Abstract
OBJECTIVES: The aim of this study was to determine the validity and properties of the Summated Xerostomia Inventory-Dutch Version in samples from Australia, The Netherlands, Japan, and New Zealand. STUDY DESIGN: Six cross-sectional samples of older people from The Netherlands (n = 50), Australia (n = 637; n = 245), Japan (n = 401), and New Zealand (n = 167; n = 86) were enrolled. Data were analyzed by using the Summated Xerostomia Inventory-Dutch Version. RESULTS: All datasets revealed a single extracted factor which explained about one-half of the variance, with Cronbach alpha values ≥0.70. When mean scale scores were plotted against a "gold-standard" xerostomia question, statistically significant gradients were observed, with the highest score seen in those who always had dry mouth, and the lowest in those who never had it. CONCLUSIONS: The Summated Xerostomia Inventory-Dutch Version is valid for measuring xerostomia symptoms in clinical and epidemiologic research.