Study type: Medical/biological study (experimental study, observational study)

Melatonin metabolite excretion among cellular telephone users. med./bio.

Published in: Int J Radiat Biol 2002; 78 (11): 1029-1036

Aim of study (acc. to author)

To evaluate the relationship between cellular telephone use and excretion of the melatonin metabolite 6-hydroxymelatoninsulfate in two populations of male electric utility workers (Study 1, n=149; Study 2, n=77).

Background/further details

Subjects collected urine samples and recorded cellular telephone use over 3 consecutive workdays. Personal 60 Hz magnetic field and ambient light exposures were characterized on the same days.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: total daily exposure of 1-10, 11-25, or >25 min/day for 3 days
-
Exposure 2: 60 Hz
Exposure duration: not specified

Exposure 1

Main characteristics
Frequency
Type
Exposure duration total daily exposure of 1-10, 11-25, or >25 min/day for 3 days
Exposure setup
Exposure source
Additional info Cellular phone use was assessed and categorized by asking participants to record the amount of time spent using a cellular phone at work on each of the three days of participation.
Parameters

No parameters are specified for this exposure.

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Exposure duration not specified
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 nT mean measured - ± 20 nT
magnetic flux density 110 nT mean measured - ± 20 nT
magnetic flux density 500 nT mean measured - ± 83 nT

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

No change in 6-hydroxymelatoninsulfate (6-OHMS) excretion was found among those with daily cellular telephone use for more than 25 min in study 1 (5 worker-days). Study 2 workers with more than 25 min cellular telephone use per day (13 worker-days) had lower mean nocturnal 6-OHMS concentrations and overnight 6-OHMS excretion compared with those without cellular telephone use. There was also a linear trend of decreasing mean nocturnal 6-OHMS/creatinine concentrations and overnight 6-OHMS excretion across categories of increasing cellular telephone use.
A combined effect of cellular telephone use and occupational 60-Hz magnetic field exposure in reducing 6-OHMS excretion was also revealed in Study 2.
Conclusion: Exposure-related reductions in 6-OHMS excretion were found in Study 2, where daily cellular telephone use of more than 25 min was more prevalent. Prolonged use of mobile phones may lead to reduced melatonin production, and elevated 60 Hz magnetic field exposures may potentiate the effect.

Study character:

Study funded by

Related articles