Dembedza 2019.

Methods	Study design: cluster‐randomised controlled trial Country: Zimbabwe Setting: smallholder farming households within villages from two maize producing districts (Mashonaland Centrla; Manicaland) Study aim: to assess the effectiveness of hermetic storage technology in reducing human aflatoxin exposure from the time of maize harvesting throughout the storage season, by measuring the levels of aflatoxin M1 present in urine from children under five years of age and women of child‐bearing age from smallholder farming households where hermetic storage technology was used to store maize grain Study dates: June 2015 to May 2016 Recruitment: all the households in each selected enumeration area (EA) were visited (1384 households) Sampling: purposive sampling of six administrative areas from each study district; random sampling of two EAs or villages from each administrative area (total of 12 EAs) Sample size justification: NR Unit of randomisation: households Total number randomised: 420 households (120 intervention 1; 120 intervention 2, and 150 control); 420 women (189 mother‐child pairs) Unit of analysis: women and children Intention‐to‐treat analysis: NR Attrition: 3 children dropped out; attrition per group unclear (number of women and children enrolled not reported per group) Relevant study limitations as reported by study authors: foods, such as vegetables and legumes, could be potential sources of exposure to aflatoxins; foods not analysed for aflatoxin content, and urinary AFM1 is not a long‐term marker of aflatoxin exposure
Participants	Inclusion criteria: availability and permanent residence of a woman between 15 years and 45 years of age and a child under 59 months in a household, or both Exclusion criteria: NR Group differences: NR Subgroups: NR Baseline characteristics of participants Overall Mother (N = 189) Mother, age: NR Marital status: NR Mother, educational level: NR Occupation: NR Mother, nutritional status: NR Mother, dietary diversity or food security measure: NR Mother, biomarker of aflatoxin exposure: NR Child (N = 189) Child, age: 6 months to 12 months,%: 51.6; 13 months to 18 months,%: 46.8; 19 months to 24 months,%: 1.6 Child, gender: female,%: 54.8 Child, nutritional status: NR Child, dietary diversity or food security measure: NR Child, morbidity: NR Child, biomarker of aflatoxin exposure: metal silo group: urine AFM1, geometric mean (GM; microg/L): 0.97; hermetic bags group: urine AFM1, GM (microg/L): 0.62; control group: urine AFM1, GM (microg/L): 0 Household (N = 420) Place of residence: NR Race, ethnicity, and religion: NR Socio‐economic status: NR Social capital: NR Household head, age: NR Household head, gender: NR Household head, educational level: NR Household, food security or dietary diversity measure: NR
Interventions	Intervention Type: hermetic storage technology Description: households received training regarding one of two types of hermetic technologies, namely hermetic storage bags or hermetic metal silos Delivery: agricultural extension officers trained households re: the use of hermetic storage bags or silos; frequency and duration of training not specified Providers: staff of the Ministry of Agriculture, Mechanisation and Irrigation Development; the University of Zimbabwe Institute of Food, Nutrition and Family Sciences, and our research partner Action Contre’ la Faim provided technical and logistical support Duration of intervention: 9 months Duration of follow‐up: 9 months Co‐intervention: NR Cost: NR Resource requirements: NR Control Type: no intervention Description: households that continued storing their maize grain in conventional storage facilities, which included mainly ordinary polypropylene bags and grass‐thatched granaries Delivery: not applicable (n/a) Providers: n/a Duration of intervention: n/a Duration of follow‐up: 9 months Co‐intervention: NR Cost: n/a Resource requirements: n/a
Outcomes	Outcomes: Urinary AFM1 concentration (child, at 3, 6, 9 months) Urinary AFM1 concentration (women, at 3, 6, 9 months)
Notes	Sponsorship source: International Development Research Centre, Canada; Australian Centre for International Agricultural Research, and Australian International Food Security Research Centre Grant No. 107838 Study title or name (study acronym): n/a Author’s name: MP Dembedza, LK Nyanga Email: Nyangael@yahoo.com Declarations of interest: yes; quotation: "The authors declare no conflict of interest." Trial registration: NR
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The study authors only stated that random allocation of interventions was performed at household level, but did not provide details re: the generation of the random sequence.
Allocation concealment (selection bias)	Low risk	No information about concealment, but random allocation was done at household level at one point in time, therefore, concealment of an allocation sequence should not be an issue.
Baseline outcome measurements similar	Low risk	Study did not report any relevant review outcomes, and therefore, this domain does not apply.
Baseline characteristics similar	Unclear risk	The study authors only reported baseline characteristics for the overall sample, not per group.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient reporting of attrition, missing outcome data, and reasons for missing outcome data; no mention of how missing outcome data were addressed. Reasons for variations in missing data and time points reported as "mainly due to the absence of some participants on the day of sample collection".
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding of personnel not reported; however, blinding of participants unlikely (intervention and control households in the same village)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding of outcome assessors not reported, but outcome measurement (urinary aflatoxin AFM1 concentrations) not likely to be influenced by lack of blinding.
Protection against contamination	Unclear risk	Households in the same village were allocated to different intervention groups, presenting a risk of contamination.
Selective reporting (reporting bias)	Unclear risk	No protocol available, and outcomes stated in the methods section were reported in the results section; personal communication with trial authors confirmed that child growth data were collected in the trial, but these results were not included in the papers provided by authors at the time of contact.
Other bias	High risk	Recruitment bias (cluster‐RCT): low risk; individuals were recruited to the trial before clusters were randomised. Incorrect analysis (cluster‐RCT): high risk; no evidence that clustering was taken into account, since the unit of analysis (women and children) was different from the unit of allocation (households) in the analysis