Vitamin D Deficiency Linked to Severity of Chronic Plaque Psoriasis

A serum 25hydroxyvitamin D deficiency is associated with severity of chronic plaque psoriasis, the relationship inverse with a psoriasis area severity index (PASI) score, according to study findings published in Psoriasis: Targets and Therapy.

Researchers aimed to investigate the 25hydroxyvitamin D (25[OH] D) level in patients with psoriasis compared with healthy control individuals.

They conducted a case-control study in the outpatient tertiary care clinic B.P. Koirala Institute of Health Sciences, Dharan, Nepal that included 180 participants (120 consecutive outpatients with psoriasis and 60 sex- and age-matched healthy control volunteers) from eastern Nepal enrolled between January and August 2021. Plaque psoriasis was a clinical diagnosis in patients, whose mean age was 42.93±14.28 years; mean duration of disease was 5.69 years and mean age at onset 37.05 years. There were 57 women in the plaque psoriasis patient group.

Case inclusion criteria included no treatment with oral or topical steroids, no vitamin D supplements and immunosuppressants, no current phototherapy or presence of chronic inflammatory diseases, aged between 18 and 65 years. Control participants had the same inclusion criteria (absent of psoriasis). Cases were moderate (50%), mild (29.2%), and severe (20.8%). Scalp involvement was observed in 49.2%, nail involvement (35%), palmoplantar involvement (15%). In addition to sex and age matching, the 2 groups did not differ significantly in daily sun exposure, Fitzpatrick skin phototype, history of smoking or alcohol intake, or diastolic blood pressure. They did vary significantly in body mass index, systolic blood pressure, and metabolic syndrome, it was noted.

The PASI was used to assess severity of psoriatic skin lesions. Chemiluminescent immunoassay was used to assess vitamin D level.

Researchers found the mean serum 25(OH) D levels in patients were 19.57±6.85 nanograms (ng)/mL and in healthy control participants, 23.63±6.40ng/mL. After adjusting for confounding factors in multivariate analysis this represented a statistically significant difference (adjusted odds ratio 2.929; 95% CI, 1.376-6.230; P <.005). They noted vitamin D deficiency (<20ng/dl) in 57.5% of patients with psoriasis vs 30% in control participants. They noted vitamin D insufficiency (<30ng/dl) in 87.5% of patients with psoriasis and 83.3% of control participants.

They observed a negative association between low serum 25(OH) D levels and severity of plaque psoriasis disease (r=-0.628; P =.01).

Study limitations include no accounting for use of sunblock or parathyroid hormone status.

Researchers concluded “The major finding of this study is the significantly reduced serum vitamin D level among psoriasis patients in comparison with control groups even after adjusting for confounding factors as well as various cardiovascular risk factors.” They added that determined by the PASI, those levels vary inversely with the severity of the disease.

Reference

Pokharel R, Agrawal S, Pandey P, Lamsal M. Assessment of vitamin D level in patients with psoriasis and its correlation with disease severity: a case-control study. Psoriasis (Auckl). Published online September 13, 2022. doi:10.2147/PTT.S369426