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

吸入别人的烟被称为被动吸烟；有时也被称为非自愿或二手吸烟（SHS）。二手烟含有4000种化学物质，其中70种会致癌。二手烟对儿童健康尤其有害，可导致胸部和耳部感染、结核病、脑膜炎和哮喘。它还与肺癌和心脏病有关。在全球范围内，40%的儿童暴露于二手住房。许多国家已经禁止在封闭的公共场所吸烟，这大大减少了成年人接触二手烟的机会。然而，对于大多数儿童来说，汽车和家庭仍然是他们最可能吸入SHS的地方。保护儿童免受二手烟危害的唯一可能方法是使汽车和家庭完全无烟。在过去的三年里，我们一直与孟加拉国达卡小学的教师、儿童和家长合作，开发并测试一项名为“无烟家庭”的干预措施。它包括由学校教师讲授的六门教学课程，四项有趣的活动和一项教育带回家的资源。教学课程有助于提高学生对吸入他人烟雾所造成危害的认识。有趣的活动包括讲故事、角色扮演、测验和游戏。这些活动有助于激励儿童采取行动，并有信心与成年人交谈，说服他们不要在家中吸烟。这种带回家的资源可以帮助孩子们展示他们在学校学到的东西，并与家人谈判，“签署”一份自愿的合同，使他们的家庭无烟。这项工作的结果表明，鼓励儿童与家人讨论限制在家中吸烟的方法是可能的。受我们发现的启发，我们现在希望计划进行一项大型研究，我们随机选择一半的学校，要么有“无烟家庭”，要么没有（但在研究结束时收到它）。我们希望研究“无烟家庭”在减少儿童接触二手烟方面的效果。我们还想知道干预是否能改善他们的肺部健康、总体生活质量、出勤率和学习成绩。我们也想研究它是否有助于改变他们对吸烟的态度，使他们将来不太可能吸烟。为了提供这些重要问题的准确答案，我们将需要招募许多学校，可能需要招募数千名儿童。我们还需要使用客观的测量方法，包括检测儿童唾液中的可替宁——一种尼古丁的化学衍生物，在接触二手烟的人体内发现。其他措施将包括评估儿童肺活量和肺活量的呼吸测试，儿童记录咳嗽、喘息等症状的问卷调查和日记，以及衡量学校表现和对吸烟态度的量表。在进行这项大型研究之前，我们计划进行一项试点研究。这项试点研究将模拟大型研究，但将以较小的规模进行。从试点研究中获得的信息将帮助我们仔细规划大型研究，并帮助我们检验我们的假设。其中包括要招收的学校和儿童的数目、具体措施的可行性和可接受性以及扩大干预所需的资源。我们建议在孟加拉国达卡司进行这项试点研究。我们将招收12所小学和360名5年级（10-12岁）儿童。我们将使用国际商定的标准和措施进行上述所有测量。一旦测量完成，一半的学校将被随机选择为“无烟家庭”，而另一半直到最后才会接受干预。我们将在干预后的2个月、6个月和12个月重复评估。研究结果将有助于我们为大规模研究制定计划。

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.