Scragg, RRademaker, MJarrett, Paul2016-06-2020152015http://hdl.handle.net/2292/29136Background There is a growing interest in the role of vitamin D beyond its effect on bone health. The vitamin D receptor is widely expressed in many different tissues, including the skin. Aim The aim was to investigate the association between 25-hydroxyvitamin D and cutaneous lupus erythematosus, and the effect of vitamin D on psoriasis. Two additional studies about the population prevalence of cutaneous lupus and the cardiovascular risk of psoriasis were undertaken. Methods Patients with cutaneous lupus were identified from multiple sources from both the hospital and the community. The database compiled was then used to clinically assess both the scarring and the activity of cutaneous lupus in association with 25-hydroxyvitamin D status. A randomised, placebo-controlled study of the effect of oral 100,000 IU monthly Vitamin D3 (cholecalciferol) was undertaken with participants who had psoriasis and had been recruited to a larger study called the Vitamin D assessment study. Results One hundred and forty-five patients with cutaneous lupus were identified. Māori and Pacific people were found to have a higher prevalence of all types of cutaneous lupus compared with the European population [relative risk 2.47 (95% CI: 1.67–3.67)] and especially discoid lupus [relative risk 5.96 (95% CI: 3.06–11.6)]. No relationship was found between cutaneous lupus (either active disease or scarring) and 25-hydroxyvitamin D levels. Sixty-five patients with mild psoriasis were recruited. The mean Psoriasis Area Severity Index was 3.0 and 3.3 in the placebo and active group respectively. No improvement in psoriasis was recorded by the addition of vitamin D3 when assessed by the Psoriasis Area Severity Index, Global Physician’s Assessment, Dermatology Life Quality Index or the Psoriasis Disability Index (p > 0.05). There was no increase in cardiovascular risk in the psoriasis participants (p > 0.05). Conclusions 25-hydroxyvitamin D status is not a significant factor for cutaneous lupus. Further research is needed to examine why Māori and Pacific peoples have high rates of cutaneous lupus. Oral vitamin D3 is not a therapeutic option for patients with mild psoriasis, and the low cardiovascular risk of a New Zealand patient cohort with mild psoriasis is confirmed.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmhttp://creativecommons.org/licenses/by-nc-nd/3.0/nz/ThesisCopyright: The Authorhttp://purl.org/eprint/accessRights/OpenAccessQ112909322