True burden of disease underestimated
Estimates of the prevalence of diabetes in New Zealand have limitations. The four national health surveys, undertaken in 1992/93, 1996/97, 2002/03, and 2006/07, examined self-reports of doctor-diagnosed diabetes only.
As national diabetes prevalence estimates have not included undiagnosed diabetes cases, the actual burden of disease has been underestimated. A number of local or workplace-based prevalence surveys conducted since 1967 have reported both diagnosed and undiagnosed diabetes, but the study populations were not necessarily representative of New Zealand's population.
National and international reports of diabetes prevalence in New Zealand have involved assumptions and modelling rather than direct measurements.
Survey methodology provides robust data
The 2008/09 New Zealand Adult Nutrition Survey (2008/09 NZANS) provided an opportunity to report the national prevalence of diabetes and prediabetes in adult New Zealanders using American Diabetes Association (ADA) criteria. The 2008/09 NZANS enquired about doctor diagnosed diabetes and a blood sample was taken for the measurement of glycated haemoglobin (HbA1c).
High prevalence of prediabetes
Overall, prevalence of diabetes was 7%, and prevalence of prediabetes 26%. Prevalence of diabetes was higher in men (8%) than in women (6%), and higher among the obese (14%) compared with the normal weight group (3%).
Coppell, K.J., Mann, J.I., Williams, S.M., Jo, E.C., Drury, P.L., Miller, J.C., Parnell, W.R. (2013). Prevalence of diagnosed and undiagnosed diabetes and pre-diabetes in New Zealand: findings from the 2008/09 Adult Nutrition Survey. New Zealand Medical Journal 126(1370),23-42.
(The New Zealand Ministry of Health funded the 2008/09 New Zealand Adult Nutrition Survey. The New Zealand Crown is the owner of the copyright of the survey data. The results presented in this paper are the work of the authors.)
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2008/09 New Zealand Adult Nutrition Survey
- A focus on nutrition: Key findings from the NZ adult nutrition survey (Ministry of Health website)
- Methodology report for the 2008/09 NZ adult nutrition survey (Ministry of Health website