Epidemiological study (observational study)

Use of mobile and cordless phones and change in cognitive function: a prospective cohort analysis of Australian primary school children epidem.

By: Bhatt CR, Benke G, Smith CL, Redmayne M, Dimitriadis C, Dalecki A, Macleod S, Sim MR, Croft RJ, Wolfe R, Kaufman J, Abramson MJ

Published in: Environ Health 2017; 16: 62

A prospective cohort study was conducted in Australia to investigate associations between the use of mobile phones and cordless phones among primary school children and effects on their cognitive function.

Cognitive function was assessed by a computerized psychometric CogHealth test and the Stroop test.
Baseline results of this study are published by Redmayne et al. (2016)

questionnaire: parents: children's mobile and cordless phone use, number of calls and SMS per week, duration of calls; child: mobile phone ownership and use, laterality of use, handedness

Group	Description
Reference group 1	no change or decrease of mobile phone use between baseline and follow-up
Group 2	increase of mobile phone use between baseline and follow-up
Reference group 3	no change or decrease of cordless phone use between baseline and follow-up
Group 4	increase of cordless phone use between baseline and follow-up

Statistical analysis method:

(adjustment:

age
sex
socioeconomic status
ethnicity, lag time between baseline and follow-up, handedness, total screen time weekly (gaming and computer/Internet use)

)

Of 412 children, a larger proportion of them used a cordless phone (76% at baseline and follow-up), compared to a mobile phone (parental report: 31% at baseline and 43% at follow-up; children reports: 57% at baseline and 68% at follow-up). The median numbers of voice calls weekly for mobile phone and cordless phone were both 2 at baseline, and 2.5 and 2 at follow-up, respectively.
Of 26 comparisons of changes in cognitive outcomes, four demonstrated significant associations. The increase in mobile phone usage was associated with a reduced response time for response inhibition, a reduced number of total errors for spatial problem solving and increased response time for a Stroop interference task. Except for a reduced detection task accuracy, the increase in cordless phone usage had no effect on the changes in cognitive outcomes. Due to the small numbers of mobile and cordless phone calls, the observed changes in cognitive tasks could be pure chance findings.
The authors conclude that they found limited evidence that change in mobile phone use or cordless phone use in primary school children was associated with change in cognitive function.

Exposure assessment of phone use is based on parental and childrens' reports.

Cabré-Riera A et al. (2021): Association between estimated whole-brain radiofrequency electromagnetic fields dose and cognitive function in preadolescents and adolescents
Redmayne M et al. (2016): Use of mobile and cordless phones and cognition in Australian primary school children: a prospective cohort study
Calvente I et al. (2016): Does exposure to environmental radiofrequency electromagnetic fields cause cognitive and behavioral effects in 10-year-old boys?
Guxens M et al. (2016): Outdoor and indoor sources of residential radiofrequency electromagnetic fields, personal cell phone and cordless phone use, and cognitive function in 5-6 years old children
Schoeni A et al. (2015): Memory performance, wireless communication and exposure to radiofrequency electromagnetic fields: A prospective cohort study in adolescents
Thomas S et al. (2010): Use of mobile phones and changes in cognitive function in adolescents
Abramson MJ et al. (2009): Mobile telephone use is associated with changes in cognitive function in young adolescents
Preece AW et al. (2005): Effect of 902 MHz mobile phone transmission on cognitive function in children
Haarala C et al. (2005): Electromagnetic field emitted by 902 MHz mobile phones shows no effects on children's cognitive function