Diabetes Data - NDSS 1997-1998 to 1999-2000 Canadian, Provincial, and Territorial Data Tables (XLS) and Research Files (CSV)

Prevalence

In 1999/2000, 5.1% of Canadians (1,196,370) aged 20 and over were living with diagnosed diabetes. This rate is higher than the self-reported rate of diabetes among people aged 20 and over found by the National Population Health Survey in 1998/99 (3.9%), or even the self-reported rate found by the more recent Canadian Community Health Survey 2000/01 (4.7%). This is consistent with validation studies showing that self-report survey data underestimate the true disease burden in the population.

NDSS prevalence estimates represent diagnosed diabetes among health services users. Prevalence may be underestimated by 30% as a result of subclinical, undiagnosed diabetes.

The crude prevalence data as presented in Appendix K of the report is available in CSV and XLS format:

NDSS_crude_prevalence_data_e.csv (41KB)
NDSS_crude_prevalence_data_e.xls (98KB)

Prevalence by sex

The figure below demonstrates that diabetes is more common among Canadian men aged 20 and older (5.4%) than among women (4.9%). An exception to the male preponderance occurs in the childbearing years (20-39), in which cases of gestational diabetes may be miscoded as type 1/type 2 diabetes.

Prevalence by age group

For both sexes, prevalence increases with age, peaking in the 75-79 age group at 15.5% (17.4% among males and 14.2% among females). People aged 65 and over account for almost 50% of diabetes cases but represent only about 15% of the population aged 20 and over. The slight decrease in prevalence in the oldest age groups (80+) may be the result of mortality associated with diabetes or an artefact of limiting the number of conditions coded per visit; increased co-morbidity at older ages increases the likelihood that conditions other than diabetes will be recorded.

Prevalence by region

The figure below compares the provinces and territories using age-sex standardized rates and 95% confidence intervals. For the majority of jurisdictions, age-sex adjusted prevalence ranges from 4.0% to 5.5%. Apparent differences among the provinces should be interpreted with caution because of the effects of different populations, different data collection procedures, and variations in the likelihood of diagnosis. For example, Manitoba's higher rate may reflect the fact that Aboriginal people represent a relatively high proportion of its population (13%) and that diabetes prevalence among Aboriginals is 3 to 5 times higher than the national rate. This emphasizes the need to identify specific populations at high risk of diabetes, such as Aboriginal groups.

Differences between provinces and territories may not result from differences in the level of diabetes in the population. For example, the territories have the highest proportion of Aboriginal peoples (22% in the Yukon, 46% in the Northwest Territories and 81% in Nunavut) but the lowest prevalence rates. This may be because of the inability of some administrative data to capture diabetes diagnoses outside the fee-for-service payment system. To investigate this, Nunavut is conducting a pilot project that includes addition of community health nurse data to NDSS, and other validation projects are under way.

Finally, differences between provinces and territories may reflect differences in the likelihood of diagnosis. For example, the three provinces with the highest prevalence (Manitoba, Nova Scotia and Ontario) also have the most established diabetes programs.

Since one of the goals of NDSS is comparable information on diabetes, the impact of these issues is being more closely examined. In the future, we expect to have a better understanding of any subtle differences in systems that may affect the data collection and, ultimately, regional comparisons.

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Mortality

In 1999/2000, the death rate among Canadian adults with diabetes was 1,393 per 100,000 (age-sex standardized to the1991 Canadian population). This includes deaths due to external injuries or other causes that may not be directly related to diabetes. This all-cause mortality of 41,483 Canadians aged 20 years and over with diabetes is 6.5 times the 1999 mortality count of 6,131 Canadians aged 20 and older whose leading cause of death was listed as diabetes.

The all-cause mortality rate seems to support past calculations estimating that the number of diabetes-related deaths is over five times the number of deaths with diabetes coded as the underlying cause. Studies have demonstrated that only 28% of death certificates with any mention of diabetes were coded with diabetes as the underlying cause of death and that diabetes was not mentioned at all for 41% of people with diabetes who died.

Mortality by sex

Across all three fiscal years, male mortality is consistently higher than female mortality among both people with diabetes and those without. However, mortality among people with diabetes relative to those without is slightly higher for women (mortality rate ratio 2.11) than for men (mortality rate ratio 1.87).

Mortality by age group

The figure below shows that for all age groups the death rate for people with diabetes is higher than the death rate for those without. The figure also shows the rate ratio, which compares mortality rates among people with and without diabetes. The rate ratio is higher in the younger age groups and gradually decreases for the older ones. This means that a 35-year-old Canadian with diabetes is 4 times more likely to die than a person without diabetes, whereas an 85-year-old Canadian with diabetes is 1.4 times more likely to die than a person without diabetes.