Background Vitamin D has the potential to modulate the immune system for patients with systemic lupus erythematosus (SLE)1, and which could potentially lead to improved clinical outcomes. Observational data have suggested a relationship between vitamin D and disease activity2. This observation has been confirmed by vitamin D3 supplementation studies, where positive immunological effects were reported in SLE patients3. Additionally a placebo controlled trial supplementing SLE patients with vitamin D3 identified a positive effect on inflammation and haemostatic markers as well as improvements in disease activity4. Research examining the relationship between vitamin D and bone mineral density (BMD) in SLE patients is limited, albeit a study has suggested a link between disease activity and BMD in SLE patients5 and thereby suggesting flares in disease activity has a negative effect on BMD. Objectives To examine for relationships between vitamin D and disease activity, damage and BMD. Methods A total of 52 SLE patients were recruited onto an observational study during the winter (November-March) and followed up during the summer months (June-July) (n=50). Total 25-hydroxyvitamin D (25(OH)D) concentration was measured using the liquid chromatography mass spectrometry method (MassChrom®, Chromsystems Gmbh, Heimburgstrasse, Germany) and BMD was measured at the lumbar spine and femur by dual energy X-ray absorptiometry (Lunar iDXA™, UK). Disease activity and damage were assessed using Systemic Lupus Activity Measure (SLAM), British Isles Lupus Assessment Group (BILAG), Systemic Lupus Erythematosus Disease Activity Index (SELENA SLEDAI) and Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR). Results Mean (SD) 25(OH)D concentrations in winter (26.9 (16.2) nmol/L) and summer (28.7 (16.7) nmol/L) were not different (P=0.439), nor were differences observed between disease activity and damage. During the winter, but not during the summer, vitamin D was a significant predictor of BILAG (r=-0.307; P=0.027) and SELENA SLEDAI (β=-0.074; SE=0.036; P=0.044), controlling for age, BMI and medications. Osteoporosis and osteopenia was present in some 4 (8%) and 21 (45%) SLE patients respectively and there were no relationships observed between disease activity and BMD. Conclusions Vitamin D inadequacy was prevalent throughout the year and undiagnosed osteoporosis was apparent in this cohort, and, therefore, suggesting routine screening of both is warranted. Wintertime vitamin D status was a predictor of disease activity at that time of year. There was no relationship, however, observed between disease activity and BMD. The lack of seasonal variability in vitamin D status might suggest sun avoidance by the SLE patients; emphasising the importance of obtaining adequate vitamin D intake from the diet and supplements for SLE patients. References Marques et al. Revista Brasileira de Reumatologia. 2010;50(1):67-80. Breslin, et al. Proceedings of the Nutrition Society. 2011 Nov;70(4):399-407. T...

Vitamin D deficiency is common in Irish adults, though there is limited research on its determinants, knowledge of vitamin D or indications for testing. We aimed to explore the determinants of vitamin D status in adults and examine knowledge and reasons for testing. The study population comprised adults who had serum 25-hydroxyvitamin D tested by general practitioners request at a Dublin Hospital in 2020. Questionnaires detailing dietary intake, sun exposure, ethnicity, biophysical factors and vitamin D knowledge were sent to a sample stratified by age, sex and vitamin D status. In total, there were 383 participants, mean age 56·0 (sd 16·6) years. Wintertime deficiency disproportionally affected non-white v. white (60 % v. 24 %, P < 0·001). The greatest predictors of deficiency were low vitamin D intake (< 10 μg/d) (P < 0·001) and non-white ethnicity (P = 0·006), followed by sun avoidance (P = 0·022). It was also more prevalent in those with lower body exposure when outdoors. The majority (86 %) identified vitamin D as important for bone health. However, 40 % were tested for non-clinical indications and half were not aware of the recommended daily allowance (RDA). Low vitamin D intake was the most important determinant of deficiency, but ethnicity and sun exposure habits were also significant predictors. The majority had no clear indication for testing and were not aware of the RDA. Public health policies to improve knowledge and vitamin D intake, especially for those of non-white ethnicity and with reduced sun exposure, should be considered.

There is an emergent association between vitamin D deficiency (VDD) and the risk of SARS-CoV-2 infection. The prevalence of VDD in Ireland is high, (1)(2)(3) particularly in older institutionalised adults (4) and low SES groups (2) as a consequence of suboptimal sun exposure, inadequate dietary intake, unfavourable lifestyle habits, and low supplementation rates; these same groups are at higher risk of SARS-CoV-2 infection. (5) This research project aimed to establish a method for area-level prediction of VDD to aid in the identification of spatial areas at higher risk of VDD which might also be more vulnerable to SARS-CoV-2 infection. This study was a retrospective cross-sectional analysis of area-level vitamin D status amongst community-dwelling adults in Ireland. Serum 25(OH)D concentrations from 7,708 GP-ordered patient samples from counties Dublin, Meath, Wicklow, and North Kildare were derived from the electronic patient database at St James's Hospital, Dublin. These samples were geo-coded by the electoral division (ED) of the residential address using the Health Atlas Ireland/GeoDirectory application. The demographic profile (ethnic mix) and socioeconomic status (the relative Pobal Haase-Pratschke affluence/deprivation score) at the ED level was based on the Census 2016 Small Area Population Statistics (SAPS) published by the Central Statistics Office. The associations between the demographic and socioeconomic parameters and the mean and median ED-level 25(OH)D were examined by univariate (one-way ANOVA with Tukey's post hoc multiple comparison test, Kruskal-Wallis with Dunn's post hoc multiple comparison test) and multivariate (linear regression, multinomial logistic regression) analyses. There were 412 EDs with indicative 25(OH)D measures. VDD at area-level was defined as mild if the mean ED-level 25(OH)D was 50 -74 nmol/L, moderate if the mean ED-level 25(OH)D was 30 -49 nmol/L, or severe if the mean ED-level 25(OH)D was less than 30 nmol/L. ED-level socioeconomic disadvantage was associated with a higher risk of mild, moderate, and severe VDD (OR 1.042 for mild VDD, p = 0.004; OR 1.059 for moderate VDD, p = 0.003; OR 1.060 for severe VDD, p = 0.071 with each one-unit reduction in relative deprivation index score). Each percentage point increment in the prevalence of Asian and Asian Irish ethnicity at ED-level was associated with a higher risk of mild VDD (OR 1.120, p = 0.041). Low socioeconomic status and the prevalence of non-white ethnicity at ED-level are predictive of VDD in community-dwelling Irish adults. These findings support the use of area-level population statistics to predict VDD at area-level.

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