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Featured researches published by Megan Parker.


PLOS ONE | 2014

Stunting, poor iron status and parasite infection are significant risk factors for lower cognitive performance in Cambodian school-aged children.

Marlène Perignon; Marion Fiorentino; Khov Kuong; Kurt Burja; Megan Parker; Sek Sisokhom; Chhoun Chamnan; Jacques Berger; Frank T. Wieringa

Background Nutrition is one of many factors affecting the cognitive development of children. In Cambodia, 55% of children <5 y were anemic and 40% stunted in 2010. Currently, no data exists on the nutritional status of Cambodian school-aged children, or on how malnutrition potentially affects their cognitive development. Objective To assess the anthropometric and micronutrient status (iron, vitamin A, zinc, iodine) of Cambodian schoolchildren and their associations with cognitive performance. Methods School children aged 6–16 y (n = 2443) from 20 primary schools in Cambodia were recruited. Anthropometry, hemoglobin, serum ferritin, transferrin receptors, retinol-binding protein and zinc concentrations, inflammation status, urinary iodine concentration and parasite infection were measured. Socio-economic data were collected in a sub-group of children (n = 616). Cognitive performance was assessed using Raven’s Colored Progressive Matrices (RCPM) and block design and picture completion, two standardized tests from the Wechsler Intelligence Scale for Children (WISC-III). Results The prevalence of anemia, iron, zinc, iodine and vitamin A deficiency were 15.7%; 51.2%, 92.8%, 17.3% and 0.7% respectively. The prevalence of stunting was 40.0%, including 10.9% of severe stunting. Stunted children scored significantly lower than non-stunted children on all tests. In RCPM test, boys with iron-deficiency anemia had lower scores than boys with normal iron status (−1.46, p<0.05). In picture completion test, children with normal iron status tended to score higher than iron-deficient children with anemia (−0.81; p = 0.067) or without anemia (−0.49; p = 0.064). Parasite infection was associated with an increase in risk of scoring below the median value in block design test (OR = 1.62; p<0.05), and with lower scores in other tests, for girls only (both p<0.05). Conclusion Poor cognitive performance of Cambodian school-children was multifactorial and significantly associated with long-term (stunting) and current nutritional status indicators (iron status), as well as parasite infection. A life-cycle approach with programs to improve nutrition in early life and at school-age could contribute to optimal cognitive performance.


Nutrients | 2016

Impact of Multi-Micronutrient Fortified Rice on Hemoglobin, Iron and Vitamin A Status of Cambodian Schoolchildren: a Double-Blind Cluster-Randomized Controlled Trial

Marlène Perignon; Marion Fiorentino; Khov Kuong; Marjoleine A. Dijkhuizen; Kurt Burja; Megan Parker; Chhoun Chamnan; Jacques Berger; Frank T. Wieringa

In Cambodia, micronutrient deficiencies remain a critical public health problem. Our objective was to evaluate the impact of multi-micronutrient fortified rice (MMFR) formulations, distributed through a World Food Program school-meals program (WFP-SMP), on the hemoglobin concentrations and iron and vitamin A (VA) status of Cambodian schoolchildren. The FORISCA-UltraRice+NutriRice study was a double-blind, cluster-randomized, placebo-controlled trial. Sixteen schools participating in WFP-SMP were randomly assigned to receive extrusion-fortified rice (UltraRice Original, UltraRice New (URN), or NutriRice) or unfortified rice (placebo) six days a week for six months. Four additional schools not participating in WFP-SMP were randomly selected as controls. A total of 2440 schoolchildren (6–16 years old) participated in the biochemical study. Hemoglobin, iron status, estimated using inflammation-adjusted ferritin and transferrin receptors concentrations, and VA status, assessed using inflammation-adjusted retinol-binding protein concentration, were measured at the baseline, as well as at three and six months. Baseline prevalence of anemia, depleted iron stores, tissue iron deficiency, marginal VA status and VA deficiency were 15.6%, 1.4%, 51.0%, 7.9%, and 0.7%, respectively. The strongest risk factors for anemia were hemoglobinopathy, VA deficiency, and depleted iron stores (all p < 0.01). After six months, children receiving NutriRice and URN had 4 and 5 times less risk of low VA status, respectively, in comparison to the placebo group. Hemoglobin significantly increased (+0.8 g/L) after three months for the URN group in comparison to the placebo group; however, this difference was no longer significant after six months, except for children without inflammation. MMFR containing VA effectively improved the VA status of schoolchildren. The impact on hemoglobin and iron status was limited, partly by sub-clinical inflammation. MMFR combined with non-nutritional approaches addressing anemia and inflammation should be further investigated.


Nutrients | 2015

Height, zinc and soil-transmitted helminth infections in schoolchildren: a study in Cuba and Cambodia.

Brechje de Gier; Liliane Mpabanzi; Kim Vereecken; Suzanne D. van der Werff; Patrick C. D'Haese; Marion Fiorentino; Kuong Khov; Marlène Perignon; Chhoun Chamnan; Jacques Berger; Megan Parker; Raquel Junco Diaz; Fidel Angel Núñez; Lázara Rojas Rivero; Mariano Bonet Gorbea; Colleen M. Doak; Maiza Campos Ponce; Frank T. Wieringa; Katja Polman

Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris trichiura infections. In Cambodia, STH prevalence was 16.8%, mostly caused by hookworm. In Cuban children, STH infection had a strong association with height for age (aB-0.438, p = 0.001), while hair zinc was significantly associated with height for age only in STH uninfected children. In Cambodian children, plasma zinc was associated with height for age (aB-0.033, p = 0.029), but STH infection was not. Only in Cambodia, STH infection showed an association with zinc concentration (aB-0.233, p = 0.051). Factors influencing child growth differ between populations and may depend on prevalences of STH species and zinc deficiency. Further research is needed to elucidate these relationships and their underlying mechanisms.


PLOS ONE | 2016

Micronutrient-Fortified Rice Can Increase Hookworm Infection Risk: A Cluster Randomized Trial

Brechje de Gier; Maiza Campos Ponce; Marlène Perignon; Marion Fiorentino; Kuong Khov; Chhoun Chamnan; Michiel R. de Boer; Megan Parker; Kurt Burja; Marjoleine A. Dijkhuizen; Jacques Berger; Katja Polman; Frank T. Wieringa

Background Fortification of staple foods is considered an effective and safe strategy to combat micronutrient deficiencies, thereby improving health. While improving micronutrient status might be expected to have positive effects on immunity, some studies have reported increases in infections or inflammation after iron supplementation. Objective To study effects of micronutrient-fortified rice on hookworm infection in Cambodian schoolchildren. Methods A double-blinded, cluster-randomized trial was conducted in 16 Cambodian primary schools partaking in the World Food Program school meal program. Three types of multi-micronutrient fortified rice were tested against placebo rice within the school meal program: UltraRice_original, UltraRice_improved and NutriRice. Four schools were randomly assigned to each study group (placebo n = 492, UltraRice_original n = 479, UltraRice_improved n = 500, NutriRice n = 506). Intestinal parasite infection was measured in fecal samples by Kato-Katz method at baseline and after three and seven months. In a subgroup (N = 330), fecal calprotectin was measured by ELISA as a marker for intestinal inflammation. Results Baseline prevalence of hookworm infection was 18.6%, but differed considerably among schools (range 0%- 48.1%).Micronutrient-fortified rice significantly increased risk of new hookworm infection. This effect was modified by baseline hookworm prevalence at the school; hookworm infection risk was increased by all three types of fortified rice in schools where baseline prevalence was high (>15%), and only by UltraRice_original in schools with low baseline prevalence. Neither hookworm infection nor fortified rice was related to fecal calprotectin. Conclusions Consumption of rice fortified with micronutrients can increase hookworm prevalence, especially in environments with high infection pressure. When considering fortification of staple foods, a careful risk-benefit analysis is warranted, taking into account severity of micronutrient deficiencies and local prevalence of parasitic infections. Trial Registration ClinicalTrials.gov NCT01706419


Maternal and Child Nutrition | 2018

Patterns of cultural consensus and intracultural diversity in Ghanaian complementary feeding practices

Nikhila Kalra; Gretel H. Pelto; Charlotte Tawiah; Stephanie Zobrist; Peiman Milani; Grace Manu; Amos Laar; Megan Parker

Designing effective interventions to improve infant and young child (IYC) feeding requires knowledge about determinants of current practices, including cultural factors. Current approaches to obtaining and using research on culture tend to assume cultural homogeneity within a population. The purpose of this study was to examine the extent of cultural consensus (homogeneity) in communities where interventions to improve IYC feeding practices are needed to address undernutrition during the period of complementary feeding. A second, related objective was to identify the nature of intracultural variation, if such variation was evident. Selected protocols from the Focused Ethnographic Study for Infant and Young Child Feeding Manual were administered to samples of key informants and caregivers in a peri-urban and a rural area in Brong-Ahafo, Ghana. Cultural domain analysis techniques (free listing, caregiver assessment of culturally significant dimensions, and food ratings on these dimensions), as well as open-ended questions with exploratory probing, were used to obtain data on beliefs and related practices. Results reveal generally high cultural consensus on the 5 dimensions that were assessed (healthiness, appeal, child acceptance, convenience, and modernity) for caregiver decisions and on their ratings of individual foods. However, thematic analysis of caregiver narratives indicates that the meanings and content of the constructs connoted by the dimensions differed widely among individual mothers. These findings suggest that research on cultural factors that affect IYC practices, particularly cultural beliefs, should consider the nature and extent of cultural consensus and intracultural diversity, rather than assuming cultural homogeneity.


Journal of Nutrition | 2017

Iron Bioavailability from Ferric Pyrophosphate in Extruded Rice Cofortified with Zinc Sulfate Is Greater than When Cofortified with Zinc Oxide in a Human Stable Isotope Study

Laura Hackl; Michael B. Zimmermann; Christophe Zeder; Megan Parker; Paul Johns; Richard F. Hurrell; Diego Moretti

Background: Extruded rice grains are often cofortified with iron and zinc. However, it is uncertain if the addition of zinc to iron-fortified rice affects iron absorption and whether this is zinc-compound specific.Objective: We investigated whether zinc, added as zinc oxide (ZnO) or zinc sulfate (ZnSO4), affects human iron absorption from extruded rice fortified with ferric pyrophosphate (FePP).Methods: In 19 iron-depleted Swiss women (plasma ferritin ≤16.5 μ/L) aged between 20 and 39 y with a normal body mass index (in kg/m2; 18.7-24.8), we compared iron absorption from 4 meals containing fortified extruded rice with 4 mg Fe and 3 mg Zn. Three of the meals contained extruded rice labeled with FePP (57FePP): 1) 1 meal without added zinc (57FePP-Zn), 2) 1 cofortified with ZnO (57FePP+ZnO), and 3) 1 cofortified with ZnSO4 (57FePP+ZnSO4). The fourth meal contained extruded rice without iron or zinc, extrinsically labeled with ferrous sulfate (58FeSO4) added as a solution after cooking. All 4 meals contained citric acid. Iron bioavailability was measured by isotopic iron ratios in red blood cells. We also measured relative in vitro iron solubility from 57FePP-Zn, 57FePP+ZnO, and 57FePP+ZnSO4 expressed as a fraction of FeSO4 solubility.Results: Geometric mean fractional iron absorption (95% CI) from 57FePP+ZnSO4 was 4.5% (3.4%, 5.8%) and differed from 57FePP+ZnO (2.7%; 1.8%, 4.1%) (P < 0.03); both did not differ from 57FePP-Zn: 4.0% (2.8%, 5.6%). Relative iron bioavailabilities compared with 58FeSO4 were 62%, 57%, and 38% from 57FePP+ZnSO4, 57FePP-Zn, and 57FePP+ZnO, respectively. In vitro solubility from 57FePP+ZnSO4 differed from that of 57FePP-Zn (14.3%; P < 0.02) but not from that of 57FePP+ZnO (10.2% compared with 13.1%; P = 0.08).Conclusions: In iron-depleted women, iron absorption from FePP-fortified extruded rice cofortified with ZnSO4 was 1.6-fold (95% CI: 1.4-, 1.9-fold) that of rice cofortified with ZnO. These findings suggest that ZnSO4 may be the preferable zinc cofortificant for optimal iron bioavailability of iron-fortified extruded rice. This trial was registered at clinicaltrials.gov as NCT02255942.


Food and Nutrition Bulletin | 2017

Results of Applying Cultural Domain Analysis Techniques and Implications for the Design of Complementary Feeding Interventions in Northern Senegal

Stephanie Zobrist; Nikhila Kalra; Gretel H. Pelto; Brittney Wittenbrink; Peiman Milani; Abdoulaye Moussa Diallo; Tidiane Ndoye; Issa Wone; Megan Parker

Background: Designing effective nutrition interventions for infants and young children requires knowledge about the population to which the intervention is directed, including insights into the cognitive systems and values that inform caregiver feeding practices. Objective: To apply cultural domain analysis techniques in the context of implementation research for the purpose of understanding caregivers’ knowledge frameworks in Northern Senegal with respect to infant and young child (IYC) feeding. This study was intended to inform decisions for interventions to improve infant and young child nutrition. Methods: Modules from the Focused Ethnographic Study for Infant and Young Child Feeding Manual were employed in interviews with a sample of 126 key informants and caregivers from rural and peri-urban sites in the Saint-Louis region of northern Senegal. Descriptive statistics, cluster analysis, and qualitative thematic analysis were used to analyze the data. Results: Cluster analysis showed that caregivers identified 6 food clusters: heavy foods, light foods, snack foods, foraged foods, packaged foods, and foods that are good for the body. The study also revealed similarities and differences between the 2 study sites in caregivers’ knowledge frameworks. Conclusions: The demonstration of differences between biomedical concepts of nutrition and the knowledge frameworks of northern Senegalese women with regard to IYC feeding highlights the value of knowledge about emic perspectives of local communities to help guide decisions about interventions to improve nutrition.


PLOS ONE | 2018

An evaluation of hemoglobin measurement tools and their accuracy and reliability when screening for child anemia in Rwanda: A randomized study

Megan Parker; Zhen Han; Elizabeth Abu-Haydar; Eric Matsiko; Damien Iyakaremye; Lisine Tuyisenge; Amalia Magaret; Alexandre Lyambabaje

Blood hemoglobin (Hb) is a common indicator for diagnosing anemia and is often determined through laboratory analysis of venous samples. One alternative to laboratory-based methods is the handheld HemoCue® Hb 201+ device, which requires a finger prick and wicking of blood into a pretreated cuvette for analysis. An alternative HemoCue® gravity method is being investigated for improved accuracy. Further, recent developments in noninvasive technologies could provide an accurate, rapid, safe, point-of-care option for hemoglobin estimation while addressing some limitations of current tools, but device performance must be assessed in low-resource settings. This study evaluated the performance of two HemoCue® Hb 201+ blood sampling methods and a noninvasive device (Pronto® with DCI-mini™ sensors) in a Rwandan pediatric clinic. Reference hemoglobin values were determined in 132 children 6 to 59 months of age by using a standard hematology analyzer (Sysmex KN21TM). Half were tested using the HemoCue® wicking method; half were tested using the HemoCue® gravity method; and 112 had successful hemoglobin readings with Pronto® DCI-mini™. Statistical analysis was used to assess the level of bias generated by each method and the key drivers of bias. The HemoCue® gravity method was the least biased. The HemoCue® wicking and Pronto® methods biases were inversely related to the Sysmex KN21TM results. Both HemoCue® sampling methods correctly classified patients’ anemic status in 80% or more of instances, whereas the Pronto® device had a correct classification rate of only 69%. The HemoCue® gravity method was more accurate than the traditional HemoCue® wicking method in this study, but its accuracy and operational feasibility should be confirmed by future studies. The Pronto® DCI-mini™ devices showed considerable promise but require further improvements in sensitivity and specificity before wider adoption.


Frontiers in Microbiology | 2018

Naturally Fermented Milk From Northern Senegal: Bacterial Community Composition and Probiotic Enrichment With Lactobacillus rhamnosus

Megan Parker; Stephanie Zobrist; Chantal Donahue; Connor Edick; Kimberly Mansen; Mehdi Hassan Zade Nadjari; Margreet Heerikhuisen; Wilbert Sybesma; Douwe Molenaar; Abdoulaye Moussa Diallo; Peiman Milani; Remco Kort

A variety of foods fermented with lactic acid bacteria serve as dietary staples in many African communities; yet, their bacterial profiles are poorly characterized. The integration of health-promoting probiotics into naturally fermented milk products could make a profound impact on human health. Here, we characterize the bacterial community composition of a naturally fermented milk product (lait caillé) from northern Senegal, prepared in wooden bowls (lahals) with a bacterial biofilm to steer the fermentation process. We incorporated a probiotic starter culture containing the most documented probiotic strain Lactobacillus rhamnosus GG (generic strain name yoba 2012) into the local fermentation process. Bar-coded 16S rRNA amplicon sequencing of lait caillé samples indicated that the bacterial community of lait caillé has high species richness with over 100 bacterial genera; however, few have high abundance. In contrast to the diverse bacterial compositions of other characterized naturally fermented milk products, the composition of lait caillé predominantly consists of the lactic acid bacteria Streptococcus and Lactobacillus, resembling the bacterial composition in regular yogurt. The bacterial community composition of lait caillé varies geographically based on the presence of some genera, including Lactoccoccus, Enterococcus, Bifidobacterium, and Bacillus, but this trend is not consistent within production communities. The diversity of bacterial communities is much higher in the lahal biofilm than in the naturally fermented milk products, which is in turn greater than in commercial yogurts. Addition of a starter culture with L. rhamnosus yoba 2012 to milk in lahals led to substantial growth of this probiotic bacterium during the fermentation process. Two independent quantitative PCR-analyses specific for L. rhamnosus yoba 2012 indicated a 20- to 60-fold increase in the total number of probiotic bacteria in the first batch after inoculation. A similar increase of the probiotic was observed in a variation of lait caillé prepared with carbohydrate-rich millet granules (thiakry) added prior to fermentation. This study shows the feasibility of integrating health-promoting probiotic strains into naturally fermented foods produced in regions with a high prevalence of malnutrition.


Acta Tropica | 2018

Soil-transmitted helminth infections and intestinal and systemic inflammation in schoolchildren

Brechje de Gier; Gisela M. Pita-Rodríguez; Maiza Campos-Ponce; Margot van de Bor; Chhoun Chamnan; Raquel Junco-Díaz; Colleen M. Doak; Marion Fiorentino; Khov Kuong; Fidel Angel-Núñez; Megan Parker; Marlène Perignon; Lázara Rojas-Rivero; Jacques Berger; Katja Polman; Frank T. Wieringa

Abstract • The objective of this study was to assess whether soil-transmitted helminth (STH) infections are associated with systemic and local intestinal inflammation in school-age children. In two studies in schoolchildren in Cuba (N = 1389) and in Cambodia (N = 2471), STH infections and calprotectin concentrations were measured in stool samples and acute phase proteins C-reactive protein (CRP) and alpha-1 acid glycoprotein (AGP) were measured in blood. Associations between STH infections and elevated concentrations of CRP, AGP and calprotectin were estimated using multiple logistic regression. The prevalence of elevated CRP concentration (≥5 mg/L) was 5.4% in both populations. Elevated AGP (≥1 g/L) was found in 39.5% of the Cambodian children and 11.3% of the Cuban children. Fecal calprotectin was elevated (≥50 mg/kg) in 9.4% of the Cambodian children and 3.7% of the Cuban children. STH infections in Cuba were mainly due to Ascaris lumbricoides and Trichuris trichiura , with prevalences of 5.2% and 3.2%, respectively. In Cambodia, hookworm was the most prevalent species (16.3%). We found no significant associations between elevated concentrations of either acute phase proteins or fecal calprotectin and STH infections. We observed a trend towards an inverse association between elevated CRP and STH infections in both studies. STH infections are not associated with either local intestinal or systemic inflammation. The trend towards less elevated CRP concentration in STH infections may indicate a reduced risk of metabolic inflammatory diseases, which merits further investigation.

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Frank T. Wieringa

Institut de recherche pour le développement

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Marion Fiorentino

Institut de recherche pour le développement

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Marlène Perignon

Institut de recherche pour le développement

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Chhoun Chamnan

Institut de recherche pour le développement

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Jacques Berger

Institut de recherche pour le développement

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