Lin 2008.

Methods	Randomised, placebo‐controlled trial conducted in Wuhan, an industrial centre in central region of China
Participants	Eligibility: inclusion criteria was age 2‐7 years. Children were recruited from kindergarten in the area. Those who had fever, diarrhoea or a recent preventive injection were excluded from the study. Underweight children with BMI age‐ and sex‐ specific 5th percentile of the first US National Health and Nutrition Examination Survey data were excluded. Children whose protein or energy intake met Chinese RDA were also excluded. Sample: 105 children were randomised to 3 intervention groups (described below). Mean age of study participants was 55 months, and proportion of boys was 61%
Interventions	There were 3 study groups. 2 of these consisted of children who were vitamin A deficient and 1 with children who were vitamin A sufficient. Vitamin A was given only to children in 1 of the vitamin A deficient groups in a dose of 100,000 IU every month for 3 months. The other 2 groups received placebo.
Outcomes	All‐cause mortality, mean serum vitamin A levels
Notes	In this review, we have included data for vitamin A deficient children who were either supplemented with vitamin A or placebo. According to WHO, China does not have a high child mortality rate (i.e. < 40/1000).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The remaining 70 vitamin A‐deficient children were randomly and equally divided into vitamin A deficient‐supplemented group and vitamin A‐deficient placebo group." Comment: the term 'randomised' is also used to describe a 3rd group that is clearly matched. This may not be an RCT.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient detail provided to make judgement
Blinding (performance bias and detection bias) Blinding of Participants	Low risk	Quote: "Children of vitamin A‐deficient‐supplemented group were given 100 000 IU (retinol equivalent) vitamin A capsules every 2 weeks for 3 months (Grubesic, 2004). Children of vitamin A‐sufficient placebo group and vitamin A‐deficient placebo group received placebo capsules in the same way."
Blinding (performance bias and detection bias) Blinding of provider	Unclear risk	Comment: although study was double randomised trial, no details of how blinding was achieved was described in the district
Blinding (performance bias and detection bias) Blinding of outcome assessor	Unclear risk	Comment: insufficient detail provided to make judgement
Incomplete outcome data (attrition bias)	Low risk	Comment: no attrition reported
Selective reporting (reporting bias)	High risk	Comment: main outcome data not reported in a manner that can be analysed
Other bias	Unclear risk	Comment: as blinding is not described, potential performance bias and other sources of bias cannot be assessed