Acute bronchitis and volcanic air pollution: a community-based cohort study at Kilauea Volcano, Hawai'i, USA

Eruption at Kilauea Volcano, Hawai'i, has continued since 1983, emitting sulfurous air pollution into nearby communities. The purpose of this cohort study was to estimate the relative risk (RR) of acute bronchitis over a period from January 2004 to December 2006 in communities exposed to the volcanic air pollution. A community-based case review was conducted using medical records from clinics and emergency rooms in exposed and unexposed study areas. Initial visits by local residents for diagnosed acute bronchitis were clinically reviewed. The cumulative incidence rate for the 3-yr period was 117.74 per 1000 in unexposed communities and 184.63 per 1000 in exposed communities. RR estimates were standardized for age and gender, revealing an elevated cumulative incidence ratio (CIR) of 1.57 (95% CI = 1.36-1.81) for acute bronchitis in the exposed communities. Highest risk [CIR: 6.56 (95% CI = 3.16-13.6)] was observed in children aged 0-14 yr who resided in the exposed communities. Exposed middle-aged females aged 45-64 yr had double the risk for acute bronchitis than their unexposed counterparts. These findings suggest that communities continuously exposed to sulfurous volcanic air pollution may have a higher risk of acute bronchitis across the life span.