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External Causes of Death Data Analysis
INCOMPLETE INFORMATION FOR EXTERNAL CAUSES OF DEATH CODING, Possible changes over time
Over the last five years, the number of deaths resulting from accidents has increased from around 4,800 in 2001 to about 5,300 in 2005. Some accidental causes have increased in number (e.g. falls, exposure to inanimate mechanical forces, exposure to smoke, fire and flames, accidental poisoning by and exposure to noxious substances) while others have decreased (e.g. transport accidents, accidental drowning and submersion) over this period.
TYPE OF ACCIDENT RESULTING IN DEATH, 2001-2005(a)
Transport accidents are the largest cause of accidental deaths in Australia, representing 31.1% of all accidental deaths registered in 2005. The number of these deaths has decreased since 2001. A decrease over this period is apparent for all of the major categories, although in 2005 there were increases recorded for two of the highest level groups of codes, car occupant injured in transport accident (V40-V49) and motorcycle rider injured in transport accident (V20-V29).
A subset of this data (motor vehicle traffic accidents) can be compared with data from the Australian Transport Safety Bureau (ATSB 2006) on deaths of road users. ATSB statistics are based on reports of road crashes from police and other organisations responsible for road safety within each jurisdiction (footnote 7).
For most of the period 1997 to 2003, data from these two sources follow a very similar pattern, with the ABS causes of deaths data slightly lower than the ATSB data. The year to year variation in the number of deaths is largely consistent in both data collections. However in 2004 and 2005 the causes of death data are not consistent with ATSB deaths data, and are much lower. The difference between the two sources of data is particularly marked for New South Wales.
COMPARISON OF ABS AND AUSTRALIAN TRANSPORT SAFETY BUREAU
The decrease in deaths due to transport accidents may be related to a lack of clear information about the mechanism at the time of coding, resulting for example in some cases being allocated to X59 Exposure to unspecified factor.
The number of registered deaths attributed to accidental falls has been steadily increasing over the last five years, from 634 in 2001 to 996 in 2005. As a proportion of all deaths recorded as being due to accidents, falls has increased from 13.1% in 2001 to 18.9% in 2005.
This increase occurred mainly in Victoria (rising from 95 cases in 2001 to 431 in 2005), reflecting the introduction of a campaign to minimise the risk of falls and fall-related injuries in that state (which included the referral of more deaths involving a fall to coroners, particularly among older people). The increase was mainly in age groups over 75 years, about two-thirds of the increase was in females, and almost all of the increase was in deaths from accidental falls certified by a coroner. This increase can be expected to continue into the future if other jurisdictions follow suit with similar campaigns.
Accident codes likely to be associated with suicides or assaults
Threats to breathing (W75-W84)
The number of deaths classified to other accidental threats to breathing has varied over the past five years. Overall there has been an increase in this period, with the highest numbers recorded in 2003 and 2004 (followed by 2005).
These codes are of particular interest as there may be a relationship to suicide given that hanging (including strangulation and suffocation) is the most common method of suicide, used in 51% of all suicides registered in 2005. The code W76 Other accidental hanging and strangulation may be related to possible suicides for which a determination of intent is not available for coding purposes, although W75 Accidental suffocation and strangulation in bed, W83 Other specified threats, and W84 Unspecified threat could also be the outcome for such cases. A small number of assaults could also be coded to these categories if information on intent is lacking. There was an increase of around 70 deaths in these particular accident categories between 2001 to 2004, with a return to 2001 levels in 2005 (102). Most of the increase in the number of cases coded to these categories occurred in New South Wales (31 deaths in 2001 to 77 deaths in 2004 and 49 deaths in 2005) and Queensland (30 deaths in 2001 to 69 deaths in 2004 and 23 deaths in 2005), across all adult age groups.
The number of deaths classified as accidental poisoning by and exposure to noxious substances has also increased over the last five years, although there has been variation over the period. The highest numbers were recorded for the 2004 and 2005 registration years (737 and 740 deaths respectively).
Poisoning (including drugs, chemicals and gases) is also a common method of suicide (representing 27.8% of suicides in 2005), and is also involved in a small number of assault cases. There was a corresponding decrease in suicides associated with this mechanism over the same period (see discussion below). The increase in accidental poisoning deaths between 2001 and 2005 has occurred mainly in age groups between 35 and 69 years, while the decrease in intentional (suicide) poisoning deaths over the same period has occurred mainly in age groups between 20 and 54 years of age. In the 15-24 years age group, the decrease in intentional poisoning deaths has occurred alongside a decrease in accidental poisoning deaths.
Inanimate mechanical forces (W20-W49)
The number of accidental deaths classified as caused by inanimate mechanical forces (e.g. falling objects, sharp glass, knife, machinery, firearms) is relatively small but has increased over the last five years, although the number recorded in 2005 (137) was lower than that recorded for 2004 (151).
Firearm discharge can also be involved in suicides (7% of all suicides in 2005) or assaults (10% of all assaults). Although the number of deaths coded to accidental firearm discharge is relatively small, the number recorded in the 2003, 2004 and 2005 registration years is higher than in 2001 and 2002. This group of codes includes W31 Contact with other and unspecified machinery, W32 Handgun discharge, W33 Rifle, shotgun and larger firearm discharge, W34 Discharge from other and unspecified firearms, and W40 Explosion of other materials. For firearm deaths there has been a decrease in intentional (suicide) firearm deaths and an increase in accidental (unintentional) firearm deaths, noticeable in the last several years. The largest increase in accidental firearm deaths over the last five years was in New South Wales (increase of 19 deaths), while suicide firearm deaths in New South Wales decreased by 58 deaths (around half of the national decrease).
Exposure to unspecified factor (X59)
The number of accidental deaths classified as X59 Exposure to unspecified factor has increased from 802 in 2001 to 1,102 in 2005. These unspecified accidents comprised 14% of all external causes of death in 2005 (up from 10% in 2001).
Almost all of the increase of around 290 deaths classified to X59 in the last five years has been in coroner-certified deaths, with most registered in New South Wales. Most of these deaths occurred in older age groups, but there have been increases in recent years for younger age groups as well.
According to ICD-10 rules, this code is used when information on both the intent and the mechanism of death is missing (but the death is clearly due to an external cause based on the existing information). A lack of information about intent means that these cases will be treated as accidents, but due to the lack of information about the mechanism, they cannot be coded as any particular type of accident. The increase in deaths coded to X59 over the last few years may be related to decreases recorded in suicides, assaults and transport accidents, and may reflect an increasing lack of information about both intent and mechanism of death.
The codes X60-X84 Intentional self-harm (suicide) include purposely self-inflicted poisoning or injury. The number of cases coded to intentional self-harm has decreased over the last five years, with the number recorded for 2005 (2,101) very similar to that recorded for 2004 (2,098). The number of suicides decreased overall by about 14% between 2001 and 2005. The decrease is most apparent in the 25-29 years, 30-34 years and 35-39 years age groups (decreases of about 29%, 22% and 29% respectively over the period), the 15-19 years age group (decrease of 24%), and the 70-74 years age group (20%).
Decreases in the number of suicides over the past five years occurred in most jurisdictions except for South Australia, where the number of suicides has actually varied over this period. (In 2001 there were 206 deaths from suicide in South Australia, decreasing to 169 in 2002 and increasing overall to 233 in 2005).
For the most common method of suicide (hanging), the number of deaths recorded over the past five years has remained at around 1,000. Deaths allocated to intentional poisoning, firearm discharge or other methods have all decreased over the same period.
METHOD OF SUICIDE, 2001-2005(a)
ACCIDENT CODES MOST RELEVANT TO SUICIDE
Some statistics on suicides are publicly available from other organisations. Many of these are also based on actual coronial records and report higher numbers of suicide deaths. There are a number of reasons why these data differ from the official statistics published by the ABS. Higher numbers of suicides will result from the use of less strict criteria to classify suicides. Relaxing the burden of proof required to conclusively code a case as a suicide, making assumptions about intent, and not requiring a legal/medical finding, make it easier to code deaths as suicide outside the ABS. Higher numbers of suicide cases will also result from accessing coronial records later in time, thereby allowing more time for coronial cases to be closed and documented.
The number of assaults (homicides) recorded relies on coroners making a finding that injuries were inflicted by another person with intent to injure or kill, by any means. As a proportion of all external causes, assaults represented 2.5% of deaths registered in 2005. The most common type of assault causing death in 2005 was assault by a sharp object (X99) with 80 deaths, followed by assault by bodily force (Y04) with 27, assault by blunt object (Y00) with 26, and assault by hanging, strangulation and suffocation (X91) with 24.
TYPE OF ASSAULT RESULTING IN DEATH, 2001-2005(a)
The number of deaths due to assaults has greatly decreased over the last five years, from 300 deaths to around 200. The lowest numbers were recorded in the 2004 and 2005 registration years (164 and 199 deaths respectively, down from 278 in 2003). The decrease between 2001 and 2005 is most evident for New South Wales (109 to 63 deaths), Queensland (60 to 29 deaths) and the Northern Territory (22 to 7 deaths). It should be noted that for the 2005 registration year, the total number of open coroner's cases was relatively high in New South Wales and Queensland.
As discussed above under accidents, some possible assault cases may have been coded as accidents due to inanimate mechanical forces or hanging/strangulation/suffocation if there was no information available to confirm the intent of the death at the time of coding.
These data can be compared with data on the number of victims of recorded crime for the category of murder. Data on victims of recorded crime is based on administrative data relating to murders reported to or detected by police and is published in Recorded Crime - Victims, Australia (cat. no. 4510.0 (ABS 2006c). While the collection methods are entirely different, the resulting figures are roughly similar up to 2003, but for 2004 and 2005 the causes of death data are lower than the recorded crime data.
CAUSES OF DEATH AND RECORDED VICTIMS OF CRIME DATA
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