UNDER THE VOLCANO - FIRE, ASH AND ASTHMA

Aims. To investigate the prevalence of respiratory symptoms in known a sthmatics, following exposure to airborne volcanic ash particles cause d by the eruptions of Mount Ruapehu, New Zealand, commencing September 1995. Method. A one page postal questionnaire was sent to 1392 previo usly identified asthmatics 2 months after the first major eruption. Re sults. Two hundred and thirty seven subjects had moved from the area, died or gone overseas since the original contact 4 years previously; t herefore the target population was 1155 subjects of whom 361 lived in the exposed area and 794 in the nonexposed areas. The response rates w ere 246 (68.1%) in the exposed group and 477 (60.1%) in the nonexposed group making a total of 723 individuals. The prevalence of nocturnal shortness of breath in the last two months was 29.3% in the exposed gr oup and 24.7% in the nonexposed (OR = 1.26, 95% Cl; 0.83-1.78). Simila rly 30.9% of the exposed group had an asthma attack in the last 2 mont hs compared to 31.9% of the nonexposed group (OR = 0.96, 95% Cl; 0.69- 1.33). Finally, 48.4% of the exposed group used asthma medication in t he 2 months following the eruption in comparison to 53% of the nonexpo sed group (OR = 0.83, 95% Cl; 0.61-1.12). Conclusions. The study showe d no association between living in an area exposed to volcanic ash par ticles and either asthma symptoms or the use of asthma medication. The re was a small but nonsignificant increase in nocturnal shortness of b reath in the exposed group.