A Systematic Review and Meta-analysis of Short-term Relationship between Ambient Air Pollution and Psoriasis

Exposure to air pollution is emerging as a risk factor for psoriasis, but with conflicting findings. The objectives of this meta-analysis were to investigate and summarize the study on the association between short-term exposure to air pollution and psoriasis. We searched the Embase, PudMed, Web of Science and Cochrane Library for indexed publications up to March 17, 2023. We extracted quantitative measures for air pollution effects on psoriasis with acute effect (single lag: lag 0 or lag 1) and short-term cumulative lag effects (cumulative lags: lag 0−5 or lag 0−7 days). The random-effect model was the primary approach used to calculate the excess risk percentage (ER%) and confidence intervals (CI) for particulate matter (PM) with diameter ≤ 10 µm (PM₁₀) and ≤ 2.5 µm (PM_2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃). For acute effect, ER% for each 10 µg m⁻³ increase of pollutants was 2.0% (95% CI: 0.4%, 3.7%) for NO₂. For the short-term cumulative lag effects, ER% for each 10 µg m⁻³ increase of pollutants was 3.0% (95% CI: 0.2%, 5.9%) for NO₂, 1.2% (95% CI: 0.3%, 0.21%) for PM₁₀ and 0.2% (95% CI: 0.2%, 0.3%) for PM_2.5. The results of subgroup analysis suggested that female may be more sensitive to PM_2.5 and compared with the warm season, the effects of NO₂ and PM_2.5 on psoriasis were more significant in the cold season. Systematic reviews have shown that short-term exposure to ambient air pollutants (NO₂, PM_2.5, PM₁₀) are associated with an increased risk of psoriasis.