A validation study of the Malocclusion Impact Questionnaire to measure oral health-related quality of life in young adolescents with malocclusion from four Arabic countries.

Abstract

Background: The Malocclusion Impact Questionnaire (MIQ) is a validated tool used to assess how malocclusion affects oral health-related quality of life (OHRQoL). This research focused on translating and culturally adapting the MIQ, then validating it in a group of Arab adolescents with malocclusion.

Materials and methods: Following translation per current guidelines, a pilot study with 20 adolescent native Arabic-speakers confirmed the comprehensiveness of the Arabic MIQ (MIQ-AR). The main study included 233 native Arabic-speaking children aged 10-16, who sought initial orthodontic advice. Construct validity was assessed by correlating the total MIQ-AR scale score with responses to global questions. Convergent validity was measured using the Child Perceptions Questionnaire (CPQ_11-14 - ISF: 16). Internal consistency and reliability were evaluated using Cronbach's alpha. Forty adolescents completed both questionnaires again after 3 weeks to assess measurement stability, using Spearman's correlation coefficient and the intraclass correlation coefficient. Additionally, principal component analysis (PCA) was conducted.

Results: The MIQ-AR demonstrated high internal consistency with Cronbach's α above 0.90 and exhibited a strong Discrimination Index. A positive, strong, significant correlation between the global questions and the total MIQ-AR score supported the construct validity of the MIQ-AR. Convergent validity was confirmed through positive, strong, and statistically significant correlation between the MIQ-AR total scores and the CPQ_11-14 scale. The test-retest reliability assessment confirmed the measure's stability over time, and the PCA yielded a two-component solution that accounted for 52.3% of the total variance.

Conclusion: The current version of MIQ-AR demonstrates strong psychometric properties in terms of validity and reliability, and appears to be a reliable instrument for assessing the impact of malocclusion on OHRQoL among Arab adolescents. However, these findings should be interpreted with caution, as they may be limited to populations like the study sample. Further testing of the measure is required across a variety of settings and further work should evaluate measurement invariance and responsiveness across countries and more representative community samples.