Table 2 Summary of parameters of vitamin D in CSU

Lower serum vitamin D levels in CSU patients than healthy controls

✓

One study showed significantly higher levels of vitamin D in CSU patients than that of controls

Wu et al. [30]

–

–

One study showed no significant difference in vitamin D levels between CSU patients and that of controls

Lee et al. [22]

✓

Twelve studies showed significant lower levels of vitamin D in CSU patients than that of controls

Thorp et al. [28]

Grzanka et al. [21]

Chandrashekar et al. [20]

Abdel-Rehim et al. [18]

Movahedi et al. [23]

Woo et al. [29]

Rasool et al. [25]

Boonpiyathad et al. [31]

Oguz Topal et al. [24]

Nasiri-Kalmarzi et al. [14]

Dabas et al. [32]

Rather et al. [33]

Vitamin D insufficiency in CSU patients more than in controls

✓

One study showed significantly higher prevalence of vitamin D insufficiency in controls than in CSU

Movahedi et al. [23]

✓

Two studies showed no significant difference in the prevalence of vitamin D insufficiency between CSU patients and controls

Grzanka et al. [21]

Boonpiyathad et al. [22] [31]

✓

One study showed significant difference in the prevalence of vitamin D insufficiency between CSU patients and controls

Oguz Topal et al. [24]

Vitamin D deficiency in CSU patients more than in controls

–

–

One study showed no significant difference in the prevalence of vitamin D deficiency between CSU patients and controls

Thorp et al. [28]

✓

Three studies showed significant difference in the prevalence of vitamin D deficiency between CSU patients and controls

Grzanka et al. [21]

Boonpiyathad et al. [31]

Oguz Topal et al. [24]

✓

One study show significant difference in the proportion of critically low vitamin D levels in the CSU patients and in acute urticaria, atopic dermatitis, and healthy controls

Woo et al. [29]

Lower serum vitamin D levels between CSU and acute urticaria

✓

One study showed no significant difference levels of vitamin D between CSU and acute urticaria patients

Lee et al. [22]

✓

One study showed significantly lower levels of vitamin D in CSU than acute urticaria patients

Woo et al. [29]

Lower serum vitamin D levels between CSU and atopic dermatitis

✓

One study showed significantly lower levels of vitamin D in CSU than atopic dermatitis

Woo et al. [29]

Lower serum vitamin D levels between CSU and allergic rhinitis

✓

One study showed significantly lower levels of vitamin D in CSU than allergic rhinitis

Thorp et al. [28]

Low serum vitamin D levels and higher disease activity

✓

One study reported a significant positive correlation between vitamin D levels and urticaria activity score

Movahedi et al. [23]

–

–

Six studies reported no association

Thorp et al. [28]

Abdel-Rehim et al. [18]

Grzanka et al. [21]

Rorie et al. [26]

Boonpiyathad et al. [31]

Oguz Topal et al. [24]

✓

Three study reported significant negative association between vitamin D levels and urticaria activity score

One study reported significant negative association between vitamin D levels and urticaria severity score

Woo et al. [29]

Nasiri-Kalmarzi et al. [14]

Rather et al. [33]

Chandrashekar et al. [20]

Low serum vitamin D levels and longer disease duration

–

–

Five studies reported no association

Thorp et al. [28]

Abdel-Rehim et al. [18]

Grzanka et al. [21]

Dabas et al. [32]

Rather et al. [33]

✓

One studies reported significant negative association

Woo et al. [29]

Low serum vitamin D levels and high ESR

✓

Two study reported significant correlation

Chandrashekar et al. [20]

Boonpiyathad et al. [31]

Low serum vitamin D levels and high CRP levels

–

–

One study reported no association

Grzanka et al. [21]

Low serum vitamin D levels and high IgE levels

✓

One study reported negative association

Abdel-Rehim et al. [18]

–

–

Four studies reported no association

Movahedi et al. [23]

Oguz Topal et al. [24]

Nasiri-Kalmarzi et al. [14]

Dabas et al. [32]

Low serum vitamin D levels and high IL-17 levels

✓

One study reported negative association.

Chandrashekar et al. [20]

Low serum vitamin D levels and TGF-β1

✓

One study reported negative association

Chandrashekar et al. [20]

Low serum vitamin D levels and thyroid autoantibodies testing

–

–

Two studies reported no association

Thorp et al. [28]

Oguz Topal et al. [24]

Low serum vitamin D levels and a positive ASST or APST

✓

One study reported significant lower levels of vitamin D in patients with a positive APST

Chandrashekar et al. [20]

✓

Three study reported significant lower levels of vitamin D in patients with a positive ASST.

Woo et al. [29]

Nasiri-Kalmarzi et al. [14]

Rather et al. [33]

–

–

Three studies reported no association between the ASST-positive and ASST-negative groups

Thorp et al. [28]

Grzanka et al. [21]

Dabas et al. [32]