikocka-Walus AA, Gabbe BJ, McDermott FT, Cameron PA. Bicycling injuries and mortality in Victoria, 2001-2006. Med J Aust 2009;190(7):353e6. 11. Bener A, Rahman YSA, Mitra B. Incidence and severity of head and neck injuries in victims of road traffic crashes: In an economically developed country. Int Emerg Nurs 2009;17(1):52e9. 12. Nicaj L, Stayton C, Mandel-Ricci J, McCarthy P, Grasso K, Woloch D, et al. Bicyclist fatalities in New York City: 1996e2005. Traffic Inj Prev 2009;10(2): 157e61. € o € m M, Eriksson A. Single-vehicle crashes and alcohol: a retrospective study 13. Ostr of passenger car fatalities in northern Sweden. Accid Anal Prev 1993;25(2): 171e6. 14. Byard RW. Accidental childhood death and the role of the pathologist. Pediatr Dev Pathol 2000;3(5):405e18. lot B, Laumon B. The injury epidemiology of cyclists 15. Amoros E, Chiron M, The based on a road trauma registry. BMC Public Health 2011;11(1):653. 16. Eilert-Petersson E, Schelp L. An epidemiological study of bicycle-related injuries. Accid Anal Prev 1997;29(3):363e72. 17. Rosenfeld H, Byard RW. Temporal trends in vehicle fatalities on South Australian roads: an analysis of the holiday road toll. Aust J Forensic Sci 2012;44(3):295e8. 18. Green H, Gilbert J, James R, Byard RW. An analysis of factors contributing to a series of deaths caused by exposure to high environmental temperatures. Am J Forensic Med Pathol 2001;22(2):196e9. 19. Langlois N, Herbst J, Mason K, Nairn J, Byard RW. Using the Excess Heat Factor (EHF) to predict the risk of heat related deaths. J Forensic Leg Med 2013;20(5): 408e11. 20. Keller T, Schneider A, Tutsch-Bauer E. Fatal intoxication due to dothiepin. Forensic Sci Int 2000;109(2):159e66. 21. Pounder DJ, Hartley AK, Watmough PJ. Postmortem redistribution and degradation of dothiepin human case studies and an animal model. Am J Forensic Med Pathol 1994;15(3):231e5. 22. Li G, Baker SP, Smialek JE, Soderstrom CA. Use of alcohol as a risk factor for bicycling injury. JAMA 2001;285(7):893e6. 23. Turk EE, Tsang Y-W, Champaneri A, Pueschel K, Byard RW. Cardiac injuries in car occupants in fatal motor vehicle collisionsean autopsy-based study. J Forensic Leg Med 2010;17(6):339e43. 24. Byard RW, Green H, James RA, Gilbert JD. Pathologic features of childhood pedestrian fatalities. Am J Forensic Med Pathol 2000;21(2):101e6. 25. Depreitere B, Van Lierde C, Maene S, Plets C, Vander Sloten J, Van Audekercke R, et al. Bicycle-related head injury: a study of 86 cases. Accid Anal Prev 2004;36(4):561e7. 26. Prahlow JA, Byard RW. Atlas of forensic pathology: for police, forensic scientists, attorneys, and death investigators. Springer Science & Business Media; 2011.
