ABSTRACT: BACKGROUND:Assessing disparities in health-related quality of Life (HRQoL) is important as a part of health-related disparities in the society. The aim of this study was to explore HRQoL among 12-year-olds in Sweden in terms of differences between years 2005 and 2009 and disparities related to sociodemographic background. METHODS:During the school years 2005 and 2009, a total of 18,325 sixth grade students in Sweden were invited to a celiac disease screening study; 13,279 agreed to participate. Jointly with the celiac screening, the children answered a questionnaire that included EuroQol 5 Dimensions-youth (EQ-5D-Y) and their parents responded to separate questionnaires about their own and their child's country of birth, family structure, their employment status, occupation, and education. In total 11,009 child-parent questionnaires were collected. Logistic regression was used to study differences in HRQoL between 2005 and 2009, and between various sociodemographic subgroups. RESULTS:Compared with 2005, children in 2009 reported more pain (OR: 1.20, 95% CI: 1.1-1.3) and more mood problems (OR: 1.35, 95% CI: 1.2-1.5). In general, girls reported more pain and mood problems and had more disparities than boys. There were no significant differences based on parents' occupation, however, children of parents with low or medium education levels reported less "mood problems" than those of parents with high education levels (OR: 0.65, 95% CI: 0.46-0.92) and (OR: 0.84, 95% CI: 0.73-0.96), respectively. A slight variation was seen in HRQoL between children with different migration background. Girls living in small municipalities reported more pain (OR: 1.51, 95% CI: 1.14-2.01), and problems performing usual activities (OR: 3.77, 95% CI: 2.08-6.84), compared to girls living in large municipalities. In addition, children living with two parents had less mood problems than children living in other family constellations. CONCLUSION:More children reported pain and mood problems in 2009 compared with 2005. To study future trends, health outcomes among children in Sweden should continue to be reported periodically. More efforts should be invested to increase the awareness of health-related disparities as highlighted in this study especially for girls living in small municipalities and children of parents with high education level.