Epidemiological study (observational study)

Prenatal and postnatal exposure to cell phone use and behavioral problems in children.

Published in: Epidemiology 2008; 19 (4): 523-529

Aim of study (acc. to author)

The association of cell phone use during pregnancy and during early childhood with behavioral problems in children was investigated in a cohort study in Denmark.

Further details

Behavioral problems in 7-year old children were assessed using the Strenghts and Difficulties Questionnaire. Prenatal exposure was defined as the use of a cellular phone by the mother during the pregnancy, postnatal exposure was defined as the current use of cell phones by the children.

Endpoint/type of risk estimation

Type of risk estimation:
  • incidence
(odds ratio (OR))

Exposure

Assessment

  • questionnaire: cell phone use during pregnancy (number of times spoken per day, proportion of time the phone was on, use of hands-free equipment, location of phone when not in use), for children: current use of cellular and other wireless phones

Exposure groups

Reference group 1 no prenatal exposure
Group 2 prenatal exposure
Reference group 3 no postnatal exposure
Group 4 postnatal exposure
Reference group 5 no prenatal and postnatal exposure
Group 6 prenatal and postnatal exposure
Reference group 7 prenatal exposure, times spoken per day: 0 - 1
Group 8 prenatal exposure, times spoken per day: 2 - 3
Group 9 prenatal exposure, times spoken per day: ≥ 4
Reference group 10 prenatal exposure, percentage of time turned on: 0
Group 11 prenatal exposure, percentage of time turned on: < 50
Group 12 prenatal exposure, percentage of time turned on: 50 - 99
Group 13 prenatal exposure, percentage of time turned on: 100

Population

  • Group:
    • children
    • children in utero
  • Age: 7 yr
  • Characteristics: cohort of mothers and newborns, born between 1997 and 1999, follow-up at the age of 7 years
  • Observation period: November 2006
  • Study location: Denmark
  • Data source: Danish National Birth Cohort

Study size

Participants 13,159
Participation rate 65
Statistical analysis method:
  • logistic regression
( adjustment: )

Conclusion (acc. to author)

About 11 % of the children were prenatally and postnatally exposed to cell phones whereas nearly half of the children had neither prenatal nor postnatal exposure. About 90 % of the children were reported to have no behavioral problems.
Prenatal and postnatal exposure to cell phones was associated with overall behavioral problems in children (OR 1.80; CI 1.45-2.23). The authors concluded that these results should be interpreted with caution. The observed association are not necessarily causal and may be due to factors not investigated in this study.

Study funded by

  • Danish Medical Research Council (DMRC), Denmark
  • Lundbeck Foundation, Denmark
  • Research Innovation Seed Grant
  • UCLA School of Public Health, USA

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