Vitamin D, PsA, and BMD

June 1, 2015

A new study suggests the importance of evaluating the vitamin D3 status and screening for comorbid conditions in patients with psoriasis or psoriatic arthritis.

Increasingly, connections are being made between low levels of vitamin D and inflammatory and autoimmune diseases.

Now a small study from Hungary appears to link vitamin D insufficiency to disease activity and joint symptoms in psoriatic arthritis (PsA) and psoriatic skin lesions -- but not to low bone mineral density (BMD) in those conditions.

The study of 72 patients with PsA and/or psoriasis in the Journal of Dermatology finds that more than half have inadequate levels of serum vitamin D3. There was a  strong correlation between higher disease activity in 28 joints (DAS28) scores in those with polyarticular arthritis and a trend toward higher Bath Ankylosing Spondylitis Disease Activity (BASDAI) scores in a subset with axial PsA.

Among the group (with a mean age 58 and slightly more women than men), psoriasis patients needing systemic therapy also displayed inadequate serum 25(OH)D3.

However, the proportion of patients with low BMD was no greater than that for the general population. This suggests that low vitamin D3 is more related to symptoms and disease activity.

Low vitamin D and vitamin D deficiency are linked to an increased risk of bone loss and some previous studies find a high prevalence of vitamin D insufficiency in PsA and psoriasis. However, this is the first study to explore bone density and clinical features of those diseases.

Based on a cut-off 25-hydroxyvitamin D, 25(OH)D3, serum level of 75 µmol/L, 63% (n=45) of the Hungarian patients had inadequate vitamin D and 56% (n=25) were vitamin D deficient.

Around 61% (n=44) of the group had a reduced BMD, but just 2 patients were in the osteoporotic range.

The researchers did find a significant correlation between a higher body mass index (BMI) and vitamin D insufficiency, with more than half the group being overweight or obese (BMI above 25 and 30).

One 2011 study of 258 PsA patients in Canada found vitamin D3 insufficiency/deficiency to be common -- but with no correlation between disease activity and vitamin D status.1

Interestingly, that study found no seasonal variation in vitamin D or disease activity among patients in southern versus northern sites.

“The findings of our study draw attention to the importance of vitamin D3 status, as well as of its regular and routine monitoring in patients with psoriasis or PA, and stress the significance of screening for comorbidities,” the Hungarian researchers conclude. “Making vitamin D3 supplementation a standard intervention in the follow-up care of this patient population should also be considered.”

 

References:

  • Touma Z, Eder L,  Zisman D, et al., Seasonal variation in vitamin D levels in psoriatic arthritis patients from different latitudes and its association with clinical outcomes. Arthritis Care & Research. 2011;63(10):1440–1447.