PT  - JOURNAL ARTICLE
AU  - Jiangwei Xia
AU  - Shu-Yang Xie
AU  - Ke-Qi Liu
AU  - Lin Xu
AU  - Pian-Pian Zhao
AU  - Si-Rui Gai
AU  - Peng-Lin Guan
AU  - Jin-Qiu Zhao
AU  - Yan-Ping Zhu
AU  - Lam C Tsoi
AU  - Philip E Stuart
AU  - Rajan P Nair
AU  - Han-Qi Yang
AU  - Yu-Ting Liao
AU  - Kaijing Mao
AU  - Mo-Chang Qiu
AU  - Zhi-Min Ying
AU  - Bin Hu
AU  - Zhi-Hua Yang
AU  - Wei-Yang Bai
AU  - Xiao-Wei Zhu
AU  - Pei-Kuan Cong
AU  - James T Elder
AU  - Zhao-Ming Ye
AU  - Bin Wang
AU  - Hou-Feng Zheng
TI  - Systemic evaluation of the relationship between psoriasis, psoriatic arthritis and osteoporosis: observational and Mendelian randomisation study
AID  - 10.1136/annrheumdis-2020-217892
DP  - 2020 Nov 01
TA  - Annals of the Rheumatic Diseases
PG  - 1460--1467
VI  - 79
IP  - 11
4099  - http://ard.bmj.com/content/79/11/1460.short
4100  - http://ard.bmj.com/content/79/11/1460.full
SO  - Ann Rheum Dis2020 Nov 01; 79
AB  - Objectives and methods With 432 513 samples from UK Biobank dataset, multivariable linear/logistic regression were used to estimate the relationship between psoriasis/psoriatic arthritis (PsA) and estimated bone mineral density (eBMD)/osteoporosis, controlling for potential confounders. Here, confounders were set in three ways: model0 (including age, height, weight, smoking and drinking), model1 (model0 +regular physical activity) and model2 (model1 +medication treatments). The eBMD was derived from heel ultrasound measurement. And 4904 patients with psoriasis and 847 patients with PsA were included in final analysis. Mendelian randomisation (MR) approach was used to evaluate the causal effect between them.Results Lower eBMD were observed in patients with PsA than in controls in both model0 (β-coefficient=−0.014, p=0.0006) and model1 (β-coefficient=−0.013, p=0.002); however, the association disappeared when conditioning on treatment with methotrexate or ciclosporin (model2) (β-coefficient=−0.005, p=0.28), mediation analysis showed that 63% of the intermediary effect on eBMD was mediated by medication treatment (p<2E-16). Patients with psoriasis without arthritis showed no difference of eBMD compared with controls. Similarly, the significance of higher risk of osteopenia in patients with PsA (OR=1.27, p=0.002 in model0) could be eliminated by conditioning on medication treatment (p=0.244 in model2). Psoriasis without arthritis was not related to osteopenia and osteoporosis. The weighted Genetic Risk Score analysis found that genetically determined psoriasis/PsA were not associated with eBMD (p=0.24 and p=0.88). Finally, MR analysis showed that psoriasis/PsA had no causal effect on eBMD, osteoporosis and fracture.Conclusions The effect of PsA on osteoporosis was secondary (eg, medication) but not causal. Under this hypothesis, psoriasis without arthritis was not a risk factor for osteoporosis.