Is Obesity a Threat to Juvenile Idiopathic Arthritis Patients?
Studies have shown that amongst adults, obese patients have approximately 4.5% increased risk of being affected with inflammatory arthritis than the normal population. A possible link between obesity and arthritis could be due to the presence of adipokines, which are, proteins released from the adipose tissue or ''fat tissues''. These proteins play an important role in regulating inflammatory/immune responses. Thus, in obese patients there is a possibility where excess of adipokines are released into the joint sockets and cause inflammation of joints leading to arthritis. Studies have reported that an increased level of leptin, a pro-inflammatory adipokine, is seen in Rheumatic Arthritis (RA) patients.
This particular study was primarily conducted to study the prevalence of obesity in patients with Juvenile Idiopathic Arthritis (JIA) and to observe if there was an association between obesity and disease activity. The study was based on a database from JIA patients attending a single pediatric rheumatology clinic in Boston from October 2009 to September 2010. The disease activity of these patients were calculated based on the Juvenile Arthritis Disease Activity Score (JADAS 27) which included four main measures: physician global assessment of disease activity, parent global assessment of child's well-being, count of joints with active disease (evaluating 27 joints), and ESR which tests the inflammation rate in the body. The children were classified as obese, overweight, normal or underweight based on their body mass index (BMI). The medication undertaken and duration of use by the patients were also noted.
Several statistical analysis methods were done to understand the association between the disease activity score (JADAS 27), obesity level and the ESR/degree of inflammation. The results showed that 18% of the patients from the study with JIA were obese, however, an exact association between obesity and the disease activity was not established. The rate of children who were obese with JIA was nearly identical to otherwise healthy children. Although earlier studies have indicated an association between obesity and worsened disease activity in RA patients, this was not observed in this particular study. Other studies have also indicated that, inflammation or increased disease activity in obese children could be due to physical inactivity and not exactly due to being affected by arthritis.
Although there were several limitations to this study such as small sample size, lack of physical activity, socioeconomic status of patients, etc., it can be regarded as one of the first studies to explore a relationship between obesity and disease activity.
To conclude, an association between obesity and disease activity in children affected with JIA was not established from this study. However, as the risk of obesity is higher in children with JIA, it is important for medical practitioners to discuss this issue with parents having children with JIA.
Obesity and disease activity in juvenile idiopathic arthritis; Christina Pelajo et al; Pediatric Rheumatology, 2012.