Objective: To characterize cognitive function in patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) in comparison with other chronic conditions, and to investigate its association with disease activity, and other psychological factors. Methods: Cross-sectional study including patients with AAV, rheumatoid arthritis (RA) (n = 30), and chronic kidney disease (CKD) (n = 29). Patients underwent a standardized neuropsychological battery (NEUROPSI). Sleep quality, fatigue, depression, and anxiety levels were assessed. Results: A total of 60 patients with AAV were included, median age of 54 years, and disease duration of 5.6 years. Prevalence of cognitive dysfunction (CD) in AAV patients was similar to RA and CKD (35%, 40%, and 39.3%, respectively, p = .88). When AAV patients with (n = 21) and without (n = 39) CD were compared, significantly more patients with CD had high disease activity (67% vs. 31%, p = .009). Abnormal performance was more frequent in the executive functions in the three groups (45% AAV, 51.7% RA, and 50% CKD), followed by language (25%, 13.8%, and 25%, respectively). Verbal and visual attentional tests were more frequently impaired in patients from the CKD group (p = .021), and psychomotor functions were more frequently affected in AAV patients (p < .05). Hospital Anxiety and Depression Scale (HADS) total score (especially anxiety) was higher in patients with memory impairment than in those with normal memory function (M = 6.79, SD = 4.53 vs. M = 4.5, SD = 3.6, p < .01). Neither Sleep Quality Index nor fatigue scale scores differed between those cognitively impaired and not impaired. Conclusions: No statistically significant differences were found in the frequency of CD among the three clinical populations. (JINS, 2019, 25, 595–602)

Systemic lupus erythematosus (SLE) is a multi-system inflammatory disease where genetic susceptibility coupled with largely undefined environmental factors is reported to underlie the aetiology of the disease. One such factor is low vitamin D status. The primary source of vitamin D is endogenous synthesis following exposure of the skin to UVB light. Photosensitivity, sunlight avoidance and the use of sun protection factor in combination with medications prescribed to treat the symptoms of the disease, puts SLE patients at increased risk of vitamin D deficiency. Decreased conversion of 25-hydroxyvitamin D to the metabolically active form, 1,25-dihydroxyvitamin D3, is possible, due to renal impairment common in SLE putting additional stress on vitamin D metabolism. The majority of studies have identified low 25-hydroxyvitamin D in SLE patients, albeit using varying cut-offs (<25 to <80 nmol/l). Of these studies, fifteen have investigated a link between status and disease activity with conflicting results. Variation with disease activity index measures used alongside methodological limitations within the study design may partially explain these findings. This review discusses the importance of optimal vitamin D status in SLE, critically evaluates research carried out to date that has investigated vitamin D in SLE, and highlights the need for a well-designed observational study that controls for diet, medication use, dietary supplements, UV exposure and seasonality, that uses sensitive methods for measuring vitamin D status and disease activity in SLE to conclusively establish the role of vitamin D in SLE.