The aim of the retrospective case-control study was to determine if the health-related quality of life of overweight and obese children is lower than for children with optimal weight, using the KIDSCREEN-52 survey of health-related quality of life. The study examined differences in health-related quality of life assessments between children with optimal weight, and obese and over-weight children, as well as evaluated parental assessments of the quality of life of their children. In total, 200 children aged 8 to 18 years and their parents participated in the study. The results of the study showed that the total quality of life of obese (p < 0.0001) and overweight (p = 0.008) children was lower than for children with optimum weight (p = 0.001). Also, the assessments of quality of life between parents of obese (p < 0.0001) and overweight (p = 0.001) children scored lower than those of parents whose children had optimal weight.

Vitamin D deficiency is common and widespread globally. Vitamin D has an immunomodulatory effect, but it is still unclear whether its deficiency is associated with higher disease activity. The aim of this retrospective study was to determine the serum concentration of vitamin D in children with paediatric arthritis (juvenile idiopathic arthritis and reactive arthritis). Prevalence of hypo-vitaminosis D among 98 children with juvenile idiopathic arthritis and reactive arthritis was determined and association between serum concentration of vitamin D and disease activity markers was found. Prevalence of vitamin D deficiency among children included in this study was 69.07%. Children with juvenile idiopathic arthritis had a significantly lower vitamin D level than children with reactive arthritis. There was a statistically significant moderate negative correlation between serum concentration of vitamin D and patient age, as well as a weak negative correlation between vitamin D level and patient body mass index. The significant correlations found between vitamin D level and inflammatory markers indicate that further research on the role of vitamin D in disease activity is needed.