Icebergs & Tsunamis: assumptions and limitations of NZ’s dementia demographic data

Government and DHB strategies for diagnosis & management of dementia assume some 50,000 New Zealanders living with de- mentia and a further 12,000 new cases every year. Further, that the majority of dementia cases go undiagnosed and that the shift- ing demographics of New Zealand will result in a ‘tidal wave’ of dementia in the coming decades.

There is a dearth of real prevalence, incidence, diagnostic & prog- nostic data for dementia in New Zealand. All of the commonly quoted figures are estimates derived from other estimates.
In the absence of hard data, these estimates are informing strategy, which dictates service development, which in turn shapes clinical practice.

This is an overview of the key prevalence, incidence, diagnostic & prognostic research, highlighting the assumptions & limitations of these studies. How likely is it that we are working from under- or over-estimates of the real problems?