Effect of smoke-free legislation on respiratory health services use in children with asthma: a population-based open cohort study in Ontario, Canada

Objective — This study will add to existing literature by examining the impact of smoke-free legislation in outdoor areas among children with asthma. We aimed to examine the effect of the 2015 Smoke-Free Ontario Act (SFOA) amendment, which prohibited smoking on patios, playgrounds and sports fields, on health services use (HSU) rates in children with asthma.

Methods — We conducted a population-based open cohort study using health administrative data from the province of Ontario, Canada. Each year, all Ontario residents aged 0-18 years with physician diagnosed asthma were included in the study. Annual rates of HSU (emergency department (ED) visits, hospitalisations and physician office visits) for asthma and asthma-related conditions (eg, bronchitis, allergic rhinitis, influenza and pneumonia) were calculated. Interrupted time-series analysis, accounting for seasonality, was used to estimate changes in HSU following the 2015 SFOA.

Results — The study population ranged from 618 957 individuals in 2010 to 498 812 in 2018. An estimated average increase in ED visits for asthma in infants aged 0-1 years of 0.42 per 100 individuals (95% CI: 0.09 to 0.75) and a 57% relative increase corresponding to the 2015 SFOA was observed. A significant decrease in ED visits for asthma-related conditions of 0.19 per 100 individuals (95% CI: -0.37 to -0.01) and a 22% relative decrease corresponding to the 2015 SFOA was observed.

Conclusion — Based on the observed positive effect of restricting smoking on patios, playgrounds and sports fields on respiratory morbidity in children with asthma, other jurisdictions globally should consider implementing similar smoke-free policies.