Smoke-free homes: The final frontier

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

Second Hand Smoke Exposure among Children in Indian Homes: Findings from the Global Adult Tobacco Survey

Children are vulnerable to second hand smoke (SHS) exposure because of limited control over their indoor environment, especially at homes. This study determines the magnitude, patterns and determinants of SHS exposure in the home among children in India. Data collected under the Global Adult Tobacco Survey (GATS) data, a household survey of adults ≥15 years of age during 2016-2017 conducted in India were analyzed to estimate the proportion of children exposed to SHS in their homes. GATS estimates and national census population projections for 2020 were also used to estimate the number of children exposed to SHS in the homes. Nearly half (46.5%) of the children <15 years of age were exposed to SHS in their homes in India which extrapolates to nearly an estimated 170 million. Children living in rural households, north-east and central regions and households with an adult smoker were more likely to be exposed to SHS. SHS exposure among children in home is high in India which calls for adoption of voluntary smoke-free homes initiative and promoting cessation among smokers.

Children Learning About Secondhand Smoke (CLASS III): a protocol for a cluster randomised controlled trial of a school-based smoke-free intervention in Bangladesh and Pakistan

INTRODUCTION

Secondhand smoke (SHS) exposure is a major cause of premature death and disease, especially among children. Children in economically developing countries are particularly affected as smoke-free laws are typically only partially implemented and private homes and cars remain a key source of SHS exposure. Currently, firm conclusions cannot be drawn from the available evidence on the effectiveness of non-legislative interventions designed to protect children from SHS exposure. Following the success of two feasibility studies and a pilot trial, we plan to evaluate a school-based approach to protect children from SHS exposure in Bangladesh and Pakistan-countries with a strong commitment to smoke-free environments but with high levels of SHS exposure in children. We will conduct a two-arm cluster randomised controlled trial in Bangladesh and Pakistan to assess the effectiveness and cost effectiveness of a school-based smoke-free intervention (SFI) in reducing children's exposure to SHS and the frequency and severity of respiratory symptoms.

METHODS AND ANALYSIS

We plan to recruit 68 randomly selected schools from two cities-Dhaka in Bangladesh and Karachi in Pakistan. From each school, we will recruit approximately 40 students in a year (9-12 years old) with a total of 2720 children. Half of the schools will be randomly allocated to the intervention arm receiving SFI and the other half will receive usual education. Salivary cotinine concentration-a highly sensitive and specific biomarker of SHS exposure-is the primary outcome, which will be measured at month 3 post-randomisation. Secondary outcomes will include frequency and severity of respiratory symptoms, healthcare contacts, school absenteeism, smoking uptake and quality of life. Embedded economic and process evaluations will also be conducted.

ETHICS AND DISSEMINATION

The trial has received ethics approval from the Research Governance Committee at the University of York. Approvals have also been obtained from Bangladesh Medical Research Council and Pakistan Health Research Council. If SFI is found effective, we will use a variety of channels to share our findings with both academic and non-academic audiences. We will work with the education departments in Bangladesh and Pakistan and advocate for including SFI within the curriculum.

TRIAL REGISTRATION NUMBER

ISRCTN28878365.