Background Vitamin D deficiency is increasingly recognised as a global health problem. The important role of vitamin D in skeletal health is well established. Studies have shown vitamin D deficiency in many autoimmune rheuamtic disorders. These patients are commonly treated with corticosteroids which is an important risk factor for osteoporosis. Therefore detection of hypovitaminosis D is important.
Objectives The aim of this study is to determinine the prevalence of vitamin D deficiency in a cohort of patients attending the Rheumatology clinic at RIPAS hospital which is a tertiary hospital in Brunei and to compare between different gender, ethnic groups and disease groups.
Methods A cross sectional study was conducted among patients attending Rheumatology clinic from Jan 2000 to Dec 2010. Demographic and clinical data was abstracted from case notes. Quantitative determination of 25(OH) vitamin D is a direct, competitive chemiluminescence immunoassay. Vitamin D deficiency was defined as 25(OH) vitamin D <50 nmol/L and severe deficiency <25 nmol/L.
Results This study comprised 292 patients, 251 female and 41male. Their mean age is 49.9 (±SD 15.57) ranging from 15-95 yrs. The main racial groups were Malays (78.4%) and Chinese (19.2%). The mean vitamin D level is 49.57 (±SD 22.22) nmol/l. The overall prevalence of Vitamin D deficiency is 57.0% and severe deficiency is 8.2%. Deficiency is more common in female than male, 60.6% vs 39% (p<0.001). Malay has the highest prevalence of vitamin D deficiency at 63.7% compared to Chinese and others groups at 32.1% and 42.8% respectively (p<0.001). Severe deficiency was found in 9.6% Malays but not among other racial groups. An analysis of variance showed significant variation among the racial groups; a post-hoc Tukey test indicated that Malay differed significant from the Chinese but not the others. There is a very weak correlation of age with vitamin D serum concentration (Spearman's rho r=0.285, p<0.05). No correlation of vitamin D level with body mass index was found.
Conclusions Hypovitaminosis D is common among Rheumagology patients in Brunei. Differences in gender and ethnic groups were found with higher prevalence among females and ethnic Malays. SLE patients have higher prevalence than those with RA. There is weak correlation of vitamin D level with age but no correlation was detected with body mass index.
Disclosure of Interest None declared