Long-term, frequent use of cellphones may raise the risk of developing non-malignant tumours in the parotid glands, which are in the jaw area near the ear.
The finding comes from a study in Israel, where cellphone use is particularly high.
Despite concern about the potential effects of the electromagnetic radio frequency fields emitted by cellphones, few studies have been able to establish an association with any health problems.
Most research has been limited to brain tumours, however, and data for long-term cellphone use are lacking, Dr. Siegal Sadetzki and associates note in the American Journal of Epidemiology. The proximity of the parotid glands to the electromagnetic field emitted during cellphone use may make them more susceptible to any adverse effects.
Sadetzki, at the Chaim Sheba Medical Centre in Tel Hashomer, and her associates surveyed otolaryngology departments in Israel to identify adults diagnosed with benign or malignant parotid gland tumours between 2001 and 2003. Their study included 460 cases and 1 266 matched individuals without parotid tumours.
Regular cellphone use (more than one call per week) for at least five years was associated with an increased risk of about 50 percent for parotid tumours.
The increased risk was statistically significant for benign tumours and for cellphone use in rural areas where average output power of phones tends to be higher because base stations are located far apart, the investigators note.
They note, however, that their findings are insufficient to establish that cellphones are the cause of the parotid tumours.