Unité mixte de recherche épidémiologique et de surveillance transport travail environnement, (UMR T9002 Inrets/UCBL/InVS), Domaine Rockefeller, 18, avenue Rockefeller, Université Lyon1, 69373 Lyon cedex 08, Université Lyon F69000 Lyon Inrets F69500 Bron, Centre international de recherche sur le cancer (CIRC), 145, cours Albert Thomas, IARC, F69008 Lyon
- Key words: France, Interphone, mobile phone, questionnaire, validation study
- DOI : 10.1684/ers.2007.0035
- Page(s) : 101-9
- Published in: 2007
As part of the European INTERPHONE study, validation studies evaluated subjects’ short-term recall of mobile telephone use. This publication presents the results of the French validation study, which included 73 volunteer subjects. After participants consented in writing, mobile telephone operators in France provided information on their actual use (number and duration of calls) for a six-month period (from 01-10-2000 through 30-03-2001). The INTERPHONE questionnaire was administered in June 2001 and again in June 2002. At enrolment subjects were not told that they would be questioned later on their mobile telephone use. The analysis compared the mean use reported with actual use provided by the operators (t test for paired samples) and used logistic regression to evaluate various factors that might explain the discrepancies. While recall of the number of calls was good (mean reported number: 195.6/month- mean real number: 162.6/month, NS), subjects considerably overestimated the average duration of calls (mean reported duration: 986 min/month/mean real duration: 377 min/month, p<0.01). Women overestimated more than men. These findings were similar in all age categories and socioeconomic groups, except office workers and craftsmen. Estimating the duration of use by call or by day (instead of by week or month) is one explanatory factor for these discrepancies. Overestimation appeared to decrease over time and was somewhat lower in 2002 than in 2001, although it was significant both years. The correlation between the real monthly number of calls and the real monthly duration of calls, as measured by the operators, is good. The number of calls appears to be a more reliable indicator of mobile telephone use than their duration.