- Study design: RCT randomised controlled trial, cRCT cluster randomised trial
- Effect direction: upward arrow ▲ = positive health impact; downward arrow ▼ = negative health impact; sideways arrow ◄► = no change/mixed effects/conflicting findings
- Sample size: final sample size (individuals) in the intervention group: large arrow
 > 300; medium arrow
50–300; small arrow
 < 50
- Study quality: denoted by row colour: green = low risk of bias; amber = some concerns; red = high risk of bias
 > 300; medium arrow
50–300; small arrow
 < 50