title: Trends in cell phone use among children in the Danish national birth cohort at ages 7 and 11 years.
abstract: We prospectively examined trends in cell phone use among children in the Danish National Birth Cohort. Cell phone use was assessed at ages 7 and 11 years, and we examined use patterns by age, by year of birth, and in relation to specific individual characteristics. There was an increase in cell phone use from age 7 (37%) to 11 years (94%). There was a clear pattern of greater reported cell phone use among children at age 7 years with later birth year, but this trend disappeared at age 11. Girls and those who used phones at age 7 talked more often and for longer durations at age 11 years. Low socio-economic status and later year of birth were associated with voice calls at age 7 but not at age 11 years. At age 11 most used cell phones for texting and gaming more than for voice calls. Further, children who started using cell phones at age 7 years were more likely to be heavy cell phone voice users at age 11 years, making early use a marker for higher cumulative exposure regardless of year of birth. As cell phone technology continues to advance, new use patterns will continue to emerge, and exposure assessment research among children must reflect these trends.
authors.affiliation: Department of Epidemiology, School of Public Health, University of California, Los Angeles, California, USA.|Department of Public Health, Danish Epidemiology Science Centre, Aarhus University, Aarhus, Denmark.
authors.forename: Madhuri
authors.initials: M
authors.lastname: Sudan
authors.affiliation: Department of Public Health, Danish Epidemiology Science Centre, Aarhus University, Aarhus, Denmark.
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
authors.affiliation: Department of Public Health, Section for Environment, Occupation, and Health, Aarhus University, Aarhus, Denmark.
authors.forename: Torben
authors.initials: T
authors.lastname: Sigsgaard
authors.affiliation: Department of Epidemiology, School of Public Health, University of California, Los Angeles, California, USA.
authors.forename: Leeka
authors.initials: L
authors.lastname: Kheifets
mesh_terms: D000367:Age Factors; D040421:Cell Phone / Q000706:statistics & numerical data* / Q000639:trends; D000075782:Cell Phone Use / Q000706:statistics & numerical data* / Q000639:trends; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009035:Mothers; D012044:Regression Analysis; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires