Inyang I, Benke GP, McKenzie R, Wolfe R, Abramson MJ. A new method to determine laterality of mobile telephone use in adolescents. Occup Environ Med. Dec 2, 2009. Ahead of print.
Most studies of mobile phone use and brain tumours have been conducted among adults and have been based on self-reported mobile phone use data from questionnaires. It has been shown in validation studies that data from questionnaires are of limited precision. There are no published studies validating questionnaire self-reports of mobile phone laterality in adolescents.
The objectives of this study were to determine laterality using hardware modified phones (HMPs) and to apply these devices in adolescents to validate self-reported data on laterality of mobile phone use, as well as on the number and duration of calls.
The HMPs employed in this study recorded date and time, number and duration of calls, transmit power levels during calls and orientation of phone to the head, every 2 seconds. A total of 30 students between 13 and 15 years old (20 boys and 10 girls) completed exposure questionnaires and used the hardware modified phones for 7 consecutive days following completion of the questionnaire. The HMP measurements were then compared with questionnaire data on laterality and with estimated typical weekly phone use.
Results and Interpretation
A total of 455 calls were monitored. The agreement between self-reports and hardware modified phone assessments was fair for laterality (kappa = 0.3, 95% confidence interval = 0.0, 0.6) and numbers of calls (intraclass correlation coefficient = 0.38, 95% confidence interval = 0.07, 0.69), but poor for duration of calls (intraclass correlation coefficient =0.01, 95% confidence interval = 0.00, 0.37). Similar results for number and duration of calls were obtained in validation studies with software modified phones in adults.
The results suggest limited validity of adolescent self-reported laterality of mobile phone use, number and duration of calls. Epidemiological studies based on self-reported mobile phone use may underestimate associations with health effects in adolescents.