A large increase in strokes among Pacific and Maori people is being blamed on poor diet, smoking and lack of exercise.
Three linked studies into the incidence of stroke in Auckland over the past 20 years have shown an overall decline in the disease, but high rates for some ethnicgroups, particularly Maori and Pacific people.
The studies, part of the wider Auckland Regional Community Stroke Study, were based at Auckland University's clinical research trials unit.
They showed a 66 per cent increase (from 128 in 1981 to 212 in 2003) for Pacific people and a 30 per cent rise (from 93 to 110) for Maori since the beginning of the 1980s.
Conversely, stroke rates for European New Zealanders decreased 19 per cent (from 306 to 249) and the overall incidence of stroke declined 11 per cent during the period.
Associate Professor Valery Feigin said it was the largest stroke incidence study of its kind in the world and showed a worrying trend in Maori and Pacific people.
"This is the first time we have an exact measure not just of the incidence of stroke, but of the outcomes, including mortality rates, long-term disabilities, and the impacts on the quality of life for sufferers across different groups."
Professor Feigin said differing lifestyles such as poor diet, smoking, little exercise and heavy drinking could explain the high rate.
Stroke rates
* 66 per cent increase in rates of strokes for Pacific Island people since 1980s.
* 19 per cent decline for Europeans in same period.
* Pacific Islanders and Maori are having strokes more than a decade younger than Europeans.
* Risk factors include smoking, obesity, diabetes and hypertension.
* Direct medical costs of strokes estimated at $150 million a year.
