DNBC Interviews 1 - 4

The four computer-assisted telephone interviews were carried out in gestational week 12 and 30 as well as when the child was 6 and 18 months old. Each interview lasted approx. 10-15 minutes.

Respons rates were high for the first two interviews, but dropped as the child got older and the mothers returned to work. 

Data sweep Invited Responders Response rate Codebook
Enrolments 101,042
Interview 1 92,892 92% Yes, DK and English
Interview 2 87,802 87% Yes, DK and English
FFQ 72,821 72% pdf of questionnaire
Interview 3 70,292 69% Yes, DK and English
Interview 4 66,764 65% Yes, DK and English

Focus areas in the two pre-natal questionnaires

  • Earlier pregnancies and childbirths, IVF treatment
  • Health in general and during pregnancy as well as medical pregnancy examinations
  • Drug use
  • Work environment
  • Home environment
  • Diet - vitamins - dietary supplements
  • Use of alcohol and tobacco
  • Sleep
  • Exercise
  • Oestrogen
  • Socio-economic variables
  • Psycho-social stress

Focus areas in the two post-natal questionnaires

  • Child diet
  • Child development
  • Child vaccinations
  • Follow-up on pre-natal questions 

Code books for all four interviews

English version of code books for interviews 1 - 4

Danish version of code books for interviews 1 - 4

The interviews were carried out under DNBC supervision

The interviewer guides - in Danish - were drafted by DNBC supervisors in collaboration with the phoning companies. The guides contain guidelines for the interviewer for every question.