The Dimensionality and Gender Differential Item Functioning of the Mini Asthma Quality of Life Questionnaire (MiniAQLQ)

The present study investigated the factor structure and item analysis of the Mini Asthma Quality of Life Questionnaire (MiniAQLQ) in a sample of 258 community-dwelling asthmatic adults between the ages of 16 and 87 years. The mean age was 56 years for males (N = 99) and 50 years for females (N = 159). This study compared the fit of three factor solutions using a maximum likelihood confirmatory factor analysis. Based on the fit indices, support was found for a hierarchical factor structure with a second-order factor of quality of life and four first-order factors of symptoms, activity limitation, emotional function and environmental stimuli. Given that the data fit an essentially unidimensional model, gender differential item functioning (DIF) was explored using Zumbo's (1999) ordinal logistic regression method with corresponding logistic regression effect size estimators. After matching males and females on the underlying varibale of quality of life, gender DIE was found on the cigarette smoke and weather or air pollution items. These findings indicate that gender influences how an individual endorses these particular items on the MiniAQLQ.