Medical/biological study (experimental study)

Effects of RF exposure of teenagers and adults by CDMA cellular phones med./bio.

By: Nam KC, Kim SW, Kim SC, Kim DW

Published in: Bioelectromagnetics 2006; 27 (7): 509-514

Aim of study (acc. to editor)

To study the effects of CDMA mobile phones on different physiological parameters in teenagers and adults.

Background/further details

Two groups consisting of 21 teenagers (15.9 +/- 2.3 years) and 21 adults (30.9 +/- 5.6 years) were exposed. Additionally, 42 subjects were regrouped to 23 male and 19 female subjects in order to see any discrepancy in the physiological parameters between the sexes.

Endpoint

different physiological parameters (blood pressure, heart rate, respiration, skin resistance)

Exposure

- CDMA
- mobile communications
- digital mobile phone

Exposure	Parameters
Exposure 1: 835 MHz Modulation type: CW Exposure duration: continuous for 30 min	power: 300 mW (maximum transmission power) SAR: 1.6 W/kg

Exposure 1

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Exposure duration	continuous for 30 min

Modulation

Modulation type	CW
Additional info	continuous clipped sine waves

Exposure setup

Exposure source	cellular phone CDMA, in test mode
Chamber	Subjects rested on the experimental bed in a supine position.
Setup	A headphone was modified to install a folder-type cellular phone on the left side of the head. The lower part of the cellular phone with buttons was wrapped up with 5 mm thick insulating material in order to prevent the subjects from feeling the generated heat.
Sham exposure	A sham exposure was conducted.
Additional info	Real and sham exposures were performed in a double blind test. However, the exposure sequence was not randomized, sham exposures were performed first in order to avoid interference with previous real exposures. Between sham and real exposures, the subject took a 30 min break.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	300 mW	-	-	-	maximum transmission power
SAR	1.6 W/kg	-	-	-	-

Exposed system:

human
partial body: head (left side)

Methods Endpoint/measurement parameters/methodology

effects on the cardiovascular system: systolic and diastolic blood pressure, heart rate
respiratory rate; skin resistance

Investigated system:

investigation on living organism

Investigated organ system:

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

In the teenager group, the physiological parameters did not reveal any significant changes regardless of real or sham exposure and exposure duration, but the skin resistance decreased significantly under real exposures. This decrease indicates that radiofrequency electromagnetic fields might stimulate teenager's autonomic nervous system, resulting in sweat secretion. Ten minutes after the exposure termination, the skin resistance returned to the initial resting value.
In contrast, there were no significant changes in the physiological parameters in the adult group, regardless of the real or sham exposure and exposure duration.
For the regrouped 23 male and 19 female subjects, all the parameters were unaffected during the exposure except for decreased skin resistance of the male subjects.

Study character:

medical/biological study
experimental study
full/main study
provocation study
double-blind study

Study funded by

Hankyong National University, Korea
Ministry of Health and Welfare, Korea

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