Children Learning About Secondhand Smoke (CLASS II): protocol of a pilot cluster randomised controlled trial

Area of Science:

• Pediatric Health
• Public Health Interventions
• Environmental Health

Background:

• Secondhand smoke (SHS) exposure significantly increases children's risk of respiratory infections and asthma.
• While public smoking bans reduce adult SHS exposure, children remain vulnerable, primarily in homes.
• A feasibility study in Dhaka demonstrated a school-based smoke-free intervention (SFI) effectively encouraged home smoking restrictions.

Purpose of the Study:

• To conduct a pilot trial of a school-based smoke-free intervention (SFI) in Dhaka, Bangladesh.
• To inform the design of a definitive cluster randomized controlled trial (RCT) assessing SFI's effectiveness and cost-effectiveness.
• To evaluate SFI's impact on reducing children's exposure to secondhand smoke (SHS).

Main Methods:

• Recruiting 12 primary schools and approximately 360 Year 5 schoolchildren (10-12 years old) in Dhaka.
• Implementing SFI with six interactive educational activities focusing on SHS knowledge, motivation, negotiation skills, and home smoke-free contracts.
• Measuring primary outcome of SHS exposure via salivary cotinine, with secondary outcomes including respiratory health, healthcare use, and academic performance.

Main Results:

• The feasibility study showed SFI's success in promoting children's negotiation of home smoking restrictions.
• Pilot trial will estimate recruitment/attrition rates, intervention acceptability, fidelity, effect size, and cost.
• Primary outcome: reduction in children's SHS exposure measured by salivary cotinine.

Conclusions:

• Findings will guide the planning of a definitive cluster RCT on SFI effectiveness.
• The pilot trial is crucial for optimizing SFI delivery and evaluation.
• Successful implementation of SFI can lead to significant reductions in childhood SHS exposure.