Background: Infants are at risk for tobacco-attributable diseases by being exposed to environmental tobacco smoke (ETS). International literature has shown that a home smoking ban can reduce ETS. The purpose of this study is to examine whether a brief feedback about urinary cotinine in infants and a counselling session about the consequences of ETS leads to a reduction of ETS.

All families with children up to an age of three years in the study region will be contacted by mail and asked for participation in this study. They will be randomised into an intervention and one control group. The intervention group will receive a ETS counselling session and detailed analysis of urinary cotinine (a biomarker of ETS) at their home. They will further receive written feedback approx. 2 weeks later. The control group will be visited and will answer a questionnaire and will receive brochures about ETS. They will receive a standard analysis feedback of urinary cotinine. There will be oine further assessment/ visit 12 months later. The outcome of this study is an anlysis of urinary cotinine and smoking behaviour and changes in cotinine and smoking behaviour.

Inclusion Criteria:

• born in 2005, 2006 or 2007,
• being exposed to environmental tobacco smoke at home by at least one parent, living in the study region of west pommerania

Exclusion Criteria: