Background/purpose: Psoriasis is a multisystem disease which has been related to vitamin-D deficiency through chronic inflammation. This psoriasis-related inflammatory state and vitamin-D deficiency may induce bone mineral density loss. The purpose of this study is to assess the relationship of psoriasis with bone mineral density, by comparing psoriatic patients with healthy controls and patients with osteopenia/osteoporosis.
Methods: A total of 185 subjects were studied; 58 psoriatic patients who had not been under systemic or biological treatment were included. Age, gender, body mass index, phosphocalcic metabolic parameters and hip and lumbar (L4) bone mineral density data were collected. These variables were compared with those collected in 61 healthy controls and 67 patients with osteopenia/osteoporosis.
Results: Psoriatic patients showed worse hip and lumbar spine bone mineral density levels than healthy controls (P = 0.001) and better levels than osteoporotic patients (P < 0.001). Multivariate analysis demonstrated a negative association of age and a positive association of body mass index in hip bone mineral density in psoriatic patients.
Limitations: The main limitations are those of cross-sectional studies, such as a lack of follow up period, and a male predominance in the psoriatic group, which is corrected employing a multivariate analysis with an adjusted model for confounding factors.
Conclusions: Bone mineral density levels in psoriatic patients are situated halfway between healthy controls and patients with osteopenia/osteoporosis. In addition, the higher body mass index in patients with psoriasis appears to confer a protective effect against further development of lower bone mineral density.
Keywords: Body mass index; bone mineral density; osteopenia; osteoporosis; psoriasis; vitamin-D.