Causes of death among Status Indians and other people living in the Bella Coola Valley local health area, 1987–2001

An estimated 2285 people live in the Bella Coola Valley, a remote coastal community in British Columbia. Approximately 46% of these are of aboriginal descent,[1-3] compared with an estimated provincial aboriginal population of 3.6%.[3] Bella Coola is one of the most isolated communities in British Columbia. The closest referral hospital is more than 450 km away by road in Williams Lake or 2 hours away by air in Vancouver. Bella Coola is served by three physicians at any given time.[4]

The Bella Coola Valley and Bella Bella (a similar-sized, remote coastal community with similar demographics) are located in the Central Coast Regional District[5] (see the Figure). According to data from the British Columbia Vital Statistics Agency, people living in this regional district have the lowest life expectancy in all of British Columbia (Table 1).[6]

Unfortunately, health data are not routinely collected or analyzed at the regional district level, nor are they available at the rural community level in Canada. According to the World Health Organization and other researchers, this lack of public health information at the community level is one reason a community may not be moved to act on the betterment of its own health.[7-9] If comprehensive health data were available at the community level, aboriginal and nonaboriginal community leaders interested in designing self-determined primary health care programs would have a guide when setting health priorities for their particular communities.

In British Columbia, the most detailed community health information available is at the local health area level. Bella Coola Valley is located in Local Health Area (LHA) 49, which includes the communities of Anahim Lake and Nimpo Lake.[10] According to BC Vital Statistics, the average total population of LHA 49 during the years 1997–2001 was 3401.[11] Although LHA 49 includes communities not located in the Bella Coola Valley, the people living in Nimpo Lake and Anahim Lake do visit Bella Coola for their medical care, and they do see Bella Coola physicians who drive to Anahim Lake for a weekly doctors’ clinic. BC Vital Statistics routinely standardizes LHA data using the demographic terms shown here (see the “Demographic terms box”) so that comparisons can be made with British Columbia and other local health areas.[11] According to BC Vital Statistics data,[12] the age-standardized mortality rate (ASMR) of 74.68 per 10 000 standard population, standardized mortality ratio (SMR) of 1.4, the potential years-of-life-lost standardized rate (PYLLSR) of 84.6, and the potential years-of-life-lost index (PYLLI) of 1.9 for people living in the Bella Coola local health area are among the worst in all of British Columbia.

To the best of our knowledge, no one has yet looked at differences in mortality rates between aboriginal people and nonaboriginal people living in a rural local health area—let alone at the community level. It is possible that the higher mortality rates reported for LHA 49 are due to the fact that relatively more aboriginal people live in this health region. It is well known that the health of aboriginal people lags behind that of nonaboriginal people.[3]

In Canada, three groups of aboriginal people are recognized: First Nations (formerly referred to as Indians), Metis, and Inuit.[3] First Nations people can, in turn, be separated into Status Indian and non-Status Indian populations. Status Indians are First Nations people who are registered on the official Indian Registry in Ottawa and are entitled to receive provisions outlined under the Indian Act. With respect to causes of death for aboriginal people in British Columbia, mortality data are available for only the Status Indian population. However, there are no known Inuit people living in LHA 49; there are fewer than 50 Metis living in LHA 49; and a recent review of the Bella Coola Clinic population reveals 98.4% of the aboriginal people are First Nations people and almost all of these are Status Indians. Since the vast majority of aboriginal people living in LHA 49 are Status Indians, we consider Status Indians to be a reasonable surrogate group for all Bella Coola residents who have aboriginal ancestry.

This led us to ask:

1. What are the main causes of death for people living in the Bella Coola Valley and LHA 49?
2. Are there differences in causes of death for Status Indians and people who are not Status Indians living in this local health area?

Methods

Ethics approval to review BC Vital Statistics health-related information pertaining to the aboriginal and nonaboriginal people living in the Bella Coola Valley was obtained from the Behavioral Sciences Screening Committee for Research at the University of Northern British Columbia. Research was then carried out in a participatory fashion, following the recommendations outlined in recently published policy statements on working with aboriginal peoples.[13-15] The goal of these recommendations is to make the relationship between aboriginal people and nonaboriginal health care providers a fair and honorable one. There was consultation with the Nuxalk Band Council, community members, and local health care providers on our plans to study determinants of health and disease for people living in the Bella Coola Valley. We received letters of support from the Nuxalk Band Council, from the Bella Coola Transitional Health Authority, and from the Central Coast Regional District. Dr Harvey Thommasen also participated in a potlatch asking for community support and explaining the types of health projects he was doing and was planning to do.

British Columbia’s Vital Statistic Agency provided data on underlying causes of death for the Bella Coola Valley for 1986–2001 (Table 2). These data relate only to people listing Bella Coola or Hagensborg as a home address and so exclude people listing Anahim Lake or Nimpo Lake as a home address.[16]

From British Columbia’s Health Data Warehouse, we obtained detailed mortality data for LHA 49.[17] Deaths were assigned to LHA 49 based on the usual residence of the decedent, and included Bella Coola (VOT ICO), Hagensborg (VOT IHO), Anahim Lake (VOL IRO), and Nimpo Lake (VOL ICO).[16] Data were obtained for specified 5-year periods, the most recent being 1997 – 2001 and the most distant being 1993–1997. Age-standardized mortality rates (per 10000 standard population) and potential-years-of-life-lost standardized rates (per 1000 standard population) were calculated using the 1991 Canadian Census population figures. Standardized mortality rates and a potential-years-of-life-lost index were calculated using BC Vital Statistics population data released in 1998.[17]

BC Vital Statistics does not routinely provide aboriginal ancestry information for mortality data at either the community level (e.g., Bella Coola Valley) or the local health area level (e.g., LHA 49). However, a number of registered Indian bands recently asked the First Nations and Inuit Health Branch, Health Canada, to provide them with mortality and hospital morbidity data relevant to their own populations.[18] After receiving approval from the Bella Coola Nuxalk Band, we asked Dr Andrew Jin of the First Nations and Inuit Health Branch to provide a summary of deaths and hospitalizations among Status Indian and non-Status Indian residents of LHA 49. He was able to provide us with this data for the years 1987–1996 (Table 4 and Table 5). (A detailed description of Dr Jin’s methodology is available elsewhere.[18-21)

Causes of death reported for the Bella Coola Valley and LHA 49 were coded according to the International Statistical Classification of Diseases, Ninth Revision (ICD-9), and then aggregated into the major diagnostic categories used by BC Vital Statistics in their tabulations of death statistics. Causes of death reported by the Health Data Warehouse were classified according to the more recent International Statistical Classification of Diseases, Tenth Revision (ICD-10).

Results

Table 2 shows the number of deaths and the percentage of total deaths for each cause in the Bella Coola Valley and in British Columbia as a whole. Cardiovascular disease and cancer are the most common causes of death in both the Bella Coola Valley and British Columbia. The Bella Coola Valley has a disproportionately large percentage of deaths due to external causes, which include motor vehicle accidents, other kinds of transport accidents, drowning, falls, accidental poisonings, fire- or smoke-related accidents, suicides, and homicides.

Table 3 shows the causes of death for the Bella Coola local health area 1997–2001. Cardiovascular disease and cancer and are once again listed as the most common causes of death. External causes of death are also listed as common. According to BC Vital Statistics, the number of external causes of death in LHA 49 is statistically higher than one would expect given the population of this health area. Motor vehicle accident deaths are the most common of external causes of death in LHA 49. Alcohol-related deaths are also common for LHA 49 and occur at statistically higher rates than expected. Mortality data for LHA 49 during 1993–1997 were practically identical to that reported for the 1997–2001 time period.[11]

Table 4 shows causes of death for non-Status Indian residents of LHA 49 and Table 5 shows causes of death for Status Indian residents. The results are consistent with data presented in Tables 1, 2, and 3. Interestingly, the overall standardized mortality ratio for both Status Indian and non-Status Indian people living in LHA 49 is 1.4 times that of the non-Status Indian population of British Columbia.

Discussion

The data summarized here show that the mortality experience of Status Indians living in the Bella Coola Valley is very similar to the experience reported for the entire British Columbia Status Indian population. Cardiovascular disease and cancer are the leading causes of death, while external causes of death and alcohol-related deaths occur at rates significantly higher than those reported for other residents of British Columbia.[24]

According to an analysis of leading causes of death for Status Indians in British Columbia in 1991–1999, motor vehicle accidents were responsible for the largest number of Status Indian deaths from external causes (426 deaths); the associated age-standardized mortality rate was nearly four times the rate for all other residents of the province. In LHA 49, the age-standardized mortality rate associated with motor vehicle accidents was 11.35.

Surprisingly, the mortality experience of non-Status Indian residents in LHA 49 is the same as that of Status Indian residents. The overall standardized mortality ratio for both populations is 1.4 when compared with residents of British Columbia who are not Status Indian. The standardized mortality ratio associated with motor vehicle accidents in LHA 49 is also identical for Status Indian and non-Status Indian residents, 3.1.

The standardized mortality ratio is said to be a good measure for comparing mortality data that are based on a small number of cases or for comparing mortality data by geographical area.[18]

A report on injuries in seven predominantly rural health regions in British Columbia also found that the age-standardized mortality rate related to motor vehicle accidents was higher than the BC rate in four of seven health regions, and that the Cariboo Health Region had the highest rate. The Bella Coola local health area is, in fact, one of the local health areas that make up the Cariboo Health Region.[25]

The data presented here can help health care planners design school-based and community-based health programs for the Bella Coola Valley that reduce cardiovascular risk factors (e.g., with optimal management of diabetes, hypertension, obesity, and hypercholesterolemia), promote healthy eating and physically active lifestyles, and identify families at higher risk of developing cancer. In addition, the early identification and treatment of teens and young adults with alcohol-abuse tendencies and the development of strategies to decrease external causes of death make sense for the Bella Coola Valley. External causes of death are, by definition, almost always preventable and plans should be developed to address risk conditions at the community level as soon as possible. The provincial medical health officer’s 2001 annual report notes that unintentional motor vehicle deaths could be reduced if society works intensively and strategically to improve road conditions, increase seat belt usage, enforce traffic laws, and punish those who drive under the influence of alcohol.[3]

Conclusion

Epidemiologists warn that caution is advised when interpreting mortality rates based on small numbers of deaths because yearly fluctuations can have a large impact on the estimates. LHA 49 has a small population (3400) compared with all of British Columbia (3.8 million). Nevertheless, mortality data for 10 years were analyzed three different ways and the consistency of the findings suggest the results have relevance to health care planners responsible for managing resources for the Bella Coola Valley. The data confirm that cardiovascular disease and cancer are the most common causes of death for people living in the Bella Coola Valley and Local Health Area 49, and that external causes of death—especially motor vehicle accidents—occur at rates higher than expected. Both Status Indian and non-Status Indian people in the area have a standardized mortality ratio of 1.4, suggesting ethnicity is not the only reason for the relatively poor health reported for rural communities in British Columbia.

Acknowledgments

We would like to thank Dr Rob Reid for reviewing the initial data set and suggesting how best to present the data. We would also like to thank Peter Schaub, cartographer for the Centre for Health Services and Policy Research, University of British Columbia, who kindly provided us with local health area maps. Funding from a Coasts Under Stress National Sciences and Engineering Research Council grant was used to pay research assistants to collect and tabulate the Bella Coola data. Dr Thommasen would like to acknowledge the Vancouver Foundation and the Community-Based Clinician-Investigator Program for financial support.

Competing interests
None declared.

 Table 1. Life expectancy by British Columbia regional district, 1986–2001.

Source: David O’Neil, Chief, Demography, Population Section, BC Vital Statistics, February 2003.

 Table 2. Causes of death in Bella Coola Valley (BCV), 1986–2001 and British Columbia (BC), 1999.

Source: Lisa Thackery, Information and Resource Management, BC Vital Statistics Agency

 Table 3. Causes of death for all residents, Bella Coola Valley local health area (LHA 49), 1997–2001.

* Observed deaths are statistically different from expected deaths (P <0.05, two-tailed)
+ Significance based on fewer than five cases.
Source: Health Data Warehouse[17]

 Table 4. Causes of death among non-Status Indian residents of LHA 49 (Bella Coola), 1987–1996.

*1997 Status Indian population (people who registered to get their MSP of BC premiums paid by Health Canada, on the grounds that they had Indian status)
† Expected number of deaths, indirectly age- and gender-standardized, based on age- and gender-specific death rates in the reference population.
Source: BC Vital Statistics Agency[18]

 Table 5. Causes of death among Status Indian residents of LHA 49 (Bella Coola), 1987–1996

* Total 1997 population of area estimated by BC Vital Statistics based on the number of people who registered to have their BC MSP premiums paid by Health Canada on the grounds that they had Indian status.
† Expected number of deaths, indirectly age- and gender-standardized, based on age- and gender-specific death rates in the reference population.
Source: BC Vital Statistics Agency[18]

Harvey V. Thommasen, MD, CCFP, Carol Thommasen, RN, BSN, Paul Martiquet, MD, CM, CCFP, MHSc, and Andrew Jin, MD, MHSc

Dr Thommasen is adjunct professor in Community Health at the University of Northern British Columbia in Prince George. Ms Thommasen is the Nursing Program Officer at the University of Northern British Columbia. Dr Martiquet is a medical health officer with North Shore/Coast Garibaldi Health Services. Dr Jin is an epidemiology consultant with Health Canada.