Trends in Folic Acid Awareness and Behavior in the United States: The Gallup Organization for the March of Dimes Foundation Surveys, 1995–2005

Objective: To summarize changes in folic acid awareness, knowledge, and behavior among women of childbearing age in the United States since the U.S. Public Health Service (USPHS) 1992 folic acid recommendation and later fortification. Methods: Random-digit dialed telephone surveys were conducted of approximately 2000 women (per survey year) aged 18–45 years from 1995–2005 in the United States. Results: The percentage of women reporting having heard or read about folic acid steadily increased from 52% in 1995 to 84% in 2005. Of all women surveyed in 2005, 19% knew folic acid prevented birth defects, an increase from 4% in 1995. The proportion of women who reported learning about folic acid from health care providers increased from 13% in 1995 to 26% in 2005. The proportion of all women who reported taking a vitamin supplement containing folic acid increased slightly from 28% in 1995 to 33% in 2005. Among women who were not pregnant at the time of the survey in 2005, 31% reported taking a vitamin containing folic acid daily compared with 25% in 1995. Conclusions: The percentage of women taking folic acid daily has increased modestly since 1995. Despite this increase, the data show that the majority of women of childbearing age still do not take a vitamin containing folic acid daily. Health care providers and maternal child health professionals must continue to promote preconceptional health among all women of childbearing age, and encourage them to take a vitamin containing folic acid daily.

     

Autosomal trisomy and maternal use of multivitamin supplements

Recent reports suggest that women carrying certain polymorphisms of folate genes associated with suboptimal folate status might be at increased risk for having a child with Down syndrome or other autosomal trisomies, and hypothesized that maternal use of multivitamin supplements might reduce such risk. To evaluate this hypothesis, we examined data from a population-based case-control study, and contrasted cases of Down syndrome, trisomy 18, and trisomy 13, with unaffected controls. Periconceptional multivitamin use, compared to no such use, was associated with an odds ratio (OR) of 0.9 (95% confidence interval [CI], 0.6-1.3) for having a pregnancy affected by an autosomal trisomy. The OR was 0.8 (95% CI, 0.5-1.3) for Down syndrome and 1.4 (95% CI, 0.5-3.6) for trisomies 13 and 18, with little variation by maternal race or age. Periconceptional multivitamin use was not associated with a major reduction in the risk for common autosomal trisomies.     

Epidemiology of the early amnion rupture spectrum of defects

We used data from the population-based Metropolitan Atlanta Congenital Defects Program to study the epidemiology of the early amnion rupture spectrum of defects. For the period 1968 through 1982, we identified 45 patients among 388,325 live births, for a birth prevalence rate of 1.16 per 10,000. The prevalence for male infants was 0.91 and for female infants, 1.44. The defects occurred 1.76 times more often in blacks than in whites (95% confidence interval 0.98, 3.13). Infants of young, black multigravidas (less than 20 years, more than one pregnancy) showed the highest rate (6.2), and infants of older, black multigravidas showed the lowest rate (0.5) (rate ratio = 12.4, 95% confidence interval 4.2, 36.4). These findings suggest that young, black multigravidas are at much higher risk than are older, black multigravidas of having infants with this spectrum of defects. Ascertainment (diagnostic) differences between hospitals probably account for some of the racial discrepancy in birth prevalence, but they do not explain the maternal age effects in black multigravidas. Because the higher rates for blacks probably reflect more accurate diagnoses, the findings also suggest that a closer estimate of the true birth prevalence may be about 3 per 10,000 live births.     

Maternal fever,multivitamin use,and selected birth defects: evidence of interaction?

BACKGROUND: Multivitamin use has been associated with lower risks for some birth defects. We evaluated whether multivitamin use modified birth defect risks associated with febrile illness, a common and possibly teratogenic exposure. METHODS: From the population-based Atlanta Birth Defects Case-Control Study (1968-1980) we selected seven defects (neural tube defects, cleft lip and palate, cardiac outflow tract defects, ventricular septal defects, atrial septal defects, omphalocele, and limb deficiencies) because of their inverse relation with multivitamin supplement use documented in previous analyses. We defined four exposure categories from combinations of multivitamin use (periconceptional use compared with no use) and febrile illness (early pregnancy compared with no illness). The reference category was no multivitamin use and no illness. RESULTS: Febrile illness with no multivitamin use was associated with generally increased risk for the seven defects and the combined group (odds ratio = 2.1, 1.7, 1.5, 1.9, 2.9, 4.4, 3.3, and 2.3, respectively). With multivitamin use, however, the risk estimates associated with febrile illness were generally lower (odds ratio = 0.6, 1.1, 0.0, 1.5, 0.0, 0.8, 0.0, and 0.8, respectively). Some of the associated 95% confidence intervals included one. CONCLUSIONS: The pattern of findings suggests that multivitamin use might decrease the risk associated with febrile illness.     

Inconsistencies in coding of race and ethnicity between birth and death in US infants. A new look at infant mortality, 1983 through 1985.

OBJECTIVE--To ascertain the consistency of the racial and ethnic classification of US infants between birth and death and its impact on infant mortality rates. SUBJECTS--All US infants born from 1983 through 1985 who died within a year. DESIGN--We used the national linked birth/infant-death computer tape, augmented with information on infants' race and ethnicity at death, to compare the coding of race and Hispanic ethnicity at birth and at death. We also assessed infant mortality rates by race and ethnicity as defined (1) by the standard algorithm and (2) by the rule that, beginning in published tabulations for 1989, assigns newborns the race of their mothers. Finally, we estimated infant mortality rates based on consistent coding of race and ethnicity at birth and death. RESULTS--Inconsistency in the coding of race is low for whites (1.2%), greater for blacks (4.3%), and greatest for races other than white or black (43.2%). Most infants reclassified at death (87.3%) are classified as white at death. Inconsistency in coding is lower for non-Hispanic whites (3.5%) and non-Hispanic blacks (3.3%) than for Hispanic populations (30.3%). Compared with the standard algorithm for calculation of infant mortality, consistent definition at birth and death produces rates 2.1% lower for whites, and higher for all other groups--3.2% for blacks, 46.9% for American Indians, 33.3% for Chinese, 48.8% for Japanese, 78.7% for Filipinos, and 8.9% for Hispanics. CONCLUSIONS--The coding of race and ethnicity of infants at birth and death is remarkably inconsistent, with substantial impact on the estimation of infant mortality rates. A need exists to reconsider the nature and definition of race and ethnicity in public health.     

Reevaluating the benefits of folic acid fortification in the United States: economic analysis, regulation, and public health

Before a 1996 US regulation requiring fortification of enriched cereal-grain products with folic acid, 3 economic evaluations projected net economic benefits or cost savings of folic acid fortification resulting from the prevention of pregnancies affected by a neural tube defect. Because the observed decline in neural tube defect rates is greater than was forecast before fortification, the economic gains are correspondingly larger.Applying both cost-benefit and cost-effectiveness analytic techniques, we estimated that folic acid fortification is associated with annual economic benefit of 312 million dollars to 425 million dollars. The cost savings (net reduction in direct costs) were estimated to be in the range of 88 million dollars to 145 million dollars per year.     

Is there etiologic heterogeneity between upper and lower neural tube defects?

Neural tube defects are thought to arise from two different embryologic mechanisms depending on the level of the defect: neurulation defects associated with anencephaly and upper spina bifida and canalization defects associated with lower spina bifida. To investigate whether the risk profiles of neural tube defect cases differ according to the level of the defect, the authors examined data from the Atlanta Birth Defects Case-Control Study. Cases were infants live- or stillborn from 1968 to 1980 with these defects, and controls were infants without defects randomly selected and frequency matched to cases by race, birth year, and hospital of birth. By multivariate polychotomous logistic regression, 1,186 controls were compared with cases: 145 with anencephaly, 59 with upper spina bifida (cervical/thoracic lesions), and 100 with lower spina bifida (lumbar/sacral lesions). Infant's sex and sibling recurrence of neural tube defects were the only factors for which the case subgroups significantly differed in risk. The risks associated with selected maternal exposures during the first trimester of pregnancy did not differ among the case subgroups. Although these results do not support the concept that upper and lower neural tube defects differ in risks from exogenous factors, differences in sibling recurrence and in risks by sex between the two groups suggest an underlying heterogeneity in genetic susceptibility factors.     

Does maternal cigarette smoking during pregnancy cause cleft lip and palate in offspring?

To investigate the relationship between maternal cigarette smoking and the risk of oral clefts in offspring, we examined data from the Atlanta Birth Defects Case-Control Study, which included 238 cases of cleft lip with or without cleft palate and 107 cases of cleft palate ascertained by the Metropolitan Atlanta Congenital Defects Program from 1968 through 1980. In all, 2809 infants who served as controls were frequency matched to cases by race, period of birth, and hospital of birth. Maternal periconceptional exposures to smoking were investigated through use of a structured questionnaire. Smoking exposure was defined as reported maternal smoking during the periconceptional period (from 3 months before conception to 3 months after pregnancy began). Offspring of smoking mothers were 1.6 and 2.0 times more likely than offspring of nonsmoking mothers to have isolated cleft lip with or without cleft palate and cleft palate, respectively. On the other hand, offspring of smoking mothers were not at increased risk of having cleft palate or cleft lip with or without cleft palate that are associated with other defects. Adjustment for potential confounding variables did not alter these results. A relatively modest effect of smoking may be explained by the presence of underlying etiologic heterogeneity in oral clefts and differential susceptibility to smoking. Because of the inconsistencies in the literature on the relationship between smoking and oral clefts, these results suggest the need to refine oral clefts into more homogeneous subgroups in epidemiologic studies of these defects.     

Does periconceptional multivitamin use reduce the risk of neural tube defects associated with other birth defects? Data from two population-based case-control studies

The role of periconceptional folic acid in the prevention of neural tube defects (NTDs) is well established. However, it is not clear whether a protective effect exists for the subset of nonsyndromic NTD with other “unrelated” major structural birth defects (NTD-multiples). This question is important to investigate because of shared pathogenetic mechanisms between NTD and other types of birth defects, and because of the epidemiologic differences that have been shown between NTD-multiples and NTD-singles. We analyzed data from two population-based case-control studies of NTDs, Atlanta 1968–1980, and California 1989–1991, to assess whether periconceptional multivitamin use reduces the risk of NTD-multiples. Maternal vitamin histories were assessed for 47 and 65 NTD-multiples cases and 3,029 and 539 control babies in Atlanta, and California, respectively. There was a substantial risk reduction associated with periconceptional multivitamin use (−3 to +3 months) for NTD-multiples (pooled odds ratio = 0.36, 95% C.I. 0.18–0.72) that persisted after adjustment for maternal race/ethnicity and education. Also, no specific types of NTDs or NTDs with specific defects explained the risk reduction with vitamin use. These data suggest that multivitamins reduce the risk of nonsyndromic NTD cases associated with other major birth defects. The implication of this finding for the role of vitamins in the prevention of non-NTD birth defects should be further explored. © 1996 Wiley-Liss, Inc.