Epidemiological study (observational study)

Prenatal and Postnatal Cell Phone Exposures and Headaches in Children epidem.

By: Sudan M, Kheifets L, Arah O, Olsen J, Zeltzer L

Published in: Open Pediatr Med Journal 2012; 6: 46-52

Aim of study (acc. to author)

The association of mobile phone use during pregnancy and during early childhood and headaches in children was investigated in a cohort study in Denmark.

Further details

When the children reached seven years of age, mothers were invited to complete a questionnaire that focused on the child's exposures (e.g., maternal mobile phone use during pregnancy, child's mobile phone use at the age of 7 years), lifestyle, and health problems (e.g., migraine or 'often complaints of headaches, stomach aches or sickness').

Endpoint/type of risk estimation

migraine, headaches, headache-related symptoms (stomach aches or sickness)

Exposure

- mobile communications
- mobile phone
- personal

Assessment

questionnaire: mobile 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 mobile phone use

Exposure groups

Group	Description
Reference group 1	no exposure
Group 2	prenatal exposure
Group 3	postnatal exposure
Group 4	prenatal and postnatal exposure

Population

Group:
- children
- children in utero
Age: ≥ 7 years
Characteristics: cohort of mothers and newborns, born between 1996 and 2002, follow-up at the age of 7 years
Observation period: until April 2010
Study location: Denmark
Data source: Danish National Birth Cohort
Exclusion criteria: twins or triplets

Study size

Type	Value
Total	91,256
Participants	59,975
Participation rate	66 %
Evaluable	52,680

Statistical analysis method:

logistic regression

(adjustment:

socioeconomic status
maternal age, history of migraines, feelings of worry, burden, and stress during pregnancy; child's exposure to tobacco smoke, sex

)

Results (acc. to author)

According to mothers' reports, 39% out of 52,680 children were exposed prenatally, and 36% used a mobile phone at age seven years (postnatal exposure), but less than 1% used it more than one hour per week. Twenty percent of children were exposed only prenatally, 16% only postnatally, 19% both prenatally and postnatally, and 40% had no reported mobile phone exposure.
Children with mobile phone exposure had an increased risk of migraines and headache-related symptoms than children with no exposure (OR for migraine 1.30 (CI 1.01-1.68); OR for headache-related symptoms 1.32 (CI 1.23-1.40) for children with both prenatal and postnatal exposure).
The authors concluded that in this study mobile phone exposure was associated with headaches in children, but the association may not be causal given the potential for uncontrolled confounding and misclassification in observational studies such as the present study.

Limitations (acc. to author)

The results should be interpreted with caution due to limitations in exposure and outcome assessment. Additional possible confounders such as watching television, playing video games, and use of computers were not covered by the questionnaire.

Study funded by

Danish Medical Research Council (DMRC), Denmark
Lundbeck Foundation, Denmark
National Institutes of Health (NIH), Maryland, USA
Netherlands Organisation for Scientific Research (NWO; Nederlandse organisatie voor Wetenschappelijk Onderzoek); The Netherlands

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