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

The present study investigated the factorstructure and item analysis of the Mini AsthmaQuality of Life Questionnaire (MiniAQLQ) in asample of 258 community-dwelling asthmaticadults between the ages of 16 and 87 years. The mean age was 56 years for males (N = 99) and50 years for females (N = 159). This studycompared the fit of three factor solutionsusing a maximum likelihood confirmatory factoranalysis. Based on the fit indices, supportwas found for a hierarchical factor structurewith a second-order factor of quality of lifeand four first-order factors of symptoms,activity limitation, emotional function andenvironmental stimuli. Given that the data fitan essentially unidimensional model, genderdifferential item functioning (DIF) wasexplored using Zumbo's (1999) ordinal logisticregression method with corresponding logisticregression effect size estimators. Aftermatching males and females on the underlyingvariable of quality of life, gender DIF wasfound on the cigarette smoke and weather or air pollution items. Thesefindings indicate that gender influences how anindividual endorses these particular items onthe MiniAQLQ.