Relationship between vitamin B12 deficiency and oxidative stress in children (2-18 years) with juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a common inflammatory disease in childhood. Due to increased cytokine levels, diseases such as JIA generate risk for early atherosclerosis and cardiovascular disease. Homocysteine is affected to vitamin B12 levels lead to oxidative stress as a cardiovascular risk factor. Aim of this study is evaluation of vitamin B12 deficiency frequency and effects of dietary intake and supplementation on oxidative stress. 62 female and 40 male, total 102 JIA patients admitted to Cerrahpaşa Medical Faculty Children Hospital Children Rheumatology Policlinic in July-September 2014 and diagnosed by International League of Associations of Rheumatology criteria were included. Average age was 9.7±4.5 and 10.1±3.7 years in females and males, respectively. 57 patients (%55.9) were included to intervention group according to serum vitamin B12 level (<400 pg/mL) and 45 patients (%44.1) were included to control group (vitamin B12 level ≥400 pg/mL). 32 patients were excluded after study was started due to noncompliance of study protocol and 40 female and 30 male patients were continued. Subtypes of patients were 47% oligoarticular JIA, 31.4% polyarticular JIA, 10% systemic-onset JIA, 7.1% JPsA and 4.3% psoriatic arthritis (p<0.05). 1000 µg vitamin B12 supplementation was implemented 3 times to the patients who has more than 300 pg/mL vitamin B12 level and 2 times to the patients who has 300-400 pg/mL vitamin B12 level.Second consultation was carried out 110±24.3 days later. Differences between first and second consultations in average of body weight, height, height for age and body mass index of patients were determined (p<0.05). No significant difference were observed in consultation findings (p>0.05). Differences between groups in CRP, erythrocyte sedimentation rate (ESR), lipid profile levels were not differed (p>0.05). In intervention group, average serum vitamin B12 level was 281.4±85.4 pg/mL and increased to 782.9±486.1 pg/mL after supplementation (p<0.05). Daily vitamin B12 intake was above the RDA recommendation in both groups. Average homocysteine levels in intervention group were 15.4±6.4 µmol/L in first consultation, 3.4±2.2 µmol/L in second consultation and in control group 11.4±4.3 µmol/L and 8.8±3.2 µmol/L, respectively (p<0.05). Differences between average malondialdehyde levels were not observed (p>0.05). Positive correlations were found between ESR and number of joints with limited range of motion in intervention group. Besides, positive relations were established between serum vitamin B12 and number of joints with limited range of motion, serum vitamin B12 and CRP, serum folate and ESR, methotrexate dosage and homocysteine levels in control group (p<0.05). Homocysteine levels were ≤14.9 µmol/L in 59.5% of patients in intervention group and 87.9% of patients in control group in first consultation (p<0.05). After the vitamin B12 supplementation, homocysteine levels were ≤14.9 µmol/L in all patients of intervention group and 93.9% of patients in control group (p>0.05). According to these results, especially in intervention group, the reduction in homosistein level has important effect on decreasing in cardiovascular risk.