Research article

How well do adolescents recall use of mobile telephones? Results of a validation study

Imo Inyang^1,2 , Geza Benke^1,2 , Joseph Morrissey^3,4 , Ray McKenzie² and Michael Abramson^1,2

¹  Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Melbourne, Australia

²  Australian Centre for Radiofrequency Bioeffects Research, Melbourne, Australia

³  Corporate EME Research Laboratory, Motorola Florida Research Laboratories, Fort Lauderdale, Florida, USA

⁴  Department of Pharmaceutical Sciences, Nova South-eastern University, Fort Lauderdale-Davie, Florida, USA

author email corresponding author email

BMC Medical Research Methodology 2009, 9:36doi:10.1186/1471-2288-9-36

Published:	12 June 2009

Abstract

Background

In the last decade mobile telephone use has become more widespread among children. Concerns expressed about possible health risks have led to epidemiological studies investigating adverse health outcomes associated with mobile telephone use. Most epidemiological studies have relied on self reported questionnaire responses to determine individual exposure. We sought to validate the accuracy of self reported adolescent mobile telephone use.

Methods

Participants were recruited from year 7 secondary school students in Melbourne, Australia. Adolescent recall of mobile telephone use was assessed using a self administered questionnaire which asked about number and average duration of calls per week. Validation of self reports was undertaken using Software Modified Phones (SMPs) which logged exposure details such as number and duration of calls.

Results

A total of 59 adolescents participated (39% boys, 61% girls). Overall a modest but significant rank correlation was found between self and validated number of voice calls (ρ = 0.3, P = 0.04) with a sensitivity of 57% and specificity of 66%. Agreement between SMP measured and self reported duration of calls was poorer (ρ = 0.1, P = 0.37). Participants whose parents belonged to the 4^th socioeconomic stratum recalled mobile phone use better than others (ρ = 0.6, P = 0.01).

Conclusion

Adolescent recall of mobile telephone use was only modestly accurate. Caution is warranted in interpreting results of epidemiological studies investigating health effects of mobile phone use in this age group.