Association Between Genetically Elevated Omega-3 Polyunsaturated Fatty Acids and Skin Disease Risk: A Mendelian Randomization Study.

Background: Omega-3 polyunsaturated fatty acids (PUFAs) are potential targets for the treatment of skin diseases due to their anti-inflammatory and immunomodulatory effects. By leveraging a genetic approach known as Mendelian randomization (MR), we sought to determine the causal impact of PUFAs on the likelihood of developing skin diseases among individuals of European ancestry.

Methods: We integrated GWAS data from the CHARGE consortium and UK Biobank to identify genetic instruments for omega-3 PUFAs and desaturase activity, using two-sample MR to assess their associations with six skin diseases.

Results: Elevated levels of omega-3 fatty acids were found to substantially lower the probability of experiencing atopic dermatitis (0.92, [0.85,0.98]), while increased DPA levels correlated with a substantial increase in the probability of squamous cell carcinoma occurrence (2.25, [1.29,3.92]). Increased DHA levels were also associated with a reduced risk of atopic dermatitis (0.90, [0.84,0.96]) but increased the risk of solar dermatitis (1.38, [1.09,1.73]). In addition, tissue-type specific MR analysis revealed that elevated FADS1 expression in fibroblasts significantly inhibited atopic dermatitis development (β = -0.181, [-0.276,-0.0853]), while elevated FADS2 expression in non-sun-exposed skin tissues was associated with a reduced risk of squamous cell carcinoma (β = -0.562, [-0.833,-0.029]). Conversely, heightened FADS2 expression was strongly linked to a greater likelihood of developing atopic dermatitis in both sun-exposed and sun-protected skin areas (β = 0.107, [0.0348,0.179]; β = 0.192, [0.114,0.0270], respectively).

Conclusion:  This study reveals the causal role of omega-3 PUFAs and FADS expression in specific tissues and blood in skin diseases. These findings underscore the potential of PUFA biosynthesis pathways as therapeutic targets for skin disease interventions.