The prevalence and impact of vitamin D3 deficiency on chronic spontaneous urticaria: insights from a comparative study

To the Editor, Recent studies have shown complex relationships between vitamin D3 and various allergic diseases. Some suggest that vitamin D3 influences the pathophysiology of chronic spontaneous urticaria (CSU) and can improve clinical outcomes, while others indicate that supplementation may increase allergy prevalence [1]. We investigated the relationship between CSU and vitamin D3 to address these conflicting findings This study aimed to assess vitamin D3 levels in patients with CSU and compare them to a control group, examining the relationship between vitamin D3 levels and disease activity in terms of urticaria activity score (UAS7). Vitamin D3 levels were categorized as follows: less than 20 ng/ml indicated deficiency, 20–30 ng/ml indicated insufficiency, and more than 30 ng/ml indicated sufficiency. This hospital-based cross–sectional study, approved by the institutional ethics committee and registered with the Clinical Trial Registry of India (CTRI/2023/08/056420), recruited 110 CSU patients and 80 healthy controls over six months. Inclusion criteria were urticaria episodes at least twice per week for six weeks or more, with or without angioedema. Exclusion criteria included urticaria from physical factors, angioedema without urticaria, recent use of immunosuppressives, Schnitzler’s syndrome, and other conditions like systemic lupus and mastocytosis. Baseline serum vitamin D3 levels were measured using chemiluminescence. Detailed patient history, including age, sex, disease duration, angioedema, atopy, and autoimmune disease, was recorded, and disease severity was assessed using the UAS7 score. Demographic characteristics were similar between CSU patients and controls, with both groups having a higher proportion of females. CSU patients had significantly lower mean serum vitamin D3 levels (15.83±3.35 ng/ml) compared with controls (32.01±2.15 ng/ml), with a P value of less than 0.0001 (Table 1). Table 1 - Comparison of demographic characteristics and vitamin D3 levels between chronic spontaneous urticaria patients and healthy controls Parameters CSU patients (n=110) Healthy controls (n=80) Significance Age in years (Mean±SD) 29.3±10.58 27.85±11.87 0.649‡ Sex distribution- Female 73 (66.36) 45 (56.25) 0.705† Male 37 (33.63) 35 (43.75) Vitamin D3 (ng/ml) Deficiency 53 (48.18) 15 (18.75)