Development of a questionnaire for measuring health-related quality of life among children and adolescents with mouth breathing

Background: Mouth breathing can exert an influence on quality of life and should be evaluated within a multidimensional context. However, there is no specific questionnaire to measure the impact of mouth breathing on quality of life. Objective: To develop and validate a questionnaire for measuring the impact of mouth breathing on quality of life among children and adolescents. Methods: Thirty-six items were evaluated by six health care professionals, one parent and one child with mouth breathing. After a qualitative evaluation, a modified set of 32 items was developed. The modified Mouth Breather Quality of Life (MBQoL) questionnaire was submitted to a pretest with a sample of 30 children and adolescents diagnosed with mouth breathing to evaluate comprehension, the order of the items, and the form of administration. The MBQoL questionnaire was then administered to 60 children and adolescents (30 mouth breathers and 30 nose breathers) for the evaluation of construct validity, internal consistency, and reproducibility. All the participants answered the questionnaire, and 50% of each group answered the questionnaire a second time after a 1-week interval (test-retest). Results: Higher MBQoL scores (which indicated poorer quality of life) were significantly associated with mouth breathing. The Cronbach alpha coefficient for the items of the questionnaire was 0.88, and the Spearman correlation coefficient for test-retest reliability demonstrated that the questionnaire was reproducible (r = 0.993; p < 0.01). Conclusion: Through this validation study, the MBQoL questionnaire demonstrated a good performance in the evaluation of the quality of life of children and adolescents with mouth breathing and may be a useful tool in clinical studies as well as public health programs. However, further studies are needed to establish its applicability in other populations with respiration disorders.