Children Learning About Second-hand Smoke (CLASS II): A pilot cluster randomised controlled trial

Breathing in other people's smoke is called passive smoking; also sometimes referred to as involuntary or second-hand smoking (SHS). Second-hand smoke contains 4000 chemicals, 70 of which can cause cancer. SHS is particularly harmful to children's health and can lead to chest and ear infections, tuberculosis, meningitis and asthma. It is also associated with lung cancer and heart disease. Globally, 40% of children are exposed to SHS. Many countries have introduced bans on smoking in enclosed public spaces, which has significantly reduced adults' exposure to SHS. However, for the majority of children, cars and homes remain the most likely places for them to breathe in SHS. The only possible way to protect children from SHS is to make cars and homes completely smoke free.

For the last three years, we have been working with teachers, children and their parents in primary schools in Dhaka, Bangladesh to develop and test an intervention called, 'Smoke Free Homes'. It consists of six teaching lessons delivered by schoolteachers, four fun activities and one educational take home resource. Teaching lessons help to increase pupils' knowledge about the harms caused by breathing in other people's smoke. Fun activities include storytelling, role-playing, quizzes and games. These activities help to motivate children to act and feel confident in talking to adults to persuade them not to smoke inside homes. The take-home resource helps children to show what they have learned in school and to negotiate with their families to "sign-up" to a voluntary contract to make their homes smoke-free. The results of this work show that it is possible to encourage children to discuss with their families ways of restricting smoking inside their homes.

Inspired by what we found, we now wish to plan for a large study where we randomly select half of the schools to either have 'Smoke Free Homes' and half not to have it (but to receive it at the end of the study). We wish to examine how effective 'Smoke Free Homes' is in reducing children's exposure to SHS. We are also interested to see if the intervention improves their lung health, general quality of life, school attendance and school performance. We would also like to examine if it helps in changing their attitude towards smoking and makes it less likely for them to take up smoking in future. To provide accurate answers to these important questions, we will need to recruit many schools and possibly thousands of children. We will also need to use objective measurements including testing children's saliva for cotinine - a chemical derivative of nicotine found in those who are exposed to SHS. Other measures will include breathing tests to assess children's lung capacities and volumes, questionnaires and diaries to be kept by children to record their symptoms such as cough, wheeze and scales to measure school performance and attitudes to smoking. Before carrying out this large study, we plan to conduct a pilot study. This pilot study will simulate the large study but will be conducted on a smaller scale. The information obtained from the pilot study will help us to carefully plan for the large study and help us to test our assumptions. These include the number of schools and children to be recruited, feasibility and acceptability of the specified measurements and resource requirement for scaling up the intervention.

We are proposing to conduct this pilot study in Dhaka Division, Bangladesh. We will recruit a total of 12 primary schools and 360, year 5 (10-12 years old) children. We will undertake all the measurements as described above using internationally agreed standards and measures. Once measurements have been taken, half of the schools will be randomly chosen to receive 'Smoke Free Homes' while the other half will not receive the intervention until the end. We will repeat the assessments at two, six and twelve months after the intervention. Findings will help us to plan for the large study.

Background
Exposure to second-hand smoke (SHS) increases children's risk of acquiring chest and ear infections, tuberculosis, meningitis and asthma. Smoking bans in public places (where implemented), have significantly reduced adults' exposure to SHS. However, for children, homes and cars remain the most likely places for them to be exposed to SHS. Additional measures are therefore required to protect children from SHS. In a feasibility trial in Dhaka, Bangladesh, we have shown that a school-based intervention, 'Smoke Free Homes' was successful in encouraging children to negotiate and implement smoking restrictions in homes.
Objective
To conduct a pilot trial to inform plans to undertake a cluster randomised controlled trial (RCT) investigating the effectiveness and cost-effectiveness of a school-based intervention-'Smoke Free Homes'-in reducing children's exposure to SHS.
Design
Two-arm pilot cluster RCT
Clusters
To recruit 12 primary schools in Dhaka, Bangladesh
Participants
To recruit 360 school children in year 5 (10-12 years old) i.e. 30 per school
Intervention
Delivered by schoolteachers, 'Smoke Free Homes' consists of six interactive educational activities (and take-home materials) aimed to increase pupils' knowledge about SHS and related harms, motivate them to act, provide skills to negotiate with adults to persuade them not to smoke inside homes and help families to "sign-up" to a voluntary contract to make their homes smoke-free.
Control
Usual education
Outcomes
For pilot trial: estimates of recruitment and attrition rates, Intracluster Correlation Coefficient; fidelity to intervention; effect size, acceptability, cost of intervention and adverse events. For definitive trial: SHS exposure (primary outcome) from salivary cotinine; respiratory symptoms; lung functions; healthcare contacts, school attendance, smoking uptake, quality of life and academic performance. All assessment will be pre- and at 2, 6 and 12 months post-intervention.

The potential impact of this pilot and the subsequent definitive trial is likely to be high as it addresses a key priority in children's health, uses an innovative behavioural approach, employs a robust study design, engages with primary schools and attempts to measure a variety of health and educational outcomes. Our proposed research programme could lead to:

1. Wider use of 'Smoke Free Homes' or similar approaches to address second-hand smoke exposure in children. If shown to be successful, this could lead to improving children's physical health and academic performance. It might also contribute towards shifting social norms of smoking in the house and in front of children, which could encourage smokers to consider quitting. If it helps in changing children's own attitudes towards smoking, 'Smoke Free Homes' could become a successful preventative measure.

2. If shown to be successful, behavioural approaches used in our study could also be used to tackle other unhealthy behaviours such as poor diet and physical inactivity. Children's health behaviours are often determined and influenced by parental and sibling's attitudes and behaviours. Our proposed approach lends itself nicely to address other health behaviours and can result in improving family health in ways that goes beyond to what is proposed here.

3. Our proposed methods and measures can help researchers from a range of disciplines in their own research. Such methods and measures are rarely used in low-income settings causing a dearth of experience and related data. Our study will provide both experience and useful data in a setting and population group where both are scanty. Other researchers would benefit from this and can use parameters generated from this research to design and conduct their own studies.

In addition to the academic audience listed in the previous section, a broad range of non-academic audience might also be interested in this study and its findings. These will include international agencies e.g. WHO Tobacco Free Initiative that shape international tobacco control policy and international non-governmental organisations such as International Union Against TB and Lung Diseases that advocate for the implementation of tobacco control laws and strategies. At a national level, National Tobacco Control Cell, Bangladesh Anti-Tobacco Alliance, and National Curriculum & Textbook Board will be our strong allies. At a local level, head teachers at schools, local authority office bearers and health professionals could play an important role in getting our study findings into practice.

We aim to publish our trial's findings in high impact journals. This will be the best way to reach the range of academic audience likely to be interested in our study. We will regularly engage with the above-mentioned policy makers and make them aware of our intervention and its evaluation. This will help in getting our research findings into policy and practice. We will work with the education authorities in Bangladesh, which will make it easier for 'Smoke Free Home', if found effective, to be incorporated in the existing curriculum. We will do this by establishing a study Technical Working Group that will comprise of researchers, policy makers, and representatives of National Tobacco Control Cell, Bangladesh Anti-Tobacco Alliance, schoolteachers, and community representatives. Technical Working Group will meet quarterly and will help in engaging with relevant stakeholders, sharing progress on the study and its findings, and eventually getting evidence into practice. We will also disseminate our research findings in national and international conferences/seminars.