Residential greenness, genetic susceptibility, and asthma risk: Mediating roles of air pollution in UK and Chinese populations

Background

The relationship between residential greenness and asthma remains a topic of interest, especially in understanding the pathways involved and how genetic factors might influence this association. This study aimed to explore the association between residential greenness and asthma incidence, while also examining potential mediating pathways and the role of genetic susceptibility.

Methods

Data were analyzed from two independent cohorts: the UK Biobank and the Chinese Biomarkers for the Prediction of Respiratory Disease Outcomes (C-BIOPRED) study. Greenness was measured by normalized difference vegetation index (NDVI). Polygenic risk scores were constructed from 145 asthma-associated single nucleotide polymorphisms. Cox proportional hazard models and logistics regression models were used to assess the association between residential greenness and asthma incidence, and mediation analysis was conducted to explore potential mediators.

Results

Over a median follow-up of 11.85 years in UK Biobank, higher NDVI exposure was associated with reduced asthma incidence (hazard ratio per IQR increase in NDVI_300 m: 0.965, 95 % CI: 0.949–0.982). The association was more pronounced among non-smokers and individuals with highest genetic risk. PM_2.5 mediated 40.4 % (95 % CI: 5.1 %–76.4 %) of the protective effect. In the C-BIOPRED study, greenness was inversely associated with severe asthma (odd ratio: 0.645, 95 % CI: 0.441–0.943) and improved clinical outcomes.

Conclusion

Residential greenness is associated with a lower risk of asthma, particularly in genetically susceptible and socioeconomically disadvantaged populations, partially through improving air quality. Our findings advocate for integrating green space optimization into urban planning as a precision public health strategy.