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IP Online First, published on March 24, 2011 as 10.1136/ip.2010.030866
Original article
Are we homogenising risk factors for public health
surveillance? Variability in severe injuries on First
Nations reserves in British Columbia, 2001e5
Nathaniel Bell,1 Nadine Schuurman,2 S Morad Hameed,3 Nadine Caron3,4
1
Department of Surgery,
University of British Columbia,
Trauma Services, Vancouver
General Hospital, Vancouver,
Canada
2
Department of Geography,
Simon Fraser University,
Burnaby, British Columbia,
Canada
3
Department of Surgery,
University of British Columbia,
Vancouver, British Columbia,
Canada
4
Bloomberg School of Public
Health, Johns Hopkins
University, Baltimore, Maryland,
USA
Correspondence to
Dr Nathaniel Bell, Department of
Surgery, University of British
Columbia, Trauma Services,
Vancouver General Hospital,
855W. 12th Avenue,
Vancouver, BC V5Z 1M9,
Canada; nathaniel.bell@vch.ca
Accepted 28 February 2011
ABSTRACT
Background Aboriginal Canadians are considered to be
at increased risk of injury. The de facto standard for
measuring injury risk factors among Aboriginal Canadians
is to compare hospitalisation and mortality against
non-Aboriginal Canadians, but this may be too broad an
approach for injury prevention and public health if it
over-generalises injury risk.
Methods Data from this study are drawn from the
2001e5 British Columbia Trauma Registry and British
Columbia Coroner’s Service. Observed and expected
hospitalisations and mortality rates on reserves were
assessed against three different spatial aggregations of
non-reserve reference populations. Data analysis was
conducted in a geographical information system using
a Poisson probability map.
Results A total of 47 (9.6%) of 487 reserves in British
Columbia contained at least one person who was
hospitalised or died as a result of serious injury during
the study period. Of these, two reserve populations
represented 20% (n¼19) of all injury morbidity events
and 30% (n¼22) of all mortality events.
Conclusion Evidence from this study suggests that
community-based rather than provincial-based injury
reporting is less likely to over-generalise the burden of
injury among Aboriginal communities. Community-based
surveillance enables researchers to identify why severe
unintentional and intentional injury continues to burden
some communities but not others and avoids the
potentially demoralising and stigmatising effects of
current surveillance practices.
Across Canada, First Nations peoples have been
shown to experience disproportionately poorer
health outcomes than non-Aboriginal Canadians,
including an increased risk of ischaemic heart
disease,1 diabetes2 3 and many cancers.4e6 Literature on disparities in risk is emerging in injury
morbidity and mortality reports. Thus far, research
has shown that First Nations peoples are nearly five
times as likely to experience a major trauma than
non-Aboriginal populations,7 over 11 times more
likely to experience an assault that leads to
extended hospitalisation,8 five times more likely to
be hospitalised as a result of motor vehicle injury8
and over nine times more likely to die as a result of
a severe burn injury.9 Suicide rates, which are the
most commonly researched of all injuries among
Aboriginal groups, have been shown to exceed
800 times the national average among some Aboriginal communities,10 with Aboriginal Canadians
nearly four times less likely than non-Aboriginal
Canadians to have sought previous psychiatric care.11
BellCopyright
N, Schuurman N,
Hameed author
SM, et al. Injury
Prevention
(2011). doi:10.1136/ip.2010.030866
Article
(or their
employer)
2011. Produced
The de facto standard for quantifying health
disparities among Aboriginal groups has been to
draw comparisons of health outcomes between
Aboriginal Canadians and non-Aboriginal Canadians. Social scientists have challenged that this
approach is too broad as it has a demoralising and
stigmatising effect on members of the community.10 12 13 One such study in Canada found that
the heterogeneity in suicide rates among British
Columbia’s First Nations peoples make it impossible to generalise risk factors at the provincial
scale.10 However, this evidence is largely based on
case studies from a subset of the population.
Expanding on these initial findings may potentially
improve how we conceptualise health disparities
and could guide social, medical and political
solutions for each specific community.14
The purpose of this study is to assess the
magnitude of injury morbidity and mortality on
First Nations reserves, examine if incidence rates
on reserves are significantly higher or lower than
among non-reserve areas, and determine if health
disparities indicators for injury surveillance efforts
are best directed at the local, regional, or provincial
scale. Our analysis is conducted using provincewide administrative health data on major trauma
injury and mortality from British Columbia, which
has the largest concentration of Aboriginal lands in
Canada.
METHODS
Severe injury hospitalisations and deaths among
populations aged over 17years were analysed using
individual case records from the British Columbia
Trauma Registry (BCTR) and British Columbia
Coroner’s Service (BCCS) database inclusive of 1
January 2001 to 31 December 2005. In January
2006, there were nine adult level IeIV trauma
hospitals in British Columbia. All patients requiring
a trauma team consultation or a trauma team
activation at one of the province’s level IeIV
trauma centres are recorded in the BCTR. For this
study, cases from both the BCTR and the BCCS
database were stratified by injury mechanism into
unintentional, intentional self-harm, and intentional third-party categories. In British Columbia,
all injury inclusion criteria for the trauma registries
are derived using the International Classification of
Diseases, 10th revision. The BCCS uses its own
inclusion criteria when defining the mechanism of
death. All case records were extracted by one author
(NB) familiar with the coding scheme of both the
BCTR and BCCS. All in-facility deaths were
counted within the BCCS records.
1 of 7
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Original article
Figure 1 Poisson probability map
construction. The probability map is
constructed by using the spatial
adjacency functions in geographical
information systems (GIS) to identify all
areas that share a boundary with each
reserve.
Denominators for crude hospitalisation and mortality rates on
and off reserves were constructed from the 2001 census subdivision (CSD) population counts. CSD are roughly equivalent in
size to a municipality or large urban city. Each Aboriginal reserve
has a federally designated administrative boundary that is
assigned a unique CSD ID. Reserve boundaries are self-contained
geographies and are contiguous with non-reserve administrative
boundaries used by Statistics Canada. Trauma and coroner
records were linked to the CSD boundaries using the patient/
person’s postal code of residence as recorded in the BCTR and
BCCS. We used the single link indicator flags within the March
2006 postal code conversion file to assign rural postal codes that
fell within multiple CSD into a single administrative unit. While
place of residence may not reflect place of injury, previous studies
have found that 96% of unintentional injuries took place in the
census tract of the individual’s residence.15
Comparisons between injury morbidity and mortality rates
on and off reserves were analysed in a geographical information
system (GIS) using a probability mapping model.16 Probability
maps are similar to standard mortality ratios in that they
contrast observed events to expected events in a population,
but differ in that the output is the statistical significance of
the incidence rates rather than the rates themselves. In probability mapping, statistical significance of a health event, i, is
measured by the probability that shows the likelihood of
a rate occurring given the normal rate of an event within the
reference population, p. The probability value for each area
represents the likelihood that the rate observed in that area
would occur by chance if the underlying risk of injury was equal
to p.17
For this study we used the Poisson probability test. This is
appropriate for the study of injuries, as injuries, like many
diseases, occur within only a small fraction of the population
and are either present or absent. We used topological functions
of GIS to build three different scenarios to express the likelihood
that the injuries occurring on reserves were significantly higher
or lower relative to non-reserve reference populations. We
constructed a discrete probability map from the Poisson
distribution:
x
P x ¼ el l =x!
where l is the product of the reserve population count multiplied by the reference area rate. At the smallest geographical
scale, expected reference area rates were constructed from the
non-reserve CSD that were adjacent to each reserve:
2 of 7
k1
P x$k ¼ 1 + PðxÞ
x¼0
where k is the number of trauma injuries occurring among
populations living on a reserve and P(x) is the probability that
the number of cases would occur by chance if the reserve had
a similar population distribution as the surrounding reference
population(s). Only comparisons with p values of 0.05 or less are
flagged as significant. Regional comparisons were also assessed
using the health service delivery areas (HSDA) (n¼16) as these
are the administrative areas used by the provincial health
authorities for resource allocation and disease surveillance. The
regional comparisons were based on the summation of all
reserve injuries that fell within each HSDA against all nonreserve injury rates within the HSDA. The provincial comparison was based on the summation of all reserve injuries against
the number of non-reserve injuries for the entire province.
Figure 1 illustrates the process steps for constructing a
probability map in a GIS.
RESULTS
During the study period, a total of 93 persons who were
hospitalised due to a severe injury were identified as living on
a reserve up to the time of their injury. A total of 73 persons who
died while in hospital, while in transit, or at the scene as a result
of their injury were identified as living on a reserve up to the
time of their injury. Counts of non-reserve injury hospitalisations and deaths at the provincial scale are shown in table 1.
All cases with missing residential address information or with
a residential address that was out of province were excluded
from the analysis. This resulted in the exclusion of 647 records
from the BCTR and 4689 records from the BCCS.
Table 1 On and off-reserve injury morbidity and mortality counts from
the BCTR and BCCS for calendar years 2001e5
Data description
Registered (2001e5)
Valid postal code for person’s
place of residence
Occurring off a reserve
Occurring on a reserve
Hospitalisations (BCTR)
Count
Deaths (BCCS)
Count
6124
5811
8811
4122
5718
93
4049
73
BCCS, British Columbia Coroner’s Service; BCTR, British Columbia Trauma Registry.
Bell N, Schuurman N, Hameed SM, et al. Injury Prevention (2011). doi:10.1136/ip.2010.030866
Downloaded from injuryprevention.bmj.com on August 23, 2011 - Published by group.bmj.com
Original article
Table 2
Injury and mortality rate for British Columbia (crude incidence rates, 2001e5), on and off reserves
Severe injury morbidity and mortality on and off reserve for British Columbia, 2001e5
Hospitalisations
Scale
Province
On-reserve
Off-reserve
Deaths
Intentional
self-harm
Unintentional
Intentional third
party
Unintentional
Intentional
self-harm
Intentional third
party
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
83
5062
622.2*
322.1
1
130
7.5
8.3
9
526
67.5*
32.4
48
2759
368.1*
240.4
22
1121
168.7*
97.7
3
169
23.0
14.7
Rates are per 100 000.
*Rate significantly higher than non-reserve rate (p#0.05).
The 166 on-reserve injury morbidity and mortality cases
represented 1.7% of all cases in the analysis, which was
proportionate to the on-reserve population as a whole, with an
estimated 1.7% (n¼68 235) of the province’s 3 907 738 persons
residing on a reserve in 2001.18 A total of 47 of the province’s 487
reserves recorded at least one person who was injured or died as
a result of serious injury during the study period. Of these, 20%
(n¼19) of all injury morbidity events and 30% (n¼22) of all
mortality events occurred to persons who resided in areas 27 and
29. Tables 2e4 illustrate the on and off-reserve injury morbidity
Table 3
and mortality count and crude rates at the provincial, regional
and municipal scale. The ratio between observed and expected
counts of injury hospitalisations and deaths by reserves at the
HSDA scale are shown in figure 2. To protect confidentiality the
injury locations by reserve are not shown.
At the provincial scale, incidence rates of injury on reserves
were statistically higher than non-reserve areas in four of the six
classes of injuries analysed in this study. A total of 11 of the 16
HSDA contained at least one reserve where someone required
hospitalisation or died as a result of a severe injury during the
Injury and mortality rate by HSDA (crude incidence rates, 2001e5), on and off reserves
Severe injury morbidity and mortality on and off reserve by HSDA, 2001e5
Hospitalisations
Scale
HSDA
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
On-reserve
Off-reserve
Deaths
Unintentional
Intentional
self-harm
Intentional third
party
Count
Rate
Count
Rate
Count
e
12
e
98
19
419
15
415
3
240
e
614
2
635
e
111
4
864
14
415
9
602
7
224
2
115
7
83
1
162
e
35
e
262.9
e
430.9
436.8*
330.4
1515.2*
492.1
2000*
276.9
e
267.2
2105.3*
278.1
e
209.0
416.7
310.8
804.6*
433.6
286.2
374.2
880.5*
281.6
526.3
321.7
1166.7*
290.2
740.7
399.8
e
248.4
e
0
e
0
e
8
e
6
e
5
e
20
e
15
e
0
e
37
e
6
e
18
e
7
e
2
1
2
e
3
e
1
e
0.0
e
0.0
e
6.3
e
7.1
e
5.8
e
8.7
e
6.6
e
0.0
e
13.3
e
6.3
e
11.2
e
8.8
e
5.6
166.7*
7.0
e
7.4
e
7.1
e
0
e
4
1
21
2
41
e
20
e
86
e
84
e
12
e
135
2
25
1
51
1
14
1
7
e
8
1
18
e
0
Unintentional
Intentional
self-harm
Rate
Count
Rate
Count
e
0.0
e
17.6
23.0
16.6
202.0
48.6
e
23.1
e
37.4
e
36.8
e
22.6
e
48.6
114.9
26.1
31.8
31.7
125.8
17.6
263.2
19.6
e
28.0
740.7
44.4
e
0.0
e
116
e
153
21
374
12
334
e
75
e
101
e
160
e
62
1
523
2
173
3
212
3
182
1
85
4
56
1
92
e
49
e
366.6
e
442.4
391.4*
283.2
1039.0*
425.1
e
168.3
e
154.3
e
152.2
e
141.3
357.1
230.3
101.0
233.2
152.3
202.9
327.9
203.0
512.8
200.8
382.8
251.8
740.7
280.8
e
298.7
41.0
45.0
4
146
4
112
e
12
e
48
e
52
e
34
2
263
3
92
1
96
6
94
e
34
2
21
e
19
e
7
Intentional third
party
Rate
Count
Rate
e
129.6
e
130.1
74.6
110.6
346.3
142.6
e
26.9
e
73.3
e
49.5
e
77.5
714.3
115.8
151.5*
124.0
50.8
91.9
655.7*
104.8
e
80.3
191.4
94.4
e
58.0
e
42.7
e
1
e
7
e
15
1
12
e
4
e
15
e
20
e
4
e
44
1
9
1
8
e
9
e
3
e
3
e
11
e
3
e
3.2
e
20.2
e
11.4
86.6
15.3
e
9.0
e
22.9
e
19.0
e
9.1
e
19.4
50.5
12.1
50.8
7.7
e
10.0
e
7.1
e
13.5
e
33.6
e
18.3
Rates are per 100 000.
Eighteen cases from the British Columbia Trauma Registry were excluded due to overlap between census subdivision (CSD) and multiple health service delivery area (HSDA) geographical areas.
Eighteen cases from the British Columbia Coroner’s Service were excluded due to overlap between CSD and multiple HSDA geographical areas.
*Rate significantly higher than non-reserve rate (p#0.05).
Bell N, Schuurman N, Hameed SM, et al. Injury Prevention (2011). doi:10.1136/ip.2010.030866
3 of 7
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Original article
Table 4
Injury and mortality rate by CSD (crude incidence rates, 2001e5), on and off reserves
Severe injury morbidity and mortality on and off reserve by CSD, 2001e5
Hospitalisations
Scale
CSD
Area 1
Area 2
Area 3
Area 4
Area 5
Area 6
Area 7
Area 8
Area 9
Area 10
Area 11
Area 12
Area 13
Area 14
Area 15
Area 16
Area 17
Area 18
Area 19
Area 20
Area 21
Area 22
Area 23
Area 24
Area 25
Area 26
Area 27
Area 28
Area 29
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
Deaths
Unintentional
Intentional
self-harm
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
2
35
1
e
1
71
1
72
1
145
2
408
4
983
e
e
3
1112
7
1112
1
79
1
226
3
229
1
457
3
457
1
34
e
e
2
80
1
65
3
e
e
30
1
39
1
42
e
e
1
15
2
2
6
182
3
229
12
255
NA
238.5
2000
e
1538.5
257.71
2857.1
260.12
2000
266.03
2105.3*
274.16
416.67
295.82
e
e
1176.5*
316.48
522.39
316.48
666.67
516
86.207
337.29
845.07
366.99
NA
356.66
202.7
356.66
1666.7
286.8
e
e
714.29
330.03
666.67
242.18
983.6
e
e
213.6
512.82
266.58
769.23
247.86
e
e
909.09
337.46
2352.9*
314.96
1935.5*
423.16
322.6
363.46
368.1
355.85
e
e
e
e
e
1
e
1
e
3
e
10
e
37
e
e
e
43
e
43
e
e
e
8
e
8
e
17
e
17
e
e
e
e
e
e
e
3.63
e
3.61
e
5.5
e
6.72
e
11.1
e
e
e
12.2
e
12.2
e
e
e
11.9
e
12.8
e
13.3
e
13.3
e
e
e
e
e
12.4
e
11.2
e
e
e
e
e
13.7
e
11.8
e
e
e
e
e
e
e
6.98
e
9.52
e
9.77
e
e
e
e
e
5
e
5
e
13
e
68
e
147
e
e
e
151
e
151
e
2
1
10
e
12
e
49
e
49
e
3
e
e
e
4
e
5
1
e
1
1
e
1
e
1
e
e
e
3
e
e
e
18
e
13
1
14
e
e
e
e
e
18.15
e
18.06
e
23.85
e
45.69
e
44.24
e
e
e
42.98
e
42.98
e
13.06
86.2
14.92
e
19.23
e
38.24
e
38.24
e
25.31
e
e
e
16.5
e
18.63
327.9
e
1818.2*
7.12
e
6.835
e
5.901
e
e
e
67.49
e
e
e
41.85
e
20.63
30.7
19.54
1
70
NA
287.5
e
e
e
e
e
e
e
e
e
e
357.1
215.8
106.4
208.3
e
210.9
127.4
216.2
0
238.2
0
238.9
281.7
238
e
e
200
182.9
e
e
e
206.8
845.1*
230.7
e
189
e
e
e
e
512.8
182.2
e
e
952.4*
e
571.4
411.1
e
e
1062*
311.5
388.3
247.3
312.5
257.1
1
39
NA
160.2
e
e
e
e
e
e
e
e
e
e
714*
110
e
110
392
113
255
115
e
83.5
215
80.5
e
85.3
e
e
e
85.4
e
e
952
86.2
563*
95.8
667
101
656
e
e
e
e
67.7
e
e
1905*
157
e
123
e
e
354
123
e
100
56.8
100
e
2
e
e
e
e
e
e
e
e
e
e
e
48
e
61
e
55
1
49
1
2
e
2
e
2
e
e
e
7
e
e
e
1
e
1
e
4
e
e
e
e
e
e
e
e
e
e
e
e
e
e
1
5
e
7
e
8
e
8.2
e
e
e
e
e
e
e
e
e
e
e
17.6
e
19.8
e
18
127.4
17.6
666.7*
4.07
e
5.03
e
4.49
e
e
e
8.42
e
e
e
5.74
e
4.35
e
10.6
e
e
e
e
e
e
e
e
e
e
e
e
e
e
177
12.8
e
11.3
e
12.2
e
e
3
e
3
e
e
e
e
e
2
e
2
e
e
e
e
e
e
e
3
e
6
e
7
Intentional third
party
Unintentional
Intentional
self-harm
e
e
e
e
e
1
588
1
641
0
645
1
602
0
117
0
95
1
106
e
e
2
152
e
e
e
36
3
53
e
71
e
e
e
e
1
35
e
e
1
e
1
20
e
e
6
122
4
153
11
169
e
e
e
e
e
2
300
e
339
1
346
2
320
e
41
1
32
e
38
e
e
e
71
e
e
1
15
2
22
1
38
2
e
e
e
e
13
e
e
2
1
e
6
e
e
2
48
e
62
2
66
Intentional third
party
Continued
4 of 7
Bell N, Schuurman N, Hameed SM, et al. Injury Prevention (2011). doi:10.1136/ip.2010.030866
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Original article
Table 4
Continued
Severe injury morbidity and mortality on and off reserve by CSD, 2001e5
Hospitalisations
Scale
CSD
Area 30
Area 31
Area 32
Area 33
Area 34
Area 35
Area 36
Area 37
Area 38
Area 39
Area 40
Area 41
Area 42
Area 43
Area 44
Area 45
Area 46
Area 47
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
Reserve
Adjacent
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
area(s)
Deaths
Unintentional
Intentional
self-harm
Intentional third
party
Unintentional
Intentional
self-harm
Intentional third
party
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
Count
Rate
e
e
2
66
e
e
2
5
2
5
1
3
0
3
e
e
4
e
3
3
e
e
e
e
1
e
e
e
2
16
1
e
e
e
1
1
e
e
1250*
235.59
e
e
833.3
757.58
3333.3
757.58
6666.7
2400
0.0
2400
e
e
2758.6
e
833.33
431.65
e
e
e
e
666.67
e
e
e
2222.2
1019.1
NA
e
e
e
740.74
454.55
e
e
e
1
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
1
e
e
e
e
e
e
3.57
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
NA
e
e
e
e
e
e
5
e
e
e
e
e
e
e
e
2
e
e
e
2
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
1
e
e
e
e
17.85
e
e
e
e
e
e
e
e
1666.7*
e
e
e
1379
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
740.7*
e
1
157
4
86
1
51
e
e
e
e
1
6
1
6
1
1
e
e
1
4
e
e
1
e
e
11
1
6
e
e
e
e
e
e
1
2
152.7
252.8
2500*
219.6
3333
354.2
e
e
e
e
6667
4800
833.3y
4800
689.7
1250
e
e
277.8
350.9
e
e
425.5
e
e
188
487.8
170.9
e
e
e
e
e
e
740.7
481.9
e
62
1
30
e
16
e
e
e
e
e
2
e
2
e
e
e
e
e
1
1
e
e
e
1
1
e
2
e
e
e
e
e
e
e
e
e
99.8
625
76.6
e
111
e
e
e
e
e
1600
e
1600
e
e
e
e
e
87.7
1053
e
e
e
667*
17.1
e
57
e
e
e
e
e
e
e
e
e
7
e
3
e
3
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
1
e
e
e
e
e
e
e
e
e
11.3
e
7.66
e
20.8
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
28.5
e
e
e
e
e
e
e
e
Rates are per 100 000.
NA, reserve population has a base population count of zero. The primary reason for a base population count of zero is that the area is a non-residential reserve (eg, land used for resource
purposes only). In some cases, Statistics Canada may choose to suppress the population counts for all areas with fewer than 40 people.
*Rate significantly higher than spatially adjacent non-reserve rate (p#0.05).
yRate significantly lower than spatially adjacent non-reserve rate (p#0.05).
CSD, census subdivision.
study period. The number of intentional and unintentional injury
hospitalisations and deaths on reserves were significantly higher
than the number of injuries among non-reserve populations in
seven of the 11 HSDA. When analysed at the municipal scale (ie,
CSD), incidence rates of unintentional and intentional injury
morbidity and mortality were significantly higher than rates
within spatial adjacent non-reserve communities within 12 of the
47 reserves, with the rate of injury mortality within one reserve
significantly lower than the adjacent non-reserve municipalities.
DISCUSSION
Albeit with few exceptions,10 13 public health surveillance of
Aboriginal Canadian health outcomes largely fails to demonstrate whether reported health events are representative of the
majority of the population included in the analysis. This study
demonstrated that injuries on reserves are far more concentrated
than widespread. Fewer than 10% of all reserves in BC were
represented in either the BCTR or BCCS database, with 25%
(n¼41) of all hospitalizations and deaths occurring among
populations residing on two reserves. Fewer than 30% of all
reserves (n¼12) exhibited significantly higher incidence rates
than the neighbouring non-reserve areas.
These results suggest that the burden of injury among
Aboriginal communities in BC is not unlike the burden of injury
among non-Aboriginal communities. As such, the results from
this study are potentially significant as the evidence suggests
that there is no universal health indicator for measuring injury
outcomes on reserves. This is not surprising when one considers
the profound legal, cultural, geographical and political circumstances that distinguish First Nations groups from all other
population groups in Canada. For example, in British Columbia,
there are over 200 First Nations communities and nearly 500
reserve lands set aside for the exclusive use of status ‘Indians’.
First Nations peoples in British Columbia practise both
Bell N, Schuurman N, Hameed SM, et al. Injury Prevention (2011). doi:10.1136/ip.2010.030866
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Original article
Figure 2 Ratio of observed/expected
unintentional injury hospitalisations and
deaths on reserves, British Columbia,
Canada, by regional health service
delivery area, 2001e5.
Christian and indigenous religious traditions, speak over 40
languages, and reside across the full spectrum of the province’s
urban, rural and remote areas. The geographical location of the
reserves is so diverse that Indian and Northern Affairs Canada
must consider the location, distance from major population
centres, and the local climatic conditions when allocating federal
funding to First Nations communities.19 In the USA, these
complexities have challenged how healthcare providers understand major health issues among Aboriginal populations as there
is no model community or experience that can accurately serve
as a baseline population that reflects the diversity of what would
otherwise seem to be a tiny subpopulation of the country’s
landscape.20 A similar perspective is needed in Canada when
strategising for public health surveillance and prevention.
No study that employs administrative data to measure
geographical variations of injury is free from error. One of the
limitations of this study is that we probably underestimate
the burden of injury among Aboriginal communities because of
the inability to assess ‘status Aboriginal’ from the BCTR or BCCS
patient population. Unlike other provinces, there is no memorandum of understanding between the provincial health authorities and First Nations populations to enable trauma registry data
coders to identify whether the injured patient is First Nations.
This is a significant challenge to injury prevention research in
British Columbia as approximately 60% of all First Nations live
off reserves.21 Although the methods used in this study do present
a strong effort to circumvent gaps in current data availability, this
limitation should be considered when interpreting the data.
A second limitation is due partly to the increasing weight
being given to injury rates on a reserve-by-reserve basis when in
fact the population and event counts in the majority of these
6 of 7
areas are small. The Centers for Disease Control and Prevention
takes the position that ‘when the total number of deaths used to
calculate any rate (crude, age-adjusted, or smoothed) is 20 or
less, the rate is considered statistically unstable’.22 In defence of
small area analysis, the occurrence of injury cases must be
related to the population at risk of succumbing to injury. As
Aboriginal communities are typically small in numbers, data
suppression is rarely, if ever, practical. In this event, the strength
of the Poisson test is well suited for finding out whether the
actual number of cases within a small study or sample area is
unusual as the comparisons are made in reference to an expected
national or regional prevalence rate. The fact that the injury
events in this study were derived from a total of 47 of the
province’s 487 reserves should further illustrate the concentration of injury in British Columbia and the necessity of small area
analysis for injury prevention and control.
Furthermore, this study is limited by the use of administrative
data (eg, postal codes, census data) to derive population counts
on reserves. Although on-reserve population counts are widely
known to experience respondent error and other count inaccuracies, the notable benefit of using census data is that
comparable data from non-reserve populations are also readily
available from the same data source. A more troublesome limitation is gaps in geographical coding of BCCS and BCTR at the
postal code level, which could be improved upon through either
the use of geographical positioning systems or mandating more
detailed patient information collection by first responders.
Public health surveillance of Aboriginal people in Canada is
complex, involving multijurisdictional coordination, but with
increasingly greater control by Aboriginal communities in delivering and regulating culturally relevant health and wellness
Bell N, Schuurman N, Hameed SM, et al. Injury Prevention (2011). doi:10.1136/ip.2010.030866
Downloaded from injuryprevention.bmj.com on August 23, 2011 - Published by group.bmj.com
Original article
What is already known on this subject
< Trauma continues to be a significant health issue for
Aboriginal and indigenous populations in Canada and across
the globe.
< Morbidity and mortality rates of injury are disproportionately
higher among Aboriginal and indigenous populations
compared with non-Aboriginal and non-indigenous populations.
< Although the literature is limited, Aboriginal and indigenous
populations are frequently referenced in academic and
governmental documents as a particular ‘at-risk’ or ‘vulnerable’ population to injury and other diseases.
inclusion of GIS for injury prevention and control is still
emerging. Despite its ability to circumvent many of the limitations in current data availability through employing spatial
and non-spatial data linkages, stronger multidisciplinary
approaches are needed to ensure that these tools become
standard practice for injury prevention and control.
Acknowledgements The authors wish to thank the British Columbia Trauma
Registry and the British Columbia Coroner Service for access to these data. The
authors also wish to thank Dr Ian Pike from the BC Injury Research & Prevention Unit
and three anonymous reviewers for their helpful comments and suggestions.
Funding Funding for this research was provided by the Michael Smith Foundation for
Health Research (IN-RUS-0186). Funding for N Bell is provided by a fellowship
awarded by the Canadian Institute for Health Research.
Competing interests None.
Ethics approval This study was conducted with the approval of the University of
British Columbia.
What this study adds
< Incidence patterns of injury morbidity and mortality on First
Nations lands in British Columbia, Canada, are far more
concentrated than widespread. Populations who resided in
two of the province’s 487 reserves represented 25% of all
on-reserve injury mortality and morbidity.
< Results from this study support ongoing discourse that
characterising Aboriginal health outcomes to non-Aboriginal
health outcomes is too broad an approach for injury
prevention and public health.
< This study emphasises the spatial and non-spatial data linkage
tools and spatial analysis capabilities of GIS for injury
prevention and control and outlines a methodology for its
use in small-area analysis.
Contributors All authors have contributed to the drafting, conception, and writing of
this manuscript. All analyses were conducted by NB.
Provenance and peer review Not commissioned; externally peer reviewed.
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Are we homogenising risk factors for public
health surveillance? Variability in severe
injuries on First Nations reserves in British
Columbia, 2001 −5
Nathaniel Bell, Nadine Schuurman, S Morad Hameed, et al.
Inj Prev published online March 24, 2011
doi: 10.1136/ip.2010.030866
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References
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