Authors
Jarupat S, Kawabata A, Tokura H, Borkiewicz A.

Eight young female volunteers were tested in a climatically-controlled chamber for the effect of RF radiation on their secretion of salivary melatonin. They entered the chamber at 10.00 a.m. Light was controlled to simulate normal variation at different times of the day. The period from 10.00 to 19.00 was used as a time of adaptation. From 19.00 to 01.00 hrs the subjects used a cell phone for 30 minutes each hour. The phone frequency was 1900 MHz and the whole-body average SAR was 0.453-0.680 W/kg. Each subject had an exposure day and a sham-exposure day, though they did not know when they were exposed. Saliva was collected for 10 minutes at 19.00 and again at 02.00, and was later analyzed for melatonin levels.

There was no difference between the sham and exposed melatonin levels at 19.00, but there was a statistically significant difference in the 02.00 levels. The values at 19.00 were 31.16 pg/ml without the usage and 29.28 with the usage. At 02.00 the values were 68.83 and 38.42 pg/ml respectively (personal communication of the lead author).

The number of subjects in this study was small. The authors caution that more data is needed, particularly with "more careful control of the environmental factors".