Colorectal cancer screening in First Nations People living ...cebp.aacrjournals.org/content/cebp/early/2014/10/21/1055-9965.EPI... · 1 Colorectal cancer screening in First Nations

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Colorectal cancer screening in First Nations People living in Manitoba

Kathleen M. Decker1,2, Alain A. Demers1,3, Erich V. Kliewer1,3,4, Grace Musto3, Emma Shu3,

Natalie Biswanger2, Brenda Elias1, Jane Griffith1,3, Donna Turner1,3

1. Department of Community Health Sciences, University of Manitoba, Winnipeg, Manitoba

2. Screening Programs, CancerCare Manitoba, Winnipeg, Manitoba

3. Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, Manitoba

4. Cancer Control Research, British Columbia Cancer Agency, Vancouver, British Columbia

Running title: Colorectal cancer screening in First Nations people

Key words: cancer, colorectal, Indigenous health, mass screening,

Financial support: This work was supported by the Canadian Institute of Health Research

(CIHR-AQC 83508).

Corresponding author: Dr. Donna Turner, Epidemiology and Cancer Registry, CancerCare

Manitoba, 675 McDermot, Winnipeg, Manitoba R3E 0V9,

Tel: 204-787-2573

Email: [email protected]

Conflicts of interest: The authors of this study declare that there are no conflicts of interest that

could bias the results of this study. The results and conclusions presented are those of the

authors. No official endorsement by Manitoba Health is intended or should be inferred.

Word count: 3,733

Total number of tables and figures: 6

on May 29, 2018. © 2014 American Association for Cancer Research. cebp.aacrjournals.org Downloaded from

Author manuscripts have been peer reviewed and accepted for publication but have not yet been edited. Author Manuscript Published OnlineFirst on October 21, 2014; DOI: 10.1158/1055-9965.EPI-14-1008

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Abstract

Background: Since the burden of colorectal cancer (CRC) appears to be increasing in First

Nations, it is important to better understand CRC screening utilization. The objective of this

study was to describe CRC screening among First Nations living in Manitoba.

Methods: The Federal Indian Register was linked to two provincial databases. A negative

binomial model was used to compare the probability of First Nations having a fecal occult blood

test (FOBT), colonoscopy, or flexible sigmoidoscopy (FS) with all other Manitobans.

Results: First Nations who lived Winnipeg were significantly less likely to have had a FOBT in

the previous two years than all other Manitobans who lived in Winnipeg (Rate Ration

(RR)=0.40, 95% Confidence Interval (CI) 0.37-0.44). There was no difference in the likelihood

of having a colonoscopy or FS for First Nations individuals who resided in northern Manitoba

compared all other Manitobans (RR=1.04, 955 CI 0.91-1.19). However, First Nations who lived

in the rural south or urban areas were less likely than all other Manitobans to have had a

colonoscopy or FS (RR=0.81, 95% CI 0.75-0.87, rural south; RR=0.86, 95% CI 0.81-0.92,

urban).

Conclusions: First Nations living in Winnipeg were significantly less likely to be screened for

CRC using the FOBT. Colonoscopy and FS use depended on area of residence.

Impact: First Nations experience barriers that impede the use of CRC screening. Further

research is needed to understand these barriers to extend the benefit of CRC screening to this

population.




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Introduction

Colorectal cancer (CRC) is the third most common cancer and the second most frequent

cause of cancer deaths among Canadians (1). Although it is responsible for a large component of

cancer burden, CRC incidence in Canada has been declining in men and women since 2000 (1).

Recent analyses in Manitoba have also found that the incidence of CRC in the province has

decreased (2). However, when examined by ethnicity, CRC incidence for First Nations

individuals has increased over time. The age-standardized CRC incidence increased from 29.6

per 100,000 in 1984-88 to 79.0 per 100,000 in 2004-08 for First Nations individuals but

decreased from 68.4 per 100,000 in 1984-88 to 66.8 per 100,000 in 2004-08 for all other

Manitobans (2).

The observed reduction in CRC incidence among in Canada and all other Manitobans is

likely due to changes in exposures to risk factors and the early detection and removal of

precancerous polyps through screening. Several large randomized controlled trials have found

that screening for CRC using the guaiac-based fecal occult blood test (FOBT) reduced mortality

from CRC by 15 to 33% (3). In 2001, the Canadian Task Force on Preventive Health Care

recommended screening for CRC using a FOBT annually or biennially or flexible

sigmoidoscopy (FS) (with an unspecified interval) for average risk individuals over 50 years of

age (4). The Canadian Association of Gastroenterology currently recommends that average risk

individuals over 50 years of age be screened with a FOBT every two years, FS every five years,

or colonoscopy every ten years (5).

Presently, Canadian provincial screening guidelines vary slightly with respect to the

population eligible for screening and the type of FOBT recommended (guaiac-based FOBT or

fecal immunochemical test (FIT)) but the majority recommend screening using a FOBT or FIT




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every two years for individuals 50 to 74 years of age with colonoscopy follow-up for positive

screening results (6). Although the sensitivity of colonoscopy is higher than FOBT, since

colonoscopy can result in serious harms such as bowel perforation, it is not currently

recommended by any province for population-based screening (7).

In 2007, Manitoba launched a province-wide CRC screening program using the guaiac-

based FOBT Hemoccult II SENSA for average risk individuals 50 to 74 years of age. At that

time, 44% of Manitobans 50 to 74 years of age reported having had a FOBT in the previous two

years (8). Previous Canadian studies have examined screening for breast and cervical cancer

among First Nations people but none have examined the utilization of CRC screening. Since the

burden of CRC appears to be increasing in First Nations communities, it is important to

understand CRC screening utilization among First Nations people. The objective of this study

was to describe the frequency of CRC screening among First Nations people living in Manitoba

in comparison to all other Manitobans.

Materials and Methods

Setting and Population

The province of Manitoba, located in central Canada, has a population of approximately

1.2 million. Half of the population lives in the capital city of Winnipeg. In 2011, there were

105,815 registered First Nations individuals living in Manitoba, which represented 8.8% of the

provincial population (9). Registered refers to those First Nations individuals who, under the

Federal Indian Act, are entitled to Treaty rights (10). First Nations groups in Manitoba include

Ojibway, Cree, Ojibway-Cree, Dakota, and Dene. First Nations are the largest Indigenous group

in Canada (45.5% of the total Indigenous population living in Canada that includes First Nations,

Inuit, Métis and 1.9% of the total Canadian population) (11). First Nations individuals reside in




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urban and rural areas including 63 First Nations communities in Manitoba some of which are

isolated, northern communities (9).

Data sources

Three data sources were used for this study: the Federal Indian Register, the Manitoba

Health Population Registry (MHPR), and the Medical Claims database. The Federal Indian

Register is the official record identifying Registered Indians in Canada. Registered Indians are

people who are registered with the federal government as defined by the Federal Indian Act (12).

Registered Indians have certain rights and benefits that are not available to non-registered

Indians or Métis people. The Indian Register was initiated in 1951 which explains the use of the

outdated term “Indian” instead of First Nations. Permission from Aboriginal Affairs and

Northern Development Canada (the federal data steward) was received to link the Federal Indian

Register to the MHPR (13). The MHPR includes all Manitoba residents covered by the

Manitoba Health insurance program (approximately 99% of the population). Through a multi-

step data linkage process, registered First Nations individuals were identified in the MHPR

creating a First Nations file (13). The Indian Register file contained 143,274 records; 133,882

(93.4%) were successfully linked to the MHPR. This de-identified First Nations file also

included a scrambled identifier unique to CancerCare Manitoba.

The First Nations file was then linked to the Medical Claims database using the

scrambled identifier to identify individuals who had had a FOBT, colonoscopy, or FS. The

provincial Medical Claims database is generated by claims filed by physicians for payment of

services and includes a billing tariff code, service date, an International Classification of

Diseases 9th version (ICD-9) diagnosis code, and provider identification. Both the MHPR and




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the Medical Claims databases have been previously validated for accuracy and have been used

extensively to study many health outcomes (14,15).

A person was considered screened for CRC if they had at least one medical claim with a

FOBT tariff code in the two years before the last day of the screening time period and/or a

colonoscopy or flexible sigmoidoscopy in the five years before the last day of the screening time

period. Individuals who lived outside of Winnipeg were excluded from the analyses that only

examined FOBT use because a significant proportion of FOBTs in rural and northern areas are

not registered in the Medical Claims database. Therefore, rural and northern FOBT rates likely

underestimate the true FOBT utilization rate.

Statistical analyses

Descriptive statistics were used to illustrate the characteristics of the individuals in the

study. Negative binomial regression modelling was used to compare the rates of FOBT,

colonoscopy, and flexible sigmoidoscopy use in First Nations and all other Manitobans. The

following co-variables were included in the regression model: age group (50-54, 55-59, 60-64,

65-69, and 70-74), gender (female and male), area of residence (urban, north, and rural south),

and time period. These variables were included since previous research has found that CRC

screening increases with age, is higher for females than males, and may be lower for individuals

who live in a rural area (16,17). For FOBT, time period was defined as the two years prior to

December 31st of each index year. For colonoscopy and FS, time period was defined as the five

years prior to December 31st of each index year. Index years were 1996, 1998, 2000, 2002,

2004, 2006, and 2008. All analyses were conducted in SAS version 9.2 (SAS Institute Inc.,

Cary, NC).




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Ethics approvals were received from the University of Manitoba Health Research Ethics

Board, Manitoba Health’s Information Privacy Committee, the Research and Resource Impact

Committee at CancerCare Manitoba, and the Assembly of Manitoba Chief’s Health Information

and Research Governance Committee.

Results

Between 1995-96 and 2007-08, 453,124 AOM and 18,416 First Nations individuals 50

and 74 years of age were identified as living in Manitoba. Table 1 shows the characteristics of

First Nations and all other Manitobans in 1995-96 compared to 2007-08. Overall, the

distribution of demographic characteristics in 2007-08 did not change substantially from 1995-

96. In 1995-96, 2.6% of all other Manitobans lived in the north compared to 38.7% of First

Nations. This distribution changed only slightly in 2007-08 (2.6% of all other Manitobans lived

in the north compared to 36.8% of First Nations). In 1995-96, fewer all other Manitobans were

50-54 years of age (25.5%) compared to First Nations (32.4%) and more were 70-74 years of age

(17.3% for all other Manitobans compared to 9.3% for First Nations). By 2007-08, 28% of all

other Manitobans were 50-54 years of age and 12.2% were 70-74 years of age while 35% of First

Nations individuals were 50-54 years of age and 8.7% were 70-74 years of age. The sex

distribution was similar in both time periods (51.5% of all other Manitobans and 51.4% of First

Nations individuals were female).

FOBT use

Figure 1 shows the percentage of First Nations and all other Manitobans who resided in

Winnipeg who had an FOBT in the two years before the last day of each index year. For First

Nations individuals, FOBT use increased from 4.9% (95% Confidence Interval (CI) 3.9-5.9) in

1995-96 to 13.4% (95% CI 12.3-14.6) in 2007-08 (p<0.0001). For all other Manitobans who




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resided in Winnipeg, FOBT use increased from 12.2% (95% CI 12.0-12.3) in 1995-96 to 32.9%

(95% CI 32.7-33.1) in 2007-08 (p<0.0001). The average percentage change in FOBT rates per

two-year time period from 1995-96 to 2007-08 was 20.0% for First Nations and 18.2% for all

other Manitobans. However, the gap in FOBT use between First Nations and all other

Manitobans increased from 7.3% in 1996 to 19.5% in 2008 (Table 2). In all time periods, FOBT

rates were higher for all other Manitobans than for First Nations (p<0.0001).

After adjusting for gender, age group, and time period, First Nations individuals who

resided in Winnipeg were significantly less likely than all other Manitobans who resided in

Winnipeg to have had an FOBT (Rate Ratio (RR)=0.40, 95% CI 0.37-0.44, p=0.0001) (Table3).

Men were less likely to be screened for CRC in the previous two years using an FOBT than

women (RR=0.88, 95% CI 0.85-0.92, p=0.002). FOBT use was highest for individuals 65 to 69

years of age compared to those 50 to 54 years of age (RR=1.65, 95% CI 1.53-1.77, p=0.08) and

increased with time (RR=2.80, 95% CI 2.70-2.90, p=0.02 for 2007-2008 compared to 1995-96).

There were no significant interactions between any of the variables.

FOBT, colonoscopy, and flexible sigmoidoscopy use

Figure 2 shows the percentage of First Nations and all other Manitobans 50 to 74 years of

age who resided in Winnipeg who had an FOBT in the two years or a colonoscopy or FS in the

five years before the last day of each index year. In all time periods, FOBT, colonoscopy, and

FS rates were lower for First Nations compared to all other Manitobans and the differential

increased over time (p<0.0001). For First Nations who resided in Winnipeg, FOBT,

colonoscopy, or FS use increased from 11.7% (95% CI 10.2-13.2) in 1996 to 25.5% (95% CI

24.1-27.0) in 2008 (p<0.0001). For all other Manitobans who resided in Winnipeg, FOBT,

colonoscopy, or FS use increased from 18.8% (95% CI 18.6-19.0) in 1996 to 42.9% (95% CI




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42.7-43.1) in 2008 (p<0.0001). The gap in FOBT, FS, and colonoscopy use between First

Nations and all other Manitobans increased from 17.1% in 1996 to 17.4% in 2008 (Table 2).

Colonoscopy or flexible sigmoidoscopy use

Although FOBT data were only available for the city of Winnipeg, information on

colonoscopy and FS use was available for the entire province. For First Nations in Manitoba, the

rate of colonoscopy or FS use increased from 5.9% (95% CI 5.4-6.5) during 1992-96 to 12.8%

(95% CI 12.2-13.4) during 2004-08. For all other Manitobans, the rate of colonoscopy or FS use

increased from 8.2% (95% CI 8.1-8.3) in 1992-96 to 17.3% (95% CI 17.2-17.4) in 2004-08.

Figure 3 illustrates the percentage of First Nations and all other Manitobans who had a

colonoscopy or FS in the five years before the last day of each index year by area of residence.

In the north, the percentage of individuals who had a colonoscopy or FS was similar or slightly

higher for First Nations (5.2%, 95% CI 4.5-6.0 from 1992-96 to 11.4%, 95% CI 10.5-12.3 from

2004-08) compared to all other Manitobans (4.7%, 95% CI 4.2-5.3 from 1992-96 to 10.6%, 95%

CI 9.9-11.3 from 2004-08). In the rural south, the percentage of individuals who had a

colonoscopy or FS was lower for First Nations (5.6%, 95% CI 4.8-6.4 from 1992-96 to 12.6%,

95% CI 11.7-13.5 from 2004-08) compared to all other Manitobans (6.9%, 95% CI 6.7-7.1 from

1992-96 to 19.9%, 95% CI 16.7-17.1 from 2004-08). Lower rates of colonoscopy or FS use for

First Nations compared to all other Manitobans were also observed in urban areas (7.7%, 95% CI

6.5-8.9 from 1992-96 to 14.9%, 95% CI 13.8-16.1 from 2004-08 for First Nations and 9.0%,

95% CI 8.8-9.1 from 1992-96 to 17.8%, 95% CI 17.6-17.9 from 2004-08 for all other

Manitobans).

Table 4 shows the relative rate of having a colonoscopy or FS in the previous five years

by ethnicity, residence, gender, age group, and index year. In the unadjusted models, there was




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no difference in the likelihood of having a colonoscopy or FS for First Nations individuals

compared to all other Manitobans (RR=0.90, 95% CI 0.77-1.05, p=0.21). After adjusting for

area of residence, gender, age group, and year, there was a significant interaction between

ethnicity and residence. In the rural south and urban areas, First Nations were less likely than all

other Manitobans to have a colonoscopy or FS (RR=0.81, 95% CI 0.75-0.87 for the rural south,

RR=0.86, 95% CI 0.81-0.92 for urban areas, p=0.02). However, there was no difference in the

likelihood of having a colonoscopy or FS for First Nations and all other Manitobans who lived in

the north (RR=1.04, 95% CI 0.91-1.19). Males were significantly less likely to have had a

colonoscopy or FS compared to females (RR=0.82, 95% CI 0.78-0.86), p<0.0001). The relative

rate of colonoscopy and FS use increased with age (RR=1.21, 95% CI 1.14-1.29 for 50-54 years

of age to 1.85, 95% CI 1.68-2.02 for 70-74 years of age, p<0.0001) and time period (RR=1.17,

95% CI 1.14-1.19 for 1996 to 2.23, 95% CI 21.3-2.35 for 2008, p<0.0001).

Discussion

Previous analyses have found that the CRC incidence among First Nations individuals

living in Manitoba has increased over time (2). This trend has also been observed in other

jurisdictions; American Indians and Alaska Natives who live in the Unites States have a higher

burden of CRC and stable or increasing CRC mortality (18). Population-based, organized

screening using an FOBT is an important strategy that can help reduce the incidence and

mortality of CRC. Our study found that over time, the rate of FOBT use has increased for both

FN and AOMs living in Winnipeg but the participation of First Nations individuals remained

significantly lower than that for all other Manitobans (13.4% for First Nations in 2008 compared

to 32.7% for all other Manitobans). In addition, the gap in screening rates between First Nations

and all other Manitobans has increased over time. The first CRC screening guidelines appeared




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in the United States in late 1990s and in Canada in 2001; compliance with these guidelines is

likely to occur earlier and more rapidly among individuals that have fewer barriers to screening

which may partially explain the observed gap (4,19).

Screening, regardless of ethnicity, remains below the recommended Canadian national

target of 60% (20). These findings are consistent with other studies examining FOBT use among

Indigenous groups outside of Canada. In the United States, CRC screening rates using the FOBT

are lower for American Indians compared to other ethnic groups (21,22). In Australia, 17% of

individuals who identified themselves as Indigenous accepted an offer of FOBT use compared to

38.6% of non-Indigenous people (23).

Our study also found that the rate of colonoscopy or FS in the province has increased

over time for First Nations although the rate was significantly lower than that for all other

Manitobans. As well, the likelihood of having a colonoscopy or FS depended on area of

residence. First Nations individuals who lived in northern Manitoba had the same rate of

colonoscopy or FS as all other Manitobans while First Nations who lived in the rural south or

urban area were less likely than AOM to have had a colonoscopy or FS. This suggests a referral

inequity for endoscopy services for First Nations individuals based on where they reside in the

province.

Barriers to CRC screening arise from a variety of demographic, psychological, and

provider-related factors (24). In a review of literature on the equity of participation in CRC

screening among different ethnic populations, Javanparast et al. (2010) found that socio-cultural

factors play an important role in the acceptability, accessibility, and utilization of screening (16).

Culturally-specific barriers found among First Nations individuals include speaking an

Indigenous language and perceived discrimination in a health care setting (25,26). Filippi et al.




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(2012) explored American Indian women’s barriers to CRC screening and found that

embarrassment, privacy issues, fear of the procedure and possible results, and cost were key

factors in screening participation (27). Logistical issues, such as child care duties, work

schedules, long wait periods, and lack of transportation, were also important barriers (27). The

most common barriers cited among American Indian men were privacy, embarrassment, and

distrust of the health care system (28). American Indian community leaders also felt that there

was little knowledge about CRC, risk factors, or screening recommendations (24).

Additional barriers to CRC screening include the required dietary and drug restrictions

and the practicality of completing the guaiac-based FOBT (29-31). Since its introduction in the

1950s, the use of the guaiac-based FOBT has necessitated the elimination of red meat, high-

peroxidase vegetables, vitamin C, and non-steroidal anti-inflammatory drugs for several days

before and during the testing period. Newer, more sensitive guaiac-based FOBTs, such as the

Hemoccult II SENSA currently used by the CRC screening program in Manitoba, require

removing only vitamin C from the diet. Whether or not a reduction in the number of dietary

restrictions will lead to improved screening participation has yet to be determined.

Research has also found that individuals are more reluctant to participate in CRC

screening if they perceive the test as impractical, awkward, or embarrassing (32-34). The

guaiac-based FOBT requires individuals to apply a small sample from three separate bowel

movements onto a test card with the aid of a cardboard spatula (35). The responsibility for

completing the screening test by the individual and any perceived difficulty may lead to lower

levels of participation. Von Wagner et al. (2011) found that the intention to participate in CRC

screening decreased when participants were given detailed information about how to collect fecal

samples for a guaiac-based FOBT (32). The FIT, which does not require dietary restrictions and




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only one stool sample, has been found to result in significantly higher participation rates than the

guaiac-based FOBT (30,36). The effect of using a FIT on screening participation is currently

being evaluated in Manitoba.

Until 2008, CRC screening in Manitoba using the FOBT was provided opportunistically,

which relies on the recommendation and provision of the test by a primary care provider.

However, in a recent survey, only 38% of Manitobans stated that their physician had initiated a

conversation with them about CRC screening (8). Kelly et al. (2007) found that less than 40% of

Native American women and men reported a physician recommendation for FOBT screening

(37). Ideally, providing CRC screening as part of an organized, population-based program

should achieve better accessibility by directly inviting eligible individuals to participate (38).

Since its introduction, the provincial CRC screening program has used several multi-level

strategies to encourage screening participation within First Nations communities, including

working with Health Canada’s First Nations and Inuit Health Branch and local primary health

care providers, sending personalized invitation letters, media messaging, and social marketing

campaigns. Previous research has found that addressing First Nations cultural structures and

traditional ways are important aspects of reducing cancer screening disparities (24,28).

Therefore, further work exploring the comprehensibility of the FOBT kit’s instructions in First

Nations communities and the development of culturally-specific education and training is

underway.

Our findings should be considered in the context of several study limitations. FOBT data

were not available from the Medical Claims database for rural and northern Manitoba.

Therefore, the results for Winnipeg may not be generalizable to other areas of the province. We

were also not able to distinguish between colonoscopy and FS performed for screening versus




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those performed because of symptoms or for diagnostic purposes. It is likely in Manitoba that

most colonoscopy and FS are diagnostic since population-based screening using these tests is not

currently recommended.

We did not include any measures of socio-economic status (SES) in the analysis.

Previous studies have found that education and income are often independent predictors of

screening and that differences in screening uptake due to ethnicity are reduced after the

adjustment for SES (39). Finally, this study included registered First Nations who represented

93% of all First Nations living in Manitoba; it did not include First Nations not registered nor did

we distinguish between several distinct First Nations cultural groups. This information,

however, is an important part of collaborating with FN communities and planning local strategies

designed to improve cancer screening in the population.

In summary, First Nations individuals who resided in Winnipeg were significantly less

likely to be screened for CRC using the FOBT. Throughout Manitoba, First Nations who lived

in the north had the same rate of colonoscopy or flexible sigmoidoscopy as all other Manitobans

while First Nations who lived in the rural south or urban area were less likely to have had a

colonoscopy or FS. The disparities identified in FOBT, colonoscopy, and FS use are likely

related to many factors and suggest that barriers to CRC screening exist for First Nations

individuals. Addressing these barriers and improving CRC screening rates are particularly

important since the incidence of CRC in First Nations is increasing and First Nations people

have higher rates of diabetes and obesity which also increase the risk of CRC (11,40-42).

This research on CRC screening provides a baseline which can be used to assess the

effectiveness of new strategies and changes in screening service delivery. Further research is

needed to understand the barriers to CRC screening for First Nations people and to evaluate the




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effectiveness of interventions that will help extend the benefit of CRC screening to the entire

population. It is also important that future research include First Nations individuals and health

care providers when identifying barriers and solutions to the lower CRC screening rates observed

in Manitoba. Finally, more analyses are needed to evaluate whether or not the introduction of the

organized, province-wide, population-based CRC screening program in 2008 has improved CRC

screening participation for First Nations people and reduced the gap in screening observed in this

study.




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Acknowledgements

We gratefully acknowledge the statistical support of Mr. Pascal Lambert and Dr. Rashid Ahmed.

We also thank the Health Information and Research Committee, Manitoba Health and the Health

Information and Research Committee of the Assembly of Manitoba Chiefs. This work was

supported by the Canadian Institute of Health Research (CIHR-AQC 83508).




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21

Tables Table 1. Characteristics of registered First Nations and all other Manitobans in 1995-96 and

2007-08

1995-96 All other Manitobans First Nations

Region n % n %

North 5,996 2.6 3,087 38.7

Rural south 79,810 34.4 3,071 38.4

Urban 146,358 63.0 1,829 22.9

Age group

50-54 59,194 25.5 2,587 32.4

55-59 47,273 20.4 2,024 25.3

60-64 43,297 18.6 1,531 19.2

65-69 42,186 18.2 1,103 13.8

70-74 40,214 17.3 742 9.3

Gender

Female 119.650 51.5 4,106 51.4

Male 112,514 48.5 3,881 48.6

Total 232,164 7,987

2007-08

Region n % n %

North 7,828 2.6 4,987 36.8

Rural south 102,140 34.3 5,017 37.0

Urban 188,138 63.1 3,553 26.2

Age group

50-54 83,506 28.0 4,746 35.0

55-59 72,451 24.3 3,353 24.7

60-64 60,947 20.4 2,591 19.1

65-69 44,917 15.1 1,683 12.4

70-74 36,285 12.2 1,184 8.7

Gender




22

Female 150,732 50.6 7,183 53.0

Male 147,374 49.4 6,374 47.0

Total 298,106 13,557




23

Table 2. Percent increase (gap) in fecal occult blood test use (FOBT) and FOBT, colonoscopy,

and flexible sigmoidoscopy (FS) use for all other Manitobans compared to First Nations by year

Year 1996 1998 2000 2002 2004 2006 2008 Increase in FOBT use (%)

7.3 8.1 9.9 13.4 15.7 15.7 19.5

Increase in FOBT, colonoscopy and FS use (%)

7.1 8.4 9.4 12.4 13.3 13.9 17.4




24

Table 3. Relative rates of fecal occult blood test utilization for registered First Nations and all

other Manitobans who lived in Winnipeg by demographic characteristic

Crude model Adjusted model

Number of Individuals*

Rate Ratio

95% CI P Value Rate Ratio

95% CI P Value

Ethnicity <.0001 0.0001

All other Manitobans

113,070 1.00 Ref 1.00 Ref

First Nations 989 0.39 0.32 - 0.49 0.40 0.37 - 0.44

Gender 0.39 0.002

Female 62,155 1.00 Ref 1.00 Ref

Male 51,904 0.84 0.55 - 1.27 0.88 0.85 - 0.92

Age group 0.58 0.08

50-54 51,349 1.00 Ref 1.00 Ref

55-59 51,987 1.30 0.73 - 2.33 1.24 1.17 - 1.32

60-64 47,261 1.48 0.80 - 2.73 1.45 1.37 - 1.54

65-69 43,260 1.69 0.92 - 3.11 1.65 1.53 - 1.77

70-74 39,384 1.64 0.85 - 3.14 1.63 1.50 - 1.78

Year 0.003 0.02

1996 16,707 1.00 Ref 1.00 Ref

1998 18,817 1.07 0.96 - 1.19 1.10 1.08 - 1.13

2000 24,112 1.33 1.18 - 1.50 1.38 1.34 - 1.41

2002 30,940 1.56 1.40 - 1.74 1.69 1.64 - 1.74

2004 37,169 1.75 1.55 - 1.96 1.94 1.89 - 2.00

2006 47,201 2.31 2.12 - 2.50 2.39 2.31 - 2.47

2008 58,295 2.68 2.47 - 2.92 2.80 2.70 - 2.90

Notes: CI – Confidence Interval. Includes Winnipeg residents 50 to 74 years of age who had at

least one fecal occult blood test in the two years before the last day of the index year. In the

adjusted model, each variable was adjusted for all other variables. *The number of individuals in

the age group and year categories will not sum to the total number of individuals in the ethnicity

and gender categories as some individuals may have been screened more than once over the 12

year time frame.




25

Table 4. Relative rates of colonoscopy or flexible sigmoidoscopy utilization for registered First

Nations and all other Manitobans

Crude model Adjusted model

Number of Individuals*

Rate Ratio

95% CI P-value Rate Ratio

95% CI P-value

Ethnicity 0.21 0.0017

All other Manitobans 91,951 1.00 Ref 1.00 Ref

First Nations 2,975 0.90 0.77 - 1.05 0.86 0.81-0.92

Area of residence 0.0008 0.0002

Urban 158,307 1.00 Ref 1.00

North 6,424 0.67 0.57 - 0.79 0.61 0.55-0.68

Rural south 78,278 0.84 0.72 - 0.99 0.87 0.82-0.92

Area of residence: Ethnicity 0.003 0.02

North: All other Manitobans 3,969 1.00 Ref 1.00 Ref

North: First Nations 2,455 1.12 0.89 - 1.40 1.04 0.91 - 1.19

Rural south: All other Manitobans

75,653 1.00 Ref 1.00 Ref

Rural south: First Nations 2,625 0.80 0.64 - 1.01 0.81 0.75 - 0.87

Urban: All other Manitobans 156,086 1.00 Ref 1.00 Ref

Urban: First Nations 2,221 0.88 0.71 - 1.08 0.86 0.81 - 0.92

Gender 0.001 <.0001

Female 51,407 1.00 Ref 1.00 Ref

Male 43,519 0.78 0.67 - 0.91 0.82 0.78 - 0.86

Age group 0.0003 <.0001

50-54 50,470 1.00 Ref 1.00 Ref

55-59 50,844 1.20 1.00 - 1.43 1.21 1.14 - 1.29

60-64 48,074 1.41 1.17 - 1.70 1.43 1.34 - 1.53

65-69 46,774 1.62 1.34 - 1.95 1.66 1.54 - 1.79

70-74 46,847 1.75 1.45 - 2.12 1.84 1.68 - 2.02

Year <.0001 <.0001

1996 19,428 1.00 Ref 1.00 Ref

1998 22,736 1.19 1.15 - 1.23 1.17 1.14 - 1.19

2000 27,931 1.41 1.36 - 1.47 1.41 1.37 - 1.44

2002 33,655 1.63 1.55 - 1.71 1.64 1.58 - 1.71

2004 39,900 1.86 1.77 - 1.95 1.87 1.79 - 1.95

2006 46,085 2.02 1.92 - 2.13 2.04 1.95 - 2.14

2008 53,274 2.20 2.08 - 2.33 2.23 2.13 - 2.35




26

Notes: CI – Confidence Interval. Includes Manitoba residents 50 to 74 years of age who had at

least one colonoscopy or flexible sigmoidoscopy in the five years before the last day of the index

year. In the adjusted model, each variable was adjusted for all other variables. *The number of

individuals in the area of residence, age group and year categories will not sum to the total

number of individuals in the ethnicity and gender categories as some individuals may have been

screened more than once over the 12 year time frame.




27

Figure Legends

Figure 1. Percentage of First Nations and all other Manitobans who lived in Winnipeg and had a

fecal occult blood test by index year

Notes: Includes Winnipeg residents 50 to 74 years of age who had at least one fecal occult blood

test in the two years before the last day of the index year.

Figure 2. Percentage of First Nations and all other Manitobans who lived in Winnipeg and had a

fecal occult blood test, colonoscopy, or flexible sigmoidoscopy by index year

Notes: Includes Winnipeg residents 50 to 74 years of age who had at least one fecal occult blood

test in the two years or a colonoscopy or flexible sigmoidoscopy in the five years before the last

day of the index year.

Figure 3. Percentage of First Nations and all other Manitobans who had a colonoscopy or

flexible sigmoidoscopy by area of residence and index year

Notes: Includes Manitoba residents 50 to 74 years of age who had a colonoscopy or flexible

sigmoidoscopy in the five years before the last day of the index year.




Figure 1

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90

100

60

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23 128

32.9

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Perc

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First NationsAll other Manitobans

4.9 5.1 6.5 6.8 7.412.3

13.412.2 13.216.4

20.223.1

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Index Year

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Figure 2

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100

60

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25 524 629.1

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30

40

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Perc

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23.8 25.518.8 20.6

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Index Year

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Figure 3

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8

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First Nations, UrbanFirst Nations, Rural SouthFirst Nations, NorthAll other Manitobans, UrbanAll other Manitobans Rural South

2

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Index Year

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