Introduction
Ten years have passed since recommendations were made by Departments of Health in Ireland, the United States, the United Kingdom and a number of other countries on the importance of folic acid in the prevention of NTD^1,2,3. Although the initial approach of promoting increased dietary folic acid met with some success in the mid-1990s, it was considered insufficient by the United States as the sole primary preventive means of reducing the birth prevalence of NTD. Consequently they adopted mandatory fortification of staple foodstuffs with folic acid in 1998. This measure has also been strongly considered and hotly debated in European countries. In the United Kingdom, the Committee on the Medical Aspects of Food (COMA) recommendationiv that there should be mandatory fortification has not been adopted by the government. Likewise, in Ireland the Food Safety Authority of Ireland (FSAI) recommended in 1998 that fortification was complimentary to folic acid promotional campaignsv. However, there have been no moves towards food fortification. Ireland is therefore reliant on folic acid promotional campaigns aimed at women of childbearing age to reduce the NTD birth prevalence rate. It is questionable if enough women can be encouraged to take folic acid to a level that will reduce NTD. We examined trends in folic acid knowledge and uptake among pregnant women over a seven year period (1996-2002) in the eastern region of Ireland.

Methods
In the months July-September each year from 1996-2002, three hundred consecutive women attending their first antenatal booking appointment in each of the maternity hospitals (one hundred in each) in Dublin were surveyed. These hospitals provide public ante-natal services to approximately 1.4 million people, who are resident in counties Dublin, Wicklow, Kildare in the Eastern Region of Ireland. Only women who were resident in the region for two years at least were included. An interviewer administered questionnaire was used. Respondents were asked if they had heard of folic acid, if they knew why folic acid was important, if they were advised to take folic acid prior to pregnancy and the source of this advice, and whether they had taken folic acid before or during their current pregnancy. Demographic and obstetric variables examined included age, marital status, planning of pregnancy and number of previous pregnancies. Respondents were also asked if they were General Medical Services (GMS) patients; GMS patients are entitled to all medical care free of charge, including prescription drugs. Approximately one third of the Irish population are GMS patients, eligibility for which is based primarily on low income. We used GMS status as a proxy measure of poorer socio-economic status compared with non GMS, who are relatively more affluent. The data were entered on Epi Info 6.04avi software and Chi-square tests were used to examine associations of demographic and obstetric variables during the six year study period. Trend analysis for the six year period was carried out using Chi square for trend on PEPI softwarev², on the following five variables

1. having heard of folic acid
2. knowing that it could prevent NTD/spina bifida
3. having been advised to take it before their pregnancy
4. having taken it peri-conceptionally
5. having taken it during pregnancy.

Results
The response rate in each year ranged from 89% to 99%, but was over 95% in six of the seven years of the study. The demographic and obstetric characteristics of respondents in each year are presented in Table 1. Similar proportions in each year were aged 30 years or over. Likewise, the proportion who were GMS patients varied little from year to year. Less than half of pregnancies each year were planned. A higher proportion of respondents in 1996 were married compared with subsequent years and higher proportions were primigravida in 1997 and 1998.

Figure: Folic Acid Knowledge and Use 1996 - 2002

The Figure shows a continuous rise in the percentage of women who had heard of folic acid and knew that it could prevent NTD during the seven year period, stabilizing in 2001-2002. The proportion of women who were advised to take folic acid before they became pregnant rose between 1996 and 1998, then stabilized before rising sharply from 2000-2002. The proportion of respondents who took folic acid peri-conceptionally increased similarly until 1998, stabilizing thereafter. The percentage of women who took folic acid during pregnancy, rose from 14% in 1996 to 83% in 2002. The Chi-square test for trend was highly significant for all five variables (Table 2).

Discussion
This study monitored sequential yearly changes and trends in folic acid knowledge and uptake in an Irish antenatal population from 1996-2002. The demographic and obstetric characteristics of respondents in each year were essentially similar. The proportion of married women and primigravida changed over the period, reflecting a changing social trend in motherhood in Ireland. However, marital status and numbers of previous pregnancies are not significant factors in determining womens knowledge or use of folic acidv³. It is likely therefore, that any changes in folic acid knowledge and uptake during the period were real and not as a result of different demographic or obstetric characteristics in the samples during the study years.

At present, there is no compulsory fortification of staple foods with folic acid in Ireland. There is thus sole reliance on the promotion of folic acid supplements as the primary preventive means of reducing the birth prevalence of NTD. Our study shows a rising trend in awareness of folic acid and knowledge of its importance in preventing NTD. However, this is almost at saturation point following significant rising trends in the past seven years. The rapid rise in 2001/2002 in the proportion of respondents who reported being advised to take peri-conceptional folic acid is probably a reflection of a major folic acid promotional media based campaign undertaken by the Irish Department of Health & Children in late 2000 and early 2001. In addition, the fact that 83% of respondents took folic acid during pregnancy in 2002 underlines that women are acting on their knowledge, albeit rather late to be of benefit. Nevertheless, by 2002 no more than a quarter took folic acid peri-conceptionally, showing only minor changes during the previous three years. Five or six years ago, one could have argued that insufficient knowledge was a major factor in low folic acid uptake. However, this study shows that such reasoning is no longer valid and provides evidence that promotion of dietary folic acid supplements is likely to prove ineffective as the sole means of preventing NTD.

Planning of pregnancy is the crucial determinant⁸ in peri-conceptional uptake of folic acid. Unless their pregnancy is planned women of child-bearing age, no matter how well informed they are about folic acid, are unlikely to take it routinely on a daily basis. In fact between 1996and 2001only 44% of pregnancies were planned. Despite the inclusion of sexual health in school curricula and the advances in, and availability of, contraception young single women remain unlikely to have a planned their pregnancy. For these women folic acid is probably a low priority.

Current levels of peri-conceptional folic acid consumption are unlikely to impact significantly on the birth prevalence of NTD in Ireland. Data from the Dublin EUROCAT registryx in the eastern region of Ireland shows that the NTD birth prevalence rate has not changed appreciably since the mid 1990s. This is similar to reports from Birth defects registries worldwidexi. As a result of the mandatory fortification of grain, reports from North America have shown an improvement in red cell folatexii and a reduction in the birth prevalence of NTD^14,15. The main reported concerns in relation to such fortification are

1. the risk of masking undiagnosed Vitamin B12 deficiency in older people leading to neurological degeneration and
2. the possible increase in twin births.

However, in the six years since the introduction of fortification, in North America, there is no evidence of such adverse events attributable to fortification. In addition, recent studies from the United States suggest that the increase in twins births is not a result of fortification^15,16.

In Ireland, in 2004, a report by the Nutrition Sub-committee of the FSAI¹⁷ concluded that folic acid fortification at 200mg /100g would have a significant effect in preventing NTD without resulting in an appreciable risk of adverse health effects from high intakes in any population subgroup. The policy of promotion of folic acid supplements has only had limited success in preventing NTD in Ireland, and continues in the absence of an alternative. However, we believe that based on current available scientific evidence that fortification of staple food is the only practical and reliable means for primary prevention of NTD in Ireland.

Correspondence: Robert Mc Donnell, Department of Public Health,
Eastern Regional Health Authority,
Dr. Steevens Hospital, Dublin 8, Republic of Ireland.
Tel: +353 (01) 635 2750,
Fax: +353 (01) 679 2745,
E-mail:[email protected]

1. Centers for Disease Control. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR Morb Mortal Wkly Rep 1992; 41 (RR-14).
2. Expert Advisory Group. Folic Acid and the prevention of neural tube defects. London: Department of Health, 1992.
3. Cornel M, Erickson J. Comparison of national policies on peri-conceptional use of folic acid to prevent spina bifida and anencephaly. Teratology 1997; 55: 134-137.
4. Department of Health. Report on Health and Social Subjects No. 50. Folic Acid and the Prevention of Disease. Report of the Committee on the Medical Aspects of Food and Nutrition Policy, London, Department of Health, 2000.
5. Food Safety Advisory Board. The value of folic acid in the prevention of Neural Tube Defects. Food Safety Advisory Board, Dublin 1998.
6. Dean A, Dean J, Coulombier D, et al. Epi Info, Version 6. A word processing, database, statistics program for epidemiology on microcomputer. Atlanta: Centers for Disease Control and Prevention, 1994.
7. Gahlinger P, Abramson J. Computer programs for epidemiologic analysis (PEPI, Version 2). USD Inc, Georgia, 1995.
8. McDonnell R, Johnson Z, Doyle A, Sayers G. Determinants of folic acid knowledge and use among antenatal women. J Public Health Med 1999;21:145-49.
9. Morin P, De Wals P, St-Cyr-Tribble D, Niyonsenga T, Payette H. Pregnancy Planning: a determinant of folic acid supplements use for the primary prevention of neural tube defects. Can J Public Health 2002; 93: 245-8.
10. Dublin EUROCAT Registry. Twenty years of congenital anomaly surveillance in the eastern region of Ireland - Report of the Dublin EUROCAT Registry. Dublin: Eastern Regional Health Authority, 2001:11-12.
11. Rosano A, Smithells D, Cacciani L, et al. Time trends in neural tube defects prevalence in relation to preventive strategies: an international study. J Epidemiol Community Health 1999;53:630-5.
12. Caudill M, Le T, Moonie S, Esfahani S, Cogger E. Folate status in women of childbearing age residing in Southern California after folic acid fortification. J Am Coll Nutr 2001;20:129-34.
13. Mathews T, Honein M, Erickson J. Spina Bifida and anencephaly prevalence - United States, 1991-2001. Morb Mortal Wkly Rep Recomm Rep 2002; (RR-13):9-11.
14. Persad V, Van den Hof M, Dube J, Zimmer P. Incidence of open neural tube defects in Nova Scotia after folic acid fortification. CMAJ 2002;167:241-5.
15. Waller D, Tita, A, Annegers J. Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998. Pediatr Perinat Epidemiol 2003; 17: 378-383.
16. Shaw G, Carmichael S, Nelson V, Selvin S, Schaffer D. Food fortification with folic acid and twinning among California infants. Am J Med Genet. 2003;119A:137-40
17. Food Safety Authority of Ireland. Report on the mandatory fortification of flour with folic acid for the prevention of neural tube defects. Food Safety Authority of Ireland, 2004.