Tsai TY, et al. - In patients with psoriasis, researchers performed a systematic review and meta-analysis to evaluate the impact of serum homocysteine, folate and vitamin B₁₂ levels. They searched online databases on February 15, 2018 to include studies comparing serum homocysteine, folate and vitamin B₁₂levels between psoriasis patients and controls. Higher serum homocysteine and lower folate levels may be seen in patients with psoriasis vs control subjects without psoriasis. Standardized mean differences of homocysteine levels had a significant inverse association with folate levels, as seen in the meta-regression analysis.