Browsing by Author "Nelson, Rebecca"

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The effect of an intervention to reduce aflatoxin consumption from 6 to 18 mo of age on length-for-age z-scores in rural Tanzania: a cluster-randomized trial
(Elsevier, 2025-02-01) Phillips, Erica; Ngure, Francis; Kassim, Neema; Turner, Paul; Makule, Edna; Smith, Laura; Makori, Nyabasi; Cramer, Benedikt; Humpf, Hans-Ulrich; Nelson, Rebecca; Stoltzfus, Rebecca
Background Linear growth faltering continues to negatively affect children in low- and middle-income countries and is associated with poor cognitive, developmental, and educational outcomes. Laboratory and observational data suggest that aflatoxin (AF) is a contributor to stunting. Objective The Mycotoxin Mitigation Trial was a cluster-randomized, community-based 2-group trial conducted in Kongwa District, Tanzania, between 2018 and 2020. The trial assessed whether a 12-mo intervention to reduce AF consumption increased length-for-age z-scores (LAZ) at 18 mo. Methods Low-AF maize and groundnut flours were provided to the intervention group each month; skin lotion was distributed to the control group monthly. Infant and young child feeding education was delivered equally in 52 health facilities (clusters). Anthropometry and the AF blood biomarker serum AF-albumin (AF-alb) were assessed at 6, 12, and 18 mo of age. Outcomes were analyzed as intention-to-treat and per-protocol using linear mixed-effects models. Results Two thousand eight hundred forty-two maternal–infant dyads were recruited into the study. The intervention did not create a contrast in AF-alb. At 18 mo, 36% (n = 186/520) of infants had detectable levels of AF-alb compared with 54% (n = 195/364) at baseline, with no difference between groups. Mean LAZ in the intervention group at 18 mo was −1.83 (n = 1231, 95% CI: −1.93, −1.73) compared to −1.90 (n = 1287, 95% CI: −1.99, −1.82) in the control group (P = 0.28). Conclusions An intervention to reduce AF exposure did not alter AF-alb nor anthropometric measures between treatment groups. Drought and agricultural data indicated less favorable conditions for toxin production, resulting in low levels of exposure in both trial arms. Annual, seasonal, and geographic heterogeneity of AF contamination make it difficult to study in an ethically designed trial. Our formative research and early trial data indicate that stunting and intermittent AF exposure continue to be a problem in this region. However, the low-AF exposure levels during the trial led to inconclusive results.
Ethical considerations in the design and conduct of a cluster-randomised mycotoxin mitigation trial in Tanzania
(Wageningen Academic Publishers, 2022-01-24) Phillips, Erica; Turner, Paul; Ngure, Francis; Kassim, Neema; Makule, Edna; Smith, Laura; Nelson, Rebecca; Stoltzfus, Rebecca
Aflatoxins are fungal metabolites that commonly contaminate staple food crops in tropical regions. Acute aflatoxin consumption in very high concentration causes aflatoxicosis and acute liver failure, while chronic, moderate levels of intake cause hepatocellular carcinoma. The effects of frequent moderate- to high-level exposure during infancy, however, is less clearly understood. Half a billion people in low- and middle-income countries continue to be exposed to aflatoxins through dietary consumption, in part because of lack of enforcement of regulatory limits and few feasible long-term mitigation options in these settings. Several epidemiologic studies have shown an association between aflatoxin exposure in infants and young children and growth failure, but strong experimental evidence is lacking. The Mycotoxin Mitigation Trial conducted in Tanzania was a cluster-randomised trial to assess the effect of a reduced aflatoxin diet on linear growth. Prior to the design and implementation of this trial, a group of multi-disciplinary and multi-national scientists reviewed literature in biomedical, public health, environmental health ethics. In this paper we outline the most salient ethical questions and dilemmas in the potential conduct of such a study and describe the ethical precedents and principles that informed our decision-making processes and ultimate study protocol.
Ethical Considerations of the Trial to Establish a Causal Linkage Between Mycotoxin Exposure and Child Stunting
(Elsevier, 2021-06-21) Phillips, Erica; Turner, Paul; Kassim, Neema; Makule, Edna; Nelson, Rebecca; Ngure, Francis; Smith, Laura; Stoltzfus, Rebecca
Objectives Aflatoxins are fungal metabolites that commonly contaminate staple crops in tropical regions. Aflatoxin is a carcinogen and consumption at high-levels can lead to acute liver failure and aflatoxicosis. Multiple epidemiologic studies have shown an association between aflatoxin exposure in infants and young children and growth failure, but strong experimental evidence is lacking. The Trial to Establish a Causal Linkage Between Mycotoxin Exposure and Child Stunting being conducted in Tanzania is a cluster-randomized trial to assess the effect of reduced aflatoxin exposure on linear growth. Methods Prior to its design and launch, the multi-disciplinary research team conducted a critical review to determine the most salient ethical questions and dilemmas in the potential conduct of such a study and debated if and how this study could be designed to meet human subject ethical criteria. This critical review included trial protocols, methodologies and historical controversies in the areas of bio-medical, public health and environmental health research. Results This critical review identified three major questions: 1) Given what is already known about aflatoxin, should a question about the effect of this toxin on child growth be studied further in human subjects? 2) If the relationship between aflatoxin and stunting can be studied in humans, what is the most ethical study design to employ? 3)What is the most ethical intervention to randomly allocate? Conclusions Based on the critical review and in alignment with human subject principles and guidelines, we concluded that it was possible to conduct such a study. The trial and intervention were designed to advance scientific knowledge, maintain a favorable risk/benefit ratio, and respect participants, among other ethical principles.
Processing complementary foods to reduce mycotoxins in a medium scale Tanzanian mill: A hazard analysis critical control point (HACCP) approach
(Elsevier, 2024-03-22) Ngure, Francis; Makule, Edna; Mgongo, William; Phillips, Erica; Kassim, Neema; Stoltzfus, Rebecca; Nelson, Rebecca
Designing and implementing processing procedures for producing safe complementary foods in dynamic and unregulated food systems where common food staples are frequently contaminated with mycotoxins is chal- lenging. This paper presents lessons about minimizing aflatoxins (AF) in groundnut flour and AF and/or fumonisins (FUM) in maize and groundnut pre-blended flour for complementary feeding in the context of a dietary research intervention in rural Tanzania. The flours were processed in collaboration with Halisi Products Limited (Halisi), a medium scale enterprise with experience in milling cereal-based flours in Arusha, Tanzania. Using a hazard analysis critical control point (HACCP) approach for quality assurance, two critical control points (CCPs) for AF in processing the pre-blended flour were identified: 1) screening maize before procurement, and 2) blending during the processing of each constituent flour. Blending of maize flour was also identified as a CCP for FUM. Visual inspection during screening and sorting were identified as important control measures for reducing AF, but these steps did not meet the criteria for a CCP due to lack of objective measurement and verifiable standards for AF. The HACCP approach enabled the production of low AF (<5 μg/kg) and FUM (<2 μg/g) flours with low rejection rates for the final products. The paper presents practical lessons that could be of value to a range of commercial processors in similar low- and middle-income contexts who are keen on improving food quality.