Confirmatory factor analysis of the Oral Health Impact Profile

Area of Science:

• Oral Health Research
• Psychometrics
• Quality of Life Measurement

Background:

• Exploratory analyses indicated the Oral Health Impact Profile (OHIP) comprises four correlated dimensions and a higher-order factor.
• The Dimensions of Oral Health-Related Quality of Life (DOQ) Project is an international study investigating general population and prosthodontic patient data.
• Validating the factor structure of the OHIP is crucial for accurate assessment of oral health-related quality of life (OHRQoL).

Purpose of the Study:

• To corroborate previous findings on the OHIP's factor structure within the DOQ Project.
• To compare the psychometric performance of unidimensional, four-factor, and bifactor models for the OHIP.
• To identify the most interpretable and best-fitting model for assessing OHRQoL.

Main Methods:

• Confirmatory factor analyses were performed on a validation sample of 4993 subjects from the DOQ Project.
• Three models were compared: unidimensional, four-factor, and bifactor (one general, four group factors).
• Model fit criteria (RMSEA, CFI) and factor interpretability guided the selection of the best model.

Main Results:

• The four-factor model demonstrated superior psychometric performance, with strong item loadings and excellent model fit (RMSEA = 0·05, CFI = 0·99).
• The four factors identified were Oral Function, Oro-facial Pain, Oro-facial Appearance, and Psychosocial Impact.
• High inter-factor correlations and good fit of the unidimensional model suggest a single OHRQoL score is also viable.

Conclusions:

• The findings corroborate that the OHIP reliably captures four distinct dimensions of OHRQoL.
• The four identified factors provide a detailed understanding of the multifaceted nature of OHRQoL.
• A unidimensional approach using a single OHIP score is also supported, offering a simplified measure of OHRQoL.