Renner 2001.

Methods	Randomised, double‐blind placebo controlled trial. Study based in Vienna, Austria.
Participants	24 participants with CF from 1 unit in Vienna. 13 (9 female) randomised to supplementation (mean age 12.8 years; range 6.8 ‐ 27.7) and 11 (9 female) randomised to placebo (mean age 10.5 years; range 6.7 ‐ 17.3).
Interventions	3‐month 'high dose supplementation' of β‐carotene at 1 mg/kg/day followed by low dose regimen of 10mg/day for 3 months vs starch‐containing placebo.
Outcomes	Primary outcomes ‐ normalised plasma concentration of β‐carotene; number of pulmonary exacerbations, lung function.
Notes	No specific data regarding bacteria presented ‐ author contacted for more information 26 Jan 10. The control group was on average 2.3 years younger than the intervention group.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, but method of randomisation not described.
Allocation concealment (selection bias)	Unclear risk	Capsules were of identical appearance. Procedure for dispensing preparation unclear.
Blinding (performance bias and detection bias) PUFA first	Low risk	Described as 'double‐blind' but method not described. Capsules were of identical appearance. Rust 2000: Described as double blind but no further detail.
Incomplete outcome data (attrition bias) All outcomes	Low risk	There were no drop‐outs. Two publications for this trial appear to report separate outcome data.
Selective reporting (reporting bias)	Low risk	Selective reporting not identified other than the separate reporting of different outcome data.
Other bias	Unclear risk	Patient compliance not reported.