AB1432 BODY MASS INDEX AND INFLAMMATORY LESIONS IN MAGNETIC RESONANCE IMAGING IN JUVENILE IDIOPATHIC ARTHRITIS: IS THERE A LINK?

Abstract

BackgroundObesity is usually associated with low-grade inflammation in the general population. However, several studies have noted that high body mass index (BMI) in rheumatoid arthritis patients was associated with less structural damage in X-rays and in Magnetic Resonance Imaging (MRI) [1,2]. The impact of BMI on inflammatory MRI lesions in Juvenile Idiopathic Arthritis (JIA) is less studied.ObjectivesWe aimed to determine the link between BMI and inflammatory MRI lesions of sacroiliac joints in JIA.MethodsWe conducted a retrospective study including 44 patients followed for JIA meeting the International League of Associations for Rheumatology (ILAR) 2001 criteria. For each patient we collected the following data: age, age at the onset of JIA, JIA subtype, disease duration, BMI, C-reactive protein (CRP) and Erythrocyte sedimentation rate (ERS) levels, and MRI data. Disease activity was assessed using the JADAS score.Statistical analysis was performed using SPSS software.ResultsWe included 28 boys and 16 girls. The mean age was 13.65 ± 4.62 years. The mean age at the onset of the disease 9.57 ± 3.97 years. The mean disease duration was 4.34 ± 3.09 years. There was enthesitis-related arthritis in 61% of the cases (n=27), oligoarticular JIA in 14% of the cases (n=6), polyarticular JIA in 11% of the cases (n=5), and psoriatic arthritis in 7% of the cases (n=3). JIA was undifferentiated in 7% of the cases (n=3). The mean BMI was 20.22 ± 5.6kg/m². Four patients had overweight (9%). The mean CRP and ESR were 14.42 ± 19.67mg/L and 26.56 ± 20.87mm, respectively. The mean JADAS was 6.6 ± 4.7.Sacroiliac joints IRM showed bone marrow edema in 43% of the cases (n=19) and irregularities in iliac edges in 9% of the cases (n=4).Inflammatory lesions in sacroiliac joints MRI was associated with lower BMI (19.15 ± 4.28 vs 21.33 ± 6.4kg/m², p=0.036). However, there were no correlations between BMI and the following parameters: CRP, ESR, or JADAS.ConclusionOur results are consistent with other studies conducted in rheumatoid arthritis patients, which noted that high BMI was associated with less severe synovitis and bone marrow edema, and thus less severe radiologic progression [1-3]. Baker et al. suggested that patients with greater BMI have a beneficial adipokine effect on bone remodeling [3]. In addition, it seems that JIA patients with severe disease activity suffer from early weight loss. Thus, a greater BMI may stipulate a less severe JIA phenotype.