Purpose: To evaluate the psychometric properties of an oral-health related quality of life (OHRQoL) instrument for application in the population of Iranian adolescents and to assess the discriminate and convergent validity and reliability of the Persian version of the Child Oral Health Impact Profile (COHIP) in a representative sample of this population. Materials and Methods: Using multistage stratified sampling, 597 schoolchildren aged from 13 to 18 years living in the city of Isfahan were recruited to complete the Persian COHIP questionnaire. They were also examined for dental caries and malocclusion by two trained, calibrated examiners.
Results: Overall COHIP scores ranged from 15 to 135 (mean ± SD: 103.6 ± 18). Sixty-six percent of the students experienced at least one frequent oral health-related impact over the past three months. The Cronbach alpha coefficient was 0.89 for the overall score. Discriminate validity was supported by the significant difference between COHIP scores in the caries-free group and the others (P = 0.01). In addition, the questionnaire was able to differentiate among the groups by various degrees of need for orthodontic treatment (P < 0.01). Convergent validity was confirmed by significant association between the quality of life scores, the self-perceived health and oral health ratings and the self-perceived treatment need (r = 0.36, 0.57, -0.40).
Conclusion: The Persian COHIP demonstrated acceptable psychometric properties for the descriptive purposes. Some discrepancies observed between the clinical data and quality of life status were confirmed by the perceptual identity of such indices influenced by several overt and covert variables.
Keywords: adolescents, child oral health impact profile, construct validity, oral health-related quality of life