Dietary Inflammatory Index in relation to psoriasis risk, cardiovascular risk factors, and clinical outcomes: a case-control study in psoriasis patients.

Abstract

Psoriasis is an inflammatory skin disease. Despite the understanding of disease pathogenesis, the link between diet-induced inflammation and the risk of psoriasis remains underexplored. Therefore, we examined the capability of the literature-derived energy-adjusted Dietary Inflammatory Index (E-DII) as a predictive tool for inflammation, incidence, and severity of psoriasis (as indexed by the Psoriasis Area Severity Index (PASI)). We conducted a case-control study of 149 adults (75 cases and 74 controls). The E-DII score was calculated based on the dietary intake that was evaluated using a validated 168 item quantity food-frequency questionnaire. The E-DII tertile cut-offs were categorized based on the following cut points: tertiles 1≤ -1.99; tertiles 2= -2.00 to 0.60; tertile 3≥ 0.61. Logistic regression models were used to estimate the multivariable odds ratio (OR) adjusted for confounders. Patients with higher pro-inflammatory E-DII had a 3.60-times increased risk of psoriasis relative to patients in tertiles 1 (E-DIIT3 vs E-DIIT1: OR= 3.64; 95% confidence interval (CI) 1.51 to 8.79, P= 0.005). The severity of disease as indexed by PASI remained associated with E-DII (E-DIIT3 vs E-DIIT1: OR= 3.64; 95% CI 1.74 to 7.57, P= 0.015). For each unit increase in E-DII, the probability of disease severity is increased 3times. Patients consuming a more pro-inflammatory diet were at a greater risk of psoriasis. These patients also demonstrated increased disease severity relative to individuals consuming a more anti-inflammatory diet. Novelty: A pro-inflammatory diet is associated with higher psoriasis incidence. Subjects with higher DII scores had higher inflammatory markers levels.