Beta-trace protein regulates sleep through the prostaglandin D system and is present in high concentration in the cerebrospinal fluid.
The beta-trace protein levels in the blood were investigated in 40 volunteers aged 18-30 years who were exposed to a 890 MHz GSM signal for 30 minutes (for more details see Söderqvist et al, 2009a). Four blood samples were drawn at arrival at the hospital, after 30 min rest, immediately after 30 min exposure and 60 min after ending of exposure.
Furthermore, the serum beta-trace protein levels were determined in 22 volunteers in blood samples drawn at the same time intervals as in the exposure group to test the stability of the protein before analysis (no control group for exposure).
In addition, all 62 participants filled in a questionnaire on the use of wireless phones (see Söderqvist et al, 2009b).
|Group 1||group exposed to 890 MHz GSM signal for 30 min|
|Group 2||mobile phone and DECT phone use|
|Group 3||mobile phone use|
|Group 4||analog mobile phone use|
|Group 5||digital mobile phone use|
|Group 6||UMTS mobile phone use|
|Group 7||DECT phone use|
No statistically significant change of beta-trace-protein level compared to prior exposure was found in the blood of 40 volunteers exposed to 890 MHz GSM signal for 30 min. Among the volunteers to test the protein stability, the level of beta-trace protein increased significantly over time, probably due to a relaxed situation.
The analysis of the questionnaires showed that the concentration of beta-trace protein decreased with increasing number of years of combined use of mobile phones and cordless phones (beta coefficient -0.32, CI -0.60 to -0.04). The concentration of beta-trace protein decreased also with increasing number of cumulative hours of combined use of mobile phones and cordless phones, however not statistically significant (beta coefficient -0.17; CI -0.41 to 0.07).
The authors conclude that exposure to mobile phones and cordless phones may downregulate the synthesis of beta-trace protein which might be involved in sleep disturbances.
The results must be interpreted with caution since the use of mobile phones and cordless phones were self-reported by the voluteers. Awareness of exposure condition in the experimental study may have influenced beta-trace-protein concentrations.