Air Pollution, Genes Together Raise Psoriasis Risk, Study Finds

Long-term exposure to common air pollutants, including fine particulate matter (PM), nitrogen dioxide (NO₂), and nitrogen oxides (NOₓ), significantly increased the risk of developing psoriasis, a study finds.¹ The risk was even greater for individuals with high genetic susceptibility, highlighting the combined impact of environmental and genetic factors on the chronic skin disease.

This prospective cohort study is published in JAMA Network Open.

Long-term exposure to pollutants was linked to higher psoriasis risk, especially in people with genetic predispositions. | Image credit: Sergiy Serdyuk - stock.adobe.com

“To our knowledge, this investigation is pioneering in providing a comprehensive evaluation at the national level of the association of long-term exposure to air pollution with psoriasis onset,” wrote the researchers of the study. “The findings of our research suggest possible avenues for risk assessment and early intervention strategies in high-risk populations that may lead to more effective preventive measures for psoriasis.”

Air pollution is linked to the onset and worsening of various skin conditions, including premature skin aging, atopic dermatitis, acne, psoriasis, hair loss, and skin cancer.² These processes not only damage skin health but also contribute to broader public health risks, as nearly all of the global population is exposed to air quality levels that exceed World Health Organization guidelines.

The study used data from the UK Biobank, including participants who were free of psoriasis at baseline and had available data on air pollution exposure.¹ The primary outcome was the incidence of psoriasis during follow-up. The researchers estimated long-term exposure to NO₂, NOₓ, fine particulate matter smaller than 2.5 µm (PM₂_.₅), and particulate matter smaller than 10 µm (PM₁₀), and they assessed genetic susceptibility using polygenic risk scores.

Genetic analyses were restricted to White participants to reduce population stratification bias, and analyses were adjusted for potential confounders, including demographic, lifestyle, and health factors.

Among 474,055 participants, 4031 incident cases of psoriasis were recorded over a median (IQR) follow-up of 11.91 (11.21-12.59) years. Higher long-term exposure to all measured pollutants was associated with increased psoriasis risk. For each interquartile range increase in exposure for PM₂.₅ (HR, 1.41; 95% CI, 1.35-1.46), PM₁₀ (HR, 1.47; 95% CI, 1.41-1.52), NO₂ (HR, 1.28; 95% CI, 1.23-1.33), and NOₓ (HR, 1.19; 95% CI, 1.14-1.24).

Compared with participants in the lowest exposure quartile, those in the highest quartile had multivariate-adjusted HRs of 2.01 (95% CI, 1.83-2.20) for PM₂.₅, 2.21 (95% CI, 2.02-2.43) for PM₁₀, 1.64 (95% CI, 1.49-1.80) for NO₂, and 1.34 (95% CI, 1.22-1.47) for NOₓ.

In White participants, there was a strong interaction between air pollution and genetic predisposition. For example, those with high genetic risk and highest PM₂.₅ exposure had an HR of 4.11 (95% CI, 3.46-4.90) compared with those with low genetic risk and lowest exposure.

However, the researchers noted several limitations, including potential selection bias from the healthier volunteer population of the UK Biobank and limited generalizability due to the predominance of White European participants. Additionally, the polygenic risk score may not have captured all genetic factors, and the observational design was susceptible to confounding and could not establish causality. Furthermore, exposure estimates lacked data on indoor, occupational, or commuting pollution and may not have reflected real-time exposure.

Despite these limitations, the researchers believe the study suggests an association between psoriasis risk and air pollution exposure, especially among those with higher genetic vulnerability.

“Consequently, there is a need to devise and implement effective interventions aimed at mitigating air pollution and safeguarding individuals from the effects associated with psoriasis,” wrote the researchers.

References

1. Wu J, Ma Y, Yang J, Tian Y. Exposure to air pollution, genetic susceptibility, and psoriasis risk in the UK. JAMA Netw Open. 2024;7(7):e2421665. doi:10.1001/jamanetworkopen.2024.21665

2. Santoro C. Skin diseases and aging linked to air pollution. AJMC^®. May 24, 2025. Accessed August 14, 2025. https://www.ajmc.com/view/skin-diseases-and-aging-linked-to-air-pollution