Xerostomia in diabetes mellitus

To determine the prevalence of xerostomia in a group of ambulatory diabetic patients and to compare the following in patients with and without xerostomia: 1) flow rates of saliva and lacrimal fluid, 2) the presence of other symptoms suggestive of oral and extraoral dryness, 3) indexes of glycemic control, and 4) noninvasive measures of cardiovagal autonomic nervous system function.

Forty adult diabetic patients and an equal number of age- and sex-matched healthy nondiabetic control subjects were studied. Subjects who consumed xerogenic drugs or had other significant diseases were excluded from the study. A questionnaire was administered to all patients, and the following tests were performed: resting and stimulated flow rates on whole saliva; Schirmer's test (lacrimal fluid), serum glucose and HbA1, expiration-inspiration ratio, 30:15 ratio, Valsalva ratio, and the systolic blood pressure response to standing.

Forty-three percent of diabetic patients complained of xerostomia, of which 82% were women. The oral dryness was not related to age or the type and duration of diabetes. Symptoms of water loss and oropharyngeal, ocular, and vaginal dryness were much more common in the xerostomic than the nonxerostomic diabetic patients. The salivary flow rates of the diabetic subjects was consistently lower than those of healthy, nondiabetic control subjects. The mean, resting, and whole-saliva flow rate was abnormally low in the diabetic patients who complained of xerostomia; no significant differences were observed for the stimulated salivary and the lacrimal flow rates. Significant inverse relationships were shown between salivary flow and the level of HbA1; none were shown between flow and autonomic function.

Dry mouth is a common complaint among ambulatory diabetic patients. It is strongly associated with objective measurements of poor salivary flow and with other oral and extraoral symptoms of desiccation. The oral dryness is not associated with cardiovagal autonomic system dysfunction but may be due to disturbances in glycemic control.