Folic Acid and the Prevention of Birth Defects: 30 Years of Opportunity and Controversies.

For three decades, the US Public Health Service has recommended that all persons capable of becoming pregnant consume 400 µg/day of folic acid (FA) to prevent neural tube defects (NTDs). The neural tube forms by 28 days after conception. Fortification can be an effective NTD prevention strategy in populations with limited access to folic acid foods and/or supplements. This review describes the status of mandatory FA fortification among countries that fortify (n = 71) and the research describing the impact of those programs on NTD rates (up to 78% reduction), blood folate concentrations [red blood cell folate concentrations increased ∼1.47-fold (95% CI, 1.27, 1.70) following fortification], and other health outcomes. Across settings, high-quality studies such as those with randomized exposures (e.g., randomized controlled trials, Mendelian randomization studies) are needed to elucidate interactions of FA with vitamin B12 as well as expanded biomarker testing.

Children with Heart Conditions and Their Special Health Care Needs - United States, 2016.

Children with heart conditions often use more health care services and specialized care than children without a heart condition (1); however, little is known about the number of U.S. children with heart conditions and their special health care needs. CDC used data from the 2016 National Survey of Children's Health (NSCH) to estimate the prevalence of heart conditions among U.S. children aged 0-17 years, which indicated that 1.3% had a current heart condition and 1.1% had a past heart condition (representing approximately 900,000 and 755,000 children, respectively). Sixty percent and 40% of children with current and past heart conditions, respectively, had one or more special health care needs, compared with 18.7% of children without a heart condition (adjusted prevalence ratios [aPRs] = 3.1 and 2.1, respectively). Functional limitations were 6.3 times more common in children with current heart conditions (30.7%) than in those without heart conditions (4.6%). Among children with current heart conditions, males, children with lower family income, and children living in other than a two-parent household had an increased prevalence of special health care needs. These findings highlight the importance of developmental surveillance and screening for children with heart conditions and might inform public health resource planning.

Oral health conditions and dental visits among pregnant and nonpregnant women of childbearing age in the United States, National Health and Nutrition Examination Survey, 1999-2004.

INTRODUCTION: Oral diseases can be prevented or improved with regular dental visits. Our objective was to assess and compare national estimates on self-reported oral health conditions and dental visits among pregnant women and nonpregnant women of childbearing age by using data from the National Health and Nutrition Examination Survey (NHANES). METHODS: We analyzed self-reported oral health information on 897 pregnant women and 3,971 nonpregnant women of childbearing age (15-44 years) from NHANES 1999-2004. We used χ(2) and 2-sample t tests to assess statistical differences between groups stratified by age, race/ethnicity, poverty, and education. We applied the Bonferroni adjustment for multiple comparisons. RESULTS: Our data show significant differences in self-reported oral health conditions and dental visits among women, regardless of pregnancy status, when stratified by selected sociodemographic characteristics. Significant differences were also found in self-reported oral health conditions and dental visits between pregnant and nonpregnant women, especially among young women, women from minority race/ethnicity groups, and women with less than high school education. CONCLUSION: We found disparities in self-reported oral health conditions and use of dental services among women regardless of pregnancy status. Results highlight the need to improve dental service use among US women of childbearing age, especially young pregnant women, those who are non-Hispanic black or Mexican American, and those with low family income or low education level. Prenatal visits could be used as an opportunity to encourage pregnant women to seek preventive dental care during pregnancy.

Multivitamin Use Among Hispanic Women of Reproductive Age in the United States, 2013-2022.

Background: The U.S. Public Health Service and the Institute of Medicine recommend that all women capable of becoming pregnant consume 400 µg of folic acid daily to help prevent neural tube defects (NTDs). Hispanic women are at higher risk of having babies with NTDs than non-Hispanic White women. This study assessed multivitamin (MV) use, a main source of folic acid, among Hispanic women of reproductive age using a survey of solely U.S. Hispanic adults. Materials and Methods: MV use was assessed as part of Porter Novelli's Estilos survey, fielded annually through the largest online U.S. Hispanic panel, Offerwise's QueOpinas. During the study period of 2013-2022, 9,999 surveys were completed; selection was weighted to match the U.S. Census American Community Survey proportions. Log-binomial regression models were applied to estimate MV use trends by age groups, acculturation levels, and pregnancy intention. Results: Among 3,700 Hispanic women of reproductive age, overall no MV use increased from 39.3% in 2013 to 54.7% in 2022 (p for trend <0.0001), especially among Hispanic women aged 18-34 years and those classified as acculturated. Among women planning to get pregnant, daily MV use was 31.1% in 2013 compared with 18.7% in 2020-2022 (p = 0.04). Conclusions: Given the increase in no MV use among Hispanic women of reproductive age, targeted interventions may help reach at-risk groups for NTDs prevention.

Update on the impact of voluntary folic acid fortification of corn masa flour on red blood cell folate concentrations-National Health and Nutrition Examination Survey, 2011-March 2020.

BACKGROUND: Folic acid is a micronutrient that is effective at preventing neural tube defects (NTDs). In 2016, the FDA authorized the voluntary fortification of corn masa flour (CMF) with folic acid to reduce disparities in NTDs among infants of women who do not regularly consume other fortified cereal grains, in particular Hispanic women of reproductive age (WRA). METHODS: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to March 2020 assessing the impact of voluntary fortification of CMF on the folate status of Hispanic WRA. We analyzed folic acid usual intake and red blood cell (RBC) folate concentrations among non-pregnant, non-lactating Hispanic WRA, comparing pre-fortification (2011-2016) to post-fortification (2017-March 2020) data. RBC folate concentrations were used to create model-based estimation of NTD rates. RESULTS: The proportion of Hispanic WRA with folic acid usual intakes <400 µg/d did not change (2011-2016: 86.1% [95% Confidence Interval, CI: 83.7-88.5]; 2017-March 2020: 87.8% [95% CI: 84.8-90.7]; p = .38) nor did the proportion of Hispanic WRA with RBC folate below optimal concentrations (<748 nmol/L, 2011-2016: 16.0% [95% CI: 13.7-18.2]; 2017-March 2020: 18.1% [95% CI: 12.1-24.0]; p = 0.49). Model-based estimates of NTD rates suggest further improvements in the folate status of Hispanic WRA might prevent an additional 157 (95% Uncertainty Interval: 0, 288) NTDs/year. CONCLUSIONS: Voluntary fortification of CMF with folic acid has yet to have a significant impact on the folate status of WRA. Continued monitoring and further research into factors such as fortified product availability, community knowledge, and awareness of folic acid benefits would inform and improve future public health interventions.

Expanding the Massachusetts Birth Defects Monitoring Program to include additional pregnancy outcomes: Programmatic efforts and impacts on case ascertainment, 2012-2020.

BACKGROUND: Birth defects affect 1 in 33 infants in the United States and are a leading cause of infant mortality. Birth defects surveillance is crucial for informing public health action. The Massachusetts Birth Defects Monitoring Program (MBDMP) began collecting other pregnancy losses (OPLs) in 2011, including miscarriages (<20 weeks gestation) or elective terminations (any gestational age), in addition to live births and stillbirths (≥20 weeks gestation). We describe programmatic changes for adding OPLs and their impact on prevalence estimates. METHODS: Using population-based, statewide, data from the MBDMP (2012-2020), we assessed prevalence per 10,000 live births and 95% confidence intervals (CIs) with and without OPLs overall and for specific birth defects by time period, maternal age, and race/ethnicity. RESULTS: Including OPLs required amending a state statute and promulgating regulations, new data sources, and additional data processing, cleaning, and verification. Overall prevalence with OPLs increased from 257.4 (95% CI: 253.5-261.4) to 333.9 (95% CI: 329.4-338.4) per 10,000; increases were observed in all time periods, age, and race/ethnicity groups. After including OPLs, the prevalence increased for neural tube defects [3.2 (2.7-3.6) to 8.3 (7.6-9.0)], and trisomies 13 [0.5 (0.3-0.7) to 4.1 (3.6-4.6)], 18 [1.5 (1.2-1.9) to 8.2 (7.5-8.9)], and 21 [12.3 (11.4-13.2) to 28.9 (27.6-30.2)]. Cardiovascular defects increased slightly, while prevalence of eye/ear, respiratory, and gastrointestinal defects remained similar. CONCLUSIONS: Adding OPLs required substantial programmatic efforts and resulted in more complete case ascertainment, particularly for certain birth defects. More complete case ascertainment will allow for improved research, screening, and resource allocation.

Folate and vitamin B12 usual intake and biomarker status by intake source in United States adults aged ≥19 y: NHANES 2007-2018.

BACKGROUND: Folate and vitamin B12 are important biomarkers of nutritional status of populations. OBJECTIVES: This study aims to estimate folate and vitamin B12 usual intakes among United States adults and examine folate and vitamin B12 biomarker status by intake source. METHODS: We analyzed data for United States adults aged ≥19 y from National Health and Nutrition Examination Survey 2007-2018 (n = 31,128), during which time voluntary corn masa flour (CMF) fortification was started. Usual intake was estimated using the National Cancer Institute method. Folate intake included folate from natural foods and folic acid from 4 sources: enriched cereal grain products (ECGPs), CMF, ready-to-eat cereals (RTEs), and folic acid-containing supplements (SUP). Vitamin B12 intake was mainly from food and supplements. RESULTS: The median natural food folate intake (222 µg dietary folate equivalents (DFE)/d) was below the estimated average requirement (EAR) of 320 µg DFE/d. The proportions of those who consumed folic acid from ECGP/CMF only, ECGP/CMF + RTE, ECGP/CMF + SUP, and ECGP/CMF + RTE + SUP were 50%, 18%, 22%, and 10%, respectively. Median usual folic acid intakes (µg/d) were 236 (IQR: 152, 439) overall and 134, 313, 496, and 695 in the ECGP/CMF only, ECGP/CMF + RTE, ECGP/CMF + SUP, and ECGP/CMF + RTE + SUP folic acid consumption groups, respectively. Overall, 2.0% (95% CI: 1.7%, 2.3%) of adults, all of whom used folic acid supplements, consumed greater than the tolerable upper intake level (UL) of 1000 µg/d folic acid. The median usual vitamin B12 intake (µg/d) was 5.2 for vitamin B12 supplement nonusers and 21.8 for users. Consumption of RTE and/or supplements with folic acid was associated with higher serum and red blood cell folate concentrations. Vitamin B12 supplement users had significantly higher serum vitamin B12 concentrations. CONCLUSIONS: Folic acid fortification plays a critical role in helping United States adults meet the folate EAR. At current fortification levels, United States adults who do not consume supplements do not have the usual folic acid intake exceeding the UL.

A Randomized Trial of Quadruple-Fortified Salt for Anemia and Birth Defects Prevention in Southern India: Protocol Design and Methods.

Background: Women of reproductive age are at an increased risk of anemia and micronutrient deficiencies. Evidence supports the role of periconceptional nutrition in the development of neural tube defects (NTDs) and other pregnancy complications. Vitamin B12 deficiency is a risk factor for NTDs and may modify folate biomarkers that predict NTD risk at the population level. There is an interest in mandatory fortification with vitamin B12 and folic acid for anemia and birth defect prevention. However, there are limited population-representative data needed to inform policy and guidelines. Objectives: This randomized trial will be conducted to evaluate the efficacy of quadruple-fortified salt (QFS; iron, iodine, folic acid, vitamin B12) in 1,000 households in Southern India. Methods: Women 18 to 49 y who are not pregnant or lactating and reside within the catchment area of our community-based research site in Southern India will be screened and invited to participate in the trial. After informed consent, women and their households will be randomized to receive one of the following 4 interventions: 1) double-fortified salt (DFS; iron, iodine), 2) DFS + folic acid (iron, iodine, folic acid), 3) DFS + vitamin B12 (iron, iodine, vitamin B12), or 4) DFS + folic acid and vitamin B12 (QFS; iron, iodine, folic acid, vitamin B12) for 12 mo. Structured interviews will be conducted by trained nurse enumerators to collect sociodemographic, anthropometric, dietary, health, and reproductive history data. Biological samples will be collected at baseline, midpoint, and endpoint. Whole blood will be analyzed for hemoglobin using Coulter Counter. Total vitamin B12 will be measured by chemiluminescence; red blood cell folate and serum folate will be evaluated using the World Health Organization-recommended microbiologic assay. Conclusions: The results of this randomized trial will help to evaluate the efficacy of QFS to prevent anemia and micronutrient deficiencies. Clinical trial registration numbers: NCT03853304 and Clinical Trial Registry of India REF/2019/03/024479. Registration number: NCT03853304 and REF/2019/03/024479.

Vitamin B-12 malabsorption and renal function are critical considerations in studies of folate and vitamin B-12 interactions in cognitive performance: NHANES 2011-2014.

BACKGROUND: Cognitive health is a public health concern among older adults. Dietary supplement (SUP) use is common and concerns have been raised about high folic acid intake among those with vitamin B-12 deficiency and exacerbation of poor cognitive performance (PCP). OBJECTIVES: We evaluated SUP use, usual folic acid intake, and blood folate and vitamin B-12 concentrations in relation to cognitive performance. METHODS: We used NHANES 2011-2014 data on adults aged ≥60 y (n = 2867) and estimated total usual folic acid intake from diet and supplements, vitamin B-12 intake from SUPs, blood folates, vitamin B-12 concentrations, vitamin B-12 insufficiency (≤258 pmol/L), high folate (serum folate ≥59 nmol/L or RBC folate ≥1609 nmol/L), and PCP (<34 on the Digit Symbol Substitution Test). We assessed folate distributions adjusted for multiple variables, including renal function. RESULTS: Compared with persons without PCP, adults with PCP were less likely to use supplements containing folic acid (mean ± SEE: 34.4% ± 2.4%) or vitamin B-12 (mean ± SEE: 47.5% ± 1.6%). Among vitamin B-12-insufficient adults, 18.0% ± 1.6% (mean ± SEE) reported taking a vitamin B-12 supplement. Among participants with high folate and insufficient vitamin B-12 concentrations, 34.3% ± 11.5% (mean ± SEE) reported taking vitamin B-12-containing supplements. Persons with high folate and normal vitamin B-12 concentrations had lower odds of PCP [aOR (adjusted odds ratio): 0.61; 95% CI: 0.45, 0.83] than persons with normal folate and vitamin B-12. Persons with high folate and normal methylmalonic acid (MMA) had lower odds of PCP (OR: 0.56; 95% CI: 0.40, 0.78) than those with normal folate and MMA concentrations. After adjustment for renal function, elevated risk of PCP was attenuated among persons with high folate and MMA. Concurrent high folate and insufficient vitamin B-12 concentrations were not associated with PCP. CONCLUSIONS: Differential associations between vitamin B-12 and MMA highlight the need to consider renal function in studies of high folate and low vitamin B-12 status. Consumption of vitamin B-12 supplements concurrent with low vitamin B-12 status may indicate vitamin B-12 malabsorption.

Reduced Kidney Function Is Associated with Increasing Red Blood Cell Folate Concentration and Changes in Folate Form Distributions (NHANES 2011-2018).

Background: Current studies examining the effects of high concentrations of red blood cell (RBC) or serum folates assume that high folate concentrations are an indicator of high folic acid intakes, often ignoring the contributions of other homeostatic and biological processes, such as kidney function. Objective: The current study examined the relative contributions of declining kidney function, as measured by the risk of chronic kidney disease (CKD), and usual total folic acid intake on the concentrations of RBC folate and serum folate (total as well as individual folate forms). Design: Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) collected in 2-year cycles were combined from 2011 to 2018. A total of 18,127 participants aged ≥16 years with available folate measures, kidney biomarker data (operationalized as a categorical CKD risk variable describing the risk of progression), and reliable dietary recall data were analyzed. Results: RBC folate concentrations increased as CKD risk increased: low risk, 1089 (95% CI: 1069, 1110) nmol/L; moderate risk, 1189 (95% CI: 1158, 1220) nmol/L; high risk, 1488 (95% CI: 1419, 1561) nmol/L; and highest risk, 1443 (95% CI: 1302, 1598) nmol/L (p < 0.0001). Similarly, serum total folate concentrations increased as CKD risk increased: low risk: 37.1 (95% CI: 26.3, 38.0) nmol/L; moderate risk: 40.2 (95% CI: 38.8, 41.7) nmol/L; high risk: 48.0 (95% CI: 44.3, 52.1) nmol/L; the highest Risk: 42.8 (95% CI: 37.8, 48.4) nmol/L (p < 0.0001). The modeled usual intake of folic acid showed no difference among CKD risk groups, with a population median of 225 (interquartile range: 108−390) µg/day. Conclusion: Both RBC and serum folate concentrations increased with declining kidney function without increased folic acid intake. When analyzing associations between folate concentrations and disease outcomes, researchers may want to consider the confounding role of kidney function.

Periconceptional folic acid use prevents both rare and common neural tube defects in China.

BACKGROUND: Neural tube defects (NTDs) encompass a variety of distinct types. We assessed if the preventive effect of folic acid (FA) varied by NTD type and infant sex. METHODS: We examined all pregnancies with NTD status confirmation from a pregnancy-monitoring system in selected locations in northern and southern regions of China between 1993 and 1996. Women who took 400 µg of FA daily during 42 days after last menstrual period were considered FA users. We analyzed NTD prevalence by FA use status, NTD type, geographic region, and infant sex. RESULTS: Among 626,042 pregnancies, 700 were affected by an NTD. Among FA nonusers, 65 pregnancies (8.8 per 10,000) in the north and 51 pregnancies (1.2 per 10,000) in the south were affected by one of the two rare NTDs, that is, craniorachischisis, iniencephaly. FA use prevented occurrence of these two rare NTDs and reduced the prevalence of spina bifida (SB) by 78% (from 17.9 to 3.9 per 10,000) in the north and 51% (from 2.4 to 1.2 per 10,000) in the south. Among FA users, SB prevalence, including SB with high lesion level, was significantly reduced in both geographic regions. FA use reduced prevalence of anencephaly and encephalocele by 85% and 50%, respectively in the north, while it did not reduce the prevalence of these two NTDs in the south. There was a greater reduction in NTD prevalence in female than in male infants and fetuses. CONCLUSIONS: This is the first study to show that FA prevents the entire spectrum of NTD types.

Preparing for influenza after 2009 H1N1: special considerations for pregnant women and newborns.

Pregnant women and their newborn infants are at increased risk for influenza-associated complications, based on data from seasonal influenza and influenza pandemics. The Centers for Disease Control and Prevention (CDC) developed public health recommendations for these populations in response to the 2009 H1N1 pandemic. A review of these recommendations and information that was collected during the pandemic is needed to prepare for future influenza seasons and pandemics. The CDC convened a meeting entitled "Pandemic Influenza Revisited: Special Considerations for Pregnant Women and Newborns" on August 12-13, 2010, to gain input from experts and key partners on 4 main topics: antiviral prophylaxis and therapy, vaccine use, intrapartum/newborn (including infection control) issues, and nonpharmaceutical interventions and health care planning. Challenges to communicating recommendations regarding influenza to pregnant women and their health care providers were also discussed. After careful consideration of the available information and individual expert input, the CDC updated its recommendations for these populations for future influenza seasons and pandemics.

The Centers for Disease Control and Prevention's maternal health response to 2009 H1N1 influenza.

We describe the efforts of the Maternal Health Team, which was formed to address the needs of pregnant and breastfeeding women during the Centers for Disease Control and Prevention's (CDC's) 2009 pandemic influenza A (2009 H1N1) emergency response. We examined the team's activities, constructed a timeline of key pandemic events, and analyzed the Maternal Health 2009 H1N1 inquiry database. During the pandemic response, 9 guidance documents that addressed the needs of pregnant and breastfeeding women and their providers were developed by the Maternal Health Team. The Team received 4661 maternal health-related inquiries that came primarily from the public (75.5%) and were vaccine related (69.3%). Peak inquiry volume coincided with peak hospitalizations (October-November 2009). The Maternal Health 2009 H1N1 inquiry database proved useful to identify information needs of the public and health care providers during the pandemic.

Evaluation of an active population-based surveillance system for major birth defects in South Carolina.

INTRODUCTION: Birth defects are common, costly, and contribute substantially to infant mortality. The South Carolina Birth Defects Program (SCBDP) employs active population-based surveillance to monitor major birth defects statewide. We evaluated SCBDP's system attributes using published CDC guidelines. METHODS: To determine timeliness, completeness, and accuracy of birth defects information, we examined SCBDP's reports, program and education materials, advisory group meeting minutes, and strategic plan. We also met with program staff and stakeholders (n = 10) to discuss program goals and data utilization. We calculated the percentage of birth defects cases found 6 months after a birth cohort year for 2016-2018. RESULTS: SCBDP identifies 900-1,200 birth defects cases for a birth population of approximately 55,000 live births annually through active case reviews. SCBDP uses trained medical staff to abstract detailed information from maternal and infant medical records; SCBDP also has established auto-linkage with state vital statistics to capture demographic and birth data. SCBDP is timely and captures 97.1% (range 96.7-97.6%) of birth defects cases within 6 months after the birth cohort year closes. Active case identification using medical records as the primary data source improves quality assurance and completeness, while prepopulating demographic information improves timeliness. CONCLUSIONS: Given that birth defects significantly contribute to infant morbidity and mortality, monitoring these conditions is important to understand their impact on communities and to drive public health actions. SCBDP active surveillance and rigorous data quality practices provide the program with timely, complete, and accurate birth defects data.

Evaluation of a hospital-based surveillance system for birth defects in Chennai, India.

The Birth Defects Registry of India-Chennai (BDRI-C) was created in 2001 to monitor birth defects and provide timely referrals. Using established guidelines to evaluate surveillance systems, we examined the following attributes of BDRI-C to help strengthen the registry: simplicity, flexibility, data quality, representativeness, acceptability, timeliness, and stability. We reviewed BDRI-C documents, including reporting forms; interviewed key informants; and calculated data completeness, coverage, and reporting time. BDRI-C captured 14% of the births in Chennai April 2013 - March 2014. About 7% of institutions in Chennai registered in BDRI-C, and of those registered, 37% provided data in 2013. Median reporting time was 44 days after birth in 2013. BDRI-C is a useful, simple, flexible, and timely passive birth defects surveillance system; however, improvements can be made to ensure BDRI-C is representative of Chennai, data processing and quality checks are on-going, and the system is acceptable for member institutions and stable.

Systematic Process Framework for Conducting Implementation Science Research in Food Fortification Programs.

Food fortification has proven to be an effective approach for preventing micronutrient deficiencies in many settings. Factors that lead to successful fortification programs are well established. However, due to the multisectoral nature of fortification and the added complexities present in many settings, the barriers to success are not always evident and the strategies to address them are not always obvious. We developed a systematic process for identifying and addressing gaps in the implementation of a food fortification program. The framework is composed of 4 phases: (1) connect program theory of change to program implementation; (2) develop an implementation research agenda; (3) conduct implementation research; and (4) analyze findings and develop/disseminate recommendations for next steps. We detail steps in each phase to help guide teams through the process. To our knowledge, this is the first attempt to outline a systematic process for applying implementation science research to food fortification. The development of this framework is intended to promote implementation research in the field of food fortification, thus improving access to and effectiveness of this key public health intervention.

Prevalence of anaemia among pregnant women in South-East China, 1993-2005.

OBJECTIVE: To report the prevalence of anaemia by demographic characteristics and its secular trend over 13 years for south-east Chinese pregnant women, and to determine the focus of anaemia prevention in Chinese pregnant women. DESIGN: Prospective study of the data on Hb concentration and other demographic information from a large-scale population-based perinatal health surveillance system in south-east China. SETTING: Fourteen cities or counties in Jiangsu and Zhejiang provinces. SUBJECTS: A total of 467 057 prenatal women who had participated in the perinatal health-care surveillance system and delivered babies from 1 January 1993 to 31 December 2005 and had a record of Hb in all three pregnancy trimesters. RESULTS: The overall prevalence of anaemia among pregnant women was 39.6 % from 1993 to 2005. Anaemia prevalence increased from the first (29.6 %) to the second (33.0 %) and third (56.2 %) trimesters. The prevalence of anaemia was higher in villagers, in women with less education and in women with higher gravidity or parity. The prevalence of anaemia in all of the trimesters was higher in the spring, summer and autumn and lower in the winter. The prevalence decreased from 1993 to 2005, from 53.3 % to 11.4 % for the first trimester, 45.6 % to 22.8 % for the second trimester and 64.6 % to 44.6 % for the third trimester. CONCLUSIONS: The prevalence of anaemia among pregnant women in Jiangsu and Zhejiang provinces decreased substantially from 1993 to 2005. However, anaemia in the third trimester is still a severe public health problem among pregnant women in these areas.

Population RBC folate concentrations can be accurately estimated from measured whole blood folate, measured hemoglobin, and predicted serum folate-cross-sectional data from the NHANES 1988-2010.

BACKGROUND: RBC folate (RBF) is an indicator of folate status and risk of neural-tube defects. It is calculated from whole blood folate (WBF), serum folate (SFOL), and hematocrit (Hct). SFOL and/or Hct are sometimes unavailable; hemoglobin (Hb) is generally available in surveys. OBJECTIVES: We assessed the ability of different RBF approximations to generate population data in women aged 12-49 y. METHODS: Using SFOL, RBF, Hct, Hb, and mean corpuscular Hb content (MCHC) from prefortification (1988-1994) and postfortification (1999-2006, 2007-2010) NHANES we applied 6 approaches: #1) assume SFOL = 0; #2) impute SFOL (population median); #3) impute Hct (population median); #4) estimate Hct (Hb/MCHC); #5) assume SFOL = 0 and estimate Hct; and #6) predict SFOL (from WBF) and estimate Hct. For each approach, we calculated the paired percentage difference to the "true" RBF and estimated various statistics. RESULTS: For 2007-2010 (unweighted data), the median relative difference from "true" RBF was lowest for approaches #2 (-0.74%), #4 (-0.96%), and #6 (-1.15%), intermediate for #3 (-3.36%), and highest for #5 (4.96%) and #1 (5.78%). The 95% agreement limits were smallest for approach #1 (2.33%, 13.0%) and largest for #3 (-20.8%, 11.3%). Approach #2 showed concentration-dependence (negative compared with positive differences at low compared with high RBF). Using weighted data, we found similar patterns across approaches for mean relative differences by demographic subgroup for all 3 time periods. CONCLUSIONS: We obtained the best agreement between estimated and "true" RBF when we predicted SFOL using a regression equation obtained from a subset of samples (approach #6). Alternatively, the consistent overestimation of RBF when assuming SFOL = 0 (∼6%) could be addressed by adjusting the data (approach #5). Similar observations for pre- and postfortification periods suggest applicability to low and high folate status situations, but should be confirmed elsewhere. To estimate RBF, at least WBF and Hb are needed.

Trends in Multivitamin Use Among Women of Reproductive Age: United States, 2006-2016.

BACKGROUND: Women of reproductive age can consume 0.4 milligrams of folic acid daily to reduce the risk of a neural tube defect (NTD)-affected pregnancy. Multivitamins (MVs) are one source of folic acid. MATERIALS AND METHODS: Using HealthStyles survey data (n = 9268), we assessed change in prevalence of MV use during 2006-2016 among women by age (18-24, 25-34, and 35-44 years), race/ethnicity (non-Hispanic [NH] white, NH black, Hispanic), and pregnancy status (trying to get pregnant, not pregnant nor trying to get pregnant, and pregnant) using log-binomial regression. RESULTS: Daily MV consumption decreased overall from 32.7% to 23.6% during 2006-2016 for women aged 18-44 years (p for trend <0.001). Age-specific decreases were seen in women aged 25-34 years (2006: 34.1%; 2016: 23.7%; p < 0.001) and 35-44 years (2006: 37.3%; 2016: 27.1%; p < 0.001). Decreases in daily MV intake were found among NH whites (2006: 35.4%; 2016: 24.9%; p < 0.001) and Hispanics (2006: 30.6%; 2016: 22.1%; p < 0.001), but remained unchanged among NH blacks (2006: 23.7%; 2016: 21.8%; p = 0.87). Daily MV intake remained unchanged for women trying to get pregnant (2006: 40.2%; 2012: 38.3%; p = 0.19), decreased for women not pregnant nor trying to get pregnant (2006: 31.3%; 2012: 21.3%; p < 0.001), and fluctuated for pregnant women (2006: 53.8%; 2012: 71.0%; p = 0.21). Prevalence of no MV consumption increased significantly across all age and race/ethnicity groups. CONCLUSIONS: Overall MV intake decreased for the past decade and varied by age, race/ethnicity, and pregnancy status. Innovative messaging and targeted interventions for increasing folic acid intake are needed to reduce NTDs.

Defining the plasma folate concentration associated with the red blood cell folate concentration threshold for optimal neural tube defects prevention: a population-based, randomized trial of folic acid supplementation.

BACKGROUND: For women of reproductive age, a population-level red blood cell (RBC) folate concentration below the threshold 906 nmol/L or 400 ng/mL indicates folate insufficiency and suboptimal neural tube defect (NTD) prevention. A corresponding population plasma/serum folate concentration threshold for optimal NTD prevention has not been established. OBJECTIVE: The aim of this study was to examine the association between plasma and RBC folate concentrations and estimated a population plasma folate insufficiency threshold (pf-IT) corresponding to the RBC folate insufficiency threshold (RBCf-IT) of 906 nmol/L. METHODS: We analyzed data on women of reproductive age (n = 1673) who participated in a population-based, randomized folic acid supplementation trial in northern China. Of these women, 565 women with anemia and/or vitamin B-12 deficiency were ineligible for folic acid intervention (nonintervention group); the other 1108 received folic acid supplementation for 6 mo (intervention group). We developed a Bayesian linear model to estimate the pf-IT corresponding to RBCf-IT by time from supplementation initiation, folic acid dosage, methyltetrahydrofolate reductase (MTHFR) genotype, body mass index (BMI), vitamin B-12 status, or anemia status. RESULTS: Using plasma and RBC folate concentrations of the intervention group, the estimated median pf-IT was 25.5 nmol/L (95% credible interval: 24.6, 26.4). The median pf-ITs were similar between the baseline and postsupplementation samples (25.7 compared with 25.2 nmol/L) but differed moderately (±3-4 nmol/L) by MTHFR genotype and BMI. Using the full population-based baseline sample (intervention and nonintervention), the median pf-IT was higher for women with vitamin B-12 deficiency (34.6 nmol/L) and marginal deficiency (29.8 nmol/L) compared with the sufficient group (25.6 nmol/L). CONCLUSIONS: The relation between RBC and plasma folate concentrations was modified by BMI and genotype and substantially by low plasma vitamin B-12. This suggests that the threshold of 25.5 nmol/L for optimal NTD prevention may be appropriate in populations with similar characteristics, but it should not be used in vitamin B-12 insufficient populations. This trial was registered at clinicaltrials.gov as NCT00207558.