Effect of age on variability of parotid salivary gland flow rates over time

Background: although several reports indicate that qualitative and quantitative assessments of parotid salivary function are age-stable in healthy adults, there have been no studies of the influence of age on the variability of repeated parotid now rates. Objective: to examine the influence of age on the variability of repeated parotid flow rates in unmedicated, healthy adults. Materials and methods: we assessed unilateral unstimulated and 2% citrate-stimulated parotid flow rates and collected responses to a five-item subjective xerostomia questionnaire in 14 subjects aged 20-40 years and 14 subjects aged 60-80 years. All subjects were healthy and unmedicated. We collected saliva and asked subjects to complete the questionnaire at baseline, 1 h and 2 h. Results: unstimulated and stimulated parotid flow rates were similar at each time point in young and older subjects, and remained stable over the collection period. There were no differences in the standard deviations of the three collections of unstimulated and stimulated flow rates between young and older subjects. There were no differences between questionnaire responses between the two groups, and no change in response over time. Conclusions: there is no increased age-related variability in parotid salivary flow rates over repeated measures. Stimulated parotid flow rates are stable over 2 h in healthy people, and are similar in young and older individuals. These results suggest that parotid glands have a large secretory reserve.