Send to

Choose Destination
Diabetes Care. 2015 Jul;38(7):1299-305. doi: 10.2337/dc14-2474. Epub 2015 Apr 7.

Prevalence of Prediabetes and Undiagnosed Diabetes in Canada (2007-2011) According to Fasting Plasma Glucose and HbA1c Screening Criteria.

Author information

Dalla Lana School of Public Health, Toronto, Ontario, Canada Public Health Ontario, Toronto, Ontario, Canada Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
Public Health Ontario, Toronto, Ontario, Canada.
Dalla Lana School of Public Health, Toronto, Ontario, Canada.
St. Michael's Hospital, Toronto, Ontario, Canada Institute of Health Management Policy and Evaluation, University of Toronto, Toronto, Ontario, Canada.



To provide the first population-based estimates of prediabetes and undiagnosed type 2 diabetes prevalence in Canada.


We combined two fasting subsamples of the Canadian Health Measures Survey, which were restricted to nonpregnant adults ≥20 years of age (N = 3,494). Undiagnosed diabetes was defined as not having self-reported type 2 diabetes but having blood glucose measures that met Canadian guidelines (i.e., fasting plasma glucose [FPG] level of ≥7.0 mmol/L or hemoglobin A1c [HbA1c] level of ≥6.5% [≥48 mmol/mol]). Prediabetes was defined as an FPG level of ≥6.1 and <7.0 mmol/L or an HbA1c level of ≥6.0% and <6.5% (≥42 and <48 mmol/mol). All estimates were weighted using survey sampling weights. CIs were calculated with the bootstrap method.


According to FPG levels, the prevalence of undiagnosed type 2 diabetes in Canadian adults was 1.13% (95% CI 0.79, 1.62), contributing to ∼20% of total type 2 diabetes prevalence (5.62 [95% CI 4.52, 6.95]). Compared with FPG levels, the undiagnosed prevalence was greater using HbA1c level as a criterion (3.09% [95% CI 1.97, 4.81]), ∼41% of the total number of cases of diabetes (7.55 [95% CI 5.98, 9.49]). The HbA1c-only criterion resulted in a threefold increase in prediabetes prevalence overall and a sixfold increase among females (FPG 2.22%, HbA1c 13.31%). Screening based on FPG only identified older undiagnosed case patients, with a mean age of 58.7 years (95% CI 59.9, 63.4). Similarly, using HbA1c identified younger individuals with prediabetes, with reduced BMI and waist circumference compared with FPG levels.


In this first study of a nationally representative sample with biospecimen measures, we found that the prevalence of undiagnosed type 2 diabetes and prediabetes was significantly higher using HbA1c levels compared with FPG levels. Further evaluation is needed to fully assess the impact of using the HbA1c criterion.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center