Acute bronchitis in communities exposed to volcanic air pollution from Kilauea Volcano, Hawaii, USA

Twenty-five years of eruption at Kilauea Volcano continued to expose downwind Hawaiian populations to sulfurous air pollution. Emissions of sulfur dioxide gas, routinely measured by the Hawaiian Volcano Observatory, averaged 2,034 tons per day during 2004-2006. This study (Phase II of the Kilauea Volcano Health Study) estimated the incidence of diagnosed acute bronchitis in unexposed and exposed communities on the island over the 3-year period. Medical records from clinics and emergency rooms in the study areas were reviewed for visits of diagnosed acute bronchitis in local residents. Case records were reviewed for evidence of clinical presentation and diagnostic accuracy, resulting in a total of 683 visits for acute bronchitis in the study communities. The cumulative incidence rate was 117.74 per 1,000 in unexposed communities and 184.63 per 1,000 in exposed communities. Relative risk (RR) estimates were standardized for age and gender, revealing an elevated risk [RR = 1.57 (95% CI = 1.36 – 1.81)] for acute bronchitis in the exposed communities. Most affected were exposed children and middle-aged adults. Smoking was more common within the unexposed cases (27%) than the exposed cases (19%). This study has demonstrated that communities continuously exposed to relatively low levels of sulfurous volcanic air pollution have a higher risk of acute bronchitis.