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.
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.
The Summated Xerostomia Inventory–Dutch Version is valid for measuring xerostomia symptoms in clinical and epidemiologic research.