Respiratory hospital admission risk near large composting facilities

Abstract Background Large-scale composting can release bioaerosols in elevated quantities, but there are few studies of health effects on nearby communities. Methods A cross-sectional ecological small area design was used to examine risk of respiratory hospital admissions within 2500 m of all 148 English large-scale composting facilities in 2008–10. Statistical analyses used a random intercept Poisson regression model at Census Output Area (COA) level (mean population 310). Models were adjusted for age, sex, deprivation and tobacco sales. Results Analysing 34,963 respiratory hospital admissions in 4656 COAs within 250–2500 m of a site, there were no significant trends using pre-defined distance bands of >250–750 m, >750–1500 m and >1500–2500m. Using a continuous measure of distance, there was a small non-statistically significant (p = 0.054) association with total respiratory admissions corresponding to a 1.5% (95% CI: 0.0–2.9%) decrease in risk if moving from 251 m to 501 m. There were no significant associations for subgroups of respiratory infections, asthma or chronic obstructive pulmonary disease. Conclusion This national study does not provide evidence for increased risks of respiratory hospital admissions in those living beyond 250 m of an outdoor composting area perimeter. Further work using better measures of exposure and exploring associations with symptoms and disease prevalence, especially in vulnerable groups, is recommended to support regulatory approaches.