Air pollution and emergency department visits for conjunctivitis: A case-crossover study

Area of Science:

• Environmental Health
• Epidemiology
• Public Health

Background:

• Conjunctivitis is a common condition leading to emergency department visits.
• Ambient air pollution is a growing public health concern with potential links to various health outcomes.

Purpose of the Study:

• To investigate the association between ambient air pollution levels and emergency department (ED) visits for conjunctivitis in Ontario, Canada.
• To analyze these associations across different urban regions within the province.

Main Methods:

• Utilized time-series analysis of 77,439 ED visits for conjunctivitis from April 2004 to December 2011.
• Employed a time-stratified case-crossover design with meta-analysis to pool inter-city results.
• Calculated odds ratios for ED visits per interquartile range increase in pollutant levels, controlling for temperature and humidity.

Main Results:

• Significant positive associations were found between nitrogen dioxide (NO2) and fine particulate matter (PM2.5) and ED visits for conjunctivitis in females.
• In males, significant associations were observed for NO2, ozone (O3), PM2.5, and sulfur dioxide (SO2) at various lags.
• Specific pollutants and lag times showed stronger associations, with notable findings for NO2 at 7-day lag in females and O3 at 0-day lag in males.

Conclusions:

• Ambient air pollution is associated with an increased risk of emergency department visits for conjunctivitis.
• The strength and temporal trends of these associations differ based on sex, age, and season.
• Findings underscore the importance of monitoring air quality for public health protection related to eye infections.