Folate and vitamin B12 status and predicted neural tube defects risk among nonpregnant women of reproductive age from the Malawi National Micronutrient Survey, 2015-2016

BACKGROUND

Maternal folate and vitamin B12 deficiency can lead to serious adverse pregnancy outcomes. There are no nationally representative estimates on folate and vitamin B12 status among women of reproductive age (WRA) in Malawi.

OBJECTIVE

We assessed folate and vitamin B12 status among nonpregnant WRA in Malawi and predicted the risk of folate-sensitive neural tube defects (NTDs) were they to become pregnant.

METHODS

Using data from the cross-sectional, nationally representative 2015-2016 Malawi Micronutrient Survey, we calculated the proportion of folate and vitamin B12 deficiency and insufficiency by demographic characteristics among 778 nonpregnant WRA (15-49 years). We predicted NTD prevalence using red blood cell (RBC) folate distributions and a published Bayesian model of the association between RBC folate and NTD risk. Analyses accounted for complex survey design.

RESULTS

Among WRA, 8.5% (95% CI: 6.2, 11.6) and 13.3% (10.0, 17.4) had serum (<7 nmol/L) and RBC folate (<305 nmol/L) deficiency, respectively. The proportion of vitamin B12 deficiency (<148 pmol/L) and insufficiency (≤221 pmol/L) was 11.8% (8.6, 16.0) and 40.6% (34.1, 47.4), respectively. RBC folate insufficiency (<748 nmol/L, defined as the concentration associated with the threshold for elevated NTD risk: >8 cases per 10,000 births) was widespread: 81.4% (75.0, 86.4). The predicted NTD risk nationally was 24.7 cases per 10,000 live births. RBC folate insufficiency and higher predicted NTD risk were more common among WRA living in urban areas or with higher education.

CONCLUSIONS

These findings highlight the importance of nutritional and NTD surveillance in Malawi and the opportunity for improving folate and vitamin B12 nutrition among Malawian WRA.

A multicenter analytical performance evaluation of a multiplexed immunoarray for the simultaneous measurement of biomarkers of micronutrient deficiency, inflammation and malarial antigenemia

A lack of comparative data across laboratories is often a barrier to the uptake and adoption of new technologies. Furthermore, data generated by different immunoassay methods may be incomparable due to a lack of harmonization. In this multicenter study, we describe validation experiments conducted in a single lab and cross-lab comparisons of assay results to assess the performance characteristics of the Q-plex™ 7-plex Human Micronutrient Array (7-plex), an immunoassay that simultaneously quantifies seven biomarkers associated with micronutrient (MN) deficiencies, inflammation and malarial antigenemia using plasma or serum; alpha-1-acid glycoprotein, C-reactive protein, ferritin, histidine-rich protein 2, retinol binding protein 4, soluble transferrin receptor, and thyroglobulin. Validations included repeated testing (n = 20 separately prepared experiments on 10 assay plates) in a single lab to assess precision and linearity. Seven independent laboratories tested 76 identical heparin plasma samples collected from a cohort of pregnant women in Niger using the same 7-plex assay to assess differences in results across laboratories. In the analytical validation experiments, intra- and inter-assay coefficients of variation were acceptable at <6% and <15% respectively and assay linearity was 96% to 99% with the exception of ferritin, which had marginal performance in some tests. Cross-laboratory comparisons showed generally good agreement between laboratories in all analyte results for the panel of 76 plasma specimens, with Lin's concordance correlation coefficient values averaging ≥0.8 for all analytes. Excluding plates that would fail routine quality control (QC) standards, the inter-assay variation was acceptable for all analytes except sTfR, which had an average inter-assay coefficient of variation of ≥20%. This initial cross-laboratory study demonstrates that the 7-plex test protocol can be implemented by users with some experience in immunoassay methods, but familiarity with the multiplexed protocol was not essential.

Relation between Timing of High-Dose Vitamin A Supplementation and Modified-Relative-Dose-Response Values in Children 12-23 Months in Uganda

BACKGROUND

High-dose vitamin A (VA) supplements (VAS) can temporarily affect VA status. Hence, micronutrient surveys might need to be timed around VAS campaigns to accurately estimate VA deficiency (VAD) prevalence. Little is known about optimal timing of micronutrient surveys when the modified-relative-dose-response (MRDR) is used as a VA indicator.

OBJECTIVES

We evaluated the association between days since the end of a VAS campaign and MRDR values in children aged 12-23 mo in Uganda.

METHODS

We pooled data from 2 cross-sectional, population-based surveys in eastern Uganda conducted in 2015-2016 (n = 118 children). We estimated the prevalence of VAD (MRDR ≥0.060). Days since the end of a VAS campaign ("days since VAS") was calculated as the interview date minus the end date of the VAS campaign. The MRDR value was assessed using HPLC. We excluded children whose MRDR values were below the limit of detection (<0.007). We used linear regression to evaluate the association between days since VAS and log-transformed MRDR. In adjusted analyses, we controlled for potential confounders. Statistical analyses accounted for the surveys' complex design.

RESULTS

The prevalence of VAD was 5.2% (95% CI: 1.1%, 9.3%). Mean days since VAS was 54.1 d (range 39-68 d). Days since VAS was not associated with log-transformed MRDR in unadjusted analyses ($\hat{\beta } = \ $0.0055; 95% CI: -0.009, 0.020; P = 0.45) or adjusted analyses ($\hat{\beta } = $ -0.0073; 95% CI: -0.024, 0.010; P = 0.39).

CONCLUSIONS

MRDR measurement through a nutrition survey began as early as 1.3 mo after the end of a VAS campaign in eastern Uganda. Days since the end of a VAS campaign was not associated with MRDR in Ugandan children aged 12-23 mo. Future studies should consider longitudinal designs and evaluate time since VAS and MRDR in children of different ages and in regions with higher VAD prevalence.

Vitamin A deficiency has declined in Malawi, but with evidence of elevated vitamin A in children

BACKGROUND

Reduction of vitamin A deficiency (VAD) in Malawi coincided with introduction of vitamin A-fortified staple foods, alongside continued biannual high-dose vitamin A supplementation (VAS).

OBJECTIVE

We describe coverage of vitamin A interventions and vitamin A status in the 2015-2016 Malawi Micronutrient Survey.

METHODS

Food samples and biospecimens were collected within a representative household survey across 105 clusters. Retinol was measured using ultraviolet excitation fluorescence (sugar) and photometric determination (oil). Preschool children (PSC, aged 6-59 mo, n = 1102), school-age children (SAC, aged 5-14 y, n = 758), nonpregnant women (n = 752), and men (n = 219) were initially assessed for vitamin A status using retinol binding protein (RBP) and modified relative dose response (MRDR). Randomly selected fasted MRDR participants (n = 247) and nonfasted women and children (n = 293) were later assessed for serum retinol, retinyl esters, and carotenoids. Analyses accounted for complex survey design.

RESULTS

We tested sugar and oil samples from 71.8% and 70.5% of the households (n = 2,112), respectively. All of the oil samples and all but one of the sugar samples had detectable vitamin A. National mean retinol sugar and oil contents were 6.1 ± 0.7 mg/kg and 6.6 ± 1.4 mg/kg, respectively. Receipt of VAS in the previous 6 mo was reported by 68.0% of PSC. VAD prevalence (RBP equivalent to <0.7µmol retinol/L) was 3.6% in PSC, and <1% in other groups. One woman and no children had MRDR ≥0.060 indicating VAD. Among fasted PSC and SAC, 18.0% (95% CI: 6.4, 29.6) and 18.8% (7.2, 30.5) had >5% of total serum vitamin A as retinyl esters, and 1.7% (0.0, 4.1) and 4.9% (0.0, 10.2) had >10% of total serum vitamin A as retinyl esters. Serum carotenoids indicated recent intake of vitamin A-rich fruits and vegetables.

CONCLUSIONS

Near elimination of VAD in Malawi is a public health success story, but elevated levels of vitamin A among children suggests that vitamin A interventions may need modification.

An Integrated Enhanced Infant and Young Child Feeding (IYCF) and Micronutrient Powder Intervention Improved Select IYCF Practices Among Caregivers of Children Aged 12-23 Months in Eastern Uganda

BACKGROUND

There is little evidence of the impact of integrated programs distributing nutrition supplements with behavior change on infant and young child feeding (IYCF) practices.

OBJECTIVE

We evaluated the impact of an integrated IYCF/micronutrient powder intervention on IYCF practices among caregivers of children aged 12-23 mo in eastern Uganda.

METHODS

We used pre-post data from 2 population-based, cross-sectional surveys representative of children aged 12-23 mo in Amuria (intervention) and Soroti (nonintervention) districts (n = 2816). Caregivers were interviewed in June/July at baseline in 2015 and 12 mo after implementation in 2016. We used generalized linear mixed models with cluster as a random effect to calculate the average intervention effect on receiving IYCF counseling, ever breastfed, current breastfeeding, bottle feeding, introducing complementary feeding at age 6 mo, continued breastfeeding at ages 1 and 2 y, minimum meal frequency (MMF), minimum dietary diversity, minimum acceptable diet (MAD), and consumption of food groups the day preceding the survey.

RESULTS

Controlling for child age and sex, household wealth and food security, and caregiver schooling, the intervention was positively associated with having received IYCF counseling by village health team [adjusted prevalence difference-in-difference (APDiD): +51.6%; 95% CI: 44.0%, 59.2%]; timely introduction of complementary feeding (APDiD: +21.7%; 95% CI: 13.4%, 30.1%); having consumed organs or meats (APDiD: +9.0%; 95% CI: 1.4%, 16.6%) or vitamin A-rich fruits or vegetables (APDiD: +17.5%; 95% CI: 4.5%, 30.5%); and MMF (APDiD: +18.6%; 95% CI: 11.2%, 25.9%). The intervention was negatively associated with having consumed grains, roots, or tubers (APDiD: -4.4%; 95% CI: -7.0%, -1.7%) and legumes, nuts, or seeds (APDiD: -15.6%; 95% CI: -26.2%, -5.0%). Prevalences of some IYCF practices were low in Amuria at endline including MAD (19.1%; 95% CI :16.3%, 21.9%).

CONCLUSIONS

The intervention had a positive impact on several IYCF practices; however, endline prevalence of some indicators suggests a continued need to improve complementary feeding practices.

Retinol-binding protein, retinol, and modified-relative-dose response in Ugandan children aged 12-23 months and their non-pregnant caregivers

Retinol-binding protein (RBP), retinol, and modified-relative-dose response (MRDR) are used to assess vitamin A status. We describe vitamin A status in Ugandan children and women using dried blood spot (DBS) RBP, serum RBP, plasma retinol, and MRDR and compare DBS-RBP, serum RBP, and plasma retinol. Blood was collected from 39 children aged 12-23 months and 28 non-pregnant mothers aged 15-49 years as a subsample from a survey in Amuria district, Uganda, in 2016. DBS RBP was assessed using a commercial enzyme immunoassay kit, serum RBP using an in-house sandwich enzyme-linked immunosorbent assay, and plasma retinol/MRDR test using high-performance liquid chromatography. We examined (a) median concentration or value (Q1, Q3); (b) R² between DBS-RBP, serum RBP, and plasma retinol; and (c) Bland-Altman plots. Median (Q1, Q3) for children and mothers, respectively, were as follows: DBS-RBP 1.15 µmol/L (0.97, 1.42) and 1.73 (1.52, 1.96), serum RBP 0.95 µmol/L (0.78, 1.18) and 1.47 µmol/L (1.30, 1.79), plasma retinol 0.82 µmol/L (0.67, 0.99) and 1.33 µmol/L (1.22, 1.58), and MRDR 0.025 (0.014, 0.042) and 0.014 (0.009, 0.019). DBS RBP-serum RBP R² was 0.09 for both children and mothers. The mean biases were -0.19 µmol/L (95% limits of agreement [LOA] 0.62, -0.99) for children and -0.01 µmol/L (95% LOA -1.11, -1.31) for mothers. DBS RBP-plasma retinol R² was 0.11 for children and 0.13 for mothers. Mean biases were 0.33 µmol/L (95% LOA -0.37, 1.03) for children, and 0.29 µmol/L (95% LOA -0.69, 1.27) for mothers. Serum RBP-plasma retinol R² was 0.75 for children and 0.55 for mothers, with mean biases of 0.13 µmol/L (95% LOA -0.23, 0.49) for children and 0.18 µmol/L (95% LOA -0.61, 0.96) for mothers. Results varied by indicator and matrix. The serum RBP-retinol R² for children was moderate (0.75), but poor for other comparisons. Understanding the relationships among vitamin A indicators across contexts and population groups is needed.

The Co-Occurrence of Overweight and Micronutrient Deficiencies or Anemia among Women of Reproductive Age in Malawi

BACKGROUND

In low-resource settings, urbanization may contribute to the individual-level double burden of malnutrition (DBM), whereby under- and overnutrition co-occur within the same individuals.

OBJECTIVE

We described DBM prevalence among Malawian women by urban-rural residence, examined whether urban residence was associated with DBM, and assessed whether DBM prevalence was greater than the prevalence expected by chance given population levels of under- and overnutrition, which would suggest DBM is a distinct phenomenon associated with specific factors.

METHODS

We analyzed nationally representative data of 723 nonpregnant women aged 15-49 y from the 2015-2016 Malawi Micronutrient Survey. DBM was defined as co-occurring overweight or obesity (OWOB) and ≥1 micronutrient deficiency or anemia. We used Poisson regression models to examine the association between urban residence and DBM and its components. The Rao-Scott modified chi-square test compared the observed and expected DBM prevalence.

RESULTS

Nationally, 10.8% (95% CI: 7.0, 14.5) of women had co-occurring OWOB and any micronutrient deficiency and 3.4% (95% CI: 1.3, 5.5) had co-occurring OWOB and anemia. The prevalence of co-occurring OWOB and any micronutrient deficiency was 2 times higher among urban women than rural women [urban 32.6 (24.1, 41.2) compared with rural 8.6 (5.2, 11.9), adjusted prevalence ratio: 2.0 (1.1, 3.5)]. Co-occurring OWOB and anemia prevalence did not significantly differ by residence [urban 6.9 (0.6, 13.2) compared with rural 3.0 (0.8, 5.3)]. There were no statistically significant differences in observed and expected prevalence estimates of DBM.

CONCLUSIONS

This analysis shows that co-occurring OWOB and any micronutrient deficiency was higher among women in urban Malawi compared with rural areas. However, our finding that co-occurring OWOB and any micronutrient deficiency or anemia may be due to chance suggests that there may not be common causes driving DBM in Malawian women. Thus, there may not be a need to design and target interventions specifically for women with DBM.

An Integrated Infant and Young Child Feeding and Micronutrient Powder Intervention Does Not Affect Anemia, Iron Status, or Vitamin A Status among Children Aged 12-23 Months in Eastern Uganda

BACKGROUND

Micronutrient powders (MNP) can reduce iron deficiency and anemia in children.

OBJECTIVE

We evaluated the impact of an integrated infant and young child feeding (IYCF)-MNP intervention on anemia and micronutrient status among children aged 12-23 mo in Eastern Uganda. The intervention focused on MNP distribution, IYCF education, and caregiver behavior change.

METHODS

Population-based cross-sectional surveys representative of children aged 12-23 mo in Amuria (intervention) and Soroti (nonintervention) districts were collected in June/July 2015 at baseline (n = 1260) and 12 mo after implementation at endline in 2016 (n = 1490). From pooled capillary blood, we assessed hemoglobin, malaria, ferritin, retinol binding protein (RBP), C-reactive protein, and ɑ1-acid glycoprotein. Ferritin and RBP were regression-adjusted to correct for inflammation. Caregivers reported sociodemographic characteristics and MNP knowledge and practices. Linear regression estimated the difference-in-difference (DiD) effect of MNP on hemoglobin, ferritin, and RBP, and logistic regression estimated DiD effect of MNP on anemia (hemoglobin <11.0 g/dL), iron deficiency (ferritin <12.0 µg/L), iron deficiency anemia (hemoglobin <11.0 g/dL and ferritin <12.0 µg/L), and vitamin A deficiency (VAD; RBP equivalent to <0.70 µmol/L retinol: <0.79 µmol/L at baseline and RBP <0.67 µmol/L at endline).

RESULTS

In Amuria, 96% of children had ever consumed MNP versus <1% of children in Soroti. Fifty-four percent of caregivers reported organoleptic changes when MNP were added to foods cooked with soda ash. Adjusting for age, sex, malaria, recent morbidity, and household-level factors, the intervention was associated with -0.83 g/dL lower hemoglobin (95% CI, -1.36, -0.30 g/dL; P = 0.003) but not with anemia, ferritin, iron deficiency, iron deficiency anemia, RBP, or VAD.

CONCLUSIONS

Despite high program fidelity, the intervention was associated with reduced hemoglobin concentrations but not with change in anemia or micronutrient status among children aged 12-23 mo in Eastern Uganda. Contextual factors, such as cooking with soda ash, might explain the lack of effectiveness.

Predictors of micronutrient powder sachet coverage and recent intake among children 12-23 months in Eastern Uganda

We evaluated predictors of micronutrient powder (MNP) sachet coverage and recent intake using data from a cross-sectional survey representative of children aged 12-23 months in Amuria district, Uganda. In June/July 2016, caregivers were interviewed 12 months after implementation of an integrated MNP and infant and young child feeding pilot (N = 761). Logistic regression described predictors of (a) high-MNP sachet coverage (received at least 60 sachets/6 months) and (b) recent intake (consumed MNP during the 2 weeks preceding the survey) among children who had ever received MNP and had complete data (N = 683). Fifty-nine percent (95% Confidence Interval [CI] [53.8, 64.2]) of children had high-MNP sachet coverage, and 65.4% (95% CI [61.0, 69.9]) had recent intake. MNP ration cards (Adjusted Odds Ratio [AOR] 2.67, 95% CI [1.15, 6.23]), organoleptic changes to foods cooked with soda ash (AOR 1.52, 95% CI [1.08, 2.14]), having heard of anaemia (AOR 1.59, 95% CI [1.11, 2.26]), knowledge of correct MNP preparation (AOR 1.89, 95% CI [1.11, 3.19]), and current breastfeeding (AOR 2.04, 95% CI [1.36, 3.08]) were positively associated with MNP coverage whereas older child age (18-23 vs. 12-17 months) was inversely associated with coverage (AOR 0.32, 95% CI [0.23, 0.50]). MNP ration cards (AOR 2.86, 95% CI [1.34, 6.09]), having heard an MNP radio jingle (AOR 1.40, 95% CI [1.01, 1.94]), knowledge of correct MNP preparation (AOR 1.88, 95% CI [1.04, 3.39]), and the child not disliking MNP (AOR 1.90, 95% CI [1.13, 3.22]) were positively associated with recent intake. Interventions that increase caregiver knowledge and skills and focus on older children could improve MNP coverage and recent intake.

Integrating micronutrient status assessment into the 2015-2016 Malawi Demographic and Health Survey: A qualitative evaluation

Demand for national-level micronutrient status data continues to grow, yet little is known about the implementation of different approaches for collecting these data. We conducted an evaluation of the process of linking the 2015-2016 Malawi Demographic and Health Survey (MDHS) and 2015-2016 Malawi Micronutrient Survey (MNS). We conducted 24 in-depth interviews with stakeholders from the Malawi government and international agencies and field staff. Interview questions explored perceptions of what worked and what was challenging during three phases of implementation: preparation; data collection; and data analysis, reporting, and dissemination. Data were analysed using thematic analysis. Results showed that there was strong government interest to integrate the MDHS and MNS. Perceived benefits included potential cost savings and lower respondent burden. However, government and international agency stakeholders did not view the linkage of the surveys to be a fully integrated approach. The lack of full integration produced challenges throughout implementation, such as complex field logistics and duplication in nutrition indicators assessed and reported. Some stakeholders believed integration was not attainable primarily due to timing. The MDHS and MNS were originally designed as stand-alone surveys, and planning for each survey was at an advanced stage once the government sought to integrate the surveys. Additionally, the MNS could not be incorporated as a module within the MDHS given the complexity of the MNS data collection and short timeframe for planning. These findings can inform decisions about implementing the next MNS and may be transferable to other countries that are conducting micronutrient surveys to address data gaps.

Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings

This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of ±7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0  g/L), WHO Colour Scale (0.5-10.0  g/L), paper-based devices (5.0-7.0  g/L), HemoCue® Hb-201 (1.0-16.0  g/L) and Hb-301 (0.5-6.0  g/L), and Masimo Pronto® (0.3-14.0  g/L) overestimated concentrations; (2) Masimo Radical®-7 both under- and overestimated concentrations (0.3-104.0  g/L); and (3) other methods underestimated concentrations (2.0-16.0  g/L). Most mean concentration comparisons varied less than ±7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.

An Integrated Micronutrient Powder Intervention Improved IYCF Practices Among Caregivers of Children 6–23 Months in Eastern Uganda (P10-131-19)

Objectives

We evaluated the impact of an integrated infant and young child feeding (IYCF) – micronutrient powder intervention on IYCF practices among caregivers of children 12–23 mo in Eastern Uganda.

Methods

We used pre-/post- data from two population-based, cross-sectional surveys representative of children aged 12–23 mo in Amuria (intervention) and Soroti (non-intervention) districts. Caregivers were interviewed in June/July at baseline 2015 (N = 1260) and 12 mo after implementation in 2016 (N = 1490) about their IYCF practices the day preceding the survey. Logistic regression estimated the double-difference effect of the intervention on core World Health Organization (WHO) IYCF indicators: child ever breastfed, current breastfeeding, bottle feeding, complementary foods introduced at age 6 mo, consumption of vitamin A-rich fruits or vegetables, consumption of animal-flesh foods, minimum meal frequency (MMF) (received food ≥3 times for breastfed children and ≥4 times for non-breastfed children), minimum dietary diversity (MDD) (received foods from ≥4 of 7 WHO food groups), and minimum acceptable diet (MAD) (MDD and MMF among breastfed children, and ≥2 milk feeds, MDD not including milk feeds, and MMF among non-breastfed children). Analyses were weighted and accounted for complex sampling design.

Results

After controlling for child age and sex, household wealth, household food security, and caregiver education, the intervention was positively associated with MMF (Adjusted Prevalence Difference-in-Difference [APDiD] 18.6%; 95% Confidence Interval [CI] 11.2, 26.0) and MAD (APDiD 5.6%; 95% CI 0.02, 11.2). The intervention was associated with 21.8% higher prevalence of timely introduction of complementary feeding (95% CI 13.4, 30.1) and with increased consumption of both vitamin A-rich fruits/vegetables (APDiD 23.5%; 95% CI 12.5, 34.5) and animal-flesh foods (APDiD 9.1%; 95% CI 1.5, 16.7). The intervention did not affect breastfeeding or bottle feeding practices. Despite program impact, prevalence of some IYCF practices were low in Amuria at endline including MAD (19%) and MMF (21%).

Conclusions

The integrated IYCF intervention had a positive impact on many core WHO IYCF practices; however, low endline prevalence of some indicators suggests a continued need to improve complementary feeding practices in Eastern Uganda.

Funding Sources

Funding or in kind technical support provided by the Ministry of Health Uganda, World Food Programme, and the U.S. Centers for Disease Control and Prevention (CDC).