Exposure to airborne emissions from confined swine feeding operations as a trigger of childhood respiratory symptoms.

摘要

During the 1999--2000 school year, the North Carolina Department of Health and Human Services conducted a statewide population-based survey of middle school students to assess the prevalence of asthma-related symptoms, medication use, barriers to adequate medication and behavioral consequences of the reported symptoms. This research extends the benefit and utility of the statewide survey by exploring the relationship between asthma symptoms among surveyed students and in-school exposure to airborne emissions from confined animal feeding operations (CAFOs) located near public school buildings. To estimate the extent to which students may have been exposed during the school day to air pollution arising from swine CAFOs, we used publicly-available data about 2,343 swine CAFOs, geographic information about the locations of schools where the surveyed students were enrolled and survey-based reports of environmental health conditions inside the school buildings (n = 265) to generate exposure estimates for each school. The prevalence of the estimated exposures across categories white, non Hispanic enrollment and economic disadvantage at the public schools was evaluated to assess the role of race and socio-economic status in the potential for swine CAFO exposure. The association of estimated school-level exposure with the prevalence of wheezing among children aged 12 to 14 years old was evaluated using data about respiratory symptoms and other characteristics self-reported by the adolescents. Economic disadvantage increased across categories of proximity to one or more swine CAFOs, reported livestock odor and increasing strength of the odor. Among the 58,169 black and white students in our analyses, the prevalence of wheezing during the past year was slightly higher at schools estimated to be exposed to airborne effluent from the operations and the associations were strongest among students who self-reported allergies to cat, dog, dust, grass or pollen. Overall, these findings identify a plausible association between the estimated exposure and wheezing symptoms among adolescents and may have implications for school personnel, particularly those in economically disadvantaged communities, who are concerned about airborne exposure to effluent from swine CAFOs and the potential health impact of such exposures on adolescents' respiratory health.