GEOGRAPHICAL VARIATION IN THE PREVALENCE OF ASTHMA SYMPTOMS IN NEW-ZEALAND

Aims. To examine geographical variations in the prevalence of asthma s ymptoms in a random population sample of New Zealand adults aged 20-44 years. Methods. A one page asthma symptom questionnaire was sent to 3 1 470 people aged 20-44 years. The questionnaire asked about respirato ry symptoms, asthma attacks and asthma treatment. Those who had not re sponded after two reminder postcards were followed with a telephone ca ll where possible. Results. A response rate of 82% (25 664) was achiev ed. The 12 month period prevalence of asthma (defined as woken by shor tness of breath, or an attack of asthma in the past year, or current a sthma medication) was 15.2% overall, but was higher in females (17.0%) than in males (13.2%); the prevalence was 22.1% in Maori, 20.6% in Pa cific Islanders and 14.3% in non Polynesians. In North Island electora tes, the highest age and ethnicity standardised prevalences were found in some of the electorates in the Auckland and Wellington urban regio ns although prevalence was also high in some rural electorates includi ng Raglan (18.0%), Horowhenua (18.4%) and Wairarapa (18.4%); the lowes t prevalences were found in other rural electorates including King Cou ntry (5.5%), Matamata (10.1%) and Rotorua (10.3%). In South Island ele ctorates, the highest prevalences were found in some electorates in th e Christchurch and Dunedin urban areas, and the lowest prevalences wer e again found in rural electorates including Clutha (11.3%), Rangiora (9.5%) and Wallace (9.4%). Conclusions. This study confirms the previo usly reported high frequency of asthma symptoms in New Zealand adults, with higher symptom prevalence in Maori and in women. It shows signif icant urban/rural differences, as well as marked differences in preval ence between various rural areas. The reasons for these patterns are u nclear and require further study.