Association of long-term air pollution and allergen exposure with endotype shift in chronic rhinosinusitis with nasal polyps.

BACKGROUND

Chronic rhinosinusitis with nasal polyp (CRSwNP) is classified into type 2 and non-type 2 inflammation based on mucosal cytokine level. For 20 years, the type 2/non-type 2 ratio has increased, potentially influenced by air pollution and aeroallergens.

OBJECTIVE

To investigate the association between long-term exposure to air pollutants and aeroallergens and the endotype shift in CRSwNP.

METHODS

We enrolled 2358 patients with CRSwNP from Guangzhou and 416 from Ghent. Endotypes were defined using a diagnostic model or interleukin 5 levels in nasal polyps. Pollutant exposure was estimated based on residential ZIP code. Generalized additive models with restricted cubic splines and generalized linear mixed models were used to assess the effects of particulate matters (PMs) less than or equal to 2.5 µm, PM less than or equal to 10 µm, nitrogen dioxide, sulfur dioxide, ozone, and aeroallergen exposure on type 2 CRSwNP risk compared with non-type 2.

RESULTS

Higher air pollutant exposure was linked to a lower type 2/non-type 2 ratio. In Guangzhou, every 1 μg/m3 increase in 3-year cumulative PMs less than or equal to 2.5 µm exposure was associated with an odds ratio of 0.97 (95% CI: 0.96-0.98, P < .001) for type 2 CRSwNP. In Ghent, the relative risk was 0.78 (95% CI: 0.65-0.94, P = .009) for the same exposure increase. Elevated total IgE and Dermatophagoides pteronyssinus sensitization increase type 2 risk than non-type 2 CRSwNP in Guangzhou, whereas allergic rhinitis, elevated total IgE, pollen sensitization, and multi-allergen sensitization increased type 2 CRSwNP risk in Ghent.

CONCLUSION

Decreasing long-term air pollution exposure and increasing allergen sensitization are associated with higher type 2/non-type 2 CRSwNP ratio, highlighting the role of environmental factors in endotype shifting.

TRIAL REGISTRATION: Chinese Clinical Trial Registry Identifier: ChiCTR2400082123.