Serum Vitamin D and Caries in Juvenile Idiopathic Arthritis

Objectives: To investigate the association between vitamin D and caries in children with juvenile idiopathic arthritis (JIA).
Methods: Children with JIA were invited to participate in an inter-disciplinary, multi-center, longitudinal clinical cohort study in Norway (NorJIA Study). The study included a comprehensive medical and oral examination, including imaging, blood tests and patient/parent-reported questionnaires on physical activity and dietary intake of vitamin D. Using the DMFS/dmfs indices, caries registration (dentin caries only), was limited to 4 index teeth (first permanent molars at ≥10years, primary second molars at <10years). Blood samples were measured for 25-OH-vitamin D. Cut-off value for vitamin D insufficiency was set at 50nmol/L. Chi-squared statistics were used for measuring a potential difference in caries prevalence between the two vitamin D groups. Bivariate logistic regression analysis was used to assess the association between vitamin D status and caries.
Results: In total, 224 children, aged 4-16 years, were included (59% females, mainly fair-skinned). Median age was 12.7 years (interquartile range (IQR):9.4-14.7), median age at disease onset was 5.9 years (IQR:2.3-10.4) and median disease duration was 4.6 years (IQR:2.7-8.4). Nearly 45% had oligoarticular arthritis and 40% had active disease at the baseline visit. Mean vitamin D was 61.4±22.3nmol/L, and 30% had insufficient levels. Mean daily dietary intake was 10.5±9.6µg/day, and 66% had lower intake than recommended (10µg/day). Caries was found in 46% of children with Vitamin D level <50nmol/L compared to 19 % in those with vitamin D level ≥50nmol/L. Children with lower vitamin D level were three times more likely to have dentin caries compared to those with higher level (OR:3.65, 95%CI:2.0-6.8).
Conclusions: Vitamin D status was significantly associated with dentin caries at baseline. This association will be assessed longitudinally.