Ortega 2015.

Methods	Country: Spain Setting: community (primary paediatric care) Type: RCT (cluster)
Participants	1101 smoking parents of babies younger than 18 months
Interventions	Intervention: brief intervention based on the '5 A's' approach, carried out during regular well baby visits at paediatric primary care team offices, lasting less than 10 minutes each time and with at least 3 occurrences: at baseline, at 3‐month follow‐up, and at 6‐month follow‐up Control: usual care
Outcomes	Child exposure: hair nicotine level and parents' reported measures to avoid baby's exposure to tobacco smoke pollution at home, in the car, and in other settings Target behaviour change: smoking away from child in home, in car, or in other setting
Type of intervention	Mixed (primary paediatric care includes both well‐ and ill‐child healthcare services)
Notes	Conflict of interest: none declared Source of funding: Spain’s National Committee on Smoking Prevention (Comité Nacional de Prevención del Tabaquismo) and the Public Health Agency of the Catalan Government (Direcció General de Salut Pública, Generalitat de Catalunya)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised using SPSS version 15.0, with primary care teams as the unit of randomisation
Allocation concealment (selection bias)	Low risk	Not specified, but allocation was randomised by a central computer
Incomplete outcome data (attrition bias) All outcomes	Low risk	83% follow‐up rate
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not blinded but biological measure (objective)
Other bias	High risk	• Groups were statistically significantly different at baseline. • Hawthorne effect/observer bias in control group