Thomas S, Heinrich S, Kühnlein A, Radon K. The association between socioeconomic status and exposure to mobile telecommunication networks in children and adolescents. Bioelectromagnetics. Jul 13, 2009 Ahead of print.
Mobile phone use is especially high among young people. An estimated 94% of German adolescents own a mobile phone, as do 44% of youth between the ages of 6 and 13 years. Previous studies have investigated different predictors of mobile phone use, such as age and sex. However, few have studied the association with socioeconomic status (SES). Results of the association between SES and mobile phone ownership have been conflicting, while consistent evidence exists that adolescents with lower SES use their mobile phones longer and more frequently than those with a higher SES. Since mobile phone exposure may have a negative impact on health, identifying groups with highest use may be important in directing preventive measures.
The objective of this study was to investigate the association between SES and self-reported as well as measured exposure to mobile telecommunication networks in children and adolescents living in Bavaria (Southern Germany).
The study took place between 2006 and 2008 in 4 Bavarian cities. Participants were randomly recruited from registration offices in the 4 cities. Overall, 1,498 children (aged 8-12 years) and 1,524 adolescents (aged 13-17 years) were included in the study, with a response rate of 52%. Adolescents, and children and their parents, completed a computer assisted personal interview with questions on SES, mobile phone and cordless phone use, and potential confounding variables (age, sex, social support). Children’s SES was defined based on parental education, job, and household income while adolescent SES was based on their own level of education and their parents’ job position. For both children and adolescents, SES was classified as low, medium, or high. After the interview, children and adolescents obtained a mobile phone dosimeter for a 24h measurement. Measurements were made every second and only exposure during waking hours was considered.
Children, younger adolescents, and girls were more willing to participate in the study. Only 3% of the children and 1% of adolescents had a low SES. According to self-reported phone use, half of participating children and 92% of adolescents owned a mobile phone, although most (96% of children and 77% of adolescents) did not use their phone daily. Children rarely used text messages, compared to 36% of adolescents who sent text messages nearly daily. All measured exposures to mobile telecommunication networks were far below the ICNIRP reference level and ranged from a mean of 0.13-0.92 among all subjects. Among children, the proportion of mobile phone owners was highest in the lowest SES group, while all adolescents owned a mobile phone regardless of SES. A significant inverse association between SES and duration of daily use was seen for children and adolescents. Sending text messages and measured exposure levels did not differ significantly between the 3 status groups.
Interpretation and Limitations
The higher ownership and use of mobile phones among adolescents and children of low SES is in accordance with previous studies and may be because in Germany, mobile phones are still considered a symbol of high SES status. It may also be that parents with a low SES are less concerned about possible adverse health effects of mobile phone use than are parents with high SES, which is supported by a survey of parents of children in the current study. The major limitation of this study was the small number of participants with low SES, which may represent differential participation by SES. Also, income information was missing for 252 children, and was imputed, which may have caused bias.
An association between SES and self-reported exposure was seen while an association between SES and measured exposure was not.