Vitamin D status in patients with chronic plaque psoriasis.
BACKGROUND
Vitamin D could have important immunomodulatory effects in psoriasis.


OBJECTIVE
To measure 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH) and calcium serum levels in patients with psoriasis and the associations with some relevant clinical features.


METHODS
A cross-sectional study was conducted over 1 year including 145 patients with chronic plaque psoriasis, 112 patients with rheumatoid arthritis (RA) and 141 healthy controls. 25(OH)D, PTH and calcium serum levels were measured in a centralized laboratory. Demography, comorbidities, disease severity and exposure time to sunlight (which was derived by questionnaire) were collected.


RESULTS
The prevalence of vitamin D deficiency [25(OH)D levels <20ngmL(-1) ] in patients with psoriasis was 57·8% vs. 37·5% in patients with RA and 29·7% in healthy controls (P<0·001). In winter, the prevalence of vitamin D deficiency rose to 80·9% in patients with psoriasis, to 41·3% in those with RA and to 30·3% in healthy controls (P<0·001). Patients with psoriasis or psoriatic arthritis did not differ in 25(OH)D serum levels nor in the prevalence of vitamin D deficiency. In the logistic regression analysis, vitamin D deficiency was associated with psoriasis independently of age, sex, body mass index, calcium, PTH levels and season of blood sampling. A limitation is that the study design does not allow a causal or temporal relationship between vitamin D deficiency and psoriasis to be established.


CONCLUSIONS
Vitamin D deficiency may be common in patients with psoriasis, especially in winter.
Department of Medicine, Section of Dermatology and Venereology, Section of Rheumatology III Division of Geriatrics, University of Verona, Verona, Italy. paolo.gisondi@univr.it
P
P
Gisondi
M
M
Rossini
A
A
Di Cesare
L
L
Idolazzi
S
S
Farina
G
G
Beltrami
K
K
Peris
G
G
Girolomoni
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood; D002118:Calcium / Q000378:metabolism; D016022:Case-Control Studies; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D011565:Psoriasis / Q000097:blood* / Q000150:complications; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000175:diagnosis*
D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium