In type 2 diabetes, a high prevalence of oral problems has been detected. These problems include mouth dryness, an increase in periodontal disease, oral Candida, and swelling of the parotid glands (1). Salivary flow rates have often been found to be significantly reduced in type 2 diabetic patients (2), although these findings have not been confirmed (3). Scintigraphic changes correlate well with salivary gland abnormalities (4) and histopathological changes (5). This technique has gained widespread acceptance in evaluating a variety of salivary glandular disorders (6,7). The aim of the present study was to test whether patients with type 2 diabetes suffer from impaired salivary function using objective and quantitative salivary scintigraphy.
A total of 40 patients with type 2 diabetes for 10 years and 36 healthy age- and sex-matched control subjects (13 women and 23 men aged 56.2 ± 13.3 years) were enrolled in the study. All of the type 2 diabetic patients had good blood glucose control by analysis of HbA1c (3–8%) concentration (8). None had other systemic diseases or presented with autonomic neuropathy during orthostatic testing (9). In accordance with a previously established questionnaire, each type 2 diabetic patient was asked 10 specific questions related to oral dryness or oral health (10). These type 2 diabetic patients were separated into two subgroups. Group 1 consisted of 20 patients (13 men and 7 women aged 54.2 ± 14.5 years) with xerostomia, and group 2 consisted of 20 patients (13 men and 7 women aged 55.2 ± 13.4 years) without xerostomia. All of the study and control subjects were asked to refrain from drugs known to affect salivary secretion for at least 1 week and to fast overnight before the salivary scintigraphy. After intravenous injection of 5 mCi Tc-99m pertechnetate, sequential images at 1 min/frame were acquired for 30 min. The 1st- and 15th-min uptake ratios (URs) were calculated from the tracer uptakes in the four major salivary glands over the background regions of interest. Saliva excretion was stimulated by one tablet of 200 mg ascorbic acid given orally 15 min postinjection of the tracer. Then, the maximal excretion ratios (ERs) of the four major salivary glands after sialagogue stimulation were calculated. In all of the four major salivary glands, type 2 diabetic patients with xerostomia had significantly lower URs and ERs the 1st- and 15th-min compared with control subjects and type 2 diabetic patients without xerostomia (all P < 0.01). However, no significant differences in the 1st- and 15th-min URs and ERs were found between control subjects and type 2 diabetic patients without xerostomia (all P > 0.05) (Table 1).
Salivary scintigraphy is a readily available minimally invasive diagnostic test used to evaluate salivary gland function. Scintigraphy is a particularly valuable tool because it produces a dynamic, objective, and quantitative measurement of the major salivary gland function and allows for differentiation of abnormalities in saliva production (UR) and secretion (ER). From a review of the literature, no published studies have used salivary scintigraphy to evaluate salivary function of type 2 diabetic patients. Xerostomia is a subjective sensation of dryness of the mouth and is believed to be a common complaint among type 2 diabetic patients (8). It is usually associated with salivary gland hypofunction (1). In our study, significantly impaired salivary function was found in type 2 diabetic patients with xerostomia on salivary scintigraphy. Our results suggest that this discrepancy can be resolved by not classifying patients according to presence of xerostomia. In this study, impaired salivary function (represented by significantly decreased URs and ERs), in type 2 diabetic patients with xerostomia was demonstrated on objective and quantitative salivary scintigraphy. However, a larger series of type 2 diabetic patients is necessary to confirm our findings.
Scintigraphic data from type 2 diabetic patients and healthy control subjects
. | 1st-min UR values . | 15th-min UR values . | ER values . | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
RPG . | LPG . | RSG . | LSG . | RPG . | LPG . | RSG . | LSG . | RPG . | LPG . | RSG . | LSG . | |
Group 1 | 2.0 ± 0.6 | 2.0 ± 0.8 | 3.3 ± 0.9 | 3.8 ± 1.2 | 4.5 ± 1.2 | 4.3 ± 1.3 | 5.5 ± 1.8 | 5.7 ± 1.8 | 0.50 ± 0.10 | 0.46 ± 0.09 | 0.46 ± 0.13 | 0.39 ± 0.09 |
Group 2 | 5.2 ± 1.1 | 4.8 ± 0.8 | 5.6 ± 1.4 | 6.3 ± 1.4 | 8.5 ± 1.9 | 9.2 ± 2.1 | 10.3 ± 3.3 | 10.6 ± 2.8 | 0.60 ± 0.14 | 0.60 ± 0.14 | 0.54 ± 0.08 | 0.47 ± 0.11 |
Control subjects | 4.6 ± 1.1 | 4.7 ± 1.0 | 5.7 ± 1.8 | 5.9 ± 1.6 | 8.8 ± 2.3 | 8.7 ± 2.1 | 10.3 ± 3.0 | 10.5 ± 2.8 | 0.64 ± 0.10 | 0.62 ± 0.10 | 0.55 ± 0.06 | 0.51 ± 0.10 |
. | 1st-min UR values . | 15th-min UR values . | ER values . | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
RPG . | LPG . | RSG . | LSG . | RPG . | LPG . | RSG . | LSG . | RPG . | LPG . | RSG . | LSG . | |
Group 1 | 2.0 ± 0.6 | 2.0 ± 0.8 | 3.3 ± 0.9 | 3.8 ± 1.2 | 4.5 ± 1.2 | 4.3 ± 1.3 | 5.5 ± 1.8 | 5.7 ± 1.8 | 0.50 ± 0.10 | 0.46 ± 0.09 | 0.46 ± 0.13 | 0.39 ± 0.09 |
Group 2 | 5.2 ± 1.1 | 4.8 ± 0.8 | 5.6 ± 1.4 | 6.3 ± 1.4 | 8.5 ± 1.9 | 9.2 ± 2.1 | 10.3 ± 3.3 | 10.6 ± 2.8 | 0.60 ± 0.14 | 0.60 ± 0.14 | 0.54 ± 0.08 | 0.47 ± 0.11 |
Control subjects | 4.6 ± 1.1 | 4.7 ± 1.0 | 5.7 ± 1.8 | 5.9 ± 1.6 | 8.8 ± 2.3 | 8.7 ± 2.1 | 10.3 ± 3.0 | 10.5 ± 2.8 | 0.64 ± 0.10 | 0.62 ± 0.10 | 0.55 ± 0.06 | 0.51 ± 0.10 |
Data are means ± SE. RPG, right parotid gland; LPG, left parotid gland; RSG, right submandibular gland; LSG, left submandibular gland.
References
Address correspondence to Dr. Chia-Hung Kao, Department of Nuclear Medicine, Taichung Veterans General Hospital, 160 Taichung Harbor Rd., Section 3, Taichung 40705, Taiwan. E-mail: [email protected].