DEVTA trial 2013.

Study characteristics
Methods	Factorial design, cluster‐randomised trial conducted in Northern India
Participants	Eligibility: children aged 1–6 years Sample: total clusters were 72; 36 clusters in vitamin A group, 36 in control group. Authors claimed to include 1 million children in the trial
Interventions	Experimental group: vitamin A 200,000 IU every 6 months for 5 years. Vitamin A was supplemented on mass treatment days by village childcare workers. Capsules were open and poured into child's mouth Control group: no intervention Factorial design was: group I: usual care group II: 6‐monthly vitamin A group III: 6‐monthly albendazole group IV: 6‐monthly vitamin A plus albendazole
Outcomes	All‐cause mortality; cause‐specific mortality due to diarrhoea, pneumonia, measles, and malnutrition; mean vitamin A serum levels; prevalence of Bitot's spots, and measles and pneumonia morbidity
Notes	Study was conducted in Uttar Pradesh, India. Study utilised the infrastructure of the Integrated Child Development Services, which maintains childcare centres called Anganwadi childcare centres across the state. The other intervention as part of the factorial design was albendazole for deworming. Study was approved by King George's Medical University. Surveillance for disease outcomes was performed every 6 months, and children were not selected randomly for that but chosen from  Anganwadi childcare lists. Deaths were recorded by 18 full‐time, motorcycle village‐to‐village monitors.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Neighbouring blocks (clusters), in groups of four (where possible in the same district), were randomly allocated in Oxford, UK", and "[a]part from the district each block was in, no relevant details of it were known to those generating the random allocation". Comment: most likely done.
Allocation concealment (selection bias)	Low risk	Quote: "Apart from the district each block was in, no relevant details of it were known to those generating the random allocation".
Blinding (performance bias and detection bias) Blinding of participants	High risk	Comment: intervention was given on mass treatment days, and used no placebo tablets. So participants most likely were not blinded to treatment allocation.
Blinding (performance bias and detection bias) Blinding of provider	High risk	Comment: again, intervention was delivered on mass treatment days by AWC and treatment was known to Anganwadi childcare centres.
Blinding (performance bias and detection bias) Blinding of outcome assessor	High risk	Comment: outcomes assessors seemed aware of the treatment allocation and control, as parents were asked if their children received intervention on mass treatment days.
Incomplete outcome data (attrition bias)	Low risk	Comment: loss to follow‐up was 2%.
Selective reporting (reporting bias)	Low risk	Comment: the trial was registered as NCT00222547, and prespecified outcomes were mentioned in protocol and analysed accordingly.
Other bias	High risk	Comment: there were concerns that surveillance for implementation of intervention and assessment of outcomes were not rigorous.