Tear gas exposure and its association with respiratory emergencies in infants and older adults during the social uprising of 2019 in Chile: an observational, longitudinal, repeated measures study.

Objective: To evaluate if extensive use of tear gas during the Chilean social uprising of 2019 was associated with a higher frequency of respiratory emergencies and bronchial diseases in a residential vulnerable population.

Design: Observational, longitudinal, repeated measures study.

Settings: Six healthcare centres (one emergency department and five urgent care centres) in the city of Concepción, Chile during 2018 and 2019.

Participants: This study was conducted on daily respiratory emergencies and diagnosis. Daily frequency of urgency and emergency visits are administrative data, publicly available and previously de-identified.

Primary And Secondary Outcome Measures: Absolute and relative frequency of daily respiratory emergencies in infants and older adults. A secondary outcome was the relative frequency of bronchial diseases (International Classification of Diseases 10th Revision, ICD-10: J20-J21; J40-J46) in both age groups. We finally measured the rate ratio (RR) of bronchial diseases above the daily grand mean, since the number of visits with these diagnoses in several days was zero. Tear gas exposure was assessed as the uprising period. Models were adjusted by weather and air pollution information.

Results: Percentage of respiratory emergencies during the uprising rose by 1.34 percentage points (95% CI 1.26 to 1.43) in infants and 1.44 percentage points (95% CI 1.34 to 1.55) in older adults. In infants, the emergency department experienced a larger increment in respiratory emergencies (6.89 percentage points; 95% CI 1.58 to 2.28) than the urgent care centres (1.67 percentage points; 95% CI 1.46 to 1.90). The RR of bronchial diseases above the daily grand mean during the uprising period was 1.34 in infants (95% CI 1.15 to 1.56) and 1.50 in older adults (95% CI 1.28 to 1.75).

Conclusions: The massive use of tear gas increases the frequency and probability of respiratory emergencies and particularly bronchial diseases in the vulnerable population; we recommend revising public policy to restrict its use.