Wilson 2001.

Methods	Country: USA Setting: paediatric pulmonary service of a paediatric hospital RCT
Participants	87 parents of children 3 to 12 years of age with asthma who were ETS exposed. (At baseline, 61% of intervention group maternal caregivers smoked vs 42% of controls.)
Interventions	All children examined at baseline by a paediatric pulmonary specialist, and their treatment was adjusted as appropriate. Intervention: Caregiver received 3 nurse‐led sessions over a 5‐week period, employing behaviour change strategies and basic asthma and ETS education, along with repeated feedback on the child's urinary cotinine level (measured each session). The child and other family members were sometimes involved. Control: Caregivers received basic asthma advice from a nurse, along with the statement that ETS is to be avoided. Mothers who requested the cotinine result were told whether or not cotinine had been detected.
Outcomes	At 12 months: • Urinary cotinine • Acute asthma episodes Secondary study outcomes: • Hospitalisation • Prohibition of smoking in the home • CPD • Parent‐reported exposure of children and asthma control
Type of intervention	Child with health problems (respiratory disorders)
Notes	Follow‐up cotinine data obtained in 51/87 (59%)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomization design with blocks of length four"; no further information provided
Allocation concealment (selection bias)	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Intention‐to‐treat analysis conducted; "attrition rates on the cotinine data were equivalent in the intervention and control groups" (25/44 intervention, 26/43 control)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical measure used