Full title: the effects of health literacy on disease control in adolescents with asthma.

Objective: Increased health literacy (HL) improves the management of chronic diseases. Data on the HL levels of adolescents with asthma are limited. In this study, we aimed to investigate the HL levels of adolescents with asthma and the effect of HL levels on asthma control. Methods: Our research included 81 adolescents with asthma and 47 age and sex-matched controls. The validated version of the European Health Literacy Survey Questionnaire (HLS-EU-Q16) was utilized to estimate the participants' health literacy levels. In addition, the Asthma Control Test (ACT) was used to determine the degree of asthma control. Results: No significant difference between the asthmatic adolescents ( n  = 45, 55.6%) and the control group ( n  = 28, 59.6%) has been established in terms of the number of participants who were considered to have adequate HL ( p  = 0.658). The difference between the patient and control groups in health care, disease prevention, health promotion, and overall HL scores was determined non-significant. According to the ACT scores, the overall median HL score was significantly higher in patients with controlled asthma {34.4 (14.6:50)} than in those with uncontrolled asthma {32.3 (16.7:48.9)} ( p  = 0.037). It was determined that there was a difference in the distribution of controlled asthma, uncontrolled asthma, and controls in HL subgroups (poor, problematic-limited, sufficient, and perfect HL) ( p  = 0.002). Conclusion: The level of HL is associated with asthma control. A significant proportion of asthmatic adolescents who participated in our research displayed low HL scores. Further studies should be conducted to increase the HL levels of adolescents to achieve better asthma control.