The study cohort comprised 50 healthy volunteers (25 men, 25 women) with a mean of mobile phone use of seven years. Mobile phone use was assessed by questionnaire (more than half of the subjects used the mobile phone at least five times a day and only 2 % used the phone twice a day). A total of 40 participants (80%) used the right ear more frequently.
For collection of saliva samples the parotid glands were stimulated with citric acid.
No exposure details are available.
In subjects whose dominant side was the right, the overall mean parotid gland flow rate was significantly higher than the rate from the left parotid gland. In subjects whose dominant side was left, the overall parotid flow rate was almost identical to that of the right parotid gland. Overall, a 2.54-fold increase in salivary secretion rate was found between the dominant and non-dominant sides.
Lower total protein concentration was found in the dominant compared with the non-dominant mobile phone side among the right dominant cell phone users. However, no significant differences were found between the protein concentrations of the two parotid glands in subjects whose dominant side was left.
The authors conclude that parotid glands adjacent to the handheld mobile phone respond by elevated salivary rates and decreased protein secretion reflecting the continuous insult to the glands.