What is the impact of access to green space on asthma in the North West of England?

Abstract Background In the United Kingdom, asthma prevalence is amongst the highest in the world, with 18% of adults reporting asthma in the previous year. Natural environments can affect asthma through multiple pathways, including reducing asthma admissions by decreasing pollutants, and pollen exacerbating asthma symptoms. We aim to explore associations between different environmental metrics and asthma medication at primary healthcare provider (PHP) catchment level to better understand this complex relationship. Methods We use 2024 prescribing data from 344 PHPs in the North West of England to generate our asthma medications outcome. We link these data to environmental metrics (including distance to green space) and socio-demographics. Distances to green space are measured as neighbourhood green space (min. size 10ha, max. distance 1km), wider green space (min. size 20ha, max. distance 2km), and district green space (min. size 100ha, max. distance 5km). We use linear regression to explore associations between environmental metrics and asthma medications (mean monthly total quantity) at PHP catchment level. Results Preliminary results show an association between distance to green space and mean monthly quantity of asthma medications adjusting for number of patients registered per PHP. A greater distance to wider green space is associated with higher quantity of asthma medications (β: 0.480, 95% CI: 0.123-0.837, p = 0.009); greater distance to neighbourhood and district green space are associated with lower quantity of asthma medications (β: -0.511, 95% CI: -0.976--0.047, p = 0.031; β: -0.096, 95% CI: -0.151--0.041, p = <0.001). Conclusions The results suggest that distance to green space is associated with quantity of asthma medications at PHP level. These findings can be utilised in urban planning decisions to maximise both health and environmental benefits. Further research at household level is required for causal exploration of how green spaces can reduce asthma prevalence. Key messages • Distance to green space has an impact on quantity of asthma medications at primary healthcare provider catchment level, depending on the size of the green space. • Findings can be utilised in urban planning decisions to maximise benefits to both health and the environment.