Growth Assessment and Vitamin D Level in Egyptian Juvenile Idiopathic Arthritis Patients

Background Juvenile idiopathic arthritis (JIA) is one of the most common rheumatic diseases in childhood and is frequently associated with growth retardation. Vitamin D is critical to bone mineral metabolism and to the growth and development of the skeleton. We aimed to evaluate growth pattern and Vitamin D level in patients with JIA and its different subtypes. Materials and Methods 80 JIA patients and 80 healthy controls were included. For all patients and controls we assessed body weight, standing height, body mass index (BMI), Serum 25(OH) D3. Thyroid function tests were assessed to exclude patients with hypothyroidism or autoimmune thyroiditis, liver and renal function tests, calcium, phosphorus, alkaline phosphatase, fasting blood sugar were done to evaluate other causes of short stature. Results JIA patients' mean height, weight, and BMI were significantly lower compared to controls (135.4±22.1 vs. 145.7±21.8, p=0.042 for height), (34.6±13.6 vs. 39.8±11.4, p=0.039 for weight) and (18.52±3.96 vs. 21.73±5.43, p= 0.041 for BMI). Mean serum 25(OH) D3 level was significantly lower in JIA patients than controls (15.69±6.6 ng/ml vs. 31.62±4.9 ng/ml, p<0.0001), patients with systemic onset and seropositive polyarthritis (RF positive) have the lowest 25(OH) D3 level compared with other JIA subtypes. There was significant negative correlation between steroid dose, duration and JIA patients' height (r= -0.456, p=0.017 and r=-0.776, p=0.001 respectively). Serum 25 (OH) D3 level was significantly correlated with patients' height and BMI (r=0.33, p=0.029 and r=0.32, p=0.043). Conclusion The nutritional status of JIA patients is multi-factorial. Onset subtype and low level of vitamin D were found to have an effect on growth parameters as height and body mass index in patients with juvenile idiopathic arthritis.