Vitamin D-binding protein and its potential role as a biomarker in psoriasis and related conditions

Abstract

1 Abstract1.1

Introduction

Psoriasis is a common chronic inflammatory skin disease linked to other medical conditions such as psoriatic arthritis (PsA). Recently, higher levels of vitamin D-binding protein (DBP) have been reported among psoriasis patients. Moreover, DBP has been found higher among psoriasis patients reporting arthropathy. Given the current lack of a reliable biomarker for psoriasis and PsA, these findings are particularly interesting. This master thesis seeks to explore the potential association between DBP levels and psoriasis severity, PsA/joint pain and total serum 25(OH)D levels in a cohort of psoriasis patients.

1.2 Method

The study utilized raw data from a previous RCT conducted at the University Hospital of North Norway. It included 115 participants with mild active plaque psoriasis and low serum 25(OH)D levels. Participants were randomized to receive cholecalciferol or placebo for 4 months. Psoriasis severity was measured using Psoriasis Area Severity Index (PASI) score. Data included self-reported arthropathy, current joint pain, serum 25(OH)D levels, and serum DBP levels. Potential relationships between measures were explored using linear regression. The analyses were not predefined in the RCT protocol and should be considered explorative.

1.3 Results

At baseline, a significant positive correlation was found between PASI score and DBP levels, but the direction of this relationship reversed and became non-significant after 4 months. There was no correlation between DBP levels and self-reported arthropathy, current joint pain, nor serum 25(OH)D levels. Moreover, we found no statistically significant difference in the change of DBP levels between the intervention groups.

1.4 Conclusion

This explorative analysis found no reliable relationship between DBP levels and psoriasis severity, PsA, self-reported joint pain nor total serum 25(OH)D levels. Additionally, four months of oral supplement of vitamin D gave no statistically significant change in DBP levels. Further studies are warranted to investigate the relationship between DBP and psoriasis.