Text Equivalents - Chapter 1 - Epidemiology of Tuberculosis in Canada

Figure 1. Reported tuberculosis incidence and mortality rates in Canada, 1924-2010

The line graph shows the trends in the incidence rate (solid trend line) and the all-cause mortality rate (dashed trend line) for all TB cases reported in Canada for the years 1924 to 2010. The horizontal axis shows the reporting years from 1924 to 2010 and the vertical axis displays the rate per 100,000 population.

Between 1924 and the 1946 the TB incidence rate increased from 44 per 100, 000 to a high of 103 per 100,000 population. Between 1946 and 1970 the rate of TB in Canada rapidly declined to 21.2 cases per 100,000 population. Since 1970 the decrease in the overall reported incidence rate has been gradual. Between 2000 and 2010 the reported incidence rate has remained stable at approximately 5.0 per 100,000 population.

Between 1924 and the early 1970s the mortality rate from all causes for TB cases declined steadily with a more rapid decline starting in 1950 and carrying through 1965. Since 1975 the mortality rate from all causes has remained stable at 0.4 per 100,000 population.

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Figure 2. Reported TB cases and incidence rates in Canada, 1990-2010

The graph shows the number of reported TB cases (vertical bars) and the reported incidence rate (solid line) in Canada for the years 1990 to 2010. The horizontal axis shows the reporting year. The vertical axis on the left side of the graph shows the number of reported cases and the vertical axis on the right side of the graph shows the reported incidence TB rate per 100,000 population.

Between 1990 and 2010, the number of reported cases has steadily declined from around 2,100 cases to 1,600 cases. Between 2005 and 2010 the annul number of reported cases has remained stable at around 1,600 case. Similarly, the rate has slowly declined over the period from approximately 7.0 per 100, 000 in 1990 to approximately 5.0 per 100 000 for the past six years.

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Figure 3. Reported TB incidence rate by sex and age group in Canada, 2010

The graph shows the reported TB incidence rate by age group showing the differences between males and female for the year 2010. The horizontal axis shows the age-groups analysed (<1, 1-4, 5-14, 15-24, 25-34, 35-44,45-54, 55-64,65-74 and 75+). The vertical axis shows the incident rate per 100,000 population. Data for females are represented by a solid pink trend line and males by a solid red trend line.

The graph shows very little difference in the incidence rates between male and females for the age groups from < 1 to 25-34. Between <1 and 14 year of age, the rate goes from approximately 3.0 per 100,000 down to less than 1 per 100,000. Between the 5 and 34 years of age, for both males and females, the reported incidence rate slowly increases to approximately 6 cases per 100,000 population. However by 44 years the incidence rate for males starts increasing relative to females and by the 75+ age group the incidence rate for male (13.6 per 100,000 population) is over 2 times the rate reported for females (5.7 per 100,000 population).

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Figure 4. Percentage of reported TB cases by population group in Canada, 1970-2010

The graph shows the percentage of reported TB cases by origin group (foreign-born represented by the solid line trend line, Canadian-born non-Aboriginal represented by the dashed trend line and Canadian-born Aboriginal population represented by the dotted trend line) for the years 1970 to 2010. The horizontal axis represents the year cases were reported and the vertical line represents the percent of the total cases reported (0%– 100%).

In 1970 the Canadian-born non-Aboriginal population made up almost 68% of all reported cases in Canada, the foreign born population made up 18% of the cases and the Canadian-born Aboriginal population made up approximately 15% of reported cases. The graph shows that the percentage of cases represented by the Canadian-born non-Aboriginal population steadily decreased and by 2010 they represented 12% of the cases. During the same time the percentage of cases represented by the foreign-born population steadily increased, and by 2012 foreign-born individual made up 67% of all cases. Finally between 1970 and 2010 the percentage of cases represented by Canadian-born Aboriginal remained constant and by 2010 only increased slightly to 21% of all reported cases.

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Figure 5. Reported TB incidence rate by population group in Canada, 2000-2010Footnote *

This graph shows the reported incidence rate of TB cases by origin group (foreign-born represented by the solid line trend line, Canadian-born non-Aboriginal represented by the dashed trend line and Canadian-born Aboriginal population represented by the dotted trend line) The horizontal axis represents the year cases were reported and the vertical line represents the rate per 100,000 population.

Between 2000 to 2010 the Canadian-born Aboriginal population reported the highest incidence rates of all three origin groups ranging from 20 and 30 cases per 100,000 population. The reported TB incidence rate in the foreign-born, between 2000 and 2010 displays a slow but steady decline from 21 per 100,000 in 2000 to 14.5 per 100,000 population by 2010. For the period 2000 to 2010, the reported incidence rate for TB in the Canadian-born non-Aboriginal population remained steady at approximately 1 per 100,000 population.

Footnote *
Population denominators obtained from Statistics Canada

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Figure 6. Reported TB incidence rates by province/territory, Canada, 2010Footnote *

The bar-graph shows the reported TB incidence rate by province and territory for the year 2010. The horizontal axis shows the ten provinces as well as the North which combines the rates for Northwest Territories, Nunavut and Yukon. The vertical axis displays the rate per 100,000 population. For the ten provinces, the rates are all below 11 per 100,000. The rate for the North, however, is many time higher at 105 cases per 100,000 population.

Footnote *
Population denominators obtained from Statistics Canada

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Figure 7. Number of reported TB cases by population group and province/territory in Canada, 2010Footnote *

The bar-graph shows the breakdown of the number of reported TB cases by province, across origin groups (from top to bottom: foreign-born, Canadian-born Aboriginal and Canadian born non-Aboriginal). For Alberta, BC, Ontario and Quebec, the majority of cases were foreign-born. In Manitoba, Saskatchewan and the North, the majority of cases were Canadian-born Aboriginals.

Footnote *
Population denominators obtained from Statistics Canada

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Figure 8. Reported TB disease incidence rates in Canada by population group, 2001-2010

This graph shows the trend lines for the reported incidence rate of TB cases by Aboriginal group (Inuit, First Nation on–reserve, First Nation off–reserve, and Métis) and the trend line for the Canadian-born non-Aboriginal population, for the years 2001 to 2010. First Nations (on- and off-reserve) and Inuit account for the majority of incident cases of TB in Aboriginal peoples in Canada. From 2001 to 2010, the rate of TB was highly variable in the Inuit population. In 2003 the reported incident rate for the Inuit population was 22.1 per 100,000 population. The reported incidence rate for the Inuit rose to approximately 200 cases per 100,000 population in 2010. The graphs show that the reported incidence rates for First Nations (on- and off-reserve) were relatively stable over time with the First Nation on-reserve population having slightly high incidence rate (range 21.6 to 30.4 per 100,00 population) than the First nations off-reserve population (range 18.6 to 27.8 per 100,000 population).

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Figure 9. Distribution of active TB cases and incidence rates for Aboriginal populations, 2010

The bar-graph shows the breakdown of the number of reported TB cases and the reported incidence rates for the Canadian-born Aboriginal population by province, for 2010. The horizontal axis shows the reporting provinces and territories, the left-hand vertical axis shows the number of reported cases and the right-hand vertical axis shows the incidence rate per 100,000 population. The majority of the Aboriginal cases were reported from Manitoba (76), Nunavut (99) and Saskatchewan (70). The highest reported incidence rate was reported from Nunavut at 333.0 per 100,000.

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Figure 10. TB cases and incidence rates among Canadian-born-Aboriginal Populations by age group, 2010

This bar graph shows the breakdown of the TB cases reported among the Canada-born Aboriginal populations in 2010 by age-group (< 5, 5-14, 15-24, 25-34, 35-44, 45-54, 55-64, 65-74 and 75+) with the bars representing the number of reported cases and the trend line showing the rate per 100,000 population. The majority of the reported cases in Aboriginal individuals was reported in adolescents and young adults between the ages for 15 and 44 years of age. A substantial number of cases in Canadian-born Aboriginal individuals was reported in children under the age of 15, and the incidence rate was much higher than that seen in other Canadian populations. The highest reported incidence rate, 69 per 100,000 population, was reported for those individuals 75 years of age and older.

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Figure 11. Reported foreign-born TB cases in Canada, 2000-2010: time from arrival in Canada to diagnosis, in years

The bar graph shows the number of foreign born cases reported by the time difference between the year of arrival into Canada and the year in which the TB was diagnosed. The horizontal axis shows the years from arrival into Canada to year of diagnosis and runs from 0 to 54 years. The vertical axis shows the number of reported cases. Of the foreign-born TB cases reported in Canada between 2000 and 2010 for which the date of arrival was reported, 11% were reported within the first year of arrival, 22% by the second year of arrival and 44% within 5 years.

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Figure 12. Percentage of reported foreign-born TB cases in Canada by WHO TB epidemiologic region, 1970-2010

The line graph shows the changing trends in the percentage of foreign-born cases by epidemiological regions as set out in the STOP TB partnership/WHO TB (African Region – high HIV prevalence countries, Africa Region – low HIV prevalence countries, Americas, Eastern Europe Region, Eastern Mediterranean Region, Established Market Economies, Central European Region, South East Asia Region, and Western Pacific Region). During the period 1970 to 2010 the percentage of cases from established market economies decreased, whereas the percentage of cases reported from the Western Pacific and South-East Asia regions increased. In 2010, 42% of reported cases in the foreign-born population were born in the Western Pacific Region followed and an additional 25% were born in the South East Asia Region.

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Figure 13. Percentage of reported cases by diagnostic site and origin in Canada, 2010

The bar chart shows the percentage of reported TB cases by diagnostic site (primary, pulmonary, other respiratory, miliary, central nervous system, peripheral lymph node and other) across origin groups (Canadian-born Aboriginal represented by the white bar, Canadian-born non-Aboriginal represented by the rose bar and foreign-born represented by the red bar). Also included is the overall percentage of cases by diagnostic site for all cases reported in Canada. Sixty-four percent of all reported TB cases in 2010 were diagnosed with pulmonary TB. Peripheral lymph node was the second most commonly reported site, at nearly 13% of cases in the same year. Slight differences were observed when comparing the three origin groups. A greater proportion of cases in Aboriginal individuals were diagnosed with primary disease, and a greater proportion of foreign-born individuals received a diagnosis of peripheral lymph node TB.

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Figure 14. Percentage of pulmonary cases by sputum smear microscopy result: Canada, 2000-2010

The area graph shows data for the pulmonary TB cases diagnosed between 2000 and 2010. The data show the percentage of reported cases diagnosed with active pulmonary TB by sputum smear microscopy results (sputum smear positive, sputum smear negative or sputum smear unknown). Between 2000 and 2010, on average 33% of all reported pulmonary cases were smear negative, 41% were reported as smear positive and lab microscopy results were not reported for 26% of pulmonary cases.

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Figure 15. Percentage of reported TB cases by HIV status, Canada, 1997-2010

The stacked bar graph shows data on the HIV status for all reported TB cases diagnosed between 1997 and 2010. For each year the bars show the percentage of cases for which HIV status was unknown, the percentage that was positive and the percentage that was negative. Between 1997 and 2010 the percentage of cases for which the HIV status (positive or negative) was reported as unknown has decreased from 94% of cases to 59% of cases. In 2010, the HIV status for 60% of the reported cases remained unknown, 2% were positive and 38% of all cases were reported to be HIV negative.

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