Neural tube defects (NTDs), which include spina bifida and anencephaly, are serious malformations that occur in the developing fetus during the first 17--30 days after conception (1). Consumption of supplements containing folic acid can reduce NTDs 50%--70% (2,3). In the United States, approximately 4000 pregnancies are affected by NTDs each year, including approximately 140 infants in Michigan. In 1992, the US Public Health Service recommended that all women of childbearing age consume at least 400 µg of folic acid daily (4). In 1998, the Institute of Medicine reaffirmed that recommendation and added that women capable of becoming pregnant take 400 µg of synthetic folic acid daily from fortified foods and/or supplements and consume a balanced, healthy diet of folate-rich foods (5). This report summarizes findings from
the 1998 Behavioral Risk Factor Surveillance System (BRFSS) about multivitamin use and folic acid knowledge among women of reproductive age in Michigan. The
findings suggest that public health campaigns that promote the consumption of folic acid should target women who are young, unmarried, obese, smoke, eat few fruits and vegetables, and have a low level of education.
BRFSS is an ongoing, state-based, random-digit--dialed telephone survey of
the US civilian, noninstitutionalized population aged
>18 years (6). In 1998, 2613
persons were interviewed in Michigan. Analysis was restricted to 739 women of
reproductive age (aged 18--44 years).
Multivitamin use was defined as taking a folic acid-containing multivitamin or a
folic acid supplement at least once a day. Knowledge of folic acid use was defined as
having answered that the reason health experts recommend that women take folic acid
was to prevent birth defects. Univariable and multivariable logistic regression models
were used to determine risk factors for multivitamin use and knowledge of folic
acid. SUDAAN was used to account for the complex study design
(6). Age, race, education, marital status, fruit and vegetable consumption, smoking, and weight
status (overweight: body mass index [BMI]
>25.0 kg/(height2)[in meters] <30.0 or obese:
BMI >30.0 kg/[(height2]) were identified as variables of interest and included in
the multivariable analysis.
Overall, 42.4% of women reported taking a multivitamin or folic acid
supplement daily. Multivitamin use increased with age, from 33.1% for women aged 18--24
years to 48.1% for women aged 40--44 years. The prevalence of women who used
a multivitamin was highest among those who were consumers of five or more fruits
and vegetables a day (54.9%), college educated (49.9%), aged 35--39 years
(49.6%), former smokers (47.4%), married (46.0%), not overweight (44.5%), and white
(44.2%). After multivariable analysis, the following groups were
statistically significantly less likely than their respective comparison group to use a
multivitamin daily: women aged 18--24 years, women who had a low level of education,
women who ate less than five fruits and vegetables a day, and obese women.
Overall, 30.0% of women had knowledge of folic acid use, defined as
responding that the prevention of birth defects is the reason to take folic acid. The prevalence
of women with folic acid knowledge was highest among women who were
college graduates (42.2%), aged 25--29 years (39.8%), former smokers (37.0%),
married (35.8%), ate five or more fruits and vegetables a day (34.9%), not overweight
and white (31.5%). Multivariable analysis indicated that women who
were high school graduates, current smokers, and unmarried were statistically
significantly less likely than their respective comparison group to have correct knowledge of
folic acid use. Women aged 18--29 were statistically significantly more likely than
their respective comparison group to have correct knowledge.
Reported by: M Reeves, A Rafferty, Bur of Epidemiology; JC Simmeron, J Bach,
Michigan Birth Defects Registry, Michigan Dept of Community Health. State Br, Div of Applied
Public Health Training, Epidemiology Program Office; Maternal and Child Health Br, Div
of Reproductive Health, National Center for Chronic Disease Prevention and Health
Promotion; and an EIS Officer, CDC.
The findings in this report indicate that younger women, women
with low education, women with low fruit and vegetable consumption, and obese
women were associated with lower levels of reported multivitamin use. Being unmarried or
a current smoker was associated with low folic acid knowledge, and having
less education (an indicator of low socioeconomic status) was associated with both
low levels of multivitamin use and low folic acid knowledge. Eating few fruits
and vegetables and smoking also are correlated with socioeconomic status.
Therefore, socioeconomic status is a marker for low folic acid knowledge and low
multivitamin use in Michigan, as has been shown in previous studies
(7). Because low education level was associated with low folic acid knowledge, a continued educational
effort from medical and nutritional professionals is needed to increase knowledge
and support behavior change (8).
The findings in this report are subject to at least four limitations. First,
because BRFSS excludes persons aged <18 years, folic acid knowledge and
prevalence estimates do not represent the entire reproductive-aged population. Second,
BRFSS excludes persons without telephones; therefore, data may underestimate the
number of women of reproductive age from low socioeconomic groups. Third, the data
are self-reported and the validity of the data is unknown. Finally, because the
overall sample size is relatively small, some estimates are unreliable, as indicated by the
wide confidence intervals.
Through a 3-year cooperative agreement with CDC, the Michigan Department
of Community Health (MDCH) Division for Vital Records and Health Statistics and
the Hereditary Disorders Program seek opportunities to increase awareness of
NTD prevention through conferences, presentations, and the distribution of folic
acid literature to public and professional audiences. The School Health Unit at MDCH
also identifies opportunities for folic acid education in curricula developed for the
Michigan Model for Comprehensive School Health Education, which reaches
approximately 950,000 Michigan students and their families.
Other organizations, such as the March of Dimes and the Association of
Women's Health, Obstetric and Neonatal Nurses are implementing folic acid campaigns
and educational programs to help prevent NTDs in Michigan. The March of Dimes
Greater Michigan Chapter has partnered with grocery stores in the Grand Rapids area to
print folic acid messages on store grocery bags, and the Southeast Michigan Chapter
has disseminated folic acid messages through public service announcements
and partnerships with faith based organizations, corporations, representatives from
the Arab and Hispanic communities, and professional medical groups.
The public health community should continue to use multiple strategies to
increase folic acid intake and consumption. The current level of folic acid in fortified food (140
per 100 g cereal grain product) is intended to increase a woman's intake
by approximately 100 µg per day
(9). Although the current levels of fortification may
not be sufficient to provide the necessary dietary intake of folic acid for many women
who become pregnant, fortification has had a substantial effect on increasing folate
levels (10). Because approximately 50% of pregnancies are unplanned, all women
of childbearing age should be encouraged to consume 400
µg of folic acid from fortified foods and/or supplements and to consume a balanced, healthy diet of folate-rich foods.
- CDC. Knowledge and use of folic acid by women of childbearing age---United
States, 1995 and 1998. MMWR 1999;48:325--7.
- Milunsky A, Jick H, Jick SS, et al. Multivitamin/folic acid supplementation in early
pregnancy reduces the prevalence of neural tube defects. JAMA 1989;262:2847--52.
- MRC Vitamin Study Research Group. Prevention of neural tube defects: results of
the Medical Research Council Vitamin Study. Lancet 1991;338:131--7.
- CDC. Recommendations for the use of folic acid to reduce the number of cases of
spina bifida and other neural tube defects. MMWR 1992;41(no. RR-14).
- Institute of Medicine. Dietary reference intake: folate, other B vitamins, and
choline. Washington, DC: National Academy Press, 1998.
- CDC. Health risks in America: gaining insight from the Behavioral Risk Factor
Surveillance System. Atlanta, Georgia: US Department of Health and Human Services, CDC, 1997.
- Wasserman CR, Shaw GM, Selvin S, Gould JB, Syme SL. Socioeconomic status,
neighborhood social conditions, and neural tube defects. Am J Public Health 1998;88:1674--80.
- Pastuszak AL. Changing human behaviour is the greatest challenge in the folic acid
saga. Frontiers in Fetal Health--A Global Perspective 1999;4:1--3.
- Mills JL. Fortification of foods with folic acid---how much is enough? N Engl J
- CDC. Folate status in women of childbearing age---United States, 1999. MMWR