Venkatarao 1996.

Study characteristics
Methods	Individually randomised trial conducted in India
Participants	Eligibility: infants aged 6 months Sample: 909 infants. 50% boys
Interventions	3 intervention groups Group I: mother and infants both received vitamin A Group II: mother received vitamin A while infant received placebo Group III: both mother and infant received placebo Dose of vitamin A for infant was 200,000 IU
Outcomes	All‐cause mortality and cause‐specific mortality due to diarrhoea and respiratory disease; incidence of diarrhoea and respiratory disease morbidity
Notes	We included the data for groups I vs II.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Each pair of subjects enrolled for the study was randomly allocated to one of the following three groups: (i) AA‐Both mother and infant received vitamin A, the former soon after delivery and the latter at 6 months; (ii) AP: mother received vitamin A but her infant received a placebo (Sesame oil); and (iii) PP: both mother and infant received placebo, the former Vitamin E and the latter Sesame oil". Comment: insufficient detail to form a judgement.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient detail to form a judgement.
Blinding (performance bias and detection bias) Blinding of participants	Low risk	Quote: "At the age of 6 to 6Vi months, the infant was weighed again and given the appropriate syrup by the Medical Officer from coded bottles, supplied again by the Statistical Section at the Camp Office". Comment: probably done.
Blinding (performance bias and detection bias) Blinding of provider	Low risk	Comment: as above; probably done.
Blinding (performance bias and detection bias) Blinding of outcome assessor	Low risk	Comment: as above; probably done.
Incomplete outcome data (attrition bias)	Unclear risk	Quote: "4 each in the AA and AP groups and 5 in the PP group were withdrawn from the trial on medical grounds such as congenital abnormalities, epileptic fits or jaundice. Migration accounted for the loss of 34 infants in the AA group, 25 in the AP group and 20 in the PP group while 7, 9 and 7 were excluded due to other miscellaneous reasons. Of the remaining 263, 255 and 256 infants in the three group, 233 in the AA and 228 each in the AP and PP groups were followed‐up very regularly and form the basis for analyses in this report". Comment: they provided specific information about losses by group. However, it is unclear why 263 (group I), 255 (group II) and 256 infants (group III) that remain after attrition is described in the results as only 233 in the group I and 228 each in group II and III being used as the basis for analysis.
Selective reporting (reporting bias)	Unclear risk	Comment: did not reference a protocol or trial registration number and did not state that all measured outcomes were reported.
Other bias	Low risk	Quote: "Quality control of the morbidity data collected by the field investigators was undertaken throughout. As long recall periods pose problems, the collection of morbidity data was intensified from once a fortnight to once a week when the study had been in progress for 9 months". Comment: authors attempted to minimise other biases such as recall bias, though specific details of "quality control" were not provided.