Elsevier

The Lancet

Volume 369, Issue 9563, 3–9 March 2007, Pages 750-756
The Lancet

Articles
Trends in diabetes prevalence, incidence, and mortality in Ontario, Canada 1995–2005: a population-based study

https://doi.org/10.1016/S0140-6736(07)60361-4Get rights and content

Summary

Background

The prevalence of diabetes has been increasing greatly, but WHO's predicted 39% rise in the global rate of diabetes from 2000 to 2030 might be an underestimate. We aimed to assess diabetes trends in Ontario, Canada.

Methods

Using population-based data, including a validated diabetes database from the province of Ontario, Canada, we examined trends in diabetes prevalence and mortality from 1995 to 2005, and incidence from 1997 to 2003, in adults aged 20 years or older.

Findings

Age-adjusted and sex-adjusted diabetes prevalence increased by 69%, from 5·2% in a population of 7 908 562 in 1995 to 8·8% of 9 276 945 in 2005. Prevalence increased by 27% from 6·9% in a population of 8 457 720 in 2000 to 8·8% of 9 276 945 in 2005. Although prevalence rates have remained higher in people aged 50 years or older (7·1% of 3 675 554) than in those aged 20–49 years (3·5% of 5 601 391), rates increased to a greater extent in the younger population (94% vs 63%, p<0·0001). A 31% increase occurred in yearly incidence over 6 years, from 6·6 per 1000 in 1997 to 8·2 per 1000 in 2003. The adjusted mortality rate in people with diabetes fell by 25% from 1995 to 2005.

Interpretation

The prevalence of diabetes in Ontario, Canada increased substantially during the past 10 years, and by 2005 already exceeded the global rate that was predicted for 2030. This increase in prevalence is attributable to both rising incidence and declining mortality. Effective public-health interventions aimed at diabetes prevention are needed, as well as improved resources to manage the greater number of people living longer with the disease.

Introduction

The number of people with diabetes has increased substantially during the past 20 years,1, 2, 3 making it one of the most costly and burdensome chronic diseases of our time. Diabetes is one of the leading causes of blindness and the most common cause of end-stage renal disease in developed countries.4, 5 It is also an important cause of cardiovascular complications.6 Furthermore, the treatment is complex and costly, with direct health-care costs of diabetes ranging from 2·5% to 15% of health budgets.7

According to the latest WHO report,7 the number of people worldwide with diabetes increased from 30 million to 171 million between 1985 and 2000; an estimated 4·6% of adults aged 20 years or older are now affected.3 Prevalence rates are generally higher in developed countries than in developing ones (6·3% vs 4·1%), but developing nations have seen the greatest rise, with about a 25% increase in diabetes rates since 1995.2, 3

This increase in diabetes has been mainly attributed to a rise in new cases of type 2 diabetes,8 which in turn is driven by increasing obesity rates9, 10, 11, 12, 13, 14 and ageing of the population.15 The increased migration of susceptible populations, accompanied by shifts in lifestyle, has also added to the diabetes burden in developed countries.16, 17, 18 Additionally, improved survival in people with diabetes might have also contributed to the increasing prevalence of the disease.19, 20

Rates of diabetes are expected to continue to increase. WHO has predicted that the global diabetes prevalence in adults will reach 6·4% by 2030,3 representing a 60% increase since 1995,2 and a 39% rise from 2000 to 2030.3 However, these projections are likely to be underestimates, since they were based on an unwarranted10, 11, 12, 13, 14 assumption that obesity rates would remain constant.3

Using a validated diabetes registry derived from hospital records and physician claims,21 we describe trends in diabetes prevalence, incidence, and mortality in Ontario, Canada, from 1995 to 2005. We aimed to determine whether diabetes prevalence rates rose beyond predicted levels during that period, and to examine the contribution of changes in incidence and mortality to changes in prevalence.

Section snippets

Data sources and study population

Data were obtained from anonymised, administrative health-care databases that included records for all individuals eligible for coverage under the government-funded Ontario health plan. As in other Canadian provinces, this health plan is available to all residents; therefore, almost all Ontarians are represented by these datasets. With a population of 12 million, Ontario is the largest and most ethnically diverse Canadian province, and contains both rural and urban areas. Patient records are

Results

An 81·6% increase (from 4·9% to 8·9%) in the crude prevalence of diabetes in Ontario adults took place between March 31, 1995, and March 31, 2005, (p<0·0001 for trend by year). Ageing of the population accounted for only a small proportion of this increase, since the age-adjusted and sex-adjusted prevalence increased by 68·6%, from just over 5% in 1995 to nearly 9% by 2005 (Table 1, Table 2). Prevalence increased by a third during the first 5 years, and by another quarter from 2000 to 2005 (

Discussion

We have shown that the prevalence of diabetes increased steadily from 1995 to 2005, by an average of 6·2% a year. By 2005, the age-adjusted and sex-adjusted adult prevalence of diabetes in Ontario, Canada reached 8·8%, representing a 69% increase since 1995. This rise has already exceeded the 60% global increase and the 65% Canadian increase that were projected to occur in the 35 years from 1995 to 2030.2, 3 WHO predicted that a global increase in diabetes prevalence rates of 39% would take

References (29)

  • KM Flegal et al.

    Prevalence and trends in obesity among US adults, 1999–2000

    JAMA

    (2002)
  • CL Ogden et al.

    Prevalence of overweight and obesity in the United States, 1999–2004

    JAMA

    (2006)
  • PT Katzmarzyk et al.

    Prevalence of class I, II and III obesity in Canada

    CMAJ

    (2006)
  • Health Status: Health indicators

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