The prevalence of asthma symptoms, bronchial hyperresponsiveness and atopyin New Zealand adults

Aims. To examine the prevalence of asthma symptoms, bronchial hyperresponsi veness (BHR) and atopy in a random population sample of New Zealand adults. Methods. A random sample of 2004 adults, aged 20-44 years, in Hawkes Bay, W ellington and Christchurch, were selected from respondents to a one-page re spiratory screening questionnaire and invited to take part in further testi ng. Subjects attending the testing centres' laboratories underwent a detail ed respiratory symptom questionnaire, Phazet testing to eleven common aller gens, blood samples for total and specific IgE, and measurement of bronchia l hyperresponsiveness. Subjects who did not wish to participate were encour aged to complete the questionnaire by telephone. Results. A participation rate of 67% (1257 of 1877 eligibles) was achieved. We found a high prevalence for all measures of asthma in the previous 12 m onths: wheezing was reported by 28.5%, waking with shortness of breath by 7 .7%, a physician diagnosis of asthma by 15.9% and asthma medications were u sed by 8.5%. Bronchial hyperresponsiveness was found in 24.9%, atopy in 34. 8% and elevated serum IgE levels in 30.5%. Asthma symptoms (in the past 12 months) and atopy decreased with increasing age,whereas bronchial hyperresp onsiveness increased with age. Females reported higher prevalences of wakin g with coughing (45.9%), nasal allergies (43.5%) and skin allergies (48.8%) compared to males (30.5%, 31.9% and 37.0%, respectively). There were no si gnificant regional differences. Conclusions. Asthma symptoms, bronchial hyperresponsiveness and atopy are a ll common in adult New Zealanders. Their prevalence is associated with age, gender and current smoking but there are no significant regional differenc es between Hawkes Bay, Wellington and Christchurch.