Intended for healthcare professionals


Effect of mass media campaign to reduce socioeconomic differences in women's awareness and behaviour concerning use of folic acid: cross sectional study

BMJ 1999; 319 doi: (Published 31 July 1999) Cite this as: BMJ 1999;319:291
  1. H E K de Walle, epidemiologista,
  2. K M van der Pal, epidemiologistb,
  3. L T W de Jong-van den Berg, professorc,
  4. W Jeeninga, epidemiologistd,
  5. J S A G Schouten, epidemiologistd,
  6. C M de Rover, epidemiologiste,
  7. S E Buitendijk, epidemiologistb,
  8. M C Cornel, epidemiologist (m.c.cornel{at}
  1. a Department of Medical Genetics, University of Groningen, NL-9713 AW, Groningen, Netherlands
  2. b Netherlands Organisation for Applied Scientific Research (TNO) Prevention and Health, PO Box 2215, NL-2301 CE, Leiden, Netherlands
  3. c Social Pharmacy and Pharmacoepidemiology, Groningen Institute for Drug Studies, NL-9713 AW, Groningen, Netherlands
  4. d Gemeenschappelylie Gezondheids Dienst, Midden-Brabant, PO Box 3024, NL-5003 DA, Tilburg, Netherlands
  5. e GGD Region Achterhock, Gezellenlaan 10, NL-7005 AZ, Doetinchem, Netherlands
  1. Correspondence to: Dr Cornel
  • Accepted 11 March 1999

In September 1995, a mass media campaign on the use of folic acid to reduce the risk of fetal neural tube defects started in the Netherlands.1 Special emphasis was placed on reaching women in low socioeconomic categories. We describe the effect of the campaign on awareness and use of folic acid in relation to socioeconomic status

Subjects, methods, and results

We measured the effect of the campaign by comparing two cross sectional studies—one conducted before the campaign and one conducted after the campaign We asked pregnant women in four regions of the Netherlands attending their first or second antenatal visit to fill out a questionnaire; all did so.

We took highest fulfilled education, a recognised indicator of socioeconomic status, and merged it into three levels: low, middle, and high. We used multivariate logistic regression to calculate adjusted odds ratios for high versus low education. The methodology has been described elsewhere.2

In both studies, 90% of the pregnancies were planned. After the campaign, 89.1% (1437/1612) of the respondents had heard about folic acid and 76.9% (1240) had heard about it before their pregnancy; the table shows how this is related to level of education.

Awareness and use of folic acid according to level of education before and after campaign. Values are number (percentage) unless stated otherwise

View this table:

In 1996, 53.5% (862) of all the respondents used folic acid (25.1% (411/1636) in 1995) in some part of the advised period (from 4 weeks before conception to 8 weeks after) and 21.0% (339) used it during the entire advised period (4.8% (78) in 1995). The adjusted odds ratios for education and use of folic acid decreased after the campaign but were not statistically significant (P=0.99 for some use and P=0.86 for use during entire period).

In 1996, 25.8% (146/565) of the women who knew about folic acid before their pregnancy and who were aware of the advised period did not take it (49.2% (184/374) in 1995). The reasons for not taking folic acid did not differ much before and after the campaign. The main reasons were being pregnant already; disliking taking drugs during pregnancy; eating healthy food, or not thinking about the possibility of taking folic acid. Reasons for not taking folic acid were not associated with level of education.

After the campaign, of the informed women who did not take folic acid, 37.8% (28/74) of high educated women versus 54.5% (60/110) of low educated women (P=0.02) would consider taking folic acid in a next pregnancy.

Finally, we sought the opinion of women who did not take folic acid about fortification of food with folic acid (only 1996 survey) Overall, 63.6% (311/489) preferred to take folic acid in food rather than by tablet; this was not associated with level of education.


After the 1995 campaign in the Netherlands, awareness and use of folic acid had increased considerably. Before the campaign an increase of the knowledge to match the level of knowledge of adverse effects of alcohol and smoking was considered adequate—that is, 70% of women planning a pregnancy should know about the advice. The result of our study (in 1996, 76.9% had heard about folic acid before pregnancy) meets this criterion and is thus satisfactory. However, odds ratios for socioeconomic differences in awareness and use of folic acid have not significantly decreased.

For low educated women an increase in the percentage aware of folic acid before pregnancy of 36% was achieved, whereas the increase for high educated women was 31%. The increase in use of folic acid was 29% for low educated women and 31% for high educated women, and for use during the entire advised period the increase was 15% for low educated women and 22% for high educated women. Thus it is clear that low educated women have profited from the campaign, but that socioeconomic differences remained.


This study was carried out by the Netherlands Organisation for Applied Scientific Research (TNO) Prevention and Health in cooperation with the University of Groningen (Department of Social Pharmacy and Pharmacoepidemiology and the Department of Medical Genetics), Municipal Health Service (Midden-Brabant), and Municipal Health Service's Achterhoek region.

Contributors: MCC, LTWdJ-vdB, and SEB initiated the studies. JSAGS was one of the initiators for focusing on socioeconomic status. KMvdP was involved in the daily coordination of the studies. HEKdW, KMvdP, WJ, and CdR took care of the data collection. HEKdW and KMvdP analysed the data. HEKdW wrote the paper and LTWdJ-vdB and MCC edited the paper. MCC, LTWdJ-vdB, and HEKdW will act as guarantors for the paper.


  • Funding This study was subsidised by the Ministry of Health, Welfare and Sports after approval of the committee for socioeconomic health inequalities.

  • Competing interests None declared.


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