WEDNESDAY, Jan. 22, 2025 -- Exposure to particulate matter (PM) with diameters of 10 µm (PM₁₀) or with diameters that are 2.5 µm or smaller (PM_2.5) seems to have a protective effect on melanoma risk, potentially due to the reduction in ultraviolet radiation exposure, according to a study published online Jan. 17 in the Journal of the European Academy of Dermatology and Venereology.

Francesco Bellinato, M.D., from the University of Verona in Italy, and colleagues conducted a case-control study involving 2,575 participants (1,473 melanoma patients and 1,102 healthy controls) to examine the association between PM₁₀ and PM_2.5 long-term exposure and melanoma risk.

The researchers found that most melanoma patients had Fitzpatrick phenotypes 2 and 3 (59 and 36 percent, respectively). The average melanoma Breslow thickness was 1.01 mm; 68.15 percent of cases were diagnosed at stage 0 or IA. Higher PM₁₀ and PM_2.5 levels had a protective effect in multivariate logistic regression (odds ratios, 0.89 and 0.72, respectively). A reduced risk for melanoma was also seen in association with darker skin phototypes (Fitzpatrick 4) and cigarette smoking.

"Our findings suggest a neutral or even beneficial effect of exposure to higher PM₁₀ and PM_2.5 levels on melanoma risk," the authors write. "These results are preliminary and should be interpreted with caution because of many potential residual confounding factors."