ArticlesTrends in diabetes prevalence, incidence, and mortality in Ontario, Canada 1995–2005: a population-based study
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)
- et al.
Diabetes mellitus as a contributor to the risk of acute myocardial infarction
J Clin Epidemiol
(2002) - et al.
Differences in risk factors, atherosclerosis, and cardiovascular disease between ethnic groups in Canada: the Study of Health Assessment and Risk in Ethnic groups (SHARE)
Lancet
(2000 July 22) - et al.
Rising prevalence of diabetes: evidence from a Danish pharmacoepidemiological database
Lancet
(2003) - et al.
Trends in the prevalence and ratio of diagnosed to undiagnosed diabetes according to obesity levels in the US
Diabetes Care
(2004) - et al.
Global burden of diabetes, 1995–2025: prevalence, numerical estimates, and projections
Diabetes Care
(1998) - et al.
Global prevalence of diabetes: estimates for the year 2000 and projections for 2030
Diabetes Care
(2004) The epidemiology of chronic kidney disease
Kidney Int Suppl
(2005)- et al.
Important causes of visual impairment in the world today
JAMA
(2003) Global Strategy on diet, physical activity and health: diabetes
Diagnosis and classification of diabetes mellitus
Diabetes Care
(2005)
Prevalence and trends in obesity among US adults, 1999–2000
JAMA
Prevalence of overweight and obesity in the United States, 1999–2004
JAMA
Prevalence of class I, II and III obesity in Canada
CMAJ
Health Status: Health indicators
Cited by (526)
Temporal Trends in Type 1, Type 2, and Gestational Diabetes in Pregnancy: Impact of Rural Residence, Ethnicity, and Material Deprivation
2023, Canadian Journal of DiabetesPrevalence and predictors for being unscreened for diabetic retinopathy: a population-based study over a decade
2023, Canadian Journal of OphthalmologyReal-World Examination of Revascularization Strategies for Left Main Coronary Disease in Ontario, Canada
2023, JACC: Cardiovascular InterventionsTreating chronic diseases without tackling excess adiposity promotes multimorbidity
2023, The Lancet Diabetes and Endocrinology